WHITNEY LIBRARY

HARVARD UNIVERSITY

.J. D. WHITNEY

Sturgis Hooper Professor

IN THE

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TRANSACTIONS

OF THE

GEOLOGICAL SOCIETY,

ESTABLISHED NOVEMBER 13, 1807.

' * VOLUME THE FIFTH.

Quod si cui mortalium cordi et curae sit, non tantum inventis haerere, atque iis uti, sed ad ulteriora penetrare ; atque non disputando adversarium, sed opere naturam vincere; denique non belle et probabiliter opinari, sed certo et ostensive scire ; tales, tanquam veri scientiarum filii, nobis (si videbitur) se adjungant.

Novum Organum , Prcefatio.

itontiotti

PJilNTKD AND SOLD BY WILLIAM PHILLIPS , GEORGE-YARD , LOMBARD-STREET .

< 18^1.

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ADVERTISEMENT

THE Editors of the Transactions of the Geological Society are directed to make it known to the Public, that the Authors alone are responsible for the facts and opinions contained in their respective

papers.

Geological Society,

Sept. I, 1821.

It is requested that all letters and communications to the Secretaries, and presents to the Society, be addressed to the House of the Geological Society, No. 20, Bedford Street 9 Covent Garden, London »

ERRATA.

344 for	Berezowsky ....	read Berezovsky
ib.	Lagoda	Ladoga
||^ mmmmmmrn	Walaam . T t T T T ,	- Valaam
ib.	Platten Sea	— — Platten See
345	Kevgnemy	— — Kevynemy
395	Bechka	■ - — - Rechka
ib.	Newsky	Nevsky
ib.	Cester Back. ....	Gester Bach
398 —	bog...	bay
ib.	Biabova	Riabova
ib.	Capsala	Copsala
ib.	Riflhnva T T	— — . , Riahnva
ib.	Corpsala	Copsala
399	Palcova	Pulcova
ib.	Jossna	Tosna
411	Pavloosk	Pavlovsk
412	Pavloosk	Pavlovsk
422	Skoovkza ......	Skvovitza

OFFICERS AND COUNCIL OF THE GEOLOGICAL SOCIETY, ELECTED FEBRUARY 2, 1821.

PRESIDENT.

The Right Honourable Earl COMPTON.

Rev. WILLIAM BUCKI.AND, F.R.S. Prof. Min. Oxford.

JOHN MAC CULLOCH, M.D. F.R. & L.S.

VICE-PRESIDENTS .

HENRY WARBURTON, Esq. F.R.S. WILLIAM HYDE WOLLASTON, M.D. F.R.S;

SECRETARIES .

ALEXANDER HENDERSON, M.D. | Mr. THOMAS WEBSTER.

FOREIGN SECRETARY .

HENRY HEULAND, Esq.

TREASURERS .

DANIEL MOORE, Esq. F.R.A, & L.S. | JAMES VINE, Esq.

COUNCIL.

Hon. HENRY GREY BENNET, M.P. F.R.S. WM. BLAKE, Esq. F.R.S.

JOHN BOSTOCK, M.D. F.R. & L.S.

HEN. JAMES BROOKE, Esq. F.R. & L.S.

H. T. COLEBROOKE, Esq. F.R. & L.S.

G. B. GREENOUGH, Esq. F.R. & L.S.

THOMAS CHARLES HARRISON, Esq. FREDERICK MOYSEY, Esq.

W. H. PEPYS, Esq. F.R.S.

THOMAS SMITH, Esq. F.R. & L.S. CHARLES STOKES, Esq. F.R.A. & L.S. JOHN TAYLOR, Esq.

KEEPER, OF THE MUSEUM AND DRAUGHTSMAN ,

Mr. THOMAS WEBSTER.

TRUSTEES OF THE GEOLOGICAL SOCIETT.

■

GEORGE BELLAS GREENOUGH, Esq.

Sir ABRAHAM HUME, Bart. M.P.

WILLIAM BABINGTON, M.D.

ROBERT FERGUSON, Esq.

DAVID RICARDO, Esq. M.P.

JOHN WISHAW, Esq.

SAMUEL WOODS, Esq.

TRANSACTIONS

OF THE

GEOLOGICAL SOCIETY,

ESTABLISHED NOVEMBER 13, ISO?.

VOLUME THE FIFTH.

PART THE FIRST.

Quotl si cui mortalium cordi et curae sit, non tantum inventis haerere, atque iis uti, sed ad ulteriora penetrare ; atque non disputando adversarium, sed opere naturam vincere ; denique non belle et probabiliter opinari, sed certo et ostensive scire ; tales, tanquam veri scientiarum filii, nobis (si videbitur) se adjungant; ut omissis naturae atriis, quae infiniti contriverunt, aditus aliquando ad interiora patefiat.

Novum Organum , Prcefatio .

LONDON:

PRINTED AND SOLD BY WILLIAM PHILLIPS , GEORGE TARO LOMBARD STREET.

1819.

V

.V'

CONTENTS.

L

II.

On the Island of Sals ettc. By Stephen Babington, Esq. of the Hon.

East India Company's Civil Service, Bombay. Communicated by

William Babington, M.D. - - - . - p. I

Remarks on the Hills of Badacson , Szigliget, SfC. in Hungary % By Richard Bright, M.D. Member of the Geological Society - p, 4

III. Some Observations on a Series of Specimens presented to the Geological Society by the Hon. H. Grey Bennet. By Arthur Aikin, Esq. F.L.S. Member of the Geological Society , and Secretary to the Society of

p. 9

IT. Remarks on the Chalk Cliffs in the neighbourhood of Dover, and on the Blue Marie covering the Green Sand near Folkstone. With an Appendix , containing some account of the Chalk Cliffs , S?c. on the Coast of France opposite to Dover. By William Phillips, Esq. F.L.S. Member of the Geological Society - - - p. 16 47

V. Remarks on the Fossils collected by Mr. William Phillips near Dover

and Folkstone. By James Parkinson, Esq. Member of the Geological

SocietV p.52

VI. Notes accompanying a Set of Specimens from the Himalay Mountains.

By James Fraser, Esq. of Calcutta. Communicated by Captain Basil Hall, R.N. - - . . - - p. 60

VII. Observations on the Follies and Watercourses of Shropshire and of

parts of the adjacent counties. By Arthur Aikin, Esq. F.L.S. Member of the Geological Society , Sec. Afc. - - " P* 73

CONTENTS.

VIII. On the Form of the Integrant Molecule of Carbonate of Lime.

By David Brewster, LL.D . F.R.S. Lond. Ed. Member of the Geological Society ------ P*

IX. Description of some new Fossil Encrini and Pentacrini , lately dis-

covered in the neighbourhood of Bristol By George Cumberland,

Esq. Honorary Member of the Geological Society - - p. 87

X. On the Limestone Beds on the River Avon , near Bristol ; with a

Description of the Magnesian Beds that repose on their basset edges »

By George Cumberland, Esq . 8?c, 8fC. - - - p. 95

XI. On the Strata of the Northern Division of Cambridgeshire . By

Francis Lunn, Esq. In a Letter addressed to G. B. Greenough,

Esq, President of the Geological Society - - - p. 114

XII. Memoir on the Geological Relations of the East of Ireland . By

Thomas Weaver, Esq. Member of the Royal Irish Academy , of the Wernerian Natural History Society , and of the Right Honorable and Honorable the Dublin Society - - - p. 117

XIII. On the Modifications of the Primitive Crystal of the Sulphate pf

Barytes. By William Phillips, Esq Sfc. 8>c. - - p- oOj

I. On the Island of Salsette .

By STEPHEN BABINGTON, Esq.

OF THE HONORABLE EAST INDIA COMPANY’S CIVIL SERVICE, BOMBAY. Communicated by WILLIAM BABINGTON, m.d.

[Read 19th January, 1816.]

The columns of Dharaire are situated on the eastern face of a; range of hills, which at a distance appears to form part of the Island of Salsette, but which is in reality insulated by a creek which branches from the river that divides the northern extremity of Salsette from the Mahratta coast, and which, passing along the foot of the hills, meets the sea again towards the south-west, its whole length being not probably more than four or five miles.

The general appearance of the range of hills, when seen from the eastward, justifies the conjecture that columns might be traced wherever the surface of the rock has become exposed ; but the clus- ters of pillars which are the most remarkable, are within two hun- dred yards of the northern extremity.

Nearly the whole of the rock in this particular spot is laid bare^ and the columnar form is to be observed even at the base of the hill. The loftiest columns however spring from the earth at about one- third of the height of the hill. There are three distinct clusters ; those in the center and to the left are nearly of equal size, but the mass on the right is considerably less lofty.

Vol. V. A

2 Mr. BabingTON on the Island of Salsette .

The general appearance of each cluster, viewing it from the base, is that of a bundle of reeds, the pipes of an organ, or a section of a honey-comb ; the height of the most lofty columns is about fifty feet, and although in some instances horizontal fractures are discovered, they appear to be the effect of accident, as the greater number of pillars are single shafts.

On ascending the hill it is perceived that there are other clusters of columns rising in succession behind the principal one, each being elevated about eight or ten feet above the cluster immediately be- low it.

The diameter of each column in the three clusters above described, is about twenty inches, but there are columns in the neighbourhood of more than double that size.

The number of the sides of each column varies from four to seven, and in one instance the four exposed sides of a column, led to a conclusion that the whole figure was an octagon. The figures which occur most frequently are irregular pentagons and hexagons. When the figure has only four sides, the sides are nearly of an equal size ; the same observation applies also, though not so uni* versally, to the pentagons, but the hexagons and seven sided figures have frequently one or more sides not exceeding two inches in diameter.

Almost all the columns face the east, perhaps a little northerly, and incline to the south-west. The angle of inclination is extremely variable, but the three main clusters lie nearly in the same parallel, and incline about twenty degrees from the perpendicular. The in- clination of many of the surrounding columns is as great as sixty or seventy degrees.

The rock of which these columns are composed, is internally of a light bluish grey colour, its exposed surface is of a dark reddish

Mr. Babington on the Island of Salsette. 3

brown colour, resembling the rust of iron, and the stone to the depth of about three quarters of an inch has undergone partial de- composition, and assumes a dirty red colour. The stone is suf- ficiently hard to strike fire with steel, but it is easily scratched by a file : its fracture is irregular and its grain not 'very close.

I am informed the rocks along the whole of the western shore of Salsette, particularly near a place called Versooa, have the columnar form. The western hills of Bombay bear traces of the same form- ation also, but the Bombay rock is much darker in colour, closer in grain, and of greater specific gravity and hardness, than that of which the Dharaire pillars are composed ; and the different shafts of which the clusters are made up, are cemented together by thin strata of a lighter coloured substance, instead of, as at Dharaire, merely fitting closely to each other.

II. Remarks upon the Hills of Badacson , Szigliget , &c, in Hungary .

By RICHARD BRIGHT, m.d.

MEMBER OF THE GEOLOGICAL SOCIETY.

[Read 17th May, 1816.]

The small town of Keszthely in Hungary, is situated on the north and west shore of the Balaton Lake, or Platten See. The country around is generally flat and alluvial, but a low ridge of limestone hills covered with forest, stretches towards the north and west, leaving a strip of marshy land between it and the lake. The road runs along the raised bases of these hills, and conducts towards Tapolcza, leaving the lake several miles to the south. The country now exhibits one extensive and marshy plain, in the midst of which are seen a few. small detached mountains whose sides are clothed with vineyards and their summits broken with rocks. Of these I visited the four most striking, namely, Csobantz, Badacson, Szigliget, St. Gyorgay-hegye ; and it is from two of these that the specimens which accompany these observations were obtained.

In ascending Csobantz, we first came to a pit dug in the side of a hill, which presented nothing but a horizontally stratified yellow sand, generally crumbling down under slight pressure, and full of glittering particles, I believe micaceous. A few paces farther we found extensive scoriated masses firmly fixed, and to all appearance

Dr. Bright upon the hills of Badacson , Sxigliget, idc. 5

in their natural situation, forming part of the solid rock. Proceeding a little higher, the rock was a species of greenstone, or perhaps lava, but suffering considerably from the action of the weather, and then thickly beset with little hollows, slightly indented and about the size of a pea ; this was of a light grey colour, and in its structure quite amorphous. Still higher, the same rock became more hard, and shewed a tendency to assume a vertical columnar division.

Such was the formation of this hill, of which however I possess no specimens.

The lower part of the hill Badacson, was completely covered with vegetables, but on ascending about half way we found the whole strewed with fragments fallen from above, amongst which were masses of very vesicular scorise.

The path leads through columnar rocks, called the Iron Gateway, formed of a very compact, hard, dark coloured stone, of a crystal- lized texture, rather resembling clinkstone. In other parts, towards the summit, the rock is of a greyer colour, containing numerous small particles of olivine and a few vesicular cavities. It here as- sumes the general, though not regular columnar form, and splits again horizontally into layers of six or seven inches in thickness. The highest part of this insulated hill is covered with wood, and many of the oaks have attained a large size where their growth has been favoured by an irregular natural excavation, formed by the disposition of the surface. Descending on the west side of the hill where the rock was more denuded than at the part we had first ap- proached, I was not a little surprised to meet with a sandstone con- glomerate, bearing a very exact resemblance to the only rocky mass which occurs on the ascent of Hekla, and is found forming complete mountain ranges in Iceland, as will be found ably described by Sir George Mackenzie.

6 Dr. Bright upon the hills of Badacson , Szigliget , xsfc.

The third hill, named Szigliget, presented at its base, and below the village of that name, the same conglomerate, and to appearance the whole hill was composed of this substance. On ascending how- ever towards a ruined castle which stands upon the summit, I ob- served this conglomerate assuming a more bold and rocky form, and on examination found that it was of a much harder texture, and the parts of which it was composed appeared more completely amalgamated together. After proceeding a few steps farther I found myself upon a regular vein, of about 12 or 14 feet in thick- ness, running almost perpendicular downwards as far as vegeta- tion allowed the rock to be visible, and upwards to the summit.

This vein was of a very compact and heavy substance, of a dark colour, with sparkling crystallized particles ; and was upon the whole a mineral which I did not hesitate to consider basaltic green* stone. Towards each side, for the width of two or three feet, it was broken into irregular angular flat pieces, and might be called shat- tery, but towards the centre it was more firm, and very decidedly split into irregular horizontal columns.

The junction of this vein with the surrounding rock is abrupt and well marked ; yet they adhere closely together, and with some care may be procured united in the same specimen.

With respect to the mass of rock ; it is composed of what appear to be innumerable fragments of basalt or lava with small white crys- tals disseminated through them. These fragments are united by a yellow-brown semicrystalline matrix, and in parts wdiere least com- pact shewing distinct grains as of rubbed siliceous sand. Through this mass are distributed collections of vesicles giving the precise appearance of scorias, but not presenting a defined edge of separation, as if they had been included masses ; but on the contrary so forming a part of the substance of the rock as to suggest an idea that the

Dr. Bright upon the hills of Badacson, Szigliget , EsV. 7

whole had been very nearly, if not quite in a state of fusion, at the time when it assumed this appearance; and this view of the subject is rather confirmed by the very intimate union which exists between all the parts of the conglomerate. It is however possible that the scoriated appearance does actually arise from scoriae included in the mass, so that on the application of intense heat a partial fusion takes place, by which the matrix and the included substances have been closely united together.

Upon the summit of the hill and forming the foundation of the castle, the conglomerate, still containing the same substances, is found in a form somewhat different, disposed in beds of various thickness with a very distinct separation between them, both sur- faces of the beds being composed of projecting and slightly adhering angular particles of which the greater part is composed. These beds are perhaps at an angle of about 45° to the horizon. They are several yards distant from the vein, part of the general conglomerate filling up the intervening space.

The important conclusion to which these facts incline my mind is, that a vein which resembles in its characters a true basaltic green- stone, has owed its origin to the action of fire.

No one can look upon the hills of which I have been speaking, and observe how insulated they are from all mountain chains, mark their form, their abrupt sides and their flattened tops, without being convinced that they are but remnants left by some convulsion, tear- ing away parts which either connected them together, or made of each a more perfect whole. We must therefore put their form en- tirely out of consideration, and look upon them simply in the light of fragments, retaining their natural situation.

As such then we find in the first a hard columnar mass, in close connexion with a great mass of scoriated lava, over which it lies.

S Dr. Bright upon the hills of Badacson , Szigliget , &c.

In the second, we find the upper part composed of a mass of stone with vesicles in it, and which on comparison will be found to differ very little from the Icelandic lavas of Havnefiord. The under part of the mountain consists of a tuffa, or conglomerate, probably volcanic.

In the third, the very same tuffa is found at the bottom ; there is however no hard or columnar mass above it. The elevation is con- siderably less than that of the other two ; which may perhaps be accounted for by this deficiency, but we find extending to the sum- mit a black columnar vein passing through the conglomerate, to which it adheres firmly on both sides. The conglomerate is here more compact than elsewhere, and contains within it appearances of scoriae.

Taking then these facts in connexion, does it not seem that the conglomerate which forms the lower part of the second hill, and the greater part of the third, was in its situation before either the vein in the one, or the cap in the other, were deposited. That this was probably the result of some ancient volcano, or of eruptions of sand and scoriae which proceeded from a volcano that afterwards poured forth its stream, forming a thick covering over the surface of the deep sandy plain, and sinking into those fissures or crevices which existed in its course.

III. Some Observations on a series of Specimens presented to the Geological Society , by the Hon . H. G. Ben net.

By ARTHUR AIKIN, Esq.

MEMBER OF THE GEOLOGICAL SOCIETY.

[Read 21st February, 1817.]

On the 15th of June, 1794, a stream of lava flowed from Mount Vesuvius into the sea. The town of Torre del Greco, situated on the shore of the bay of Naples, was in part overwhelmed and buried under the fiery torrent. On the 16th of June, 1795, accord- ing to the testimony of M. Breislak, in his “ Topografia Fisica della Campania,” the lava had so far cooled, that a thermometer placed in the crevices rose only to 178° Fahr. and new buildings were already begun to be erected on the warm lava. In digging foundations for these houses, the ruins of those which had been overwhelmed by the lava, were occasionally broken into, and several articles were thus recovered which had been exposed to a heat of greater or less intensity, for the space of a year. The most complete and curious collection of these was made by the late Dr. Thompson. Many interesting specimens, however, were acquired by the Hon. H. G. Bennet, and with his accustomed liberality, have been presented by him to the Geological Society. By his desire I have examined these specimens, and the following notice is offered to the candour of the Members, instead of the dry detail of a mere catalogue.

Vol. V.

B

10

Arthur Aikin, Esq. on a series of

The earthy matter adherent to some of the specimens, and which I consider as haying formed part of the lava, No. 11, is deeply coloured by oxide of iron, has a completely earthy appearance, and is in general but little coherent. The only distinct minerals which I have observed to be contained in it are, scales of yellowish and silvery white mica, usually very minute, and pieces (which appear to be fragments) of finely granular carbonate of lime, effervescing strongly with acids.

The specimens of glass in this collection are particularly interest- ing, as shewing a variety of changes which this substance is capable of undergoing, by the continued action of a moderate degree of heat.

No. 1 is a fragment of a looking-glass, seeming at first sight to have undergone no alteration, except that the metallic lustre of the silvering is gone, and the upper surface of the glass appears as if it were dirty : this dirt, however, is not to be removed by washing with water, and on inspection with a lens appears to be the com- mencement of a decomposition or change of structure, for in the dull parts are seen many small circular portions that still retain their lustre, and some little cavities appear where the substance of the glass has been more rapidly acted on than elsewhere*

No. 2 are specimens of glass exhibiting the next change of structure : some of these are merely become dull and almost opake superficially, the interior being unaltered ; in others may be seen the commencement of a fibrous structure, penetrating from each surface

to the depth of about one-eighth of an inch into the interior of the

* •

mass*

Nos. 3 and 4 are masses composed of flat pieces of glass, which having been softened by exposure to a heat almost equal to their fusion, have sunk down upon each other, without, however.

