GEOLOGICAL EXCURSIONS THE ISLE OF WIGHT, AND ALONG THE ADJACENT COAST OF DORSETSHIRE. LONDON : PRINTED BY R. CLAY, BREAD STREET RILL. geological Excursions THE ISLE OF WIGHT, ADJACENT COAST OF DORSETSHIRE : ILLUSTRATIVE OF THE MOS INTERESTING GEOLOGICAL PHENOMENA, AND ORGANIC REMAINS. GIDEON ALGERNON MANTELL, ESQ. LL.D. E.R.S. AUTHOR OP " THE MEDALS OP CRRATIO.V;" '"THOUGHTS ON ANIMALCULES;*' rHEHFIEIjD " That beautiful Island, which he who once sees never forgets, through \hatever part of the wide world his tutu re path may lead him." Sip. Walter Sci.tt's Sur^eorCs Daughtet LONDON HENRY G. BOHN, YORK STREET. COVENT GARDEN. MDCCCXLYII. HIS ROYAL HIGHNESS PRINCE ALBERT, AS A TESTIMONY Of ADMIRATION AND RESPECT FOE HIS ROYAL UIGHNESS's LIBERAL ENCOURAGEMENT OE BRITISH SCIENCE AND ART, AND ARDENT SUPPORT OP EVERY ATTEMPT TO AMELIORATE THE CONDITION AND PROMOTE THE HAPPINESS OE THE HUMAN RACE, THESE UNPRETENDING PAGES ARE, BY PERMISSION, MOST RESPECTFULLY INSCRIBED, BY HIS ROYAL HIGHNESS'S HUMBLE AND DEVOTED SERVANT, GIDEON ALGERNON MANTELL. Chcstbr Square, London. 2091 1 76 PKEFACE. The Isle of Wight is described by Sir Walter Scott, as " that beautiful Island, which he icho once sees, never forgets, through whatever part of the wide world his future path may lead Mm." And if this favoured spot deserve such an encomium from the Poet, and the ardent admirer of beautiful and picturesque scenery, it possesses stronger claims to the attention of the natural philosopher, for the strata of which it is composed, present phenomena of the highest interest, and abound in those " Medals of Creation" which elucidate some of the most important revolutions, recorded in the early pages of the earth's physical history. The geological characters of the Isle of Wight are well known to the scientific inquirer, through the labours and publications of Sir Henry Englefield, Mr. Thomas Webster, and other able observers ; while the beautiful models of the stratification of viii I'UKFACE. the Undercliffj and southern coast, constructed l.\ Captain Tbbetson, and the collection of fossils accompanying them, which arc exhibited in the Polytechnic Institution of London, afford an instructive exposition of the strata and organic remains of this interesting district. Bui notwithstanding these admirable illustra- tions, I may venture to affirm, that the Geology of the Island is but little known or regarded by the majority of the intelligent persons, who every season flock by thousands to its shores, and rapidly traversing the accustomed routes, visit the picturesque localities noted in the numerous hand- hook-, and take their departure, without suspecting thai they have been travelling over a country, rich with the spoils of nature, and teeming with objects of the highesl interest to the instructed observer. Even the inhabitants, with hut a few honourable exc( ptions, manifest an extraordinary degree of apatb.3 in ever} thing relating to the Geology of the Island. In vain will the stranger seek for public collections, illustrative of its physical struc- ture, and fossil remains. In one week, it would be easj for a practical geologisl to collect a more instructive series of specimens, than is contained PREFACE. IX in the Museum of the Scientific Institution of the capital of the Island — Newport. Conceiving that this indifference and neglect may, in a great measure, be attributable to the want of a popular guide to the geological phenomena of the Island, for the well informed, but unscientific visitors, I have attempted to supply the deficiency in the present volume ; which is designed to afford a familiar explanation of the physical structure of the Isle of Wight, and of the adjacent coast of Dorsetshire, and of the organic remains which abound in many of the localities that will come under our notice, in the course of these Ex- cursions. For the convenience of the geologist, and of others who may be desirous of investigating the stratification of the Island in detail, a list is subjoined of the principal works and memoirs hitherto published on the subject, and of which a general review is comprised in the following pages. 19, Chester Square, Pimmco. January, 1847. " If we look with wonder upon the great remains of human works, such as the columns of Palmyra, broken in the midst of the desert; the temples of Pestum, beautiful in the decay of twenty centuries; or the mutilated frag- ■ Greek sculpture in the Acropolis of Athens, or in our own museums, of the genius of artists, and power and riches of nations now passed .may; witli how much deeper feeling of admiration must we consider those grand monuments of nature which mark the revolutions of the Globe; conti- iken into islands, one land produced, another destroyed; the bottom oftheo* a fertile soil; whole races of animals extinct, and the d exuviae of one class covered with the remains of another, and upon the graves of past generations— the marble or rocky tomb, as it were, of a former animated world — new generations rising, and order and harmony established, and a system oi life and beauty produced out of chaos and death ; proving the infinite power, wisdom, and goodness of the Okeat Cause of all tilings'" Sir H. Davy. TABLE OF CONTENTS. Hints for Visitors to the Isle of Wight, p. 17. Description of the Plates, pp. 23 — 30. Figures of Fossil Shells from the Freshwater Tertiary Deposits of the Isle of Wight, PL I. Fossil Shells and Teeth of Mammalia from the same strata, PL II. from the Marine Tertiary Deposits, PI. III. ■ of the Greensand Deposits, PI. IV. do. do. PI. V. from the Wealden Deposits, PI. VI. Plan of the Geological Structure of the Isle of Wight, PL VII. p. 94. Alum Bay, from Headon Hill, PL VIII. p. 146. Displaced Strata at Headon Hill, PI. IX. p. 150. Chalk Cliffs at Freshwater'Gate, PL X. p. 194. Compton Bay, from Afton Downs, PL XL p. 210. Blackgang Chine, from the Seashore, PL XII. p. 234. Vertical Chalk and Flint Strata on Brading Down, PL XIII. p. 252. Wealden Cliffs, in Compton Bay, PL XIV. p. 274. Culver Cliffs, from the Sea, PLXV. p. 336. View of the Dorsetshire Coast, from Worbarrow Hill, PL XVI. p. 370. Lulworth Cove, from the West, Pl.XVLl. p. 376. West Lulworth and Cove, PL XVIII. p. 330. Durdle Cove, PL XIX. p. 386. Geological Map of the Isle of Wight, PL XX. \>. 30. This Map is inserted opposite p. 430. XM CONTENTS. Chapter I. — Introductory, 31. Geological principles, 57. Geology of the South-east of England, 50. Tabular arrangement of the strata, 63. Order ul' superposition of tlie .strata, 65. London eocene deposits, Go. Chalk formation, 66. Wealden formation, 68. London and Brighton J section, 72. Geological mutations, 74. Chapter II.— South-western railway, 77. Strata of the London basin, 78. London clay. mi. Artesian wells, 81. The railway sections, 83. South- ampton station. 86. Southampton to Ryde, SO. Geological structure of the Isle of Wight, 90. Rivers of the Isle of Wight, 'Ji>. From Cowes to Ryde, 97. Chapter III.— Freshwater eocene strata, J00. Binstead quarries, 102. i ,'. rein-deer, 103. Eocene strata at Binstead, 105. Fossil charas, 108. land and river shells, 110. Fossil turtles, 112. Fossil remains of extinct mammalia, 115. Chapter IV.— From Hyde to Culver Cliff, 121. Geology of Whitecliff Bay, 124. The strata and organic remains, 127. Sandown Bay, 132. Red Cliff, 135. Bones of the Iguanodon, 137. t hapter V.— From Ryde, through Newport, to Alum Bay, 139. The river Medina, 140. Newport to Calbourne and Alum Bay, 142. The coast from Ryde to Alum Bay, 145. Headon Hill and Alum Bay, 149. Geology of Headon Hill and Alum Bay, 153. Sequence of Geological mutations, 159. Organic remains, 160. Yarmouth and Lymington, 162. ( hristchurch Bay. 164 strata of Hordwell Cliffs, 166. Hordwel] tip-Mis, in. Chapter VI.— The Chalk formation, 17.;. Subdivisions of the cretaceous '"■ 17; '- Han alk through the Isle of Wight, 176. The upper and lower chalk, 17.S. Chalk and flint, 170. Silicified fossils of thecb.dk. 181. Fossil animalcules, 183. The Firestone, 1*5. The Gait, ind, 189. Summary of the Cretaceous system, 192. Chapter VI] -From Yarmouth to Freshwater Gate, 194. Scratchell's Vertical chalk strata, 199. Shattered flints, 202. The Chalk il configuration oi chalk hills, 206. from ical sections of the southern 213. Pebbles and Shingle, 216. CONTENTS. Xlll Chapter VIII. — From Compton Bay to Atherfield Point, 219. Atherfiehl cliffs, 221. Greensand series, 223. Neocomian, or Atherfield strata, 227. Greensand fossils, 229. The cliffs at Blackgang Chine, 233. IheUnder- cliff, 237. Geological structure of the Undercliff, 240. Fossils of the Firestone strata, 242. Fossil fuci, 247. Southern range of Chalk Downs, 249. Coast of the Undercliff, 251. The coast from Ventnor to Sandown Bay, 257. Chapter IX.— The Wealden formation, 262. Nature of river deposits, 264. Wealden strata of the Isle of Wight, 269. Excursion to Brook Bay, 271. Cliffs from Compton Chine to Brook Point, 272. Brook Point, 277. Petrified trees, 279. Structure of the fossil wood, 282. Chapter X.— Organic remains of the Wealden, 286. Fossil vegetables, 286. Endogenites erosa, 288 Fossil cycadeous plants, 290. Clathraria Lyellii, 292. Fossil shells, 299. Sussex and Petworth marble, 299. Fossil freshwater bivalves, 302. Unio Valdensis, 302. Fossil cyprides, 305. Fossil fishes, 307. Chapter XI. — Fossil bones of reptiles, 309. The Iguanodon, 312. The Hylaeosaurus, 322. Megalosaurus, 323. Cetiosaurus, 324. Streptospon- dylus, 325. Plesiosaurus, 325. Fossil turtles, 326. Imprints on sand- stone, 326. Ancient ripple-marks, 328. Summary of the Wealden formation, 331. The Country of the Iguanodon, 332. Voyage round the Isle of Wight, 335. Chapter XII. — Voyage from Yarmouth to Swanage, 345. Swanage Bay, 348. The Purbeck strata, 353. Fossils of the Purbeck strata, 354. The Portland oolite, 359. Geographical distribution of the strata, 361. Southern coast of Purbeck, 362. Kimmeridge coal, 367. South-west coast, 368. Worbarrow Bay, 375. Lulworth Cove, 376. Fossil trees, 383. Durdle Cove, 385. Chaldon Downs, 389. Ringstead Bay, 390 Pseudo-volcano, 392. The Isle of Portland, 393. The petrified forest, 395. Organic remains, 400. Retrospect, 403. The Oolitic epoch, 404. The Wealden epoch, 405. The Cretaceous epoch, 406. The Tertiary epoch, 407. The Pre-historic epoch, 408. Corollary, 409. List op Works relating to the " Geology of the Isle of Wight, and the Coasts of Hampshire and Dorsetshire," 415. Index of Places, 419. General Index, 421. Geological Map of the Isle of Wight, opposite p. 430. LIST OF LIGNOGRAPHS. tion from London to the Southern Coast of the 1. 01 Wight, p. 71. 2. Diagram of the original position of the Tertiary, Chalk, and Wealden Form jtions, p. ', k 3. [deal Section tV London to the Southern Coast of the Islf. of Wight, p. 75. issil Skull of a Hi i s o Binstead, p. L04. i p] of < ■ • . from Whitecliff Baj , p. li 19. li. Sternal plate of a Fossil fresliu ater Tl'KTLi:, from Binstead, p. 110. on of thi Carapace of a Fossi] Turtle, from St. Helen's, p. 111-. 8. Diagram of the Eocene Strata in Whiteclifi Bay, p. L26. 9. Section from Shanklin to Bembridge Down, across Sandown Bay, p. 1 ! \ \t t.t.Y of the Medina, near Itookley, p. 111. 1 1. Diagram of the Eocene Strata at Alum Bay and Headon Hill, ]i. 155. 12. Fossil Rotalia, in flint, p. I s I L3. Nautilus elegatis, from nearVentnor, p. 186. I 1. Ammonites various, from near Bonchurch, p. 187. 15. Ammonites Mantetti, from near Bonchurch, p. 187. 16. Section from Aeton Downs to Grange Chine, p. 215. ction from Barn's Chine to St. Catherine's Down, p. 215. 18. Section from 1>i;hok POINT to ShALCOMB DOWN, p. 220. 19. Fossil Teeth of a species of Wybodus, from Atherfield, ]). 233 20. Section of the Underi mi i. near Ventnor, p. 256. 21. Leaf of Lonchopieris Manielli, from the Cliff near Brook, p. 287. Stem, of Clathrai Brook Bay, p. 293. 23. Clathraria Lyellii, from Bonchurch, p. 297. 24. Petiole oi I sttii, p. 296. 25. Fossil Gy prides, from Brook Bay, p 2(J. Thigh-bone of tin / tanodon, from Brook Bay, p. 315. II \ I ooth ol thi from Brook Bay, p. : i I T - - tion across Sw w m,i Bay, p. 348. 19. \ polished slice of Pi rbei e Marble, p. 353. 80. A Tooth of the Swanagi Fossil I u,i p. 357. outh-wes! Coasl ofthe Isle oi Pdrbeck, p 31 I or Bays, on the i loasl of Pdrbeck, p. ■'>', I. on of • it. \\ e ' ridi ol Lin wori b I !o\ e, p. 157!'. tion of the Bast side of Lulworth Cove, p. 380. 85. Strata in the (iiii on the Basl of Li lwortb Cove, p. 384. 86. Cliffs from Whitenori Point to Bats-Corner, p HINTS FOR VISITORS Wbt ^jsle of TOt$t. As the tourists from Southampton, Gosport, Portsmouth, &c, generally land either atRyde or Cowes, the following Excursions are so arranged, as to afford an explanation of the geological phe- nomena, when proceeding from either of those towns, to the eastern, or western, extremity of the Island. But as the preliminary sketch of the Geology of the South-east of England (p. 59), conveys a general idea of the structure of the country, it is immaterial at what place the observer may commence his explorations. " Brannons Travelling Map of the Isle of Wight" will be found very convenient for reference ; and " Barbers Picturesque Illustrations,'''' which contains numerous excellent engravings of the most inter- esting scenery, will serve as a beautiful illustrative Atlas to our geological descriptions. B [8 HINTS FOIl TOURISTS. (.'owes. — In tlic vicinity of this town there are no interesting sections of the strata easily acces- sible to visitors, nor any locality rich in organic remains. The blocks of freshwater limestone scattered along the shore, contain the usual fossils of the tertiary lluvio-inarine deposits. Ryde.* — The freshwater tertiary strata are fully displayed in the vicinity of Ryde. A de- lightful walk to the village of Binstead, conducts to several quarries of the limestone which is extensively used as a building material along the northern district of the Island. Fine specimens may here be collected of fossil freshwater shells, (see PL I. and II.); and these quarries are worth visiting again and again, for the chance of finding teeth or bones of mammalia, similar to those which occur at Montmartre, near Paris, and of which some relics have been discovered at Binstead, by Mr. Pratt, and Mr. Prestwich, (see PL II.). From Hyde, the Tertiary strata at Brading, Bembridge, St. Helen's, and White Cliff Bay — the Chalk at Culver Cliffs — and the Wealden deposits at Sandown Bay — may be visited; and afterwards the Firestone, Gait, and * At Ryde information may be obtained as to the best localities, and mode of visiting them, of Mr. G. FoWLSTOKE, Lapidary, 1, Victoria Arcade; who has generally on sale a choice collection of pebbles and other specimens, te Island; man; oi the so called I li ol W igh( arc either German or Scotch agate^ ' HINTS FOR TOURISTS. 19 Greensand, of the Chalk formation at Shanklin, and along the Undercliff. If the direct road from Ryde to the western extremity of the Island is taken, we pass by several quarries at Binstead, on the road-side ; and traverse the interior of the Island, by that pic- turesque spot, Wooton Bridge, to Newport, and from thence to Alum Bay. Grove's hotel, on the summit of the hill, is an excellent resting-place for the visitor desirous of examining the highly inter- esting tertiary strata at Headon Hill, and Alum Bay. From Cowes, by Newport, the same route may be taken. By the steamers we may proceed to Yar- mouth,* which is the best locality for surveying the western parts of the Island. The tertiary strata at Colwell Bay, Headon Hill, and Alum Bay, are within a moderate distance ; and magnificent sections of the Chalk are displayed from the Needles, along Scratchell's Bay to Freshwater Gate (see PI. X.). From the latter place ex- cursions may be made either over Afton and Shalcomb Downs, (see PI. XI. and XII.), or under the Cliff by Compton Bay, to Brook Point, * Mr. Butler, of the Bugle Inn, Yarmouth, an intelligent pracitcal Ornithologist, will afi'ord the stranger the requisite information as to the most interesting localities, and the best means of visiting them. He has often accompanied me in my geological rambles. B l 2 20 PEDESTRIAN TOUR BOUND THE ISLAND. where the fossil forest of the Wealden is exposed. From Brook, the Atherfield Coast-guard station may be visited, where there is a foot-track down the Cliff to the sea-shore, near the junction of the freshwater beds of the Wealden, with the marine strata of the Greensand above ; a locality, which the researches of Dr. Fitton have made classic ground to the geologist. A pedestrian tour round the Island may be accomplished in ten or twelve days, and the prin- cipal localities visited, and a good collection ob- tained of the organic remains peculiar to each formation. The following notes of a trip made last summer by my young friends, the Messrs. Gladstone, of Stockwell, ma)-, perhaps, be useful to some of my readers. ■■ Monday. — By railway from London to Southampton — to by steamer. Examined the blocks of freshwater lime- bore • and collected specimens of Limn: us, (PI. I. figs. ::. ! . Planorbis (PI. I fig. 1 . and other shells. By coach to Newport ; walked to Carisbrook Castle, and after a stroll ihc ruins, examined the chalk pits of Mountjoy, Rode to Calbourne, and visited the quarries of tr> shwater limestone. Walked to Grove's hotel on the summit of the hill, over Alum Hay. In the afternoon strolled to the sea- Bhoreal the fool ofHeadon Hill, and along Alum Bay; collected numerous fossil shells from the freshwater strata at the former, and marine Bhells from the London Clay at the latter place. Wednesday.- Walked over the Down- to Freshwater Gate: ami from thence bj Alton and Mialcomb Downs to Brook Point PEDESTRIAN TOUR HOUND THE ISLAND. 2 I where we examined the fossil forest of the Wealden. Pro- ceeded by Brixton through Atherfield to Blackgang Chine ; the unfavourable state of the weather prevented our reaching Ather- field Point. Thursday. — Proceeded along the Undercliff by St. Lawrence, Yentnor, Bonchurch, and Luccomb Chine, toShanklin ; stopping occasionally to collect specimens, and enjoy the scenery. Went along the shore to Dunnose Point, and gathered numerous fossils: among which were some leaflets of the Wealden fern {Lonchopteris Mantelli), associated with terebratula, and tri- gonice. Slept at Shanklin. Friday. — Walked by the sea-side to Sandown Bay, where we collected many Wealden fossils ; proceeded to Braciing. Saturday. — Visited the Culver Cliffs and White Cliff Bay, and obtained many fossils similar to those from the north-western part of the Island. In the evening walked to Ryde. Monday. — Went to the quarries at Binstead, and collected several good specimens of fossil freshwater shells of the same species as those at Calbourne. Left for Portsmouth ; visited the Dock Yards : to London by the late train." These young gentlemen went unattended, and without any previous knowledge of the Isle of Wight, except what they had gathered from con- versations with me, and returned home with an instructive series of the organic remains of the Island; thus affording a practical illustration of Mrs. Barbauld's admirable story of "Eyes and No Eyes? " To discover order and intelligence in scenes of apparent wildness and confusion, is the pleasing task of the geolo- gical inquirer."