11

Specimens from Torre del Greco ,

becoming actually united or incorporated, although some of the pieces are more or less vesicular. Externally they are partly of an opake white and partly of a dingy purple ; the interior surface of the vesicles being also of this latter colour ; the recent fracture exhibits a very pale sea green colour, passing into yellowish, and trans- parent, but with little or no lustre ; the structure is confusedly, and divergingly radiated, resembling considerably the commoner varieties of Prehnite. The external surface, in many parts, presents stellated groups of minute shining white crystals. Its hardness is such that it scratches glass with great ease ; it yields, however, to the file.

No. 5 shows the ultimate degree of change, the structure having become cellular, and the fracture compact.

Nos. 6 and 7 are specimens of glass which have actually under- gone fusion, and are converted into more or less cellular masses, en- veloping pieces of lava and other matters. The structure and general appearance of these differ much less from that of ordinary glass than the specimens above described.

No. 10 is a parcel of small glass beads, the form of which is but little altered, although they have been agglutinated together, and the structure has become cellular.

No. 8 is a cellular slag of a dirty brown and yellowish colour, the origin of which is not very apparent : perhaps it has been produced by an intimate mixture of glass and of lava.

No. 9 is a fragment of common pottery. The blue vitreous glazing has become more or less cellular, but the pottery itself has undergone no change. It may also be mentioned that in No. 6, already described, a piece of porcelain is inveloped in the glass ; this fragment does not appear to have been in the least degree softened, but its fracture displays a more granular structure than ordinary, and a glimmering lustre.

s 2

12 Arthur Aikin, Esq. on a series of

From the above described specimens, we may conclude that glass when exposed to a long continued natural heat, undergoes changes of structure very analogous to those which have been produced on this substance in our laboratories, by burying it in red hot sand, except that (as might be expected) the slower process has produced the more crystalline structure. The slight change of structure produced in those specimens, which have actually undergone fusion, also coincides in a remarkable manner with the experiments of Reaumur, who first directed the public attention to this interesting subject, which has since been applied, very ingeniously and plausibly at least, to the solution of a very important class of geological phenomena.

The changes produced on bars and utensils of iron, are not less remarkable than those which have already been described, and since they have not been anticipated by analogous experiments, made pur- posely in the laboratory, I shall take the liberty of mentioning them somewhat in detail.

No. 12 is a mass of iron, probably a piece of a cylindrical bar. The external part of the specimen, although rifted longitudinally, exhibits a considerably compact structure, and appears to be a mix- ture of the black and red oxides of iron ; it dissolves without effervescence in muriatic acid, and acts on the magnetic needle, but not very powerfully. The interior is a mass of grey oxide in confusedly octohedral crystals, acting very strongly on the magnetic needle, but not possessed of polarity.

Nos. 13 and 14 differ but very little from No. 12, except that some of the cells are lined with a white vitreous substance, from which acicular crystals of the same have shot from one side of the eell to the other.

No. 16 is part of a tube which has been reduced to the state of

Specimens from ’Torre del Greco.

13

magnetic oxide ; the cavity is lined with minute brownish red transparent crystals of oxide of iron.

No. 19 is a mass, apparently broken from No. 13, in the interstices of which are well defined crystals of specular iron ore.

No. 20 is a mass of iron reduced to the state of crystalline black oxide, and differs from all the other specimens, in being possessed of magnetic polarity, both in mass and in fragments.

No. 15 is a mass, probably part of a bar, with lava adherent to it : the whole is in the state of magnetic oxide, except a central cylin- drical piece a few inches long, and about one-fourth of an inch thick. This piece, on being bent backwards and forwards once or twice, breaks, and exhibits a completely crystalline structure, with a tin white colour and lustre. It has no polarity, but acts powerfully on the magnetic needle, and is soluble in muriatic acid, with a copious disengagement of hydrogen gas. It is therefore iron in the metallic state, having acquired, by the long continued action of heat, a crys- talline arrangement, and is probably entirely free from carbon.

No. 17 is an agglutinated mass of nails. The thicker ones appear to have been of cast iron, and are converted into a dark grey oxide, the thinner ones appear to have been of bar iron, and are still malleable, but in colour and structure resemble the specimen just described.

No. 18 is a key, the central part of which is in the metallic state, while the exterior is in the state of red, and of magnetic oxide.

From this series we may conclude — First. That the proportion of free sulphur in the lava, if any, must be very minute, since there is not the least appearance of any iron pyrites. — Secondly. That iron, by exposure for a sufficient length of time to a temperature by no means sufficient to melt it, or even materially to alter its form, may be converted either into massive oxide, with a perfectly crystalline

14

Arthur Aik in, Esq. on a scries of

structure, and sometimes possessed of magnetic polarity, or into crystallized oxide, the latter being manifestly, in many cases at least, produced by sublimation, thus shewing the volatility either of iron or of its oxide, at a much lower temperature than has ever before, I believe, been observed.

The other metals contained in this collection, namely, copper and lead, offer but few circumstances worthy of remark.

No. 19* is a heap of copper coins, the legends on some of which are still very visible. These pieces are cemented together by crystalline red oxide of copper, so that a section of the mass would present an alternation of thin laminas of metallic copper and of red oxide. The metallic portion appears to be softer than ordinary copper, and presents no traces of crystalline structure.

Nos. 20* 21, 22, are specimens of copper now converted into red oxide, mixed with green and blue carbonate.

Nos. 23 and 24 are specimens of copper converted into semi- transparent red oxide, with more or less of an external crystalline form.

No. 25 is a small bell, the figure of which is but little altered ; it is, however, entirely converted into alternate layers of red oxide of copper, and of white oxide, probably of tin.

No. 26 is a mass of common pins, retaining much of their original figure, but rifted longitudinally. The structure of each pin has become concentric, like a stalactite, and the surface is covered with extremely minute crystals, which I consider as red oxide of copper.

No. 27 is metallic lead, the surface being more or less oxidated. Mixed with the lead, and partly separated from it, are little crystal- line masses, with rectangular joints, that have all the external characters of galena. This galena, I am inclined to consider, not

IS

Specimens from Torre del Greco .

as produced by the union of sulphur from the lava with lead, but rather as the effect of a depuration of the lead in consequence of long exposure to heat. The uncommon softness of the metallic lead in these specimens, is a circumstance certainly favourable to this theory.

Nos. 28, 29, 30, are specimens of compact minium, with a glimmering lustre, and a semi-crystalline structure. The latter of these has evidently been a mass of common shot.

IV. Remarks on the Chalk Cliff's in the neighbourhood of Dover , and on the Blue Marie covering the Green Sand, near Folkstone,

By WILLIAM PHILLIPS, Esq. f.l.s.

MEMBER OF THE GEOLOGICAL SOCIETY.

[Read 2d January, 1818.]

The natural section of the chalk, presented by the cliffs extend- ing from Dover about eight miles eastward towards Deal, and five miles westward towards Folkstone, affords the opportunity for observing the nature of that formation, and the numerous falls on the shore, occasioned by accident or design, give more immediate access to the study of the organic remains they inclose.

The highest point of the range is in the immediate neighbourhood of Folkstone, about a mile north of the town, and is, according to the survey published by the Board of Ordnance, 575 feet above the level of the sea. From the signal-house, above Folkstone, the depression of the cliff towards Dover, is very gentle. The hill on which Dover Castle stands, is, at its highest part near the Turnpike, 390 feet high* : — and if we suppose the cliff, where the castle walls terminate, to be 50 feet lower, which must be near the fact, we shall assume it to be in that place, 340 feet high. From this place, the cliff, generally speaking, declines in height gradually towards Deal, terminating about a mile from that place, and disappearing near

* Geological Transactions, Vol. IV. p. 437.

Mr. Wi l l [ a m Phillips on the Chalk Cliffs near Dover . 1 7

Walmer Castle, beneath rubble and alluvial matter with which it is there covered to the depth of 15 or 20 feet.

In this long range of cliffs, which in many places forms an imme- diate barrier to the sea, it is not to be expected that every part should be equally accessible to investigation. Between Deal and Dover there is but little difficulty, nor for nearly half the way from Dover towards Folkstone ; but in the latter half of that distance, an im- mense fall, or rather, it should seem, repeated falls have taken place; so that that part of the cliff of which the beds remain in situ , is, at its extremity beneath the signal-house, nearly a mile from the shore. The ruin lying between this cliff and the sea, for about three miles in length, affords scenery inferior in beauty to the “ Undercliff” of the Isle of Wight, only because from its want of soil, it is less susceptible of cultivation ; while from the same cause its grandeur is more striking. The greatest part of it, however, is sufficiently covered by herbage to have become a pasturage for cattle. The cliff, bounding this ruin towards the sea, is, from its position, evidently not in situ ; and it is equally clear that the enormous masses of which it is composed, have fallen forward from near the summit of the cliff in situ . On the probable cause of this large ruin, I shall pre- sently offer a few remarks.

In the less precipitous parts of the cliff, and particularly along that part of it, between which and the sea the ruin lies, it is in a consi- derable degree covered by herbage ; which however does not prevail so greatly as to prevent the observation, that it is, throughout its whole length from Walmer Castle to Folkstone, very distinctly stratified; that the strata are numerous, regular, and perfectly de- fined, although from the nature of the cliff it is not possible every where to trace the stratification. The chalk with numerous flints, that with few flints, that without flints, and the grey chalk, all appear Vol. V.

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Mr. William Phillips on the

in the course of this range ; and with them are connected some beds consisting almost wholly of organic remains, that have not, I believe, been described as occurring in other places. The strata lie in the following order, and are collectively about 820 feet thick.

1st. The chalk with numerous jlints ; it is about 350 feet thick, and may be thus divided ;

I. With few organic remains, lying upon

II. A bed consisting chiefly of organic remains ; in which numerous flints of peculiar forms are interspersed, and a few beds of flint run along it. This bed, I term, the chalk with interspersed jlints .

2d. The Chalk with few jlints ; this stratum is about 130 feet thick.

3d. The Chalk without finis is 140 feet thick, and consists of

I. A stratum containing very numerous and thin beds of organic

remains, 90 feet thick.

II. A stratum about 50 feet thick, with few organic remains.

4th. The Grey Chalk ; this is estimated to be not less than 200 feet

in thickness.

I propose to offer a few observations on the nature and stratifi- cation of these deposits, upon the flints of such as inclose them, on the stratification of the green sand of Folkstone, and on the blue marie overlying it in the neighbourhood of that place.

The accompanying sketch (Plate 1.) exhibits the range of these cliffs, from the signal-house above Folkstone to Walmer Castle. It is essential to be noticed, that they do not run in the same direction throughout their whole length. From the signal-house above Folk- stone to the South Foreland, their general bearing is N.E. by E.; * from the latter place the cliff is somewhat curved to St. Margaret’s Bay; whence, to Walmer Castle, its direction is nearly due north.

19

Chalk Cliffs near Dover .

Although the stratification is every where visible in a greater or less degree, it is best observed by tracing the junction of the chalk without flints, with the superincumbent bed of organic remains. This is visible with little interruption for five miles from the signal house above Folkstone to the foot of Shakspeare’s Cliff, in which distance it dips only about 300 feet, in the direction of N.E. by N.

Proceeding from St. Margaret’s Bay, the beds of flint appear to have nearly the same dip towards the north: whence it may be concluded that the chalk strata in the neighbourhood of Dover dip somewhat less than a degree towards a point between N.E. by E. and N.

CHALK WITH NUMEROUS FLINTS.

I. With few Organic remains .

The low range of cliff between Walmer Castle and St. Margaret s Bay, being about five miles long from north to south, consists alto- gether of the chalk with numerous flints. The rise of the cliff is gradual ; its highest part being that immediately contiguous to St. Margaret’s Bay, where it scarcely attains 200 feet in elevation. In consequence of its nearly uniform hardness from the base to the summit, it is almost precipitous, and suffers but little from decay or casual fall ; but it is so low in some places, as at Kingsdown Bay for instance, as scarcely to exceed 20 feet above the beach. The beds of flints are frequent and thin, being on an average scarcely two feet, apart; and the flints are obviously separate from each other. But a remarkable deviation from this general rule is observable immediately on the west of St. Margaret’s Bay ; where a con- tinuous stratum of flint, about an inch and a half thick, rises from the beach, and is readily traced at least two miles from that

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Mr. William Phillips on the

bay : soon afterwards another rises which is about half an inch thick, and is visible for nearly a mile about 20 feet below the former.

Quitting St. Margaret’s Bay for Dover, the chalk with numerous flints appears to rise gradually ; forming, at the latter place, when viewed from the shore, apparently about one-third the whole height of that part of the cliff upon which the castle stands. Soon after leaving St. Margaret’s Bay, the beds of flint begin to increase in distance and in thickness ; in the latter respect they go on increasing to that part of the cliff which is immediately beneath the castle;, where the thick beds, protruding at least two feet beyond the chalk, give rise to the idea of their consisting each of one mass of flint, but which their rugged edges, as viewed from below, seem to render at least doubtful. Some of these beds exceed a foot in thickness.

The chalk with numerous flints is again visible on the height west of the Castle, at a still greater elevation. That it forms the upper part of this height, was proved in making the extensive fortifications on its summit, as well as the openings a little beneath, it, immediately below the citadel, which were intended for the reception of some part of the troops stationed at Dover during the war.. These openings are in an unfinished and ruinous state, but they served to convince me of an interesting fact. Each of these four chambers is driven into the hill about 100 feet, and is perhaps 20 wide and 1,5 feet high ; and in each, the only roof left to support the superin- cumbent chalk is a bed of flint ► I do not say of flints, being con- vinced that the whole, is one nearly-continuous, though not regularly tabular and evenly-disposed mass. The belief of the existence of this fact, in regard to at least many of the beds of flint in the upper chalk near Dover, was previously entertained, by observing the workmen on the shore cleave several blocks of chalk, each 8 or 10 feet square, close to the beds of flint passing through them; and in

Chalk Cliffs near Dover . cl\

every instance, examination proved that the flint of each bed so exposed, was connected together : not that it formed one plane surface; but, though varying in thickness from 6 to 18 inches, the flint would, if It could be taken off* whole, have exhibited occasional cavities, which, collectively, would have formed but a small pro- portion of the whole surface. A man who had been employed on this work during eighteen years, , assured me that he had always observed the same fact*

Among the fragments of flint thrown aside, I noticed many having surfaces,, evidently the consequences of fracture, that were opake and white ; and as, on breaking these flints anew, they were always black internally, it seemed possible that this whiteness and opacity might be owing to the disintegration of the fractured surface by long exposure. The examination, however, of the beds of flint in these blocks of chalk, shewed the futility of this supposition;; for the flint then exposed for the first time, was found to be cracked through in several places, from one cavity to the next : and the fractured surface was in every instance, more or less white and opake. Such a fracture seems explicable only by the supposition of a contraction having taken place in the flint while in its natural position. Nor does it appear to me at all improbable that a con- traction had actually taken place. Flint newly disengaged from its natural bed, is much more brittle, requires a much lighter blow to break it, than flint that has been long exposed.* This may perhaps be owing to the moisture or water belonging to the flint in its natural state, but which it loses in great measure by the joint action of the air and sun.

* The flint gravel used for mending the roads round London, is in some places provi- dently taken from the pit some time before it is wanted, and exposed to the action of the air and sun: for this practice the alleged reason is, that it hardens; which, probably is-- the fact..

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Mr. William Phillips on the

In some instances these naturally fractured surfaces, while yet imbedded in the chalk, were so close together as scarcely to admit the edge of a knife between them; ift others they were half an inch apart, the intermediate space being filled with chalk. As the opake white substance, which in some cases only surrounded the edges of the fractured surface, did not project beyond the central part, still retaining the black colour of the internal part of the flint, it is clear that it was not a coating; but on the contrary, this circumstance seems to furnish strong, if not conclusive evidence of its being the consequence of disintegration, proceeding from causes that have not hitherto been explained. The alluvium of the surrounding country corroborates the supposition; every where it includes a multitude of fragments of flint, the broken surfaces of which always exhibit the same appearance of disintegration.

It is also I believe to the progress of disintegration that we are to ascribe the existence of the white opake coating by which the mass of every flinty stratum is more or less covered, while yet. in its natural bed. In no instance did I observe any well defined line of separation between the flint and the opake coating, which not unfrequently is half an inch thick, and which by exposure to the sea becomes more compact, and hard enough to admit of a conchoidal fracture. Between its outer surface and the black flint, it is not uncommon to observe two or three thin bands of flint. If the white substance be the consequence of disintegration, it seems remarkable that these bands should have been thus left untouched. In order to ascertain the nature of the white substance surrounding the flint, I selected with care three portions. One from without the band— another from between the band and the flint — and the third of one in wThich there was no band. These my brother took with a view to determine what proportion of each

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Chalk Cliffs near Dover.

consisted of lime, in case any should be found. The two first consisted wholly of siliceous matter; the last of 86 per cent, of silica and 14 of carbonate of lime. All the fragments were of a granular texture, and sufficiently hard to cut glass ; each also left a whitish, streak on the finger when rubbed with considerable pressure upon it ; the last in the greatest degree.

Large fragments of striped flint of a grey colour are often dis- coverable among those 'which have been taken from the inferior beds in the, upper chalk, but they frequently contain a nucleus of black flint, from which the grey stripes diverge as from a common centre.

Such flints as are interspersed in the chalk of the stratum with numerous flints, have usually some organic appearance. They are occasionally found in pear-shaped masses resembling the head of the alcyonium ; sometimes in the form of nearly perfect spheres, which are solid, and do not commonly exceed half an inch in dia- meter, but are often much less. Others of no particular external form, have internal cellular or ramifying cavities which seem to indicate the, same origin. Others again seem so decidedly to have been formed around sponges, that the flint has entered all the ramifi- cations, the forms of which therefore remain.

It is not uncommon to find flints inclosing many of the shells observable in the chalk, and impressions of the few varieties of echinus common to that of Dover, the shells having been replaced by carbonate of lime, or the space they once occupied being left vacant; so that the internal cast of the shell, which is of flint, is in some cases connected with the surrounding mass by fine filaments of siliceous matter, arranged precisely in the order of the small perforations commonly visible in the shell, which therefore must have been formed while the shell was yet entire. Shells enclosed

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Mr. William Phillips on the

in flint are usually filled with the same substance ; if only adhering to, or partially imbedded in it, they are always I believe filled with chalk.

About 40 feet below the summit of the cliff beneath the castle walls, lies a bed of a substance greatly resembling hard chalk marie, parallel to the beds of flint. It is about 18 inches thick, and is dis- tinguishable from below by its being of a brownish yellow colour ; and being harder than the chalk, it protrudes, presenting a rugged knotty surface. Such portions of it as fall, are collected by the lime- burner, who can convert them into lime only by using coal, instead of the ashes usually employed in the burning of chalk. Between this bed and the summit, a horizontal crevice is visible in the chalk, indicating the presence of a bed of soft chalk marie, but I had no opportunity of ascertaining the fact. Several other beds of hard chalk marie are visible in the upper chalk east of the castle, between the beds of flint.

II. Bed of Organic Remains with interspersed Flints .

When viewing the middle part of the cliff from its base beneath Dover castle, a singular roughness is visible. On ascending the green slope of some ruin, I found that it proceeded in a great degree from its having inclosed a vast multitude of organic bodies of various kinds, amongst which the remains of a few varieties of the echinus, and the ochreous marks of some varieties of sponge, were extremely frequent. In part also the ruggedness proceeded from a vast number of small flints irregularly interspersed through the bed, but which are not visible from below, because such parts of them as are exposed partake of the colour of the bed ; for being separate, $nd mostly small, they do not commonly shew any fracture.

Chalk Cliffs near Dover .

25

The numerous knotty projections of this part of the cliff are much harder than chalk commonly is, and than that in which they are imbedded. These remains of organic bodies do not lie in thin or separate beds ; but form one large bed, occupying about one-third part of the whole height of the cliff beneath the castle, and in the centre of it.

The beds of flint lying immediately above this bed of organic remains, are less frequent and much thinner than those which are nearer to the summit of the cliff, and some beds of flint are visible among the organic remains. Indeed there does not appear any decided line of separation between this bed and the superincumbent chalk with numerous flints, and hence their junction is left un- decided in the accompanying sketch of the cliff (Plate 1.) : we may consider this bed, though it contains comparatively very few beds of flint, as the lower part of the chalk with numerous flints.

The whole bed has, from below, a greyish appearance ; and by this it may be traced by the eye for at least two miles, dipping gently in its course, which terminates at the foot of the cliff just at St. Margaret’s bay, four miles on the east of Dover. It may be seen along the cliff at the back of the town of Dover, and is visible west of it as forming the upper part of Shakspeare’s cliff, and terminating on the summit of the cliff about two miles beyond it. Its run is discoverable, not by the exterior roughness alone, but also by the presence, near the bottom of it, of two parallel and rather thick beds of flint, which are about four feet apart, and may be seen along the whole course of the bed, as I have described it. Between these beds of flint, lies a thin bed of soft marie, which, be- coming friable and crumbling away by exposure, leaves a crevice which accompanies the beds of flint, and which is visible for the Vol. V.

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Mr. William Phillips on the

greater part of their run ; and a similar bed is visible parallel to it, about three feet beneath the lower bed of flint.

Several large masses that had fallen from this bed lay on the beach about a mile from Dover on the east ; they had lately fallen-, and as some of them had broken in the direction of the stratum, they af- forded a good opportunity for observing the nature of the bed in its less exposed state, and of discovering whether it afforded any inter- nal appearances tending to confirm the opinion I had formed of its nature, judging by the external roughnesses of this bed in the cliff. The newly broken parts shewed that the chalk of it is yellower in- ternally than the superincumbent chalk with numerous flints, which is very white ; they were also extremely rugged, and the more pro- minent parts were much harder than chalk commonly is. It was impossible to detach any of the numerous inequalities on these masses, without discovering some organic appearance. Some resem- bled vegetable stems coated with chalk of a different colour. In several instances, a cylindrical mass of whitish chalk, was surrounded by concentric coatings of the same substance of a darker colour, which sometimes amounted to ten in number. Ochreous traces of several varieties of sponge were likewise visible ; but by far the greater number of the projecting portions consisted, when detached, of shapeless masses of chalk which were considerably hard, and which in some respect or other, either by exhibiting a slightly porous texture, or a striated surface, always induced the belief of organic origin. These striated portions are very hard within ; the external striae are sometimes very regular. Among other organic remains afforded by these masses, I extricated the cast, in chalk, of a small nautilus, which hitherto I believe has not been discovered in the upper chalk.

Such is the general hardness of this bed, that the workmen em?

Chalk Cliff's near Dover. 27

ployed in blasting the cliff, and squaring the chalk for the purposes of the harbour, always leave untouched such masses of it as fall, except they belong to the lower part of the bed ; which, containing fewer organic remains, is readily squared. The axe, when struck upon the chalk of the upper or middle part of this bed, returns a sound so exactly similar to that of striking upon flint, that the workman could only convince me that no flint was there, by clearing away what he had struck.

Throughout this bed of organic remains, numerous thin veins of a grey colour run, generally speaking, parallel with the stratum. These veins however, are not straight, but undulate, terminating imperceptibly, being again renewed a little above or below. Some masses that had been split by the workmen along these veins, gave the opportunity of examining their nature, and it became very evi- dent that they originated in the presence of some organized body. It was easy to detach from every part of the newly exposed surface, hard conical masses, striated from the summit to the base by lines of a dirty brown colour, which were glossy and moist : and where the continuity of the cone was accidentally interrupted by fracture on the side, the same appearance was discoverable within. It was evi- dent that the nearly horizontal part of these grey veins connected together the neighbouring conical masses. Wherever a flint or a shell was imbedded in contact with one of these veins, it exhibited superficially the same striated appearance as the conical masses of chalk.

The flints interspersed through this bed of organic remains are generally of remarkable forms, and shew either internal or external evidence of their having been formed in or upon some organized body. They are not uncommonly of a nearly spherical shape ; and when solid, there is uniformly, as far as my observation goes, a

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Mr. William Phillips on the

28

small indented circle upon each : when not solid, they always con- tained a nucleus having the appearance of a sponge of the same shape as the flint : these rarely exceed an inch in diameter. Others are cylindrical, and inclose another flint of the same form ; others (and they are numerous) are conical, having a flat base, around which is always indented an oval, within which there is sometimes the in- dented mark of a sponge : some of these are solid, others are lined with tuberculated chalcedony of a bluish aspect ; these are about two inches high : a thin lining of blue chalcedony, which is extremely greedy of moisture, is by no means uncommon within some of the flints of this bed. There are others very common to it, whose ex- ternal marks, consisting either of deep indentations or small rugged projections, bespeak the probability of their formation being in some way or other connected with organic matter. But there are other flints which it is not easy to describe. They inclose a cylindrical flint, resembling the stem or a branch of a vegetable, which, passing along the mass, is visible at each end, where sometimes it divides into numerous little branches : another of the same description crosses it, giving to the external flint a peculiar shape, and inducing the belief that it must have been deposited around some organic substance, of which the form is preserved by the internal ramifications. The whole of these flints are numerous in this bed of organic remains ; but I did not discover any resembling them in form and character in any other part of the chalk.

The numerous shells of the echinus, or rather the calcareous spar which has replaced them, are almost always whole ; rarely was one visible that had suffered depression ; but the chalk with which they are filled, instead of being finer than that in which they lie, as is frequently the case in the echini of the upper part of the chalk with numerous flints, is on the contrary much coarser and of a somewhat sandy aspect.

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Chalk Cliffs near Dover .

This bed of organic remains with interspersed flints, is separated from the bed on which it lies, the chalk with few flints, by a bed of marie two or three inches thick, which lies about 15 feet below the two beds of flint mentioned at p. 25. The exterior roughness of the bed is however far less, and the interspersed flints are fewer, for 10 or 12 feet of its lowest part, than in the middle or upper part of it.

CHALK WITH FEW FLINTS.

The chalk of this stratum is soft and white, though not of so pure a white as that with numerous flints. It contains a few thin beds of organic remains, which, arguing from the ochreous characters that are frequently visible, may be considered as being chiefly of sponges: these beds are most frequent and determinate just below the thin bed of chalk marie forming the separation between this and the superin- cumbent stratum. About 20 feet below that bed, two somewhat thicker beds of soft chalk marie run parallel with each other and with the line of separation, and at about three feet apart. As the marie shivers by exposure, these two beds may readily be traced along the cliff as crevices, rising from beneath the beach about two miles east of Dover, and pursuing their course without interruption, except such as is caused by the occasional falls of the cliff, quite to its termination beneath the castle : they are also very visible in some parts of the cliff above the town, where its surface is exposed. Traces of them may be seen on Shakspeare’s cliff ; but from their position in it, and in that further west, as well as from the nature of the cliff itself, which is too precipitous to be easy of access, they cannot readily be traced along it.

The marie of these beds commonly shivers by exposure in a di-

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Mr. William Phillips on the

rection parallel with the stratum ; but undulating grey veins pass along it, and here and there may be extricated from them small conical masses in every respect similar to those which have already been mentioned in page 27.

Just beneath the thin bed of marie forming the line of stratifica- tion, two thin beds of separate flints are very visible, but not lying in the same manner as those belonging even to the thinnest beds in the chalk with numerous flints ; their largest surfaces are not parallel with the stratum ; but on the contrary, as they lie in every direc- tion, they do not form an even line in regard to each other ; and this is the general character of the few thin beds of flints occurring in this stratum, which do not continue for any considerable distance. Flints sometimes lie in the occasional thin beds of sponges which appear on the face of the cliff, and sometimes exhibit impressions of them on the surface. The flints interspersed in the chalk of this stratum are frequently cylindrical, and are sometimes in the form of the bulbous head of the alcyonium, or in shapes resembling vege- table stems : such flints I have observed. here and there of more than two feet in length and scarcely exceeding half an inch in diameter, but they were always cracked across in several places.

The grey veins so numerous in the lower part of the superior stratum, are almost as frequent in this, but prevail most just above or below the thin beds of organic remains and of flints above- mentioned, and in the neighbourhood of those numerous and nearly parallel crevices which are so many indications of regular stratification.

The ammonite has hitherto, I believe, been supposed to be first visible in the under chalk, or that without flints. A large one lies in the cliff about a mile eastward from Dover, nearly in a horizontal position, and just above a bed of flints which runs for some distance

Chalk Cliffs near Dover . Si

only a foot or two above the base of the cliff, and there are many interspersed flints within a few feet all around it. Two other am- monites from 12 to 18 inches in diameter, are visible at low water, in chalk, belonging evidently to that with few flints, but whether it be in situ or not, it is difficult to determine. One of them is distinctly oval.

About a mile and a half east of Dover, and near the place at which this stratum rises from the beach, I found the cast of a nautilus in it.

Iron pyrites is by no means uncommon ; it usually occurs in globular masses, coated by crystals having the form of the octohe- dron, which sometimes are attached to a flint : in one instance it was observed filling up the cracks in one. One mass had been formed around a terebratula, of which the shell, filled by pyrites remained, but in a friable state. This stratum yielded to my search pectinites, terebratulse, and the palates and vertebrae of fishes. A nearly perfect specimen of one species of the striated shell or ino- ceramus, perhaps the only one hitherto discovered, was found by the workmen employed in squaring the chalk ; it was nearly filled with flint, and was partially imbedded in it.

Several excursions along the cliff between Dover and Folkstone, both at its base and on its summit, as well as the- occasional oppor- tunity of ascending or descending it, enabled me at length satisfac- torily to discern the nature of the connexion of the chalk with few flints, with that on which it reposes, namely, a thick stratum with- out flints, enclosing numerous thin beds of organic remains, lying nearly close together.

A thin bed of soft marie lies between these strata. It may be readily traced along the cliff, as a crevice, for a considerable dis- tance, but is most conveniently viewed while ascending Shaks- peare’s cliff from the town. Flints are here and there visible a few

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Mr. William Phillips on the

feet above this bed of marie, but not one was discoverable below it. Between this and a similar bed of marie nine or ten feet beneath it, are to be seen many of those thin beds of organic remains, which are characteristic of the stratum on which the chalk with few flints reposes. Both these beds of marie are also seen in the most ele- vated part of the low cliff, between Shakspeare’s cliff and the town of Dover.

CHALK WITHOUT FLINTS.

I. Stratum containing numerous thin beds of Organic Remains .

This stratum, both internally and after exposure, is yellowish and without flints ; for not one was visible in it, either in the cliff, or in the numerous masses lying at its base : in hardness, it exceeds the chalk with interspersed flints.

The low cliff immediately contiguous to Dover on the west, con- sists wholly of the chalk of this stratum, except the summit of its most elevated part, which consists of the chalk with few flints $ but in this place it does not so decidedly appear to consist of a num- ber of thin beds of organic remains, as it does after rising from the beach at Shakspeare’s cliff ; nevertheless it manifestly consists of a vast accumulation of organic exuvise. This stratum may be traced without interruption for nearly four miles ; but the summit of the cliff between Dover and Folkstone, for the tatter half of the way, quite to its termination near the signal house above the latter place, decidedly belongs to the chalk with few flints : a close examination of it discovers here and there a few interspersed flints, and a single bed of them is visible about 40 feet below the summit, just half way between the two places. Wherever a path is practicable, the cliff

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Chalk Cliffs near Dover .

is so sloping as to be covered with a verdure which prevents an accurate discovery of the stratification by ascending it, and it can- not always be seen from either above or below.

The external roughness occasioned by the numerous thin beds of organic remains in this stratum, is far less considerable than that of the chalk with interspersed flints. Still the same appearance of sponges is visible after long exposure, but they lie closer together, and when detached are less. The few are not unfrequently sepa- rated by the remains of shells, so small as to be nearly in a state of comminution, a large proportion of them being varieties of the striated shell or inoceramus. The two varieties of the echinus so common in the chalk with interspersed flints are occasionally seen in this bed, but are less numerous. Ammonites from 12 to 18 inches in diameter and of a circular form are not uncommon : I saw several, all of which lay parallel to the strata. Though the thin beds of organic matter are nearly in contact in the lower part of the stratum, they are more separate in the upper part of it.

Through one of the many large masses lying on the shore, a bed about nine inches thick took its course, consisting of remains essen- tially differing from the rest. It consisted chiefly of ramose appear- ances about half an inch in diameter, and the masses detached from it greatly resembled those of the alcyonium visible in the sand of the Isle of Wight, described by fig. 12, pi. 29. vol. 2, of the Geological Transactions.

In this stratum I did not perceive any traces of pyrites, so common in other parts of the cliff*. It includes grey veins similar to those of the chalk with interspersed flints and of that with few flints, but they are far less numerous, and though the organic remains which occasion them are similar, they are much smaller.

Vol. V.

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Mr. William Phillips on the

II. Chalk without Flints, and with few Organic remains. .

This stratum rises immediately at that part of the base of Shak- speare’s Cliff which is nearest to Dover, and is separated from the stratum containing numerous beds of organic remains, which reposes on it, by a bed of soft marie. As this marie, like all the others of the same nature that are visible in these cliffs, becomes friable and falls away by exposure, it serves as a certain guide to the stratifi- cation, and may be seen with little interruption for more than half the way to the signal-house above Folkstone, and at intervals for the other half ; so that the connexion of the two strata may be traced for five miles without difficulty. Without this aid, however, there could only have existed such hindrance as naturally arises from occasional verdure on the face of the less precipitous parts of the cliff, being those above the undercliff : for the chalk of the two strata differs greatly in appearance. That of the stratum I am describing is soft, and even white in comparison of that which lies upon it, though not so white as the chalk with few flints; and for six feet beneath the bed of marie, is of so sandy a texture occasionally, as to be even friable, but here and there it assumes the appearance and compactness of a sandstone.

The nearly horizontal crevices in other parts of the cliff appear to be nearly parallel with the stratification ; but in this, the crevices differ from that position, and are even in a transverse direction; those that are nearly vertical are numerous, giving to the chalk in many places, an angular appearance, not common to any other parts of the cliff. It runs along the base of the cliff for somewhat less than half a mile, and in that space, affords, even on a close inspection, the traces of but few organic remains.

It incloses masses of pyrites, some of which are crystallized

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Chalk Cliffs near Dover.

externally in the form of the octohedron, but their general form is spherical. Others, and they are not uncommon, are in the form of cylinders, rounded at each termination, to which there is fre- quently a short stem attached ; the whole having the appearance of organic origin. When broken across, they are always found to radiate from the centre.

Here and there appears a small bed of sponges, of which the ochreous forms are visible ; but this stratum contains none of the grey veins so numerous in the superincumbent strata. It is about 50 feet thick.

GREY CHALK.

The grey chalk differs from the strata reposing on it, in being softer. It varies considerably in different places, in respect of colour and texture; being much more sandy and less compact than in others. A fair specimen of it yielded to my brother, by analysis, 82 per cent, of carbonate of lime, and 18 of silex and alumine, chiefly of the former, and a trace of the oxide of iron.

It first rises from the beach at the foot of the low cliff conti- guous on the west to that which is known by the name of Shak- speare’s ; but its separation from the chalk without flints is not at that place perfectly defined. In less than a quarter of a mile beyond the place at which it rises from the beach, the two strata are very distinct ; the white being separated from the grey by some very thin beds of a sandy appearance and yellowish colour. As the grey chalk rises, its colour becomes deeper, and it is here and there so extremely soft, that the rain in descending the cliff, has carried down and deposited at its base considerable quantities. It is in these places particularly, that beds of sandstone from 1 to 4 or 5 inches thick, and extremely hard, take their course parallel

36

Mr. William Phillips on the

with the stratum for a short distance, projecting beyond the face of the cliff from a few inches to two or three feet. A fan-shaped projection of this kind overhangs a copious stream of pure water issuing from the grey chalk, termed Lidden spout, protruding be- yond the surface of the cliff, not less than five feet.

Not a flint is visible in this bed : its organic appearances are numerous, but do not differ considerably from those of the superior strata. Along the crevices running parallel with the stratification, the chalk is commonly of a deeper grey than the bed in general,, and incloses some still darker appearances of ramification, resem- bling in their general form some varieties of broad-leaved fuci, which are somewhat softer than the chalk in which they are imbedded. The reverse of this is occasionally observable in the more solid parts of this chalk, and where its colour is of a lighter grey ; for there it is sometimes traversed in every direction by very numerous and small ramifications of a colour still lighter. The remains of the echinus are numerous, and their shells are replaced by carbonate of lime of a grey colour : every one I saw had not only suffered depression, but the shell was also in every instance broken ; a circumstance which is the more remarkable, as it is rarely discoverable in any of the superior strata;.

Small masses of pyrites are very common, and there are some of singular forms. Thin strings of it, sometimes ramified, the branches terminating in a point, are very numerous ; but sometimes on the contrary they are terminated by a spherical bulb, or by one that is elongated and resembling the head of the alcyonium, but very small ; these are generally hollow. A remarkable crystallization of pyrites is also very common. A string of octohedrons piled with con- siderable regularity on each other, and above am inch in length, is crossed by another similar to it, — the termination of each being the.

37

Chalk Cliffs near Dover.

quadrangular pyramid of an octohedron : — -these again are crossed at right angles by another, which is terminated in like manner, so that the three have one common centre : giving to the whole the appearance of the commencing crystallization, or the skeleton, of one large octohedron. Thin beds of sponges occasionally appear, their remains being either ochreous, or of a lighter colour than the chalk itself; but these are visible only when the stratum has risen con- siderably, and near to the beginning of the undercliff. Near the stream called Lidden Spout, I found the cast of a large nautilus in grey chalk, but much harder than that of the stratum.

GREEN SAND AND BLUE MAKEEV

The investigation of the chalk cliffs being my primary object, little attention was given to the green sand. The opportunity for observing its dip was however too favorable for it to be wholly omitted. But my interest was chiefly excited in the neighbourhood of Folkstone, by a considerable deposit of a marly substance over- lying the sand at Copt Point, and which in its natural bed is of a bluish colour, and in some places so moist, as to be incapable of bearing the weight of a man, except in dry weather, which hardens the surface, cracking it in every direction. My brother found that by submitting 100 grains of this marie to the action of acid, 13 were lost, indicating the presence of nearly 30 per cent, of car- bonate of lime.

The town of Folkstone is built upon the green sand, which is known in many parts of England mediately or immediately to underlie the chalk. It incloses beds of sandstone. The cliffs on the east of the town, may be in some places 80 or 90 feet high, the upper part of which, for a considerable distance from their ter-

38

Mr. Willi an Phillips on the

mination at Copt Point consists of the blue marie, which in some parts may be from 40 to 50 feet thick.

The run of this cliff is not quite parallel with that of the chalk cliffs between the signal-house and Dover. The dip of the sand- stone lying in the green sand is about the same as that of the chalk, as it appears on the surface of those cliffs.

Although from the similarity of this bed of marie to that which is observed in other places to lie between the chalk and green sand, there can be no doubt that it passes under the chalk, yet it is not easy to discover it so interposed.

The chalk cliff turns southward towards Folkstone near the sig- nal-house, presenting a ridge which slopes rapidly ; so that the chalk is not seen in situ quite so far down as the nearest of the three Martello towers. Below that place, all is ruin for a consi- derable part of the way to Copt Point ; the colour of the chalk being lost by insensible degrees in the blue marie, and both to- gether occupy the descent to the shore for a short distance. Be- tween the second Martello tower and the shore, the descent chiefly consists of the blue marie, wrhich continues to Copt Point ; and it can scarcely be doubted that the high ground between the shore east of the Martello towers, and the Canterbury road, and perhaps still further west, consists mainly of the blue marie, which is visible soon after that road has branched from the road to Dover, in a field on the right, from which the alluvium has been removed in search of flints for mending the road. It also appears in a field at the foot of some high chalk ground behind a small farm house near the second of the Martello towers ; where a spring of pure water issues from beneath the chalk, and running over the marie makes its way down the descent, consisting chiefly of chalk ruin, into the sea.