— Dr. Paris. DESCRIPTION OF THE PLATES. ORGANIC REMAINS. PI. I. — Fossil shells, from the freshwater Eocene strata of the Isle of Wight, at Headon Hill, Calbourne, Shalfleet, and Binstead. PI. II. — Fossil shells from the same deposits; and teeth of Mammalia, from the quarries at Binstead, near Ryde. PL III. — Fossil shells from the marine Eocene depo- sits, at Alum Bay, Colwell Bay, &c. PI. IV. — Fossil shells from the Greensand strata of the Chalk formation. The Perna Mulled, a very cha- racteristic shell, is here figured. PL V. — Other shells from the Greensand : the large Scapiiite, which occurs in this division of the cretaceous deposits, is represented on a small scale, in Fig. 1 1 . PI. VI. — A few characteristic freshwater shells from the Wealden strata. PL VII. — A plan of the Geological structure of the Isle of Wight ; by Professor John Phillips. '24 GEOLOGY OF THE ISLE OF WIGHT. PI. VIII. — Alum Bay, from Headon Hill. This view is taken from the side of the hill, where the pathway from the summit of the Downs winds along the edge of the cliff, to the foot-track that con- ducts to the sea-shore. In this sketch, the nearly vertical Chalk strata which terminate in the isolated wedge- shaped masses, called " Tin Needles" are alone visible. The variegated tertiary sands and clays, that impart so remarkable an aspect to Alum Bay from the sea, form the vertical face of the cliff, on the left hand of the observer, but are not seen in this sketch. The Isle of Portland appears looming in the remote distance. PI. IX. — Tertiary Strata of Headon Hill, from THE SKA. The face of the cliff here represented, exhibits a natural section of a series of tertiary strata, principally of freshwater origin, which have been thrown down, unconformably to the marine deposits in the adjacent cliff of Alum Bay ; for while the latter are vertical, these are nearly horizontal. The foot-path runs from the Downs to the sea-shore, along the steep slope, form- ing the north side of the chasm that separates Headon Hill from Alum Bay ; its situation is indicated by the two upper figures. PL X. — Chalk Cliffs, on the west of Fresh- water Gate. The face of the cliffs to the west of the landing-place at Freshwater Gate, presents a nearly perpendicular DESCRIPTION OF THE PLATES. 25 section, 200 feet high, of the Upper Chalk, with numerous layers of flint, the strata being highly in- clined. At the base of the projecting cliff is the entrance to a large cavern, formed by the continued action of the surge on the chalk rock. PL XI.- — View of the Cliffs from beyond Compton Chine to Brook Point, as seen from near the base of afton down. The foreground is part of the southern slope of Afton Down, and consists of the flinty chalk. The pathway winds over the brow, and leads to Compton Chine, down which a rude foot-track conducts to the beach. The strata at this point are the cretaceous ferruginous sands, which emerge from beneath the Gait on the west, and are succeeded on the east by the Wealden deposits ; but the face of the cliffs along the westernmost part of Compton Bay is not seen in this sketch. The strata forming the cliffs, shown in this view, are the sands, clays, and shelly limestones of the Wealden. The first point of land jutting into the sea, and ter- minating in ledges or reefs, is the western boundary of Brook Bay ; at the base of the cliff* is the fossil forest of the Wealden. The limits of Brook Bay are shown by the head-land beyond, which is the eastern point. The farthest land on the shore is the cliff near Black- gang Chine. Saint Catherine's Hill rises in the remote distance. GEOLOGY OF THE ISLE OF WIGHT. PI, XII. — BiiACKQAiw Chine prom the sba-shobe, looking north-east. This view presents a fine natural section of the strata composing the Greensand group of the Chalk formation. The highest point in the distance is the escarpment of Saint Catherine's Hill, which is 830 feet above the level of the sea. The upper part of the cliffs is composed of alternating strata of greenish grey sand, and sandstone; from the wearing away of the friable layers, the beds of hard grit become prominent, and appear in this view as very distinct, and nearly hori- zontal, bands of rock. The cliff below the thin bed of ironstone grit, from which the cascade issues, is formed of dark-coloured clay, alternating with ferruginous sand and grit. The long-continued action of the water has produced a deep chasm, or chine, and the stream falls in a nearly perpendicular column from a height of seventy feet, to the base of the cliff, whence it rushes to the sea.* PL XIII. — Vertical Chalk Strata on Brading Down. This sketch shows the vertical position into which the originally horizontal chalk strata, have been thrown, in the central range of downs. The layers of shattered Hint nodules, render the displacement of the strata obvious to tin' most casual observer. ■ The picturesque character of this interesting spot is admirably shown in the views given bj sir Henry Englefleld, and by Mr. Barber; and also in tin- spirit. ci \ i^iuttts on the embellished letter-paper published by the bookseller! in tin- Island. DESCRIPTION OF THE PLATES. 27 PL XIV. — Cllffs of Wealdkn Clays in Oompton Bay. SEEN FROM THE WEST. In this view, the nearest cliffs are formed by the clays, sands, and shales of the Wealden, which constitute the cliffs and ledges, to beyond Brook Point, and almost as far as Atherfield. The inclined position of the strata is well shown in the sketch. The horizontal layer on the top of the cliffs, is an accumulation of drifted materials, composed of gravel, clay, and loam, which in some places is from ten to twelve feet thick, and contains bog-wood, hazel-nuts, &c. The nearest point of land is Bull-face Ledge; and that further to the east, is Brook Point, where the fossil forest forms ledges that stretch far out to sea. The extreme land is the easternmost point of Brook Bay. The view given in Plate XL shows the continuation of the cliffs from beyond Bull-face Ledge to the western point of Brook Bay. PL XV. — Culver Chalk-cliffs, from the sea. In this sketch, (reduced from Mr. Webster's), is shown the eastern promontory of the Isle of Wight, which is a vertical section of the chalk range, that extends from this point, in a westerly direction, right through the island to the Needles. The interrupted lines denote the layers of flint, and distinctly exhibit the highly inclined position of the strata towards the north. The dip varies from 50 to 70 degrees. The distance on the left, is Sandown Bay ; on the right, are seen the eocene strata of White-cliff Bay. 28 GEOLOGY OF THE ISLE OF WIGHT. VIEWS ON THE COAST OF THE ISLE OF PURBECK : Reduced from the beautiful Engravings by Mr. Webster, in Sir Henri/ Englefield's Isle of Wight. PL XVI. — View of the Dorsetshire Coast, from WoRTn Barrow, looking westward. This interesting view oi' the Dorsetshire coast, looking towards the west, is taken from Worth Barrow, a tumulus situated near the summit of a very high precipice of the chalk range. The bay included between the fore- ground and the detached rocks in the sea, is Worth Barrow Bay ; the road down to which, is seen just beyond the projecting point of the chalk cliff. The rocks bounding the bay, are the Purbcck beds, covering the Oolite. The long hill in the middle of the view is the " Sivines back" beyond which is West Lulworth Cove. The Isle of Portland appears in the distance, united to the main land by the Chesil-bank. Weymouth road is indicated by the vessels at anchor. The deep sinuosities made in the cliffs along this coast by the inroads of the sea, are well shown in this sketch.* PI. XVII. — Lulworth Cove, from the west. Lulworth Cove is an almost semicircular bay, formed by the action of the sea, on the vertical strata which constitute this part of the coast ; and in the section thus exposed, the series of rocks, from the chalk to the oolite inclusive, may be traced. A small part of the chalk Henrj Englefield'a Isle of Wigiit. p, is.".. DESCRIPTION OF THE PLATES. 29 cliff is seen on the left of the Cove, and from that to the entrance, where the oolite appears, the intermediate strata occur. The upright rocks in the sea near the foreground, are masses of the Purbeck beds on this side of the bay, while similar blocks appear on the opposite bar. The argillaceous strata on the side of the hill are curiously contorted from lateral pressure. PI. XVIII. — West Lulworth and Cove. The village of West Lulworth is situated in a deep valley, formed by an interruption of the chalk range that extends from Handfast Point, through Corfe Castle, to the coast. The Cove, which has been produced by the erosive action of the sea on the chalk cliffs, is about 1,300 feet in diameter, and vessels of a hundred tons burthen, may at all times remain here in perfect security. The hill immediately above the village, is the ter- mination of the long ridge called the Swine's bach, which is half cut into by the Cove, and presents a lofty precipitous chalk cliff. Saint Adhelm's head is in the remote distance ; the nearer headland, seen above the Cove, is Gad Cliff. PI. XIX.— Durdle Cove. In Durdle Cove, the series of deposits from the upper flinty chalk to the Portland oolite, is exposed in a nearly semicircular bay, walled in by vertical sections of these strata. The chalk appears on the right, forming the high cliff termed Bafs Comer ; and in passing from thence round the bay, the Chalk marl, Firestone, Gait, Greensand, Wealden, and Purbeck strata, may be sue- 30 GEOLOGY OF THE ISLE OF WIGHT. cessively traced to the Portland oolite, which termi- nates the point on the left of the sketch. The natural arched rock, called " Barn Door" at the entrance of the Cove, consists of Portland limestone. PI. XX. — Geological Map of the Isle of Wight. Each of the three Formations, or principal groups of deposits, of which the Isle of Wight is composed, is defined by a separate colour. The pink, denotes the tertiary Eocene strata ; the shaded parts indicate the London clay, and other marine beds, in which but few, if any, freshwater fossils occur. The blue, marks the Chalk ; the chief subdivisions of this formation, namely, the Firestone, Gait, and Green- land, being defined by a difference in the lines of shading. The sienna, indicates the Wealden deposits, which appear in the bays on the east, and w r est, of the pro- montory of the Under-cliff. *»* For the original sketch of the Geological Map. and for the drawings of Organic remains, 1 am indebted to the kindness oi Professor Woodward, of the Agricultural College, Cirencester. Allographs are by Mr. James Lee, of Prince's-square, Kennington ■ ommon. /a i < iknrvau, ****** s PL I. 4 o. /. idiiTMC.) FOSSIL SHELLS FROM Till FRESH-WATER EOCEK J .TRATA O] l n I ISLE "I « I '.I I i DESCRIPTION OF PLATE 1. FOSSIL SHELLS FROM THE FKESH-WATF.I; EOCENE DEPOSITS, Fig. 1". — Planorbis euomphalus ; the underside. 1. — The same shell on the upper side ; from Calbourne. •2 Planorbis cylind/ricus ; Calbourne. 2". — Planorbis obi us us ; Shalfleet. 3. — JAmneus longhcaius ; Binstead. 4. — Limneus fusiformis ; Headon Hill. 5. — Limueu.s maximus ; Calbourne. 0. — Palwlina angulosa; Calbourne. 7. — Bulimus elliplicus ; Binstead. S. — Bulimus eoslellalus ; Shalfleet. These fossil shells occur in the limestone and marls at Headon Hill, and in the quarries at Dodspits, Shalfleet, Calbourne, and Binstead, near Ryde. The Planorbis and Limneus, are the most abundant genera ; and casts of the common species may be seen in profusion in the cream-coloured limestones used in the walls of cottages, barns, ike, in the northern parts of the Island. PI II. UffVWlM-l'lL) (^M^jW^ POS6IL SHELLS ■ •■ ...iw.iw REMAINS, FHOW THE PBE8H-WATEH - 1 u \ i * "i i n i i- 1 i o] wn mi. DESCRIPTION OF PLATE II. FOSSIL SHELLS AND TEETH OF MAMMALIA, FROM THE FRESH-WATI .1. EOCENE DEPOSITS. SHELLS. Fig. 1 Potomomya gregaria j from Headon Hill. This shell 13 described by Mr. Sowerbv in Mineral Conehology as Mya gregaria. The genus Potomomya, (river mussels), comprises those species which inhabit rivers only, and are not found in estuaries and brackish waters. 2. — Potamides concams; Headon Hill. 3. — Melanopsis fusiformis ; Headon Hill. 4>. brevis ; Headon Hill. 5. — Neritina concava ; Colwell Bay. 0. — Melanopsis carinata ; Colwell Bay. 7. — Helix (jlobosus ; Shalfleet. 8 Potamides plicatus ; Headon Hill. 9. ■ — rentricosus ; Headon Hill. MAMMALIAN REMAINS. 10. — Upper canine tooth of Anoplotherium commune ; from Seafield near Ryde. 11. — The grinding surface of an upper molar, of Palaotherwm medium ; from Binstead. 12. — One side of the lower jaw of Palaotherium minus, with five teeth ; from Seafield.* 13", — A tooth of Diehobnne cervinum, from Binstead. 13. — The grinding surface of fig. 13 a . With the exception of the gigantic snail-shell, fig. 7, the fossil shells here delineated are abundant at Headon Hill, and in the clays and mails at Colwell Bay. The Mammalian remains are of excessive rarity, and have hitherto only been found in the quarries near Ryde, and at Headon Hill. * See British Fossil Mammals, p. 323. PL Til. rOSSIL MI1I.I.S FROM THE MARINE EOCENE STIIATA OF THE ISLE OF « [oh r. DESCRIPTION OF PLATE III. FOSSII. SHELLS FROM THE MARINE EOCENE DEPOSITS. Pig. 1. — Psammobia solida, the valves united ; from Headon Hill. 1 °. — The inner aspect of one of the shells of the same. 2. — Corbula cuspidata, the united valves; White Cliff Bay. 2°.— The inner aspect of one of the shells of the same species. 3. — Dilrupa plana ; Alum Bay. This pteropodous mollusk is abundant in the sandstone rock, thai overlies the mottled clays which intervene between the Chalk and the upper Eocene deposits. 4. — Ancitlaria subulata ; Alum Bay. 5. — Panopeea intermedia ; Alum Bay. 6. — Oytherea incrassata ; Colwell Bay. 7. — Cardita planicosta, half the natural size; Alum Bay. These shells are abundant in most of the localities of the marine tertiary clays, both in the Island and on the opposite coast of Hampshire and Sussex. The Panopeea intermedia, (fig. 5), is a well-known shell in the Bognor Rocks; and the Cardita planicosta, (fig. 7), occurs in profusion in the clay at Bracklesham Bay in Sussex. The Oytherea incrassata, (fig. 6), is found in a sandy clay at Colwell Bay, almost as perfect aud fresh as if recently left by the sea, PL IV. HELLS y ROM THE GREEK I D STRATA O] I II I ill "I Wli.lir. DESCRIPTION OF PLATE IV. In-Ml Mll'll- IKliM Till I.nU I K l.l.TI \'-^.\H DEI'mM'Iv Fig. 1 — Corbis corrugata, from the sand-rock, Atherfleld : the figure is one-half tlie size in linear dimensions of the original. 2. — Trigonia caudata . from the sand-rock, Atherfleld. 3 GerviUia anceps; from the Cracker Rocks, Atherfleld. a, denotes the markings of the hinge, which are seen in consequence of the valves being slightly displaced. Tt is represented half the size linear, of the original. These shells are often much larger, and more elongated than in the figure. 4. — Venus striato-costata ; a small shell, common in the Cracker Rocks at Atherfleld ; the figure is twice the size of the original in linear dimensions. 5. — Area TLaulini ; from the sand-rock, Atherfleld. 6. — Tenia Mullet i ; from the lower beds of sand in junction with the Wealden ; Sandown Bay. The figure is hut half the size of the original, a, the structure of the hinge ; by comparing this figure with a, figure 3, the difference of the hinge in the genera Tenia and GerviUia will he recognised. This large and remark- able shell is highly characteristic of the lower beds of the Green- sand. 7. — Venus pun. i , from Shanklin Cliff. PA V. J "--Ml. Mil. I.J.-. PROM THE GREED sand STRATA < > I ■ THE ISLE OP WIGHT. DESCRIPTION OF FLATE V. FOSSIL SHELLS FKOH THE LOWER GREEN-SAND DEPOSITS. Fig. 1. — Thetis minor ; from the ferruginous sand-rock at the base of Slianklin Cliff. 2. — Another view of the same, to show the beaks and hinge-line. 3. — Gryphea sinuata ; represented one-fourth the natural size ; it is often found much larger. From the Green-sand at Shaukliu, Ventnor, Sandown, &c. 4. — Tornatella albensis ; from the Cracker Rocks, Atherfield. 5. — Terebratula sella ; an abundant shell in the sand at Atherfield. 6. — Nucula scapha; from the sand-rock, Atherfield. The three following shells are imbedded in a fragment of the Crackers' Bock, from Atherfield. 7. — Natica rotundata. 8. — Plerocera reivsa. 9 . — Rostellaria Robin aldina. 10. — Cerithktm tmricidatum ; from Atherfield. 11 Scaphites gig as ; from Atherfield. The figure is but one-third the size, linear, of the original. This fossil is often found two feet in length, associated with Ammonites equally gigantic. PL VI. P08IIK IHBLLS FItoM THE WEALDSN STRATA OF THE ISLE OF WIGHT. DESCRIPTION OF PLATE VI. POSSIL SHELLS FROM THE WEALDEN DEPOSITS. Fig. 1. — Unio Valdensh ; from the fossil forest at the hase of the cliff at Brook-point. A young shell ; the figure is two-thirds the natural size in linear dimensions. The uppermost figure gives the inner view of the same shell, to show the hinge and mus- cular imprints. 2. — Taludina elongata, in hard clay, from near Brook-point ; large slahs of laminated clay covered with this species, associated with myriads of C\"prides, are continually laid bare hy the inroads of the sea. 3. — Pahidina Jfi/viorum ; a portion of a weathered slab of limestone, from Compton Bay. 4. — Cyrenu media; in a piece of bluish-grey limestone, composed of thin bivalves ; from Compton Bay. 5. — Potamides carbonarius ; a slab of limestone formed of this species of fresh-water shell ; from Compton Bay. I have found the Unio Yaldensn only in the cliffs, along Brook Bay ; the other fresh-water shells are ecrually abundant in Sandown Bay. The shelly limestones of the "Wealden are often used for paving, in the towns and villages of the Island. GEOLOGICAL EXCURSIONS VL\it 3)slc of imti)t. CHAPTER I. INTRODUCTORY GEOLOGICAL PRINCIPLES GEOLOGY OF THE SOUTH- EAST OF ENGLAND — TABULAR ARRANGEMENT OF THE STRATA LONDON EOCENE DEPOSITS— CHALK FORMATION — WEALDEN FORMA- TION — LONDON AND BRIGHTON RAILWAY SECTION GEOLOGICAL MUTATIONS. Introductory. — Although this work is in- tended to serve as a guide for the tourist un- acquainted with geology^ the general diffusion of the elements of the science, which has, of late years, been effected by our periodical literature, renders it unnecessary to enter at large upon the principles of this department of natural know- ledge. Happily, the time has arrived, when the grand truths relating to the physical history of the globe, have, like those of Astronomy, passed into acknowledged axioms : to remind the well-informed reader that the ancient sea and river-beds which •5C) GEOLOGY OF THE ISLE OF WIGHT. constitute the dry land of the British Isles have not been produced by the effects of a general deluge, would therefore be as derogatory to his understanding, as to explain that the apparent revolution of the sun round our planet is an optical illusion, occasioned by the rotation of the earth on its axis. We may, therefore, assume, that every intel- ligent person is aware that the rocks and stones, and solid mineral masses, composing the dry land, have originally been in a softened or fluid state, either from the effects of water, or from exposure to a high temperature — that the strata are accu- mulations of consolidated mud, sand, and other detritus, the sedimentary deposits of rivers and seas, combined with the durable remains of animals and plants, which lived either on the land, or in the water — that chalk is an aggregation of shells, corals, and amorphous particles of carbonate of lime, so minute as to be undistinguishable by the naked eye, yet easily recognisable under the microscope — that the layers and nodules of Hint have originated from