The perishable nature of the marie seems to have been the chief

39

Chalk Cliffs near Dover .

( :■ ' v.*’ { • . . ’ '

cause of the immense ruin lying beneath the cliff, at the extremity of which the signal-house stands. For the sea, having washed away the marie which formed the base of the cliff, the upper part, losing its support, has fallen down. The cliffs now forming an immediate barrier to the sea, have chiefly fallen from the stratum containing numerous beds of organic remains.*

* Since writing the foregoing, I have received from my friend L. W. Dillwyn, Esq. t>f Pentlergare near Swansea, a letter, containing the following account of a sudden rise of this marie in the Bay, and opposite to the undercliff. 4 I promised you to endeavour to recollect and give you my observations on a small island which sprung out suddenly from the sea, about a mile to the eastward of Copt Point between Dover and Folkstone. I well remember, that whilst botanizing in that neighbourhood somewhere about the year 1799, a fisherman told me that a gold mine had sprung out of the sea a night or two be- fore, and being puzzled to imagine his meaning, I begged him to conduct me to the spot, which he said was accessible at low water. As nearly as I can recollect, I found it tt) be about a acre or an acre and half in extent, and from eight to ten feet high, and so close to low-water-mark, as to be only accessible at spring tides. It was composed of a soft muddy marie filled with nodules of remarkably brilliant mundic, and containing nume- rous small nautili, which were more richly coated with nacre, and by far more irridescent than any others I had ever seen. On mentioning this island to my worthy friend the late Rev. John Lyons of Dover, he told me he thought he could account for its formation, and with a view to confirm an opinion which he had several years before communicated to the Royal Society (See Phil. Trans, for 1786), he accompanied me to the spot. Between the island and the chalk cliff in situ, and at the base of the latter, on the undercliff, we found rather a large morassy pool of fresh water. From this pool a considerable stream appeared to run underground in that direction, and to burst out again from the sands close to the island. I cannot sufficiently recollect the particulars of our observations, but as on examination we found that there had been a sinking of part of the cliff abruptly, I perfectly remember our conclusion was, that the slip of the cliff had occasioned a body of chalk to press suddenly and with great force upon a quantity of marie which had become softened by an underground stream, and forced it through the channel, so as to form an island at its mouth. Mr. Lyons had no doubt that it was the same stream which he told me he had seen losing itself gradually in the soil at some considerable distance inland, and which by loosening and softening an understratum of marie, had thus occasioned the superincumbent chalk to give way. Two or perhaps three years afterwards, I again visited the island, but it had then become, by the action of the waves, greatly reduced in height ; and, if I remember right, the marie which remained was nearly indurated. I have some of the above mentioned nautili, but they have lost most of their beautiful nacre, and owing to the late removal of my cabinets, I now hardly know where, nor have I time

40

Mr. William Phillips on the

Since the grey chalk assumes a darker colour as more of the stratum rises to view, it seems probable that it passes into the blue marie by insensible degrees. There is however a great difference in the organic remains of these two strata ; at least in their me- chanical texture ; those shells which were nacreous when recent, rarely shew the pearly lustre in the grey chalk, while those which are found in certain parts of the blue marie are rarely without it : but this is generally the case with shells originally nacreous, which are found in beds of clay ; the close texture of the clay having protected them from the action of air and moisture.

Among the numerous fragments of fossil wood imbedded in this marie, but which chiefly lie on the green sand, some are several inches in diameter, and still retain the woody fibre : they are mostly enveloped in, or the interstices of their outer part are filled with pyrites, which is commonly in a state of decomposition, one of the consequences of which is the formation of selenite in crystals, which are often well defined. These are either attached to the fossil wood, or lie imbedded near it. Some small masses of a sub- stance having the appearance of bone in a fossil state have been discovered.

By far the greater proportion of those shells of which the nacre is extremely brilliant and sometimes even irridescent, are inclosed in more compact masses of a lighter and more uniform grey colour than the marie itself. On submitting 100 parts of this substance to the action of acid, my brother found that 3 were lost, indicating the presence of 7 per cent, of carbonate of lime.

to look for them. In the course of a month or two, I however hope to send you a few specimens, and shall be most happy if the Geological Society should find them worth their acceptance. J remain, &c.

^entlergare, Nov. 15th, 1817,

L. W. Dillwyn.

Chalk Cliff's near Dover \

41

There is no doubt that this deposit is altogether analogous to that underlying the chalk at Mailing in Kent, in Cambridgeshire, and Oxfordshire, and in the latter counties provincially termed gault . In the collection of the Society specimens of the beds and of the fossils of Folkstone and Cambridgeshire are arranged together as being identical.

ALLUVIUM.

The summit of the chalk cliff near the signal-house is covered by a sand of a bright red colour of various shades, and from 10 to 20, and even in some places, 30 feet in thickness. Here and there it is intermixed with clay, when the red colour which it assumes in its purer state is less brilliant. Here and there also small glistening particles are scattered through the sand, having all the appearance of being scales of mica that have suffered by removal from their original situation, the edges being ill-defined and even ragged. Masses of sandstone, consisting of minute, rounded, and transpa- rent particles of siliceous matter, agglutinated by an ochreous ce- ment of a deep brown colour, lie in the sand, but in one place only, which is very near the signal-house, with any appearance of stratification ; but even in this instance, it is too obscure for deter- mination.

The sand continues of the varying thickness above mentioned, for at least half the way to Dover ; after which it sensibly decreases, and is nearly lost before we arrive at Shakspeare’s Cliff, except that occasionally the thin alluvium lying on that part of the cliff is somewhat coloured by it. The whole surface of the country, for a considerable distance north and north-west of the signal-house, Vol. V. f

42

Mr. William Phillips on the

consists of this sand more or less intermingled with clay. Flints are every where imbedded in it ; but are visible principally as forming a thick but irregular bed lying on the chalk, at the bottom of the sand, and of course are not in situ. These flints perfectly resemble those belonging to the chalk with numerous flints, as well as that with interspersed flints. Those lying at the bottom of the sand, which of course is intermingled with them, are ochreous externally, but are not very much broken : some were incrusted by iron in the state of radiated black haematites. This deposit of flints every where accompanies the red sand along the cliff, and appears to be thickest where the sand is deepest : but this sand is not visible for any considerable distance on the descent of the hill west of the signal-house, and down which the road from Dover to Folkstone descends ; nor on any part of the cliff east of Dover ; nor are flints bearing the same characters, that is to say, which are whole or nearly so, to be seen any where in the alluvium covering the chalk, except beneath the red sand.

.. This considerable deposit of flints bears evidence that, at some remote period, a vast destruction of the upper chalk took place, from causes which it is now impossible to ascertain. We may, however, venture to conjecture, that these cliffs were once covered by the chalk with numerous flints, and that it was swept away by one of those deluges, which there is every reason for believing to have been numerous as well as extensive. Every where along these cliffs is to be seen unquestionable evidence that such a deposit of chalk has suffered extensive luin by water. In receding from the signal-house towards Dover, the red sand is covered by a still newer alluvium, in which lie imbedded small rounded masses of chalk, from the size of a pea to that of a walnut, together with small fragments of flints and of iron-stone ; and this alluvium,

43

Chalk Cliffs near Dover .

when the red sand no longer appears, commonly lies on chalk ruin, sometimes containing flints, and which, in the lower parts, of the cliffs, is often of considerable thickness. It occurs more or less in all such places, from the termination of the red sand, about half way between Folkstone and Dover, quite to the extent of the cliff near Walmer Castle. On the low cliff, for instance S. W. of Dover, the chalk rubble is in some parts fifteen feet thick, and is covered by; alluvium holding flints of about the same thickness. On the higher parts of the cliff, however, the rubble is rarely visible ; and the newer alluvium, including Shakspeare’s Cliff to Kingsdown Bay, rarely exceeds two feet in thickness ; while on those parts of the summits of the cliff, of which the descent is quickest, as well as on the hill on which Dover Castle is built, and on the elevations for some miles east of it, the alluvium is rarely a foot thick. Descending by the Dover road to Folkstone from the signal-house, the alluvium on each side becomes less and less tinged with the red sand ; and before reaching the first chalk opening, it assumes the character of the newer allu- vium, enclosing rounded masses of chalk and fragments of flints, and is very thin. Large and numerous fragments of flint are turned up by the plough in the cultivated land forming a gentle declivity towards Folkstone, and commencing at the bottom of the hollow above which the road descends : — but nearer to Folkstone, in the lower parts of this declivity, the alluvium is very thick. In the field, for instance, which has already been mentioned, as being of the, blue marie covered by alluvium, it is nearly ten feet thick, and con- sists of clay intermingled with chalk, fragments of flint, of which the surfaces are in a disintegrated $tate, and fragments of ironstone.. The same sort of alluvial deposit seems to cover all the intermediate land between that place and Copt Point, wherever there is an operi-

f 2

44

Mr. William Phillips on the

ing, and it prevails along the summit of the blue marie from that point to Folkstone.

Along the summit of the cliff between the signal-house and Dover* and indeed wherever any considerable opening appears in the chalk* deep indentations or gullies are visible in it, which are filled with clay, and which have, as it appears to me with great probability, been attributed to the action of water on its surface.* Even when these appear beneath the sand, they are commonly filled with clay, occa- sionally inclosing flints, the surfaces of which are ochreous. They are not, however, usually imbedded promiscuously in the clay, but are more commonly arranged close to the chalk, forming a thin bed in the form of the hollow which once existed in it. This arrange- ment is visible in almost every instance. One of these gullies, which appears on the side of the road, about half way between the signal-house and the turn of the Dover road towards Folkstone* deserves mention. The road is cut through it to the depth of about fourteen feet : the fissure holding the clay is visible to that depth, but is deeper, and it is about four feet wide. A few feet from the summit, it narrows so as to appear little more than a string of clay for about a foot, when it begins to open again, but not in a line with the upper part ; and the lines of connexion between the upper and lower parts are contorted and curved*

There is one circumstance regarding the upper part of the cliffs that merits notice. Every where along them, and even in the openings beneath the surface inland, except where the chalk with numerous flints prevails, the chalk appears in small angular masses, from an inch or two to a few inches in length and breadth, and this appearance holds for a few feet under the surface \ near to which, it

* Geological Transactions, Vol. I, page 176.

Chalk Cliffs near Dover .

45

it observable, that the angular masses are always the least. In fact, the aspect is what may be termed shattery, and it prevails in so great a degree in the three openings near the turn of the Dover road below the signal-house, and on the side of the conical hill, near to which the road to Canterbury passes, that the chalk there had, at first sight* the appearance of not being in situ.

On comparing accounts of different parts of our great chalk deposit, it clearly appears that there is not every where a perfect uniformity in its strata. No such beds of organic remains as accom- pany the chalk with numerous flints and that without flints near Dover, have been described as oceuring in other places. The chalk marie underlying the chalk without flints in the Isle of Wight* is wanting near Dover ; for the grey chalk underlying it near that place differs from the chalk marie in its general colour, in not pul- verizing by exposure to air, or shivering by the action of frost ; nor does it contain nodules or beds of greater induration, except the thin beds of sandstone already mentioned : moreover, it contains nearly the same organic remains as are found in the chalk above it, while the fossils of the chalk marie in the Isle of Wight, differ from those found in the chalk in every instance but onef. The beds of sand- stone oceuring in the grey chalk of Dover, many however prove it to be analogous with the grey chalk of Cambridgeshire, although it is described by Professor Hailstone as being harder than common chalk, while the grey chalk of Dover is softer. If indeed they be analogous, the chalk without flints is wanting in Cambridgeshire,, for the flinty chalk there reposes on the grey chalk. J

* Geological Transactions, Vol. If., p. 264.

% Ibid Vol. III. p. 243.

t Ibid Vol. I. p. 179.

46 Mr. William Phillips on the Chalk Cliffs near Dover .

In the wolds of Lincolnshire that which is generally uppermost is white, and contains beds of flints. The lower is red. They are regularly stratified; and the latter rests upon a brown pebbly sand without organic remains, consisting of quartz and oxide of iron.*

In the preceding pages, allusion has occasionally been made to certain of the organic remains which I discovered in the various beds and strata composing the cliffs I have attempted to describe. These remains being numerous, and some of them not having heretofore been noticed as occurring in chalk, I have prevailed on J. Parkinson, Esq. the author of “ The Remains of a former World,” &c. to receive the whole, together with an additional number from the green sand and blue marie, collected by my friend Luke Howard, and by him presented to me, with a view to his preparing a description of them for the Geological Society. To this I was impelled, not only because it secured a more faithful description of them than could otherwise be obtained, but also on account of my own inability to perform that task, never having given particular attention to this interesting branch of geological investi- gation. I am far from believing that I was able, during a short stay at Dover, to discover all the varieties of fossils enclosed in the cliffs in its neighbourhood, having found some that were new to me in the last hour of my search. I shall hereafter offer to the acceptance of the Geological Society, all such from amongst them, as may be worthy of a place in its museum.

* Geological Transactions, Vol. III. p3 394.

APPENDIX;

Containing some account of the Chalk Cliffs 3 8$c. on the Coast of France > opposite to Dover.

appearance of a darkish line, extending with a gentle dip

Blanc Nez on the coast of France opposite to Dover, induced the suspicion that it might be owing to the existence of a bed having some analogy to one of those in the neighbourhood of Dover, which have been described as consisting chiefly of organic remains. Another and a darker line, the nature of which Was not at- -first suspected, wras afterwards observed by my friend S. Woods, Esq. Member of the Society, by the assistance of a glass. These cir- cumstances, together with some anxiety to ascertain whether the chalk of the opposite shore possesses the characteristic appearances of that in the neighbourhood of Dover, determined me to visit and examine it with attention.

Between Calais and Sangate, a village five miles on the south-west, the boundary of the sea consists of a range of low banks of white sand. At the western termination of the latter place, the cliff begins to rise, and assumes a new character ; consisting for a con- siderable distance of fragments of chalk-flint, and rounded masses of sandstone similar to those found in the alluvium covering

towards the east, along the middle of the chalk cliff forming Cape

48

Mr. William Phillips on the

the chalk and blue marie near Folkstone, imbedded in a sandy clay of a reddish brown colour. In less than a furlong this kind of deposit is confined to the summit of the rising cliff, which consists beneath of sand lying in thin beds of different colours, rising con- formably,* or nearly so, with the rise of the cliff ; but the general tint of the mass is greenish. The probability that this sand may belong to the plastic clay formation occurred to me, but I dis- covered nothing beyond the general appearance of the sand to strengthen the suspicion.

The junction of this sand with the chalk is not visible, being covered with loose sand and alluvial matter. The one however seems to abut against the other, as shewn in the accompanying sketch (PI. 1. Fig. 2).

The chalk which first appears at the base of the cliff, after passing the sand, is without flints, and exhibits but few traces of organic remains ; it perfectly resembles that which rises at the foot of Shakspeare’s cliff near Dover in softness and in sandiness of aspect, especially just below its junction with a superincumbent stratum, consisting of thin beds of organic remains. This stratum resembles so closely that which lies in the same position on the west of Dover, that no difference in its aspect or composition is visible ; and these two beds are in each place separated by a bed of soft chalk marie, which, having fallen out by exposure, has left a perfectly defined crevice along the cliff. It is this stratum of organic remains which is occasionally observable from Dover, as a darkish line, even without a glass.

Grey chalk soon after rises to view from beneath the chalk without flints or organic remains, and forms the dark line at the base of the cliff observed by S. Woods, Esq. from near Dover : it has all the characters of that which underlies a similar bed on the

Chalk Cliffs on the Coast of France . 49

west of that place. The grey chalk forms the base of the principal part of Cape Blanc Nez, and of the centre of Petit Blanc Nez. A blue marie forms the base of the latter. The junction of the marie with the grey chalk is well defined. The marie has a perfect re- semblance to that which forms the summit of the cliff between Copt Point and Folkstone, contains similar organic remains in great plenty, together with so vast a quantity of iron pyrites, that works have been established near St. Pot for the manufacture of green vitriol.

Small masses of a green sandstone, similar to that lying in the sand which forms the base of the cliff between Copt Point and Folkstone, are scattered along the shore at the foot of the chalk cliff. I expected therefore to find it underlying the blue marie. But the latter, owing in part to the looseness of its texture in dry weather, in part also perhaps to its having been turned over in search of iron pyrites for the vitriol works, forms the whole of the low bank near St. Pot ; between that bank, however, and the sea at low water, lies a large assemblage of green sandstone rocks, many of which appear to be in situ; so that no doubt can be entertained of its underlying the blue marie. The latter terminates near St. Pot, and is succeeded by a loose white siliceous sand for a considerable distance on the west ; but the sand and marie are for some little way intermingled.

While viewing Blanc Nez from the base, it is readily observed, that the stratum consisting of numerous thin beds of organic re- mains which forms its centre, is separated from the superincumbent stratum, which is much whiter and softer, and on which few traces of organic exuviae appear, by a thin crevice, indicating the presence of a bed of chalk-marie. In this softer chalk, dispersed flints are visible, and are readily cognizable by the assistance of a glass,

Vo L. V. G

50

Mr. William Phillips on the

This stratum possesses altogether the characters of the chalk with few flints, which appears in the same relative position in the cliff on the west of Dover.

About twenty feet below the summit of the eastern of the two elevations composing Cape Blanc Nez, run two parallel beds of flints, three or four feet apart : between them there is a crevice, and another about three feet below the lowest bed of flints. In these respects the summit perfectly resembles that of Shakspeare’s cliff, and of the still more elevated cliff on the west of it (see p. 25.) The chalk of the summit of Blanc Nez is however the whitest of the two ; but as, from the roughness of the exposed surface, it mani- festly consists chiefly of organic remains, I cannot hesitate to con- sider it as analogous to the chalk with interspersed flints, which forms the summit of the elevated cliffs next to Dover on the west; especially since the crevices left by the falling out of the chalk-marle, are the same in number and position in both places (see p. 25), and since also another crevice runs a few feet below,, corresponding with that noticed at p. 29 as being the boundary between the chalk with interspersed flints and that with few flints. It ought, how- ever, to be noticed, that the two remarkable crevices which are visible near Dover, in the upper part of the chalk with few flints, (see p. 29,) are not observable in that of Cape Blanc Nez.

On comparing the sketch of the cliff on the west of Shakspeare’s near Dover, with that of the eastern part of Cape Blanc Nez, it will be seen that they are composed of the same varieties of chalk ; and on comparing the whole of both sketches, it will be found that the three miles of coast, commencing about one mile on the west of Sangatte to St. Pot, consist of the same deposits as those which constitute the long range of coast between Deal and Folkstone ;

51

Chalk Cliffs on the Coast of France,

except that the upper part of the chalk with numerous flints is not visible in the former. The dip of the strata appears in both cases to be the same.

On reviewing the many remarkable points of agreement between the cliffs on each side the Straits of Dover, it seems a supposition too reasonable to be ranked among mere hypotheses, that they were once united, and that they were separated at some very remote period by an irruption of the sea, which in all probability washed away the connecting mass ; for the unreasonableness of the popular notion that the two countries were simply rent asunder by some sudden convulsion, will become apparent, when it is further stated, that the chalk without flints on the west of Dover is not less than fifty feet in thickness, while that of Cape Blanc Nez is scarcely thirty feet thick, and that each of the overlying strata at the latter place, is thinner than those near Dover, in about the same proportion ; so that the height of the cliffs on the opposite shores is very different ; — that immediately on the west of Shakspeare’s being not less than 500 feet, while that of Cape Blanc Nez does not exceed 300 feet in height. Hence, supposing the two countries to have been once united, it may be assumed that the several chalk strata became gradually thinner in approaching that part which now constitutes cliffs on the coast of France: hence also, it may be concluded that the country in the neighbourhood of Calais, once constituted a part of that tract which is now termed the chalk basin of London,

G 2

V. Remarks on the Fossils collected by Mr . Phillips near Dover and

Folk stone .*

,By JAMES Px\RKINSON, Esq.