solutions of siliceous earth in heated vapour, or water, that were periodically erupted into tin cretaceous ocean — that the fossils so abundant in the chalk, are the relics of animals and plants thai lived and died in that ancient sea, GEOLOGICAL PRINCIPLES. >7 associated with the remains of a few terrestrial species — that these accumulations of organic and inorganic materials, have gradually consolidated, and subsequently been elevated from the depths of the ocean, by those subterranean forces that are every where in action, and of which the earthquake and the volcano are paroxysmal effects — and that such transmutations of the sea and the land have been, and are, constantly taking place. Geological principles. — From the first moment that dry land appeared on the earth's surface, whatever may have been the materials of which it was composed, the disintegrating effects of atmospheric agents, and of water in motion, must have commenced. The detritus thus pro- duced, transported to the tranquil depths of the ocean, would there subside in successive layers, and a series of sedimentary strata be gradually formed ; and after the creation of living things, the durable remains of animals and vegetables must have become intermingled with the detritus of the land, and imbedded in the deposits then in progress. If the land were sterile, destitute of vegetation, and untenanted by any species of animals, the relics of the inhabitants of the sea would alone be im- bedded; on the contrary, if the sediments were c 58 GEOLOGY OF THE ISLE OF WIGHT. produced by the action of streams and rivers flowing through a country covered with forests, and swarm- ing with animal life, the strata accumulated in lakes and inland bays would teem with the remains of terrestrial and fluviatile animals and plants. The evidence which fossil remains afford of the changes that have taken place in the organic and inorganic kingdoms of nature, in periods antece- dent to all human history and tradition, is, there- fore, of the most positive and unequivocal character. If, for example, a series of strata contains exclu- sively relics of marine fishes, shells, corals, &c, it is obvious that it must have been formed in the sea ; the state of the organic remains, and the nature of the species — whether littoral, i. e. inhabi- tants of shallow waters; or pelagic, i.e. species which lived in the depths of the ocean — affording indications as to the circumstances under which the formation of the strata took place. If an in- termixture of land and fresh-water with marine species occurs, it is evident that rivers and their tributaries brought into the sea the spoils of the land, and the relics of its inhabitants. On the other hand, if an extensive tract is composed of laminated clays, sands, and marls, teeming with terrestrial and fluviatile shells, and containing STRATA OF THE S. E. OF ENGLAND. 59 waterworn bones of land-animals, and branches, leaves, and fruits of trees and shrubs, without any intermixture of marine exuviae, we have unques- tionable evidence that these strata are either the consolidated deltas of rivers, or the sediments of lakes of an extensive continent, which was clothed with vegetation, and tenanted by terrestrial quadru- peds. As the principles involved in these deduc- tions afford an easy interpretation of the geological phenomena of the Isle of Wight, I would fain hope that the subject may be rendered intelligible to the general reader, who now, for the first time, enters upon an investigation of the physical struc- ture of this interesting district. Geology of the south-east of England. — Before we proceed on our excursions, it is, however, necessary to take a comprehensive view of the Geology of the South-east of England ; for as the "beautiful Island," is but a detached mass of strata, severed at some remote period from the main land, a general idea of the nature of the for- mations of which this part of Great Britain is com- posed, will materially facilitate our comprehension of many local appearances, which, occurring as isolated phenomena, would otherwise be difficult of explanation, if not altogether unintelligible. The numerous strata, or accumulations of sedi- c2 60 GEOLOGY OF THE ISLE OF WIGHT. mentary detritus, composing the south-eastern portion of England, are separable into four well- marked natural groups or formations. I, The drift, or Alluvium and Diluvium. — These are the uppermost or superficial deposits, and consist of irregular layers of waterworn and drifted materials, containing the skeletons of extinct species of colossal herbivora — as the mastodon, mammoth, rhinoceros, hippopotamus, elk, deer, &c, and in certain localities of the remains of Carni- vora, Rodents, &c, some of extinct, and others of species still existing in these islands. These beds, which rarely exhibit indications of tranquil depo- sition, are heterogeneous layers of debris, winch have either been transported by the sea, or by river currents, or by floating ice, or driven by waves of translation occasioned by elevations of the bed of the ocean, into estuaries, bays, and creeks. II. Tertiary eocene* formation of the London basin. — This series is chiefly composed of layers of stiff, dark bluish-grey clay, abound- ing in marine shells, and having strata of sand mid gravel in the upper part, and sand, gravel, and mottled clays in the lower part, with freshwater » Eociv , a term applied by Mr. Lyell to the earliest tertiary formations. MedaU of Creation," vol. i. THE CHALK FORMATION. 61 shells and plants in some localities ; the total thickness amounts to several hundred feet. The fossils are almost entirely of extinct species. III. The chalk formation. — The white cal- careous rock called chalk is well known ; but in the nomenclature of Geology, the term Chalk for- mation comprises not only the limestone that extends over so large an area in the south-east of England, but also numerous beds of sand, sandstone, claj^, and limestone, that are very dis- similar in their appearance and chemical characters, yet so far correspond in the nature of their organic remains, as to show that the entire group was formed during the same geological epoch. In other words, that the sea and land, and their in- habitants, underwent no essential change during the period in which the entire series was deposited : it therefore constitutes, in geological language, but one formation. The organic remains of the Chalk are essentially marine ; but in some localities drifted wood and plants, waterworn bones and teeth of terrestrial reptiles, and other spoils of the land, are found associated with the shells, corals, and fishes of the cretaceous ocean ; and these have evidently been transported by rivers and streams into the bed of the sea. The fossils are, with but very few excep- 62 GEOLOGY OF THE ISLE OF WIGHT. tions, of extinct species and genera, and dissimilar to those of the tertiary strata. IV. The wealden formation. — This is an extensive series of clays, sands, sandstones, and shelly limestones, upwards of 1,000 feet in thick- ness, characterised by the entire absence of marine fossils, and the abundance of river and lacustrine fishes, crustaceans, and shells, intermingled with bones of enormous land-reptiles, and terrestrial plants and trees ; the whole group having evidently been a vast delta. The essential characters, of these formations, and of the subdivisions into which they are separated, are concisely expressed in the annexed table. OF ENGLAND, Distribution in thclsle of Wight. si Fissures in the tertiary and cre- taceous strata; the subsoil in some localities. | The northern parts of the Island. The freshwater beds prevail along the northern shore, from Headon Hill to White-cliff' Bay; the marine from Alum Bay, along the northern flanks of the chalk hills, to White- cliff Bay. The Downs from Culver Cliff to the Needles ; and from St. Ca- therine's to Shanklin Down. The UnderclifT and the south- n [ em coast are formed by the lower subdivision » of the chalk ; except in the two fol- lowing localities. Sandown Bay, between the Greensand of Red-cliff and Shanklin Chine. Brook Bay s I and along the coast, between the Greensand of Compton Bay and of Atherfield Point. C 3 TAP.n.AK AKKAMiEMFAT (if TI11C STRATA "F THF, surTU-EAST (IF EXKLAXn. A >e .h. m {«;,■»;•;;:;;■■ :■;;::;:■,•;;■;,;-: CHRONOLOGICAL SEQUENCE. 65 Order of superposition. — Such is the chrono- logical sequence of the formations of the south- east of England; in other words, these several groups of marine and freshwater sediments, have been deposited in the following order: — 1st. The Wealden : the delta of a river, composed of the spoils of a vast continent, of which no other vestiges remain. These strata rest upon a marine formation called the Oolite, but which does not come within the scope of our present observations. 2dly. The Chalk : the bed of an ocean of great extent, deposited upon the Wealden. 3dly. The Tertiary Eocene Formation : accumulated in de- pressions or basins on the surface of the Chalk.* Now, as each of these formations is many hun- dred feet in thickness, it follows that the inferior strata would for ever have been concealed from observation, had the original order of super- position remained undisturbed. But not only portions of each of the upper series appear on the surface, but even the lowermost deposits form an extensive tract of country which is diversified by hills and valleys, and constitutes one of the richest agricultural provinces of the British Isles. This distribution of the strata has originated from the displacements occasioned by those disturbing forces which elevated above the waters the ancient ocean * With the view of simplifying the subject, the Drift, or superficial alluvial deposits, will not be especially alluded to in these excursions. 66 GEOLOGY OF THE ISLE OF WIGHT. and river beds, and converted them into dry land. The nature of those changes we now proceed to consider. London eocene formation. — The London Tertiary or Eocene deposits form the area on which the metropolis is situated, as well as the sur- rounding country to a distance varying from ten to twenty or thirty miles. Around these strata the Chalk presents a distinct boundary of hills on the south, west, and north ; but on the east the range is broken, and through this chasm the Thames winds its way to the sea. From this geological character of the metropo- litan district it results, that all the lines of rail- way that proceed from London, traverse for the first ten or twenty miles beds of clay, loam, and loosely aggregated sand and gravel ; hence the numerous slips that have taken place in the embankments at New Cross, Wandsworth, Han- well, &c. ; and in all these lines it is obvious from the nature of the soil and the steepness of the cuttings, that similar subsidences will again occur. Chalk formation. — The next geological feature observable along the London railways, is the. Chalk, which is invariably traversed by steep cuttings and tunnels; as for example in the South- eastern line, from Croydon to Merstham; and in THE CHALK FORMATION. 67 the Great Western, from Maidenhead to beyond Wallingford. After passing through the Chalk, the lower subdivisions of the Cretaceous formation, viz. the Marl, Firestone, Gait, and Greensand, successively appear ; and these are followed by the Oolite on the Great Western and Birmingham lines, and by the Wealden on the South-eastern ; but on the South-western, by which we shall travel to Southampton, the Chalk and the Tertiary strata only are exposed. The Chalk, as is well known, constitutes the pre- valent geological feature of this part of England. The upper or white chalk rises into chains of hills, called downs, which are remarkable for their smooth and undulated outline, and form a well defined geographical boundary. The southern range extends from Hampshire, through Sussex to the sea-coast, terminating in the bold promontory of Beachy Head ; the northern passes from Hamp- shire through Surrey and Kent to the British Channel, and ends in the line of cliffs near Dover. The lower cretaceous strata compose ranges of hills less uniform in elevation and extent, which skirt the inner margin and escarpments of the Downs, and in some parts of Surrey and Western Sussex attain an altitude equal to that of any portion of the North or South Downs. 68 GEOLOGY OF THE ISLE OF WIGHT. Leith Hill, in Surrey, is nearly 1,000 feet above the level of the sea.* Wealden formation. — The Wealden deposits fill up the whole of the area between the North and South Downs, and are bounded on the west by the cretaceous strata of Hampshire, and on the east by the British Channel ; they form the sea- coast from Pevensey in Sussex to Hythe in Kent. Looking down upon the Wealden, from any of the heights that command a view across the district, and of the distant boundary of chalk downs — as for example from Leith Hill, or from the summit of the escarpment of the North Downs, near Reigate j- — the observer might suppose that these freshwater sediments occupy a depression or basin on the surface of the chalk, and that the strata of the North and South Downs extend under the whole of the deposits in the intervening area, as in the following diagram : — * For details, vide a " Memoir on the Geological Structure of the Country seen from Leith Hill," in the County History of Surrey, published by Mr. Ede of Dorking. t See " Wonders of Geology," vol. i. p. 342. STRUCTURE OF THE S. E. OF ENGLAND. 69 Several writers on geology have fallen into this error, and indulged in the most absurd speculations accordingly. A slight examination of the relative position of the respective strata where in contact, is, however, sufficient to show the incorrectness of this hypothesis, and to prove that the Wealden extends under the Chalk, both on the north and south, as shown in the subjoined plan, and in lignographs 2, 3. It is therefore certain that the cretaceous formation was deposited upon the Wealden ; and it is ecpially clear, that it origi- nally extended, not only over the entire district between the North and South Downs, and was connected on the west with that of Hampshire and Wiltshire, but also that it filled up the space now occupied by the British Channel, and was united with the chalk of the Isle of Wight and of the Continent. South Downs. Chalk Formation. North Downs. Wealden Formation. If we assume the original position of these ancient fluviatile and marine formations to have been as represented in the above diagram, and sup- pose that the middle portion of the chalk, a, a, were 70 GEOLOGY OF THE ISLE OF WIGHT. removed, so as to expose the underlying Wealden, we should have chalk downs on the south and north, with an intervening area of the inferior beds denuded or laid bare by the removal of the superincumbent strata. Such, in fact, would have been the actual state of the South-east of England, if the changes here contemplated had been pro- duced by the wearing away of the chalk from the underlying fluviatile sediments, and the horizon- tali ty of the strata had been maintained. But a careful examination of the phenomena under review, shows that the removal of the chalk was not effected by simple denudation, but by a force acting from beneath, which elevated the entire series of tertiary, cretaceous, and wealden forma- tions in a line bearing a general direction from east to west; by which movement an anticlinal* position has been given to the strata on each side the axis of greatest elevation. This axis is denoted in the physical geography of the district by the chain of hills called the Forest-range, that extends from the sea-coast at Hastings through the interior of the country by Crowborough, the highest elevation, to Loxwood, west of Horsham, where the Wealden disappears beneath the overlying green- AiiIk i.i.al— inclined towards each other, like the ridge-tiles of the roof of a house. SECTION FROM LONDON TO THE ISLE OF WIGHT. 71 3 q \ * sand strata. In all transverse sec- tions of the district, i. e. from north to south — whether on the coast, or | inland — the strata on the north of the | | central line dip northward, or rather £ 1 to the north-east, and those on the o * south to the south-west. There are, of a course, many local variations in the * inclination of the rocks, and nu- h merous lesser anticlinal axes, or S saddles, as they are provincially £ termed, and also longitudinal ridges and corresponding valleys, running parallel with the principal line of the disturbing force. In consequence of this displace- ment of the strata, a section drawn from London through the North Downs, across the Wealden district, through the South Downs, and car- ried on to the southern coast of the Isle of Wight, would present the arrangement shown in Ugn. 1. In this lignograph are represented the tertiary of the London basin resting on the chalk ; the chalk of the North Downs, dipping northwards • 72 GEOLOGY OF THE ISLE OF WIGHT. the anticlinal position of the Wealden ; the chalk of the South Downs, clipping southwards, with tertiary strata on the southern flank: then the depression which forms the channel of the Solent sea; the tertiary strata extending over the northern portion of the Isle of Wight ; the chalk downs of the island, dipping northward ; and, lastly, a small portion of Wealden, emerging from beneath the chalk, on the south coast, at Brook and Sandown bays. London and Brighton railway section. — A portion of this section is w T ell displayed along the line of railway from London to Brighton. Leaving the station at London-bridge, the tertiary clays with their characteristic fossils, are seen from beyond Deptford, by New Cross, Sydenham, &c. ; and approaching Croydon, beds of gravel appear, with interspersions of olive-green sand. The valley beyond Croydon, along the side of which the railway proceeds, is a thick bed of gravel resting on the chalk. Beyond the station called Stoats 1 - nest, is a fine section of the chalk with Hint, and the North Downs are traversed by a long tunnel carried through the solid chalk, and emerging near Merstham, where the firestone and marl rise to the surface. The sands and clays of the chalk are passed at the Red-hill, and Godstone stations, and the Wealden clays appear, and at SECTION FROM LONDON TO BRIGHTON. 73 Horley are succeeded by shales, limestones, sands, and sandstones, to the Crawley station. Passing through a long tunnel in the Wealden, we arrive at Balcombe, where laminated sandstone and shale are seen on each side the cutting. The general dip of the strata hitherto passed is to the north- east; but after crossing the deep wealden valley beyond Balcombe, over a magnificent viaduct, the line runs along alternating layers of sands and clays, which dip to the south-west ; we have therefore arrived on the southern side of the grand anticlinal axis of the Forest ridge. The Wealden strata continue with the same general inclination by Hayward's Heath, which is traversed by a tunnel, to beyond St. John's Common, where they disappear beneath the lowermost greensand beds of the chalk formation. The gait, firestone, and marl succeed, and, lastly, the white chalk of the South Downs, at Clayton Hill ; through the base of which a long tunnel is carried, and emerges on the Downs on the south. The remainder of the line to the Brighton station, runs over, or through, hills and valleys, of the white chalk. Thus this railway passes through two ranges of chalk hills, viz. the North and South Downs, by tunnels ; two of greensand, viz. near Red Hill in Surrey, and Hurstperpoint in Sussex; and two principal ridges 74 GEOLOGY OF THE ISLE OF WIGHT. i! I of Wealden, tiz. at Balcombe, and Hayward's Heath. Geological mutations. — The present distribution of the strata, as shown by the pre- ceding observations, appears to admit of the following explana- tion. Assuming the original de- position of the strata to have taken place as in lign. 2 — the wealden resting on the oolite, the chalk on the weal- den, and the tertiary on the chalk — the surface of the country must have consisted of the same strata as those of the immediate vicinity of London. Now if any elevatory force acted from beneath, in the di- rection of the arrow, B, the entire scries would be broken through, and the chalk with the tertiary it supported thrown into highly inclined positions to the north and south ; and if a similar disturbance took place along the area now occupied SECTION FROM LONDON TO THE ISLE OF WIGHT. 