MEMBER OF THE GEOLOGICAL SOCIETY.

[Read January 16 and February 20, 1818.]

My object in the following remarks is to give a catalogue of the fossils collected by Mr. Phillips, and to offer at the same time such desultory observations as the fossils themselves may suggest. As the search for Organic remains was confined to the cliff, the following list must not be considered as a general catalogue of the numerous fossils which these strata are known to contain.

* I take this opportunity of correcting some opinions which I formerly advanced in my paper on the strata in the neighbourhood of London, published in the first volume of the Transactions of the Geological Society. By observing similar pebbles congregated in par- ticular spots, and differing from those of other situations, as the pebbles-pf Woolwich, of the Middlesex gravel, of the Hertfordshire puddingstone, &c., I had been led to conclude, that they might have been formed at the bottom of former oceans, on the very spots, perhaps, in which they are found ; and that their figure might have depended more on chemical than mechanical action. But instructed by the paper of Count de Bournon on this subject, + I now entertain no doubt of the gravel of Middlesex having been derived from the flints of the upper chalk, and of their having acquired their present forms by attrition.

Whilst speaking of the casts of some of the echini, I stated my doubts of their having belonged to the chalk; but this, I confess, was in consequence of my not being then aware of the various species of fossil echini which the chalk contains. I also concurred in the conjecture, that the calcareous spar of the echinite contained no flint ; but I have since ascertained that a considerable portion of silex sometimes permeates the calcareous spar.

f Trait£ complet de la Chau x Carbonatee, &c. par M. le Compte de Bournon.

Mr. Parkinson’s Remarks on Fossils , Zsfc. 53

Fossils of the Chalk with numerous Flints.

Plagiostoma spinosa.

Inoceramus Cuvieri . . in fragments.

Terebratula carnea . . . Mineral Conchology, Tab. xv. fig. 5 & 6.

semiglobosa Tab. xv. fig. 9.

subundata Tab. xv. fig. 7.

Echini Many of the common species of galeae, spatangi, and

cidares, with some of the cucumerine, clavated, and slender muricated spines.

Sponges Various species, in a silicified state, sessile, ramose, or

umbellate, and some attached to a pedicle. Traces of sponge were also perceptible in the chalk.

In this bed were also found various silicified fossils, allied to sponge, but apparently of a more complex structure. That peculiar asperity of surface, by which the presence of silicified sponges and alcyonia may be detected, was observable in many of the flints of this bed. On the surface of some of these flints, collected by Mr. Phillips^ ossiculae of asteriae, and of minute encri** nites, were observed..

Fossils of the bed of Organic remains with interspersed Flints ..

Inocerami ........ Fragments of different species.

Nautilus ........ Specific character not distinguishable.-

Plagiostoma spinosa.

Terebratula lacunosa.

...... lyra .... Mineral Conchology. Tab. cxxxviii. fig. 2,

....... . umbonata New species. Length one inch; width somewhat less..

The larger valve produced one third of its length,, the produced part being sulcated, and marked with five alternate small ridges and depressions. The other part of the margin only slightly crenulated, and the rest of the shell plain, except on the upper part of each valve, where there is a circular uiiibo.- . As in the chalk with numerous flints.

Echini .

54

Mr. Parkinson’s Remarks on Fossils

These are easily found in this chalk, their texture being rendered visible by a ferruginous tint given to their remains. On immersing in very dilute muriatic acid, such parts of this chalk as exhibit, when fresh broken, a rough and granular appearance, a floccu- lent membranous substance is separated, of sufficient tenacity to hang from the chalk for the length of one-sixteenth of an inch.

There are various bodies in this bed, which cannot be regarded either as alcyonia or as sponges, but appear to be allied to them.

Sponges 1 Alcyonia /

Fossils of the Chalk with few Flints.

Vertebrae and bony palates of fishes.

Nautilus Species large, but not distinguishable.

Ammonite Species large, but not distinguishable.

Teredo ? annularis . . . New species. Shell spiral at one extremity, having

the spires detached. As it enlarges towards the other extremity it becomes slightly bowed, and ends in a straight subcylindrical tube. Shell thick to- wards the spiral end, and thin towards the other. At the distance of every quarter of an inch along the shell there are annular risings, the depressions be- tween being smooth, and rising with a circular sweep towards each rising. In its fine spathose substance the shell more resembles a teredo than a serpula, Plagiostoma spinosa . , The shell, in this bed, often retains some of its original

colouring.

pecten In fragments, too imperfect to allow of distinction.

Inocerami Same as in the two former beds.

55

from Dover and Folkstone .

An interesting specimen of an undescribed species of Inoceramus was found in this stratum (PI. 1. fig*. 3.) It is filled by and partly imbedded in flint; suf- ficient, however, is visible to allow of its being* thus characterised.

Inoceramus.

Gen. Char. A free, unequal- valved, inequilateral, eared bivalve.

Hinge, containing* an internal ligament and formed of alternate ridges and furrows, across the lower margin of the eared part.

Inoceramus Lamarckii.

Spec. Char. The valves roundish, slightly indented longitudinally, and having strong round transverse ribs, with inter- posed strim.

Mr. Sowerby having as a tribute of respect distinguished the larger species of this genus as Inoceramus Cuvieri, a grateful consideration of the advantages yielded by the classification of Lamarck has led to the assumption of his name for the designation of the present species.

From the numerous fragments found in this and the other chalk strata, it is evident that many species of this genus existed, differing very much in form and size. Thus in this species the plane of the hinge, nearly agreeing with that of the valves, the shell is nearly equivalved ; but in another species the hinge plates are placed at right angles with the valves, the teeth being disposed perpen- dicularly. Hence in this latter species the larger valve must be involutely curved, to admit of the apposition of the hinge plate of the other, perhaps, smaller and flatter valve. Other specimens show that the hinge plates are dis- posed in various intermediate oblique directions, in other species of this curious shell.

Terebratula The species found in the two former beds.

Alcyoriium A botryoidal, enteriform species, and many other bo-

dies allied to this genus.

The chalk of this bed appears to be distinguished by its greater weight and by its gritty feel, which gives the idea of its being blended with minute particles of sand.

56 Mr. Parkinson’s Remarks on Fossils

Fossils of the Bed of Organic remains without Flints.

Solen ensis ? Traces of a shell resembling it.

Fossils of the Grey Chalk without Flints.

Nautilus . Length 9, depth 6, width 5 inches: whorls oblique.

On the back are small, closely set, transverse, undu- lating striae, which agree in their direction with the contour of the shell. Fossils of this description fre- quently occur in this bed. In a quarry of building stone near to Maidstone, specimens of this fossil are found, which display innumerable variations of this oblique distortion.

? A large, transversely striated, excentric nautilus.

Not knowing whether the forms of this and of the foregoing specimen pro- ceeded from accident, or, as I suspect, from the original and natural formation of the animals, I have not ventured to give them specific designations.

. , . . ? ? A hooked multilocular shell, in form like a hamite,

marked like a scaphite. Outer border rounded, inner flat. The radii arising from the outer part are ter- minated by the union of two or three on the middle of the side, which there form a faint tubercle. One extremity is broken ; the other becomes smooth, contracts into a groove, and terminates in a mouth resembling that of ammonites bilabiatus. Sowerby, Min. Con. No. 32. The flat inner border seems to render this fossil generically different from the hamites ; but this cannot be determined by this im- perfect specimen.

Many of the multilocular shells belonging to the chalk, the blue marl and the green sand, such as the nauti- lus above described, the hamite, &c. are remarkable for the deviations from the symmetry observed in the shells of the same order that are found in the older beds.

Teredo annularis.

51

from Dover and Folhtone .

Inocerami Remains of different species.

Terebratula sulcata.

communis.

Echini Cordated and galeated species, more flattened than

those in the upper beds.

Alcyonia.

Sponges.

In many parts of this bed are perceived small white ramose forms, pervading the chalk, which possibly have been occasioned by some vegetable.

Fossils of the Blue Marie.

A first view of the fossils of the blue marie immediately discovers the remains of animals differing essentially from those of the superior or inferior strata. I have, assisted by Henry Warburton, Esq. compared the fossils of the blue marie from Folkstone with those of the pale marie from West Mailing in Kent, and with those of the Gault of Cambridge, being enabled to do so by the specimens in the collection of the Society; from which it appears that in the arrangement of the collection, these fossils have most properly been considered as belonging to the same bed. Indeed there are few fossils found at one of these three places that are not also found at one or the other of the two remaining places. Similar fossils are also found at the foot of the South Downs near to Lewes in Sussex.

Ammonites splendens . Sowerby.

auritus . . . Sowerby.

..... serratus . . Flattish, inner volutions much concealed. Strong*

slightly bowed prominent rays on the inner margin, soon becoming furcated, and passing to the outer margin, where they form two serrated edges, between which lies the siphuncle. Found also at Cambridge. ..... subplanus. . Nearly flat, the inner whorls much concealed ; rather

umbilicated. Curved rays arising in pairs from tubercles on the inner margin pass together with intermediate rays arising from the middle of the whorls to the outer margin, which is tubereulated on each side, and flat between. Found also at Mailing, and at Lewes.

Vol. Y.

H

58 Mr* Parkinson’s Remarks on Fossils

Ammonites ornatus . . . Rounded ; the inner whorls displayed. Strong flpxuous

costae arising from the inner margin alternate with others from the middle of the whorl, and terminate with those nearly in the middle of the outer margin, close to the siphuncle. Found also at Cambridge. ..... pansus .... Rounded ; the whorls rapidly encreasing. Sharp

ridges, arising furcated from tubercles on the inner side of the whorls, with irregular supplementary ones, pass over the round outer margin, and enclose the siphuncle. Found also at Mailing.

..... lautus .... Flattish ; inside of the whorls set with obliquely dis- persed ridges, terminating in tubercles; frpm each tubercle proceed two or three rays, passing in an elegant sweep to the outer margin, where they unite in pairs and form tubercles, by which the two serrato-tuberculated edges are formed, enclosing the siphuncle. Found also at Cambridge.

Some other species of ammonite are found at Mailing and at Cambridge.

Belemnite A small species, having an inner tube in the alveolus,

being the same as that found at Stutgard. Found also at Cambridge.

Hamites With plain oblique costae. Found also at Cambridge.

. . , . elegans .... Not cylindrical, but flattish. Near to each margin is

a row of tubercles, which are connected transversely by oblique costae, dividing as they rise from the tubercle of one margin, and uniting at the tubercle of the opposite margin. Between these are two intermediate costae, which pass round the whole of the limb, and with two more costae passing from each tubercle over the inner margin, form upon it a closely crenulated surface.

A hamites is also found at Mailing, but it seems to belong to a species distinct from the former two.

Pleurotoma ? Found also at Mailing, with several other species.

Teredo ? Found also at Cambridge.

Inoceramus concentricus. Cordiform, the upper part of each valve having an

extended and twisted neck, so that the beaks are placed obliquely and appear distorted. The surface

from Dover and Folkstone .

59

marked with small rounded transverse concentric risings with corresponding* grooves. Found also at Mailing and at Cambridge* Plate 1, fig. 4.

Inoceramus sulcatus . . In the position of its beaks this shell agrees with the

last. Its surface is marked with acute longitudinal grooves, commencing below the neck, and gradually enlarging as they approach the base. On the surface of the casts are seen small and close transverse rug®. Found also at Mailing and at Cambridge, The large inoceramus (Inoceramus Cuvieri,) belong* ing to the chalk, is found in the blue marie at Mailing and at Cambridge. PI. 1, fig. 5.

Pecten with large rounded cost®.

Nucula similis ..... SQwerby. Found also at Cambridge and Mailing.

.... peetinata .... Sowerby. Found also at Cambridge and Mailing. Terebratula suleata . . Found also at Cambridge.

Ajiomia terebratula . . Linn® us. Found also at Cambridge.

There are also found at Mailing and at Cambridge several species of cancer, an euomphalus, and a conical radiated madrepore. At Mailing a cordated echinus ; and at Cambridge the pentacrinite, a fossil fish, and wood in thin beds. Wood occurs also plentifully in the marie of Folkstone, lying chiefly at the Jtaft* tom of the stratum, on the green sand.

YI* Notes , accompanying a set of Specimens from the Himalay

Mountains .

* By JAMES FRASER, Esq.

OF CALCUTTA.

Communicated by Capt. BASIL HALL, r.n,

[Read 20th February, 4818.]

A FEW facts and general remarks regarding the nature and ap- pearance of the country, where the specimens of rock accompanying this communication were gathered, may assist in conveying some •faint idea of its geological structure, which the meager quantity and style of the specimens, and the utter ignorance of J:heir collector, are little calculated to effect.

It is well known that the Plains of Hindostan through which the Ganges and its subsidiary streams hold their course, are bounded on the north-east by a mountainous tract, which runs the whole way from the banks of the Burrawpooter to the Attock, or chief branch of the Indus, and, crossing that river, spreads out into a less circumscribed and less lofty highland country, the chains of which are connected with many of the chief ridges of Asia, although from our limited knowledge of the geography of those remote districts, their connexion is little understood. Indeed until the late war with Nepal rendered it important to collect information in these quarters, this great range of mountainous country, and the people it is inhabited by, were almost totally unknown to us.

Mr. Fraser on the Himalay Mountains. 61

The whole belt of hills which thus separates Hindostan from Thibet, is perfectly connected and unbroken, running in irregular ridges undivided by any valley of consequence from the one plain to the other. The line of commencement on the side of Hindostan is very distinctly marked; the hills rising from a level, which is even lower than the rest of the country, and perfectly free from rock or stone, at once into sharp ridgy and wild hills which are soon lost in the mountains from which they diverge. The other, or north-eastern side of this great belt, if we may trust to the best information that has been obtained, is less sharply defined; the hills fall more gradually into grassy and green heights and undulations, and end in a plain that slopes gently from their summits. If this is the case, it is consistent with the law which was found to hold good in the indivi- dual ridges, the more broken and precipitous faces of which always pointed to the south-west and north-west.

Of this mountainous tract, the great Himalay mountains form the central ridge, each succession of hills, however irregular may be the direction of their ranges, rising gradually as they approach this great backbone from which their origin can always be traced; but the loftiest of the mountains not included in the Himalay, so far from nearly reaching their height, appear but as their roots; while the latter highly predominating over all, rear their sharp rocky crests, Covered only with eternal snows, to a height almost incredible, in unapproachable, desolate grandeur.

The best observations have fixed the heights of some Peaks of the Himalay at about 26,000 feet above the level of the plains, and these may rise above the sea 500 feet more. Mr. Colebrooke, late President of the Asiatic Society, in a paper to be found in the twelfth vol. of the Asiatic Researches, from a number of observations and various data, lays down the chief peaks of the Himalay moun-

62 Mr. Fraser on the Hlmalay Mountain a*

tains at different heights, from 26,862 feet downwards to about 22,000. Jumnotree, whence the river Jumna takes its rise, and which was visited during the tour in which these specimens were collected, is laid down as 25,500 feet above the level of the sea; the route lay over a shoulder of this mountain, which it wTas conjectured could not be more than three thousand feet lower than its principal peaks.

This stupendous height, exceeding greatly it is believed that of any mountains explored or yet known, cannot but render the range an object of much interest in many points of view; and certainly an accurate knowledge of its structure and the composition of the loftier peaks would be a most desirable acquisition to geological knowledge. Great difficulty must be experienced however in the attainment of this, from the physical obstacles alone that present themselves to the researches of travellers, though these do not form the only ones to be encountered in such a pursuit ; in the mean time the most slender approach toward this object may perhaps excite some interest, and be received with indulgence.

The specimens accompanying these notes were collected in that portion of the hilly region which is contained between the rivers Bhagiruttee (or sacred and principal branch of the Ganges) and the Sutlej ; the former of which takes its rise in the recesses of the Himalay, the latter has its origin on the north-east face, in Thibet, and in its passage to join the Indus cuts its way through this lofty range.

The general line of the mountainous belt is here nearly from south- east to north-west, the sides of which rise abruptly from the sandy plains, as rocks from the sea. A small ridge rising in height from 500 to 750 feet, and in depth extending from three to six miles, runs next to the plains from Hurd war (the debouche of the Ganges from the hill) half way to the Sutlej ; this consists chiefly of sandstone, of a

Mr, Fraser on the Himalay Mountains . 63

soft destructible quality, of indurated clay, and sometimes of beds of rounded pebbles and gravel ; the face which is exposed to the south- west is the most abrupt and rough ; that towards the north-east is more sloping and more covered with wood ; seen from a height above them to the north-east, these low hills resemble a wave of the sea that has rolled by, and in some places shews its broken crest half turned back.

The next range of hills in this part of the country is more lofty, running from 1500 to 4 and 5000 feet in height. It is very sharp, rough, and ridgy, cut into deep shaggy dells, and the crests of the ridges are often so sharp that two persons can hardly stand abreast upon them. The rock is of a hard but very quickly destructible substance ; it seems to consist of strongly indurated clay, with a great admixture of siliceous matter; its colour a greyish brown ; its fracture is generally in straight lines, but preserving no regularity of form, and it soon moulders into dust, of which with vegetable mould the soil chiefly consists.

Just beyond this range rises a mountain entirely of limestone ; at the particular point where it fell under our notice, the division was very distinctly marked by the bed of a river, beyond which limestone usurped the place of all other rock. And though I dare not say that this vein runs universally along the range, yet we traced it subsequently far to the eastward, much beyond the termination of the great mountain, having crossed one or two perennial streams, .and rather stretching away across the hills in an easterly direction. The chief range of limestone we saw was about 7000 feet high, and exhibited an external appearance quite as different from the range on either side as were its materials from theirs.

A large perennial stream marked the division between this range of liipestone and the commencement of schistus. Hitherto the ranges

64 Mr. Fraser on the Himalay Mountains .

had run in a direction nearly parallel to the course of the great mountainous belt. From this point no such regularity was to be detected. A very lofty peak, 10,500 feet above the plains, reared itself above all others, and from this central point branches of moun- tains diverged in all directions that were again connected, after many irregular deflections, with the roots of the Himalay ridge, only disturbed by the great ravines, in which run the chief draining streams that intersect the country. These, when they rise in the snowy mountains, invariably commence their course from east-north- east to west-south-west, and then at some stubborn rock turn sharp to the south-east and continue their course to the plains.

The whole of this mass of mountains consists almost invariably of different sorts of schistus with much mica, and plentifully veined with quartz, of which many large rocks and blocks were seen, having little or no other stone among it. There were doubtless exceptions : we saw at times a sandy granulated stone in masses near large ridges, but not of a character that could be mistaken for granite. The beds of the torrents, however, exhibited blocks of granite that had evidently come from a distance, rounded and mutilated by attrition : and there was also a quantity of a blueish- grey stone, of great hardness, brought to its present position also evidently by the force of the torrent, and evincing no doubt of what materials a portion of its early bed consists. But the predomi- nating rock was schist with much mica, in all varieties of colour and hardness. Twice on the top of lofty mountains we discovered sandstone of a coarse gritty nature ; and once we were surprised to find the hill face under a very high peak, strewed with gigantic masses of a stone formed apparently of sand, mica, quartz, and small stones or gravel, united by a sort of white spar, which had the appearance at first of great hardness, but in reality was easily broken

Mr. Fraser on the Himalay Mountains, 65

and very destructible, the whole mountainside being covered with the pulverized and granulated ruins. Ascending the hill subse- quently, we found the top composed of chaotic masses of the same rock, from among which the earth seemed to have been washed away, but which still gave root to many luxuriant trees of various sorts.