75 by the Britisli Channel, Eng- land would be separated from the continent, and the small portion, now the Isle of Wight, forced into its present position, by a subsidence taking place in the direction of the arrow, a, along the present bed of the Solent Sea. The actual position of the strata, could our observations extend to a sufficient depth, would pro- bably present the section sketched in Ugh. 3 ; which is in accordance with the local phenomena that will come under review in our geological excursions round the Isle of Wight. It is obvious that if the Forest range of the county of Sussex were swept away by the encroachments of the sea, and the area it occupied buried beneath the waves, the North Downs would present a strict analogy in geological structure to the Isle of Wight ; for a 76 GEOLOGY OF THE ISLE OF WIGHT. portion of the "Wealden would appear on the south shore at the base of the chalk escarpment, and be succeeded on the north by the greensand, gait, iirestone, marl, and white chalk ; and the latter would be covered by tertiary eocene deposits.* * For detailed information on the geology of the South-east of England, and of the subjects embraced in this concise sketch, see " Elements of Geology," by Mr. Lyell, and the " Geology of the South-east of England," and the "Wonders of Geology," by the Author. On the elevation of the Wealden and the consequent changes in the relative level of the sea and land, the masterly paper of Mr. Hopkins, " On the Geological Structure of the Wealden District and of the Bas Boulonnais," (Geol. Trans, vol. vii.), should be consulted. CHAPTER II. SOUTn-WESTERN RAILWAY — STRATA OP THE LONDON BASIN — ARTE- SIAN WELLS RAILWAY SECTIONS — SOUTHAMPTON STATION FROM SOUTHAMPTON TO THE ISLE OF WIGHT — GEOLOGICAL STRUCTURE OF THE ISLAND — RIVERS AND STREAMS — FROM COWES TO RYDE. South-western Railway. — The railway from London to Southampton and Gosport lies so far to the west of the Wealden denudation of the south-east of England, which is traversed by the Brighton line (see p. 72), that all the deposits below the Upper-chalk are concealed from view, and inconsiderable cuttings through tertiary strata, and chalk, are alone exposed. The metropolitan station at Vauxhall, on the southern bank of the Thames, is situated on the alluvial silt and loam, which are spread over areas formerly covered by the waters of the river, and now constitute the subsoil of the meadows and lowlands that skirt its banks ; these beds contain shells of recent species of fluviatile mollusca. On penetrating the soil, gravel, loam, and sand are met with, in which are found bones and teeth of several kinds of large mammalia belonging to d 2 • O GEOLOGY OF THE ISLE OF WIGHT. extinct species of elephant, rhinoceros, horse, buf- falo, elk, deer, &c. ; an assemblage of organic remains common in similar deposits in other parts of England and on the Continent.* In the county of Surrey the subsoil of the dis- trict traversed by this railway in many parts con- sists of thick beds of gravel, in which fossil bones and teeth of elephants, horse, and deer, have been discovered ; but remains of this kind are more abundant in the loam and clay. The gravel is almost entirely formed of broken chalk -flints, worn by the action of water into boulders, peb- bles, and sand. It abounds in siliceous fossils of the chalk, and an interesting series of the sponges, zoophytes, and echini of that formation may be collected from the pits around the metropolis. - } - Strata of the London basin. — The ter- tiary or eocene strata of the London basin which lie beneath the accumulations of drifted materials above described, and liil up a depression of the chalk (see Han, 1, p. 71), are divided into three groups; viz. 1, Bagshot sands ; 2, London dan; 3, Plastic clay. The uppermost \ consists of beds ■ See Wonders of Geology, fifth edition, vol. i. p. 145. t The flints of the gravel often enclose beautiful examples of the micro scopic fossils which abound in many of the siliceous nodules of the chalk : the most interesting specimens of fossil animalcules in my cabinet obtained from the gravel <>n Clapham and Wandsworth commons. tiol sands; so called from the district over which they are most widely expanded. STRATA OF THE LONDON BASIN. 79 of sand and sandstone, with intercalations of marl and clay. These strata cover the London clay from near Finchley on the north to Hampstead- heath, and form part of the eminence on which Highgate is situated. The Bagshot sands appear at Egham, and extend, with some interruptions, to near Guildford ; and from the vicinity of Kingston to seven miles west of Bagshot, spreading over part of Windsor forest. Several eminences in Surrey are capped by this sand ; at Tucksbury- hill, north of Farnham, it occurs at an elevation of 500 feet.* From the siliceous nature of the soil formed by these deposits, the districts in which they occur are exceedingly sterile, sup- porting only a covering of heath and furze ; hence the numerous uncultivated wastes within a short distance of London. But where the clays rise to the surface, verdant spots appear in the midst of these desolate tracts. The situation of these argillaceous beds is indicated by the oozing of water, and the growth of rushes in the bottoms of the shallow valleys that traverse the sandy plains, and which are often covered with peat. Some of the Bagshot sandstone is remarkable for its struc- ture, which partakes more of the character of a peculiar crystallization than of a mere aggregation * Brayley's History of the County of Surrey, vol. i. p. 131. 80 GEOLOGY OF THE ISLE OF WIGHT. of siliceous particles ; a mass of the white variety recently broken strikingly resembles the surface of lump sugar. Erratic blocks of this sandstone are common on the chalk clowns of Wilts, Sussex, Kent, &c, and are provincially called the Grey Wethers ; they occur also in the superficial drift and gravel. London clay. — This deposit in the neighbour- hood of the metropolis forms a dark-blue stiff soil, and has occasional intermixtures of green and ferruginous sands and variegated clays. It abounds in spheroidal nodules of indurated argil- laceous limestone termed septaria,* which are internally traversed by veins of spar disposed in a radiated manner from the centre towards the circumference, and often contain shells and other organic remains. -j- The septaria are generally dis- tributed in horizontal layers, and lie at unequal distances from each other. Brilliant pyrites and crystals of sulphate of lime abound in the clay. Plastic clay. — Beneath the extensive and thick deposits of London clay, and interposed between them and the chalk, there occur in some localities strata of sand of various colours, alternating with layers of bluish plastic clay; and there is very * The septaria, when calcined and ground, constitute the composition called Roman a >ru ni t Medals ol' Creation, p. liT.'i. ARTESIAN WELLS. 81 constantly in the lower part of the series a bed of green sand, which abounds in oyster shells, and pebbles, and in some localities (as near Bromley) passes into a hard rock or shelly conglomerate. Lignite, leaves of land-plants, and freshwater shells are contained in some of these layers ; but in many places there are no remains of this kind found in the eocene beds immediately above the chalk; and the term plastic clay, as indicating a particular group, can only be regarded as of limited application.* Artesian wells. — From the alternation of porous sandy strata with stiff impervious clays throughout the London basin, the district around the metropolis is favourable for obtaining water, by means of the borings, termed Artesian wells ; by which perennial fountains are raised from the natural reservoir of water in the lowermost arenaceous deposits. The nature of these springs is easily explained. The beds of sand under the clay are fed by the rain that falls on the uncovered margin of the basin, and the water percolating through the porous strata, gradually * The term plastic clay (argille plastiquc) was given to this lowermost divi- sion of the eocene strata in conformity with the nomenclature of the French geologists ; but the beds thus named are less developed in the London than in the Paris basin, and do not with us possess distinctive characters suffi- ciently important to warrant their separation from the other intercalated fresh- water deposits of this formation. 