When we crossed the vein of limestone, the difference between the opposite exposures of the sides of the hills struck us forcibly. Each glen or slope with a southern or south-eastern exposure, was brown and arid in its aspect, the hills were round and lumpy, and though very rough, were yet more sloping than the others, while trees were rare, and vegetables of any sort very scantily spread over the thin rocky soil. The northern and north-western exposures on the contrary were invariably most abrupt, deep, and precipitous ; yet their rocky sides were cloathed with rich dark forests of infinite variety ; and the lower parts, though often steep, were covered with a rich plentiful mould which afforded the most extensive and the best cultivation ; the aspect was always green, rich, and various. The pointing of the naked peaks to the north and north-west, tower- ing above all, was too remarkable to pass unnoticed in any instance. This is a principle which may be traced through every range, to the Snowy hills themselves, which are remarkable instances of the general condition, as will be more particularly dwelt on below.

As we approached the snowy mountains and got among their roots, although schist continued to predominate with its quartzose veins, still exceptions became more frequent ; rocks and whole precipices occurred, formed of a very white marble-like stone, which at first we were inclined to believe limestone, or a sort of marble, but we had no means of ascertaining the fact, and were afterwards led to doubt of the existence of calcareous matter in this rock, as we Vol, V.

i

66 Mr. Fraser on the Himalay Mountains,

found varieties apparently of the same sort, which were certainly not marble. On the lofty ridges we now traversed, and under the still loftier peaks that overhung us, we frequently lost schist alto- gether, and found ourselves amid a sort of stone that possessed a semitransparence similar to that of quartz, but which broke perfectly irregularly, was very hard, exhibiting in its fracture a quantity of white shining particles. It was of all colours, grey, blueish grey, red, yellow, and much of a greenish hue. This rock was confined to heights. We lost it the moment we declined into the vallies.

The bed of the river Sutlej, over which the peaks formed of the rock last mentioned rose, exhibited only that various, heterogeneous and undecisive congregation of rocks and stones which usually occu- pies the bed of a large river which flows with much rapidity through a mountainous country, and swelled by many subsidiary streams that yield their tribute of rocks from their parent mountains, as well as of water. The water of the river was here loaded with a fine white shining sand, that was kept suspended by the turbulence of the stream, rendering it turbid, and giving to it at a distance a hue of a light dirty green : this sand was produced by the attrition of the various light coloured rocks it passed through in its course, and were deposited along its bed ; but the native channel here was of schist as usual, and the varieties of colour and consistence were very great.

We penetrated along the glen of the river Sutlej and on the cliffs forming its sides, till we reached the heart of the snowy mountains, the peaks of which rose round us on all sides, and we had here a good opportunity to confirm the observations which we had con- stantly made while viewing them at a distance. The precipitous faces pointed always to the north and north-west, save when acci- dental causes broke the face of a hill differently exposed. All the

61

Mr. Fraser on the Him at ay Mountains .

h ills, particularly the loftiest peaks which are too precipitous to retain the snow that falls on them, are distinctly stratified, the stone itself seemed lamellar and very sharp, and the strata, according to our best judgment, dipped to the north-east at an angle of about 45 degrees or something less. In those faces of precipitous rock that were turned towards us, the stratification was remarkably distinct, even in the sharpest spires. Our distance from these peaks in a straight line could not be greater than 2 to c2\ miles, and we had good glasses which gave us a very accurate view of their structure, but we had no means of discovering the nature of the rock of which they were composed. From several thousand feet below their tops, all sort of vegetation ceases, not a blade of any thing green can be detected, no living thing can be seen, no soil covers the hard bare and scarred cliffs that spire aloft, battered and shivered by the shock of weather and vicissitudes of seasons ; all that is not thus solid rock appears to consist of the moulderings and ruin of these peaks collected in the hollows at their feet.

Such were the snowy hills at Seran, a point within them to which we penetrated, and elevated three miles above the banks of the river Sutlej. On our route, returning to the south-eastward, we held our way for a considerable distance along the bed of a large stream called the river Pabur, which rises far in the north-east among the depths of the Himalay. We found along its banks a quantity of large blocks of a very hard stone, composed of mica, quartz, and a hard grey matter with darker spots, forming a sort of varied grey with a strange striated irregular texture ; this was evi- dently brought here by the violence of the stream, though some of the blocks were of great size : the neighbouring rocks were chiefly schist, some of a good compact quality and tolerably blue, and of

I 2

68

Mr. Fraser on the Himalay Mountains .

quartz in various shapes ; much limestone too was found, hard and compact in substance, generally of a grey colour with more or less tendency to blue, and veined with white in laminse ; when the rock was formed of this it sometimes exhibited a red varied appearance externally, but the fracture was of a grey white; it very often lay in strata, dipping more or less, but irregularly, and the direction could not be ascertained ; the edges of these strata, frequently pro- jected from the hill side.

Of both these stones, specimens accompany this. We also found some of the semitransparent stone mentioned before as being con- fined to the heights of lofty peaks. This region of limestone was certainly the continuation of that forming the lofty mountain early spoken of.

At Jumnotree, the source of the river Jumna, another opportunity presented itself of viewing the Himalay peaks with the advantage of close vicinity. Along the banks of that river, in its progress from the lofty mountain where it originates, we observed the same suc- cession of rock as has been detailed above ; we detected the vein of limestone thus far to the eastward, and then fell into schist and quartz, till we reached the stupendous Jumnotree, which rises in two grand peaks, deeply covered on the south-east and south with perpetual snow, but pointing a precipitous rocky face towards the north-west. We followed the river, now diminished to a rapid mountain torrent into the bowels of the mountain whence it arises from a vast number pf small rills flowing from the snow, which are collected in a pool at the bottom of a steep slope, so that we reached its very origin, and had proof that the rocks of its channel were the genuine pro- duce of the place, or of its close vicinity ; we found here nearly every sort of rock which was observed throughout our tour; two sorts predominated, — that hard grey striated stone first discovered in

Mr. Fraser on the Rimalay Mountains . 69

the bed of the Pabur, very irregular in its fracture, yet here, evidently stratified, and that pure white quartz in large rocks which has been before observed lying in laminae contrary to the general stratification, which it also experiences; and in several places from between these laminae trickles a spring of hot water, which certainly contains some extraneous matter, as it incrusts the rocks around it with a hard sandy ferruginous red substance,* of which as well as of the quartzose rock, specimens are given. Micaceous schist, of various colours, red, blue, grey, and white, is found in considerable abundance, with several varieties that I am unable to particularize, but which only exist in rounded small pieces.

The stratification of the rocks forming the banks of the Jumna in this elevated part of its bed, is most particularly evident; the strata are pretty much undisturbed, and seem always to dip to the north- east at an angle of about forty-five degrees ; this was taken by the compass as nearly as possible, and it pervaded every sort of rock whatever. The lofty peaks forming the crest of the mountain exhibited the same stratification ; and in them it was very clear, the distance being trifling, but enough to blend the smaller parts together.

It is not easy to determine the nature of the rocks forming these peaks, the power of frost and thaw destroys the lower parts, but as there are no glaciers in any part of the snowy hills, it is probable that no partial thaw and subsequent congelation takes place ; and that on the summits of these mountains a continual frost lies, pre- venting the grand operations of this powerful agent combined with the moisture generated by a thaw, in splitting the summits asunder, hut below it may act ; the avalanches have also great power, and no doubt from these causes the ruins of the loftiest peaks where the

* Carbonate of lime, coloured by oxide of iron.

70 Mr. Fraser on the Himalay Mountains .

mountains are so perpendicular, sometimes find their way below; and judging from such wrecks, and from examinations with a good glass, these peaks are formed of the same rocks as are detailed above in the description of the bed of the Jumna, especially the hard grey striated stone, (supposed by a friend to be gneiss), and quartz in laminas veining the faces of the precipices, but these exhibit many colours, red, yellow, and grey, and white, probably from accident of weather or ores, for no vegetation of lichens or mosses can take place at such an altitude.

From Jumnotree we crossed a lofty shoulder of this mountain, including about thirty miles of country, and descended into the bed of the Ganges, (here called Bhagiruttee) which we traced to its source. For a considerable portion of the road we had micaceous schist : at the loftiest elevation we could not be much more than 3000 feet short of the height of Jumnotree ; probably the difference was less. We had passed over much snow, and had experienced much severe fatigue and oppression of the chest from the rarefaction of the air at this great height. One or two of the nearer snowy peaks rose close by us to a considerable height, and from their ruins, the pass below which we were traversing was formed; there was no vegetation whatever, though the time was the 17th of July, and all the lower parts of the hill were rich with verdure. It was a savage scene of desolation and desertness. Here then we had a fair means of judging of the formation of the snowy cliffs. The rocks were apparently similar to those found in the bed of the Jumna; the gneiss predominated much, and there was a good deal of soft micaceous schist, veined with quartz : there were several varieties of a blueish grey stone, I believe whin-stone, some much harder than others; of this and the schist there are specimens. The stratification was here very obvious ; the same pointings 6f the precipitous faces and

Mr. Fraser on the Himahy Mountains . 71

the same direction and dip of the strata, as before noted. The rocks were of various colours, red, white, yellow, grey, black ; and these colours, particularly the white, often ran in strata, but frequently were irregularly diffused. The observations with the glass confirmed our opinion that the summits of the cliffs were composed only of the same rocks as the ruins at our feet.

Our descent to the Bhagiruttee was accompanied by a striking change of scenery, formed by a corresponding one in the nature of the hills. The glen of this river is deeper and darker, and the precipices on either side very far more lofty and terrible than those forming the bed of the Jumna. At this place all appearance of stratifi- cation ceased. The rocks took irregular shapes, and spired into lofty and fantastic pinnacles, and this was more remarkable as we ap- proached Gungotree, the holy place near the source, beyond which it is not practicable to go. The rock in like manner was totally different, and this difference of material produced that in the appear- ance of the mountains. It was here almost universally a hard compact stone, formed of quartoze matter, mica, and a black shining substance, each of these ingredients varying in quantity in different specimens. This stone, I then presumed, to be granite, and have since been informed that I was right. It is found of various hues and appearances, from white to grey, and yellow, with a tinge of red, and much or little spotted with its various ingredients and different tints. For some miles above the point where we descended into the river, micaceous and other schistus still held their place, but for about sixteen miles below Gungotree, nothing was seen but granite.— The lofty mountains above, thinly sprinkled with dark pines, were formed of masses and precipices of this rock, and the river that foamed below had hollowed to itself a trough in the solid stone for its passage* The mountains and peaks surrounding Gungotree are

*12 Mr. Fraser on the Himalay Mountains.

most evidently composed of the same stone ; it never affects stratifi- cation, but in fracture and formation of every kind is quite irregular and amorphous. It shoots up into crags and spires, the sharpness and boldness of which amaze, but it seems to be entirely the effect of chance, and not at all to arise from any disposition of the rock to form such in particular, for there are many forms of a round and bold nature in another style.

It is not intended to describe this spot, awfully desert as it is, nor to depict the dreadful passes by which we arrived at it, taking leave as it were of this world and entering on one of so novel and hideous, though interesting a nature. This was the extent of our travels into the Himalay mountains, and if I may at all trust to the information I received, Roodroo Himalay, the mountain whence the Bhagiruttee flows, is one of the remotest of the whole, and a very short journey would have carried me through the whole range of snow into the precincts of China. Thus the specimens taken at Gungotree may be considered as fair samples of one of the remotest and loftiest of the Himalay range.

Two days journey below Gungotree, on our return, stratification was again observed, and the rocks gradually returned to the former usual sorts, and so continued without any material change ^ill we regained the plains.

VII. Observations on the Vallies and Watercourses of Shropshire and of parts of the adjacent Counties .

By ARTHUR AIKIN, Esq. f.l.s.

MEMBER OF THE GEOLOGICAL SOCIETY, AMD SECRETARY TO THE SOCIETY OF ARTS.

[Read May 1, 1818.]

A Spectator standing on the high ground of Weston Point at the head of the estuary of the Mersey (and thus elevated about 300 feet above the sea), if he directs his view to the south, will seem to have before him a wide and nearly flat valley bounded on the right by the hills on the Welch border, and on the left by those of DeJamere forest. At the end of the valley will be clearly seen, in usual states of the atmosphere, a group of hills considerably elevated and shutting up the view in that direction. This group, even without the assistance of the map, is easily recognized to be the Breiddin hills situated on the southern bank of the Severn, and marks the point where this river, having hitherto run from its source in a north-north-east direc- tion, begins to flow east, verging more and more to the south, till at length it falls into the Bristol channel

The distance between Weston point and the Breiddin hills is almost 44 miles, and as this tract separates the waters which run into the estuary of the Dee from those which run into the Bristol channel, it becomes an inquiry of some importance in the physical geography of England to ascertain its absolute height above the level of the Vol. V.

K

74

Mr. Aikin on the V allies and Watercourses

sea. Data for determining this point with considerable accuracy are afforded by the levels of the Ellesmere canal, the main line of wThich extends between Shrewsbury and Chester, and, though not entirely executed, has been completely surveyed.

The summit line which separates the running waters lies nearly east and west. It approaches in one or two instances within a quarter of a mile of the valley of the Dee, and extends with a con- siderably indented outline from the village of Selatyn a Httle north- west of Oswestry, to the town of Whitchurch. The high level of the canal passes through this latter town, and after a descent of 128 feet joins the Chester canal, which in its progress to tideway in the^ Dee at the city of Chester, descends 170 feet 10 inches; making the elevation of the summit line or water-shed 298 feet 10 inches above the Dee at Chester. By another line between the two extreme points, surveyed but not executed, the difference of level appears to be only 292 feet ; the average of the two gives 295 \ feet, which I think may safely be assumed as nearly approaching to the truth.

If from the same summit level we compute the lockage of the canal to its intended junction with the Severn at Bagley brook, near Shrewsbury, we shall find it to amount to a fall of 140 feet. Hence the height of the Severn at Bagley brook is 1 55 1 feet above the tideway in the Dee at Chester.

In order to compare this result with that furnished by levels taken between Shrewsbury and the Bristol channel, I must first state that the height of the basin of the Shrewsbury canal at this latter town above the Severn at Bagley brook, amounts (according to information furnished to me by Mr. Telford) to 24 feet 4 inches. From this basin to the termination of the canal at Coalport on the Severn, the descent on the whole is 59 feet ; the canal at Coalport is about 16 feet above the Severn ; and the fall of the Severn itself from Coal-

75

of Shropshire and parts adjacent.

port to Gloucester where it meets the tide is 89 feet, according to a series of levels taken by direction of the late Mr. W. Reynolds of Ketley. Hence it appears that the bottom of the tide at Gloucester stands on a higher level by about 16 feet than the tide at Chester, which from the form of the Bristol channel and the well known extraordinary height of its tides, added to the greater distance of Gloucester from the sea, is all very consistent with what might have been a priori expected.

From the high level of the Ellesmere canal, already mentioned, a branch proceeds to the limeworks of Llanymynech, and is thence continued up the vale of the Severn as far as Newtown in Mont- gomeryshire. By combining the measurements thus obtained with the preceding ones, a number of interesting particulars concerning the descent of the Severn during the greater part of its course may be obtained, which I shall proceed to mention in some detail, as the rate of descent of navigable and other streams, although a most im- portant branch of natural geography, has hitherto been almost entirely overlooked.

A number of mountain torrents, rising chiefly on the eastern skirt of Plinlimmon, unite at the town of Llanidloes into one main stream called the Severn, which from that place to its entrance into the plain of Shrewsbury flows north-north-east, winding through a a valley a mile or more across. It receives on each hand the con- tributions of numerous brooks and small rivers, and thus serves as the common drainage into which the superfluous waters of a moun- tainous tract of considerable extent discharge themselves.

From Llanidloes to Newtown, a distance of at least fifteen miles measured along the bank of the river, are several rapids but no per- pendicular fall : the rate of its descent through this space I am un- acquainted with. During the remainder however of its course,

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76

Mr. Aikin on the V allies and Watercourses

namely from Newtown to tideway at Gloucester, a distance of be- tween 160 and 140 miles, not only the entire fall, but the descent through particular portions of this space are very correctly ascer- tained ; and, there being neither weir nor lock nor any other arti- ficial obstruction to the free course of the stream from the source of the river to its mouth, the ambiguity arising in other cases from these causes has no place in the present inquiry.

The Severn continues to be a torrent incapable of navigation to Pool-Quay, about twenty miles below Newtown, in which space it descends 220 feet, being at the rate of 1 1 feet per mile. From, Pool-Quay to Bagley brook at Shrewsbury, a distance of twenty- six miles, the entire fall is 96 feet, being at the rate of 3 feet 8 inches per mile. The descent however through this space is by no means equable; for the river, which while in its own valley has banks only a few feet in height, no sooner gets into the alluvial plain of Shrews- bury than it has the appearance of a ditch bounded by steep banks of gravel from 12 to 20 feet deep, the banks themselves at the same time not being sensibly higher than the rest of the marshy district which is thus intersected. Formerly, when these marshes had not been embanked, the greater part of the flood waters extended them- selves over this open space, and returning slowly into the bed of the river kept up for many days a depth of water amply sufficient for the purposes of navigation. At present however, now that all these low lands are secured by substantial embankments, a heavy fall of rain of thirty-six hours duration swells this part of the river into a turbulent torrent, rising from 10 to 20 feet perpendicular in as many hours, and declining almost as quickly from its greatest height to its usual shallowness.

From Bagley brook at Shrewsbury to Coalport (about two miles below Coalbrook-dale), the entire distance is about twenty-one

77

of Shropshire and parts adjacent .

miles ; the perpendicular descent is 50 feet 8 inches, being at the rate of about 2 feet 5 inches per mile. The greater part of this space is a sandy alluvial tract, terminated by a ridge of limestone, called the Wenlock Edge, the beds of which rising directly opposite to the course of the stream, no doubt contribute in some degree to hold up the water. It is through a breach in this limestone ridge that the Severn escapes out of the plain of Shrewsbury, and at the same time changes its easterly course for one nearly due south, which it retains to its junction with the sea. From Goalport to Bridgenorth, a distance of seven miles, it descends 14 feet 6 inches, being at the rate of almost 2 feet 1 inch per mile. From Bridgenorth to Stour- port, the fall is 41 feet 9 inches during a course of eighteen miles,, being at the rate of 2 feet 4 inches per mile. In the next thirteen miles, between Stourport and Worcester, a fall of 23 feet takes place, being at the rate of 1 foot 9 inches per mile ; and, lastly, from Worcester to tideway at Gloucester, a distance of thirty miles, the fall is only 10 feet, or about 4 inches per mile.

From the autumn of the year 1789 to the end of 1800, a register was kept at Goalport, exhibiting the depth of water in the Severn every day (except Sundays) ; as however no pains were taken to render the banks of the river at this place perpendicular, it is obvious that equal increments in height imply more than equal increments of water, even not taking into consideration the greater rapidity of the stream in times of flood. I shall however make a few extracts from this document* for the purpose of shewing the quickness with: which remarkable changes in the quantity of water discharged take place.

On January 8, 1793, the depth of water was 7 feet ; on the 9th it rose to about 17 feet, and on the next day had subsided to 3 feet..

* See Archdeacon Plymley’s Agricultural Survey of Shropshire.

78 Mr. Aikin on the Valltes and Watercourses

On January 23, 1800, the depth was 5 feet; on the 24th the water had risen to 10 feet ; on the 25th to 12 feet ; from the 26th to the 29th inclusive, the river had overflowed, and probably was from 18 to 20 feet deep ; on the 30th it had fallen to 9 feet ; and on the 31st was at 6 feet.

On January 10, 1795, the depth of water being only 2 feet 4 inches, the river was frozen over ; it continued in this state till the 9th of February, on which day a rapid thaw began ; on the 10th the ice broke up in consequence of the rise of the water ; on the 11th the flood was far above all former marks, and continued so till the 15th ; on the 16th it was already sunk as low as 5 feet.

On March 10, 1800, the depth was 4 feet; on the 14th, 15th, and 16th, the river had overflowed its banks, and therefore was at least J7 feet deep; and on the 16th it had fallen to 5 feet 6 inches.

On the 4th April, 1792, the depth was 6 feet ; on the 5th and 6th the banks were overflowed ; and on the 7th the depth of water was reduced to 7 feet 6 inches.

On April 18, 1792, the depth was 3 feet 6 inches ; on the 19th and for the two succeeding days the banks were overflowed, and by the 23d the river had fallen again to 3 feet 6 inches.

On May 29, 1792, the depth was 3 feet 4 inches ; on the next day the banks were overflowed ; and on the following day the water had fallen to 6j feet.

In the months of June, July, August, and September, no floods occurred during the twelve years that the register was kept.

From October 7th, 1789, to the 9th inclusive, the depth of water was about 6 feet 4 inches ; on the 10th it rose to at least 17 feet, continued at the same height during the next day, and on the 12th had already fallen to 7 feet 6 inches.

79

of Shropshire and parts adjacent .

On the 31st October, 1792, the depth was 5 feet ; on the 1st November the banks were overflowed ; and by the next day the water had fallen to 7 feet.

In December, the water, generally speaking, stands higher than in the other months, the floods remain longer, and are also longer in subsiding. In those cases where the water has been remarkably low for a week or more successively, the river has at length, notwith- standing its rapidity, been frozen over. Of this phenomenon there are four records in the register before me namely, December 2d, 1796, the depth of water being 1 foot 8 inches; on the l'5th of the same month the ice broke, and the water rose to 3 feet ; it continued nearly at the same height till the 22d, when the river again froze over, the depth of water being 2 feet 10 inches, and so continued till the 29th.

On the 27th December, 1798, the depth of water being only 2 feet, the river froze over and continued so till January 15th in the next year. Lastly, on the 21st December, 1799, the depth of water being 1 foot 7 inches, the river was frozen over and continued so till January 4th.

The annual quantities of rain in the district from which the Severn derives its water, Would be a most desirable and indeed almost necessary element in many important deductions from the facts already mentioned : I believe that no such observations have ever been made in this part of the country. It is well known how- ever, that the mountainous Welsh part of this district suffers consi- derably in its agricultural produce from frequent and long continued rains; and from a register kept for six years, (from 1796 to 1801 inclusive,) about eight miles south of Shrewsbury, the annual number of days in which rain fell is 191. The entire district may therefore, upon the whole, be called rainy.

80

Mr. AiKin on the Vallies and Watercourses

From the above mentioned facts it may be concluded that the navigation of a river is very precarious, and liable to long and fre- quent interruptions, even in a rainy climate, when the descent of the water exceeds 3 feet per mile; and that the highest floods run off in a few hours, even when the descent amounts to but 2 feet 5 inches in the same space.

The highest flat land in the county is Corndon marsh, elevated between 900 and 1000 feet above the sea. From this marsh arises a large brook, which after a southward course of five or six miles, arrives at the village of Moor 730 feet above the sea, and situated in the valley in which Montgomery and Bishopscastie are built, and which forms an oblique connexion between the great Montgomery- shire valley in which the Severn flows, and the valley of the Teme. From Moor the ground slopes so equally both east and west that the very uncommon circumstance here occurs of the stream dividing itself: that portion which goes off to the west, being soon joined by other streams forms the river Camlet, which after an indirect and circuitous course of about seventeen miles, falls into the Severn, above Welsh pool, having descended in this space nearly 300 feet, being at the rate of feet per mile. The eastern branch after the junction of a few brooks, forms the Onny river and falls into the Teme at BromfieJd three miles above Ludlow, having run a course of nearly equal length and fall with the Camlet.

The length of the Teme from its junction with the Onny to its termination in the Severn, about three miles below Worcester, is nearly forty-two miles, in which space it falls 367 feet, being at the rate of about 8 feet 9 inches, per mile: nearly the whole of its course is directly opposite to the rise of the strata over which it flows, which, added to the rapidity of its desqent, is obviously the

of Shropshire and parts adjacent , 81

cause of the numerous rapids and rocky ledges, and deep pools by which this river is so remarkably distinguished.

The most rapid part of the course of the Dee is between Corwen and Llangollen, where it falls over ledges of rock, and its channel is Contracted by the near approach of the steep banks. The perpendi- cular fall through the latter six miles of this space, namely from Llandysilio to Pontycysyllte, as estimated from the feeder of the Ellesmere canal, is at least 131 feet, being at the rate of 22 feet per mile, which is by far the steepest descent that I have as yet had an opportunity of measuring. The remainder of its course to tideway at Chester, is about thirty-four miles, during which it falls 174 feet, being at the rate of 5 feet 1 inch per mile. In its natural state it is wholly innavigable, but by means of a weir at Chester, the water i§ held up so as to allow the passage of small boats for two or three miles.

I shall mention only one more river within this district, namely the Stour. It rises about two or three miles north of Wolverhampton, and after a course of twenty-seven or twenty-eight miles falls into the Severn at Stourport. The entire country through which it flows is coarse sand, sandy gravel, or friable red sandstone. Its source is at least 130 feet lower than the basin of the old canal at Birmingham, and therefore it may be considered as belonging rather to a flat country ; its entire fall however is 294 feet, being at the rate of 10§ feet per mile.

If the above facts and the deductions which obviously flow from them are of importance even when relating to a district of compara- tively small extent ; if they tend, as I think they do very materially, to elucidate the physical geography of a country, and by consequence a very interesting part of geological research, namely, the present diversity in the surface of the earth, and the cause of that diversity, it is manifest that the more these observations are extended, the

VOL. V. L

82 Mr. Aikin on the V allies and Watercourses , EsV.

greater will be the accumulation of facts, and the more assured and general the reasonings founded upon them. There are few parts of England and of the south of Scotland which are not either intersected by canals or in which proposed lines of canal have not been surveyed, or the principal watercourses of which have not been levelled. All these by moderate activity on the part of persons resident on the spot may be obtained from canal offices, civil engineers, and land surveyors. The Geological Society seems to offer itself as the natural repository of these documents, being the only Institution by which they can be arranged, and classified, and applied to use, and in which their real value can be duly appreciated. May I, therefore, be per- mitted to recommend the subject to the industry and zeal of the members in general, and especially of those whose profession or local situation give to them peculiar facilities of inquiry.

VIII. On the Form of the Integrant Molecule of Carbonate of Lime.

By DAVID BREWSTER, ll.d. f.b.s. lond. & ed.

MEMBER OF THE GEOLOGICAL SOCIETY.

[Read 3d April, 1818.}

F ROM the facility with which carbonate of lime yields to me- chanical division, its primitive form was determined by Mr. Keir, of Birmingham, and by Assessor Gahn, in Sweden, long before crystal- lography, in the hands of the Abbe Haiiy, had assumed the form and dignity of a science. When this eminent mineralogist found that it refused to be divided in any other direction than by cleavages parallel to the sides of its rhomboidal nucleus, he concluded that the form of its integrant molecule was an obtuse rhomboid. This con- clusion was implicitly adopted by mineralogists, till the Count de Bournon announced the discovery of cleavages passing through the long diagonal of its rhomboidal faces, and maintained that the form of its integrant molecule was a triedral prism with inclined bases, or, one half of the primitive rhomboid divided by a section passing through the long diagonals of two of its opposite planes. Count Bournon acknowledges that in many specimens this cleavage was extremely difficult to be obtained ; that in others it was impossible to overcome the cohesion of the molecules in the direction of the

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84

Dr. Brewster on the

long diagonal ; and that in general the crystals of carbonate of lime which were susceptible of this cleavage, indicated this susceptibility by stria* * * § often very strongly marked and parallel to the great dia- gonals of two of the opposite rhomboidal faces. *

The Abbe Haiiy, in his Tableau Comparatif,')' has given the name of supernumerary joints to the cleavages observed by Bournon, and attempts, without success, to discover their nature and origin, In his observations on the simplicity of the laws of crystallisation, J he resumes the consideration of them, in reply to the observations of Bournon, but he contents himself with stating some variations in their appearance and distinctness, which lead him to conclude that they are merely accidental. §

In this state of the subject my attention was directed to the phe- nomena of multiplied images which are exhibited in numerous specimens of carbonate of lime. These coloured images, which had been examined by Dr. Robison, Benjamin Martin, Mr. Brougham, and Malus, were ascribed by all these philosophers to cracks or fissures in the crystal, by means of which the transmitted light was decomposed into the colours of thin plates ; but I have demonstrated in two papers on this subject|| that the tints of these images are the colours of polarised light produced by thin transparent veins of carbonate of lime passing through the long diagonals of the rhom- boidal planes. These veins are actual rhomboids of different thick- nesses, having their faces placed transversely to those of the

* Traite de Miueralogie, tom. II. p. 1, 2, 3, 4, 385, &c. Lond. 1808.

+ Paris, 1809, page 126.

J Journal des Mines, No. 183.

§ See Bournon’s Catalogue, p. 489, &c. Lond. 1813, where he combats with much in- genuity the opinions of Haiiy.

|| Phil. Trans, for 1815, p.270, and Edinburgh Transactions, Yol. VIII. p. 165.

85

Form of the Integrant Molecule of Carbonate of Lime.

rhomboid which they traverse, and adhering firmly to the two surfaces between which they are interposed. Their existence is always indicated by striae parallel to the long diagonals of the rhom- boidal faces. These striae are indeed the actual edges of the veins, and there can be no doubt that the cleavages observed by Count Bournon are the faces disclosed by separating the vein from the mass which embraces it. In order to determine this point by direct experiment, I took a very transparent piece of carbonate of lime, in which the veins were distinctly seen, and having placed the edge of a knife at the junction of the vein with the mass, I succeeded, by a smart blow, in separating it from the contiguous surface of the rhom- boid. In all other places, except at the edges of the vein, the rhomboid resisted every attempt to cleave it. The two disunited faces were as perfectly polished as the finest gems, and surpassed in distinctness any of the common cleavages of the spar.

That one of the two separated surfaces was the surface of a vein, and the other a surface formed by juxta-position to the vein, was not only obvious from direct examination, but was capable of being proved by various optical considerations. The two images, for example, formed by the half of the rhomboid which contained the vein, were actually depolarised by its action, while the two images formed by the other half, had suffered no change in their polarisation. Another proof, equally satisfactory, is derived from the determina- tion of the laws which regulate the action of crystallised surfaces upon light. By these laws I have been enabled to determine the direc- tion and position of the sides and angles upon any surface of a piece of opaque or transparent carbonate of lime, from which all ti aces of an external crystalline form have been obliterated. In this way the surface of a vein can always be distinguished from the surface con- tiguous to it, and by the application of this infallible test, I have

86

Dr. Brewster on the Form , &c.

ascertained that every cleavage of carbonate of lime in the direction of the long diagonal of the rhomboidal faces, arises from the separa- tion of the surface of a vein from the mass which it traverses.

Hence it follows, that the cleavages obtained by Count Bournon exist only in those specimens which are crossed by interrupting veins, and therefore that the triedral prism is not the form of the integrant molecule of carbonate of lime.

In the course of my experiments on the polarising structure of different minerals, I have discovered similar veins in arragonite, quartz, and other crystals, and, in a very perfect manner, in some of the alkaline and metallic salts. The crystallographer should there- fore be careful, while he is determining the primitive form of these or other substances, that he distinguishes the real cleavages of the homogeneous crystal from those faces which may be presented to him in cases of irregular crystallisation.

IX. Descriptions of some new Fossil Encrini and Pentacriniy lately discovered in the neighbourhood of Bristol .

By GEORGE CUMBERLAND, Esq.

HONORARY MEMBER OF THE GEOLOGICAL SOCIETY.

[Read 17th April, 1818.]

J. HE fossils represented in the accompanying drawings are so beautiful in their forms, and add so much to the history of the encrini, inasmuch as the greater part of them are of new species, that I have thought the figures of them would prove interesting to the Geological Society. The principal part of them has been discovered in the limestone beds on the river Avon near to Bristol, which pass from thence in a direction a little to the south of west to the sea at Clevedon point, at which latter place remains of this class are abun- dant. One of the beds near Clifton, called the black rock, contains parts of stems of encrini in great quantity, and sometimes white circular rings of calcareous spar. It was, I believe, first suspected by Mr. Brackenridge and Mr. Miller, of Bristol, that these latter were the hollow heads of the same animals. On polishing several specimens cut in different directions, there appeared no reason to doubt the correctness of this supposition, although the compactness of the stone rendered it impossible to extricate them.

88

Mr. Cumberland’s Descriptions of

A polished specimen of the limestone of the Black Rock contain- ing one of these supposed heads, is represented in plate 2, fig. 1.

After much research, Mr. Benton found in a crevice in these beds a specimen of one of these heads, which is now in Mr. Miller’s collection. This discovery proved the truth of the supposition, as it was evidently the section of a similar body which caused the marks before mentioned in the limestone. In these crevices, clay was found in which were many detached plates of the upper parts of encrini, apparently of different species, as well as portions of stems or trochitae, as they are usually called; among the latter were several of different species both cylindrical and pentagonal. Since that time, many gentlemen of this vicinity have sought with much activity for similar objects. Their activity has been rewarded with considerable success, as the accompanying drawings will shew. I will now proceed to describe these objects, noticing the spot where each specimen was found.

Plate 2, Fig . 2.

This specimen was discovered by mein the month of August, 1816, in a shelf of decomposing limestone, near Woodspring Abbey Farm, in the neigbourhood of Whorle in Somersetshire. It is to be regretted that these bodies are generally much broken and injured, and it is very rarely that one is found as perfect as the present specimen. Its plates are of a lightish colour, and the limestone that fills it is much harder than that in which it was imbedded.

Plate 2, Fig . 3.

Is another of the same species, from the same limestone at Wood- spring. This species has probably some resemblance in its nature

Encrini and Pentacrini discovered near Bristol. 89

to that in the British Museum, which has been called by Mr. Par- kinson, theNave Encrinus (see Organic Remains, vol.2, pi. 17 fig. 3,) as in this specimen are seen the double openings for the branching arms.

Plate 2, Fig. 4.

In November, 1816, Mr. Page discovered the specimen which is here represented in a fragment of coarse reddish limestone, containing many remains of encrini, at Burrington Combe, twelve miles from Bristol. The specimen is much weather-worn, but appears to have a considerable resemblance to the nave encrinus before noticed. The drawing is of the natural size.

Plate 2, Fig, 5 and 6

Is a fragment exhibiting the interior of one of the same species as the preceding, and from the same place; it was with much diffi- culty cleared from the limestone in which it was imbedded. A magnified representation of the arrangement of the plates is given, fig. 6. These hexagonal marks are darker than the rest of the specimen.

Plate 2, Fig, 7

Is another head, found also by Mr. Page, at the same place. It is particularly interesting, as shewing one of the passages into the branching arms which is perfectly smooth, as well as the whole of the cavity. There is also a small passage entering the stem, which is not visible in the drawing. This specimen differs from the pre- ceding, in wanting the dark hexagonal figures. The size of the drawing is that of the specimen.

Vo L. V.

M

90 Mr. Cumberland’s Descriptions of

• • ' ■ . , . f

Plate 2, Fig. 8.

Found at Burrmgton Combe, in 1817. This drawing is a little larger than the specimen, which is filled with white calcareous spar. The specimen first found, as mentioned page 88, was nearly allied to this, though not of the same species.

Plate 3, Fig. 1.

This fine encrinus was found by Mr. W. Morgan, in Clevedoii Bay, near Walton Castle, Somersetshire, in the autumn of 1817. It is, I believe, of an entirely new species, and shews both the stem and the branching arms in connexion, the arms being nearly closed together. The lower edges of the first plates are crenated in a manner different from any I have hitherto seen.

It was discovered in one of the sandy beds that alternate with the limestone at Clevedon Bay, and when first discovered, only three or four joints of the stem were visible, the rest being concealed by the sandstone. By care and perseverance it has been cleared to the extent represented in the drawing, which is a very little larger than the specimen.

Plate 3, Fig. 2.

This remarkably large specimen was found by Mr. John Morgan, partially exposed and attached to the underside of a bed in the sand- stone. Considerable difficulty occurred in obtaining it, as we were obliged to break away more than a ton weight of stone before it could be safely removed from the rock. Parts of stems of this species are common in this rock, but it is the first instance I am aware of in which the upper part has been found; it is therefoie highly interesting, as adding to the history of this species.

Encrini and Pentacrini discovered near Bristol. 91

Plate A, Fig . 1 and 2.

These two figures represent the two sides of a specimen found by me in September, 1816, near to Clevedon; and in order to make out its detail with accuracy, I have made the drawings somewhat larger than the size of the original. It was found nearly buried in a mass of very hard limestone of a grey colour.

Plate 4, Fig. 3

Is a considerable fragment of another species, a little larger than the original, which I have cleared as well as I could from a silicified stone rolled on the beach. It is interesting, as having the stem.

Plate 4, Fig . 4 and 5.

This specimen exhibits the upper joints of the stem of a penta- crinus, and the commencement of two of what appear to be the arms. It was found in a wall at Shipham, near Axbridge, in Somer- setshire, by Mr. Morgan. Fig. 5 shews the natural size.

Plate 4, Fig . 6 and 7.

This specimen was found in a magnesian sandstone in Clevedon Bay, by Mr. W. Morgan, in August, 1816. Fig. 7 represents the natural size.

1 ' .u - •< ' i ' . ».! i • .v i i \ ■' *1; ■ _ i'. - > cjlSU

Plate 4, Fig . 8, 9, 10, and 11.

This beautiful specimen was found at the same time and place as the preceding, only a very small part of it being visible. Having by much care and labour succeeded in developing it, I immediately made the accompanying drawing. The specimen had so much symmetry and was so beautifully perfect in all its parts, as to appear artificially carved. Unfortunately Mr. Morgan has since injured it

m 2

92 Mr._ Cumberland’s Descriptions of

by immersing it in dilute muriatic acid. Fig. 8 is a side view; Fig. 9 the upper part; Fig. 10 the lower, where the stem, if it had one, must have been attached. Fig. 11 the natural size. None of the joints of the arms are to be seen in this specimen, but one which I have in my own collection, and which I believe to be of the same species, exhibits part of three arms which ramify in the manner usual with pentacrini. This specimen is however too much weather-worn to be engraved.

Plate 4, Fig. 12

Represents a specimen on which are portions of the upper parts of two pentacrini of a scarce species, one of them having a part of the stem. This was also found in the magnesian sandstone at Clevedon Bay.

Plate 5, Fig. 1.

This singular specimen, which I consider to be a species of encrinus, was found by Mr. W. Morgan in August, 1816, in one of the upper strata of inclined gritty limestone, forming the east end of the ridge of rocks in Woodspring bay, near Whorle, in the Bristol Channel. Many fragments and single plates were found at the same time, but no other specimen that shewed the general form. On examining this figure it will be observed that there are three lines in which the plates are set in a regular vertical order on each other, and diminishing in size as they ascend. The other plates are differently arranged in respect to each other, and fill up the intermediate spaces, the number of the intermediate plates in each row increasing as they ascend. This figure exhibits about half of the cup-like form of the animal, and it appears that there must be two more lines of the vertically-arranged plates in the concealed portion. The edges of the plates are deeply serrated. The figure is about twice the natural size.

Encrini and Pentacrini discovered near Bristol . 93

Plate 5, Fig. 2, and 3

Are two views of a specimen in my collection which is allied to the preceding, and was found in the upper part of the same rock, near the soil. It is somewhat decomposed, but is curious from the different sizes of the plates on the two sides.

Plate 5, Fig, 4, 5, 6, and 7.

This is the part of a pentacrinus, which is situated immediately above the columnar stem ; its size is that of a common pea ; and from fig. 4 it will be seen that the stem must be unusually large in proportion. It was taken from an ochreous limestone in a state of decomposition, at Stinchcombe, in Gloucestershire, by Mr. Shrap- nell of Berkeley.

Plate 5, Fig. 8, 9, and 10.

Figure 8 represents a plate of an encrinus, of which several have been collected from the wTeather-worn sides of the black rock at Clifton, and they are often found in the clays that fill up the crevices of its strata ; but hitherto no specimen has been found in this neighbourhood in a more perfect state. In the British Museum there is one which has several plates connected together in their places, and forming the lower part of the body, whence the arms spring. The two following figures, No. 9 and 10, are from the Ashmole collection at Oxford; Professor. Buckland having allowed me to take drawings of them for the better illustration of this subject. Fig. 9, is a plate resembling those found at Clifton, but having the first joint of the arm attached to it. Fig. 10 is from a more perfect specimen. The locality of these is not known.

94 Mr. Cumberland’s Descriptions of Encrini , tsfc*

Plate 5, Fig. 11.

This specimen is from the magnesian limestone at Clevedon, and is remarkable for the appendages which arise from different parts of the stem. These are different in the order of their insertion from those which are seen in the recent pentacrinus, the latter being in regular verticillations. The manner of their insertion is also different, as they appear to be connected with more than one joint of the stem. In our present state of ignorance as to the nature of these bodies, it is desirable to collect all the materials we can, in the hope of being at length able to explain the use and nature of the various parts. At present I am unable to offer any conjecture respecting these side arms.

Plate 5, Fig, 12

Is another specimen from the same rock, consisting of several portions of stems variously bent. These occur very frequently, but we have not, as yet, satisfactorily ascertained to what species they belong.

Plate 5, Fig. 13.

I believe this to be the lower part, or attachment of the fine species, represented plate 3, fig. 1, near to which it was found.

XI. On the Limestone Beds on the River Avon , near Bristol; with a

Society having been pleased to publish in the 4th* volume

beds of the Limestone series on the Avon, beginning from the Hot- wells, and lying above the coal No. 5, I have now completed the

mighty fissure in which that river flows.

This new series consists of above 300 more beds. It will be seen that in a few instances I have been obliged to resort to computation as to thickness, because there are certain spots inaccessible, owing to partial coverings of the soil, but I have been careful not to omit notices of any intervening depositions between the beds, marking as far as I was able the organic substances they contain.

We now proceed from my No. 32 of the first seiies already pub- lished, page 197 of the 4th volume of the Geological Transactions,

description of the Magnesian Beds that repose on their basset edges .

By GEORGE CUMBERLAND, Esq.

HONORARY MEMBER OF THE GEOLOGICAL SOCIETY.

[Read May 1, 1818.]

of their Transactions, the early part of my catalogue of the thirty-two

measurement of the whole connected range, from its junction with the sandstone to its termination at a place called Cook’s folly, always accompanying the towing-path of the river Avon, and marking the

Geological Transactions, Vol. IV. p. 197.

96

Mr. Cumberland on the Strata near Bristol .

No.		Ft. In
33.	Grey and red marles without rubble	. 12
34.	A bed of iron stone divided by cracks	. . 16
35.	Clay ironstone dividing it ...	, . . 1
36.	Marie like No. 33	. 12
37.	Ironstone, a bed (by Mr. Powell’s account)	. . 12
38.	Bed of limestone, reddish	. 15

*38.

39.

40.

41.

42.

43.

44.

45.

46.

47.

48.

49.

50.

51.

52.

53.

54.

This is the heavy mass that separates the little garden of Mr. Jugland on the zig-zag walk up the hill from the large house at the end of the small crescent ; belonging to this face is the White, marley powder.

Second bed of coal, behind a house, No. 6, Hot well-crescent, now covered by buildings Rubble bed in Mr. J ugland’s garden

Limestone, mixed

Rubble

Limestone, grey and red

Horizontal or curved laminae.

Marie, yellow and red and blue, a little schistose and free

from stones

Rubbly, red, schistose, marley, and lying conformable in a

stripe

Limestone bed, grey, free from shells ....

Here we leave the garden and get on to the zig-zag walk.

Rubbly bed not easily seen .... about Bed of compact grey limestone .....

Ditto only separated by a crack . . . . .

Five more beds of limestone (grey) by computation A bed of ditto with anomia productus, of a large size, and

coral subdivided by cracks

Bed of limestone ditto grey ......

A great bed which I could not get at to measure or take specimens from, as the bathing sheds cover its base, and above it is inaccessible, but I take it to be at least 21 feet,

6

5

3

4

4

3 6

10

9

4

3

12

10

10

Mr. Cumberland on the Strata near Bristol .

97

No.

much fractured crossways, and much subdivided but not regularly; under this probably the hot springs rise

55. Limestone bed - . t . .

Separated by three rugged beds, viz.

56. Limestone fractured . . . ....

57. Ditto rotten and parted

58. Ditto more solid

59. Limestone bed regular . . .

60. Ditto . . . . . .

61. Ditto

Separation only recLloam.

62. Ditto cracked and fractured both long and crossways

63. Separation red schistose limestone with corals . . *

64. Limestone bed with anornia, productus small

*64. Separation red marie inclining to schistose, in which I found the euphorbium, a good specimen ....

65. Limestone bed of a reddish tinge, the upper part of a schis-

tose texture where most exposed ....

66. Its upper part decomposing . . . ..

67. Bed of the same but upper part not so much gone A crack with spar and coaly schistose vein

68. Limestone bed, small anornia ......

Ft. In.

2t

2 6

5

8

5

2

2

2

1

3

2 2

if

5

Second series of limestone commencing at the foot of the bold head that tei-minates the first series from Powell’s gardens, just beyond the Hot-well house, including a space of 150 of my paces.

69. A bed of grey limestone in four divisions, nothing intervening 8

70. Bubble and argillaceous marie highly schistose, one inch of

which is pure ochreous marie, and two inches of dark

compact ditto, in all 3

71. Limestone bed ........ 3

*71. A limestone bed with shells, red schistose

72. Ditto, narrowing as it ascends to the horizon . , 18

on a bed of brown schistose marie . . . . 2

VOL. V. N

wH

98 Mr. Cumberland on the Strata near Bristol.

No. Ft. In.

73. Rotten bed with shells ....... 11

bedded on brown clay as above ..... 2

74. Limestone bed, same as above with large productus . 9

beneath brown marie ...... 1

75. Limestone bed 13

on coaly schist ........ 1

76. Limestone, same ........ 1 6

on division of red marie ......

77. Limestone bed 2

under of yellow marie 2

Pipe-clay ........ 1

78. Red schist ......... 5

79. Compact bed of grey limestone without shells or other bodies

divided by a crack only ...... 3

80. A waving vein of dark red limestone, upper part almost

shale, bottom hard and red ..... 8

81. Dark grey limestone with small veins of spar; no organic

remains 2 4

82. A light grey limestone, very compact ; no organic remains . 1 6

83. Ditto .......... 1 1

separation of shale ....... 1|

84. Same limestone, very close and compact at the top of the bed 3 6

85. Limestone bed, having small anomia occurring in the middle 10

86. Ditto with shells ........ 6

87. Ditto 5

88. Ditto all same rock, no division, but the natural cracks all

veined crossways in lines or white streaks of calcareous spar .......... 2

89. Knarly bed shattery, partly solid blocks irregularly cracked

and bent, interspersed with thin solid veins of from one to two inches in thickness, of a coaly colour, efflorescing on exposure to the air, two feet irregular, then one foot shat-

tery and slaty ........ 3 4

90. Limestone, regular amorphous fracture . . . , 4

Separation beneath ©f coaly shale .... 3

Wm

Mr. Cumberland on the Strata near Bristol

99

No.

91.

92.

93.

94.

95.

96.

97.

98.

99.

100.

101.

102.

103.

104.

105.

106.

Limestone bed, compact, inclining to pale brown

Ditto . .

Ditto

Ditto .

Ditto . . .

Then very thin shale division .

Ditto ..........

Then division .......

Limestone bed dark, compact, with some few anomia All irregular in masses of limestone similar to the above, cavernous and cross veined ......

Ft. In.

1

1

1

2

3

8

2

x

-2

15

A division

A regular stripe of hard limestone, with anomia in abundance

Red marely schist

Limestone bed without shells

Red marely schist ..... ^ . f

All in a regular sweep downwards.

55 feet of irregular bending strata divided only by cracks,

making about 15 or 16 beds of limestone. ... 55

All agreeing with No. 100.

Regular strata, with shells of anomia, in part compact and

darker 4

Ditto . . ^ 7

Ditto 4

We now come to beds of grey limestone exposing their broad flat basset edges dipping exactly to the S.S.E. in an angle of 26 degrees, which is nearly the inclination of all the

series 12

Second broad flat ditto

The beds here diminish a little in thickness, as they ascend from the river, both have a few shells and com- mon anomia.

River still north and south, but here half a point to the north. Here a narrow cross vein of calcareous spar 6 inches wide cuts off the beds in a perpendicular direction — it is not quite filled up, and is discoloured by ochreous rust.

4

6

N 2

*)n tC

100

No

107.

108.

109.

110. 111. 112.

113.

114.

115.

116. 117.

118.

119.

Mr. Cumberland on the Strata near Bristol,

Ft. In.

Limestone ditto, but disturbed by fractures every way — the

rock, which has not ever been worked, ascending rapidly. 16 Same as No. 107 . . . . . . . 20

Then follows an irregular bank of Limestone spreading' out like a buttress .... 30

Ditto .......... 6

Ditto . 3

Ditto 8

Ditto .......... 26

Ditto 8

Here another vein of spar, No. 106, cuts off the strata perpendicularly, and 36 feet further from the bound stone marked B. 12. is the end of this third series of beds, where a warm spring, exactly similar to the well spring, issues out 15 feet from the towing-path; but this spring is very small, and flows only during the winter months, from December to March, or April, shrinking with dry

weather, and rising with rains.

Limestone bed ........ 4

Ditto . . . . . . . . . . 2

Ditto . . . * ..... 8

A bold angle containing 6 feet of the upper part of a new 6

stratum terminates the highest part of this lofty series, — and here a newr series begins, the first bed of which is dif- ficult to find, but dll are of the same grey good limestone, and the first at 20 paces beyond the angle northerly is Limestone ......... 6

Ditto, with veins of schist ...... 10

resting on the great broad and long face that abuts on the old lime-kiln — it is a surface of 100 feet upwards and 50 feet across, and dips not as the others do S.S.E. but nearly north and south.

Mr. Cumberland on the Strata near Bristol . 101

This extensive and elevated quarry seems to have been abandoned on account of the faults in its beds, and its being underlaid in a contrary direction to its dip, by the vast and compact bed of lime- stone that slopes from it in an angle of about 15 degrees towards the river, and unequally towards the south-west. A mass I believe without joints and impenetrable. It has shells, and is in part oolitic, and of a lighter tint than the great beds resting on it, some of which are also oolitic, and decomposing in parts. I traced the circle of this quarry and found all within reach good grey lime- stone, with a few anomia only. This point at the lime kiln, like the last described, exhibits a fragment of another bed of some mag- nitude, and irregular in its construction ; in fact it is the under- pinning of the whole mass, and seems to belong to the front of another series whose other beds have sunk out of sight, for from this spot to a bank beyond the capstern placed to assist in warping the shipping coming into port, (being 52 paces,) we find only a gap filled with rubble from the scar, and very red marie, forming a narrow valley, in which are cold springs that often flow profusely into and weaken the bank of the river that here is divested of its rocky boundary.

The curve this working has made from the river towing-path is very considerable, and above it overhangs the hole, called St. Vin- cent’s cave, which once was accessible, but has been lately rendered inaccessible by blowing away the narrow shelf that led to its en- trance.

We are still at the termination of the fourth inclining mass of rocks, each highest at the northern end, forming deeply serrated edges to- wards the north side of the river Avon, and whose summits form an inclining plain, bearing to the south of south-east, on which part the noble village of Clifton is built ; and here we may be allowed

102

Mr. Cumberland on the Strata near Bristol.

to digress, following up the rubble valley where the capstern is, till we come on the plain at Clifton turnpike, in order to point out a very extensive filling up, perfectly horizontal, of magnesian sandy limestone, with a thick under bed of breccia, conformable, containing siliceous fragments, as well as calcareous ones, both bouldered and fractured, with cavities containing spar of both sorts.

The first symptoms we discovered of it are 100 feet north of the road, where a single stone crops out, worn round.

Here follow its Beds .

1. Sandy magnesian limestone.

2. Another bed larger and angular.

3. Another cropping beyond.

4. Another cropping at 400 feet from the gate, which first in-

dicates its horizontal position.

5. A subsidence of the hill, and a long section, the first step of

the flat in which I first found an angular large piece of grey limestone imbedded in the heart of the mass, of which

6. Is a specimen of that limestone.

7. Another from a square block slipped forward on the green

sward shelf and resting on the aggregate.

8. Another more forward.

9. From a vein of limestone penetrating a fissure in the mag-

nesian bed, having stems of encrini.

10. From a bed of coarse breccia under the magnesian bed 15 feet

high, and extending the whole of its length, with great pieces of limestone, organic, oolitic, and plain, — masses of magnesian limestone, quartzose sandstone, soft sand- stone,— and all these both rounded and angular. The cement ochreous.

11. Is from a great bed of limestone, whose basset edges crop

under the magnesian about 10 feet thick*

♦Jl. From its base with organic bodies,

Mr. Cumberland on the Strata near Bristol. 103

12. From the upper surface.

13. From a ferruginous limestone bed highly impregnated with

iron, that cuts off these beds and dips conformably with them, and is cavernous, and laminated, having 20 stripes in its whole thickness of one yard.

14. The upper lamina involving quartz pebbles very small —

this stripe of dark red limestone decomposing, 1 find again at the river side north of the capstern.

We now descend and return to No. 120 on the towing-path, where the grassy valley full of rubble and red ground embraces a space equal to 90 paces, from the lower part of which a small spring issues, as before mentioned, near the capstern on the bank at No. 11, C. B. Bound mark', proceeding 41 paces from this bound-stone we find a small rising bank, a head consisting of ironstone decomposing into a marly shale, brought down from No. 11, 12, and 13 (the beds last marked) of a violet red colour, and like all the other beds before noted, in its dip covered by deeply rufous earth.

Feet

121. A solid bed of grey limestone ..... 6

122. Under it a ferruginous compact breccia without division,

the limestone and iron as it were melted into each other, and very tough, uniting into a ferruginous limestone . 7

The whole an irregular head of 20 paces long, and forming in a sort of twisted small arch upwards dipping suddenly northerly, so as to exhibit a sort of hollow way of about 12 paces broad, into which lay bending down- wards several very narrow stripes of

123. Hornstone, schistous-looking limestone in a stripe of two in-

ches each, capped by grey marie and red earth, and simi- lar stripes of magnesian limestone, and highly ferruginous limestone.

124. A second irregular mass of 20 paces long, capped by a honey-

combed-trap-looking bed : over which is red earth.

Ft.

104 Mr. Cumberland on the Strata near Bristol

No.

125 . A third mass of limestone 44 paces long, first rubbly, then a

mass of limestone that has encrinital remains.

126. Full of small stems of encrinus, &c. .... 5

127. Smaller beds alternating- with red earth for 50 paces, without

organization, and grey the least of them.

128. A darker grey limestone, and more full of organic remains.

(pdf Here on looking up we see the magnesian limestone like a wall, overhanging at the horizon the abutting edges of these inclining strata. Leaving these beds which extend from the Capstern point, is a division of 20 paces of rubbly ground, through which appear small irre- gular patches of grey limestone, the soil all deep red, and they lie sweeping to the horizon, on one point hori- zontal ; in all including a space of 140 paces to the next great iron ring and mooring chain. These broken beds of 16 feet in all, lying in deep red marie, with divisions of beds of coralloids, decomposed and ferruginous, some of red and some of grey limestone.

You see them next broken by a vein of

129. Ironstone, 13 paces from the ring and chain, and one foot

thick, which dips perpendicularly almost to the River.

Next are three limestone beds, each parted by a little red earth and veins of decayed coralloids between some of them 3

130. Another limestone bed cracked both ways, of a red earthy

colour, beginning from the chain and ring mentioned above 8

1 31. A broken bed separated by marie and rubble ... 3

132. The rubble limestone, cap of a bed • • . . 10

133. A mass of cross-fractured limestone, red oolite, within nine

paces of a bound stone marked ( N. 10. C.B.) . . q

From this boundary stone we follow on the towing-

* O

path 51 paces without any thing offering but red earth; then we come to a conformably iuclined thin bed of yel- low marie.

134. A limestone bed grey # jg

Separation red marley soil ..... 3

	Mr. Cumberland on	the Strata near	Bristol .		105
No.				Ft.	In.
155.	Limestone bed solid	.	.	1
	Separation, rubble and broken bed	.	5
156.	Limestone split in three parts	.	.	2
	Vein of grey marie, and rolls of grey limestone, inserted
	loosely		• •	5
1ST.	Limestone			6
	Separation red earth		.	3
158.	Limestone			3
	Separation red earth	.	.	1
159.	Limestone	.	.	2
	Separation red earth	....	•		4
140	Limestone . . .	. ..		1
	Separation shaley	. . . .	• •-		6
141.	Limestone			3	6

142. At this place commences a bold rising- head very rugged, and almost hanging over the towing-path, which rises over a mass of limestone that enters the bed of the river forming a precipice ; this and the three last beds belong to an ir-

regular winding bed of grey limestone beyond, whose whole surface is deeply tinged with a ferruginous coating; measuring by computation, for I could not get safely at it 35

14 3. Under which is a regular bed of ..... 15

144. And another of 18

145. Then another of ........ 6

146. Another with encrinital remains, shells and plates of echini 8

147. One of . 3

148. One of 5

149. One of 15

All these beds are coated with the dark ferruginous crust — all grejr limestone, have been formerly worked — and are separated only by cracks without any intervening body, and end at the boundary stone No. 9, C. B. where they form a winding head of some magnitude, that ter- minates as it were this fourth series by a valley as usual forming another serrated edge of this chain ; and these

Vol. V.

o

Ft. In.

106 Mr. Cumberland on the Strata near Bristol.

No.

are the beds whose basset edges are covered by the mag- nesian limestone in horizontal strata, before noticed ; some small fragments of which may be observed from the spot overlapping the highest bed in view in a thin lamina. Fragments also may be found below, that have fallen in parts.

From the boundary stone ( N. 9. C.B.) to another (BDC. 1810,) 30 paces further on, we may reckon a few broken off beds, underpinning and supporting those above mentioned, as belonging to this series ; after which we commence again where we left off, at the greatest quarry that is now working actively ; these beds are

150. Bed of red limestone . . .

151. Two others

that are covered by rubble, stones, and grass, forming a little mound. Then other small beds, under another swelling mound, covered with rubble and turf.

152. The first one a compact red -

153. Second ^ -

154*. Third |

155. Fourth

156. Fifth

157. Sixth

158. Seventh

15

15

I

3

3

3

6

6

6

Here begins the Great Quarry at boundary stone (B.D.C. 1810.J which ends with the same marked boundary stone, measuring between them 480 paces from working to working, and we shall consider it as the

Fifth Series. This Great Quarry, now working, 159. Commences with a bulky head of grey limestone, containing very rarely the large anomia, but no other shells or encri- nital remains. The further end has some beds of coral- loids, that are very abundant and very much expanded. This bulky head dips at the usual angle, and is the lower-

Mr. Cumberland on the Strata near Bristol .

No.

i6(n

161 V

162 J

163 \

mf

165

166 \ 167/

168

most of seven thick beds, capped by many thin beds, whose seams and coating are ochreous and yellow at the upper* part, where is a small filling up of a sort of magnesian marie, in which hundreds of perfect calcareous crystals lie loosely imbedded, from the size of the tenth of an inch to half an inch. This elevation of beds I take by computa- tion to be above 100 feet ; it is cut off by a slip coated thinly by spar, as most of our slips are -

Next are,

Three great beds of 12 feet each -

Two more subdivided ------

One of

Two of seven - - - - - -

A mass being a perpendicular wall -

Under which appears another slip facing the south with a surface : next are,

Six beds— -coated by a thin regular bed -

Another followed by three other smaller -

Another slip of 20 feet ------

Two more beds 12 feet each -

One bed 9 feet; one 7 feet; one 9 feet ; one 4 ; one 3 feet ; one 6 feet --------

One 4