82 GEOLOGY OF THE ISLE OF WIGHT. accumulates till a reservoir is formed beneath the central plateau of clay. If this stratum be penetrated, the water must necessarily rise to the level of the fluid in the highest part of the subterranean lake, and may therefore flow to the surface, or even escape in jets, to a considerable height above it. Such is the phenomenon of the Artesian wells in and near London. The impermeable clay confines the water contained in the sand beneath ; the engineer perforates this bed with his borer, and introduces tubes for the passage of the pure element to the surface, and the exclusion of the brackish water that may ooze from the saliferous strata above ; for although the wells sunk into the London clay yield no water, the sands alternating with the argillaceous beds afford a limited quantity. The prevalence of various saline minerals, how- ever, in the clay, such as the sulphates of iron, lime, and magnesia, generally renders the water derived from this source unfit for domestic pur- poses ; and the borings are carried down to the sands of the plastic clay before a copious supply of excellent water can be obtained.* The total • Tin' most remarkable instance of success in obtaining a perennial foun- tain from a deep Bource by the process oi boring described in the text, is thai of Sri m lit , Dear Paris. An Artesian well is there carried to the extraordinary depth of I. miii I., i, |iassinn through the entire thickness of the eocene strata THE RAILWAY SECTIONS. 83 thickness of the London clay, in some situations, is estimated at nearly 1,000 feet; the wells on the Surrey side of the Thames are from 100 to 600 feet deep. The Railway sections. — The above pre- liminary remarks will enable the observer to un- derstand the nature of the strata of which transient glimpses may be obtained on each side the railway in the rapid transit from London to Southampton, on which we now proceed without further com- ment. Although no considerable sections of the eocene strata are traversed by this line, yet here and there the characteristic soil of the Lon- don clay may be seen in the cuttings, where the surface has not acquired a covering of turf. On Wandsworth Common the banks on each side are composed of this clay with a superficial capping of gravel and sand. When the railway was in progress numerous fossils were dug up ; and even now the slips of the embankments which occa- sionally take place, expose specimens of nautili and other shells, petrified wood, &c* of the Paris basin, and the underlying chalk, firestone, and gait, to the green- sand. The water rises in a powerful column to the height of 30 feet above the highest part of Paris, and has a temperature of 91° Fahrenheit ; being sufficiently warm for the heating of green-houses, &c. * See " Geological Survey of Surrey" in iirayiey's History of the County, vol. i. pi. 1, 2, in which several of the fossils discovered in the clay of Wand.s- worth Common are figured. 84 GEOLOGY OF THE ISLE OF WIGHT. At Esher the clayey district of the Bagshot sands prevails and overlies the London clay, which in our further progress is generally concealed by the sands of this subdivision of the eocene strata. At Goldsworth-hill, four miles north of Guild- ford, a deep section of the Bagshot sands is ex- posed, consisting of greenish and yellowish sands, in which fossil teeth and other remains of several kinds of fishes (principally of the Shark family), and casts of shells, have been discovered. The most interesting fossil obtained is a large tooth of a Saw-fish, which, at that time, was the only known instance of the genus Pristis in the English strata ; but subsequently, examples of the teeth have been found in the clay of Bracklesham, in Sussex. The other teeth are referable to three kinds of car- tilaginous fishes, and with them were associated teeth and palatal bones of Bays, and vertebrae of osseous fishes, of species common in the clay of Sheppey; also a portion of the carapace or buckler of a freshwater turtle.'* At Weybridge the banks show an example of false stratification, as it is termed, of white and fawn-coloured sands, with the usual capping of gravel and clay. At Woking Common the Bag- • Notice- of Fossils discovered in the Bagshot Sand at Goldsworth-hill, Surrey) by the Rev. Dr. Backhaul. Proceeding* <>f the Geological Society of London, vol. ii. p, 687. THE RAILWAY SECTIONS. 85 shot sands still prevail, their sterile surface being- covered with heather and broom, except in a few places, where interspersions of clay produce ver- dant spots, which appear like oases in the desert. Greenish clays and marls, alternating with sand, are next seen, and extensive plains clothed with heather, and dotted with clumps of pines and firs. Between Woking and Farnborough many sections of the Bagshot sands are passed, and at the Wing- field station the country presents the same geo- logical character. Although from the rapidity of our progress but transient glimpses can be ob- tained of the adjacent district, yet the character of the vegetation, and the appearance of the un- enclosed tracts, destitute of all traces of habitation, save a few solitary turf cabins, convey some idea of the nature of the untractable soil produced by these siliceous deposits. Such, indeed, is the general aspect of sterility in the worst parts of the Bagshot-heaths, that when the adjacent fertile region is hidden from view, a stranger might sup- pose himself transported to a desolate mountain moor in the border countries.* About three miles before we reach the station at Basingstoke,-]- the Chalk emerges, and is seen * Mr. Warburton on the Bagshot Sands, Geol. Trans, vol. i. p. 49. t The picturesque ruins of the Chapel of the Holy Ghost, said to have been erected temp. Edward IV., on the right of the station at Basingstoke, are 86 GEOLOGY OF THE ISLE OF WIGHT. covered with a bed of tertiary sand; and at Andovcr-road station the railway cutting exposes a good section of the Upper-chalk, which now continues, in greater or less thickness, surmounted in some places by patches of tertiary clays, and in others by gravel and loam, till we approach Southampton, where it is wholly concealed by the alluvial and eocene deposits. At the Winchester station, which is on the chalk of the Hampshire. downs, we have a fine view of the river valley, in which stands the venerable city of the immortal Alfred, hallowed by so many glorious associations of the olden time ; and we catch a glimpse of that precious monument of antiquity, the Hospital of Saint Cross, with occasional views of the crystal streams of the river Itchin, as they pursue their tortuous course through the verdant chalk-valley to Southampton-water. Southampton station. — The accumulations of alluvial gravel and loam around Southampton are in many places of considerable thickness. The organic remains hitherto discovered in these beds are but few; comprising only some detached bones, and a tooth of a mammoth, and bones of a species worthy the notice of the traveller. An elegant hexagonal turret tower at tlu- south-west, and part of the east ami south walls, are visible from the railway. SOUTHAMPTON ARTESIAN WELLS. 87 of horse and deer; and as the tertiary strata are in a great measure obscured by the superficial deposits, there are no productive localities of fossils in the immediate vicinity of Southampton. The nature of the strata to a considerable depth, has been ascertained by the borings lately under- taken to obtain a more ample supply of water for the inhabitants, than that yielded by the numerous private wells in the town. These are sunk through the bed of gravel which overlies the London clay, to a depth of from 10 to 25 feet, this clay forming the water shed or natural tank of the surrounding district. At the railway station an Artesian well, which overflows from a depth of 220 feet at the rate of ten gallons per minute, was formed by boring till the beds of sand of the plastic clay, which lie between the London clay and the chalk, were reached ; the water in this well rises, there- fore, from the same geological source as the springs near London. A few years since it was resolved to obtain a more copious and constant supply for the town, by sinking an Artesian well on the Common. The operations were commenced in 1838, and have now reached a depth of 1,260 feet, at an expense of 24,000/. The following is the section made by the borings : — 88 GEOLOGY OF THE ISLE OF WIGHT. Drift, or alluvial soil . . . . 38 feet. London clay 304 * — Plastic sands and clays ... 97 — Chalk 821 — This well yields by pumping 15,000 cubic feet of water daily, but the quantity is only one half of that required, and it will be necessary to continue the borings till the firestone is reached (probably a further depth of from 1 50 to 200 feet) before an adequate flow of water is likely to be obtained.f The impervious blue chalk-marl or gait, which underlies the firestone, generally supports an abun- dant sheet of water ; but whether a stream will rise to the surface is extremely uncertain, and depends on the level from which the water is derived that feeds this subterranean reservoir, and the condition of the basin which sustains \t.\ The branch of the South-western railway that extends to Gosport, cuts through a few ridges of tertiary clays, sands, and gravel, capped with drift, but these present no sections of particular in- • Many of the characteristic shells of these strata were brought up by the borer. t See an admirable Address on this subject to the Mayor of Southampton and the Members of the Artesian Well Committee, by the Very Rev. Dr. Bnckland; July, 1845. At the late meeting of the British Association of Science at Southampton, the president, Sir Roderick Murchison, and several other eminent geologists, examined the borings, and recommended the con- tinuance of the operations till the firestone was reached. ; In the chalk districts of t he south-cast of Sussex copious streams of the purest water rise from the junction of the grey mail with the white chalk. SOUTHAMPTON TO RYDE. 89 terest.* At Stubbington, between four and five miles west of Gosport, near which the line passes, many interesting fossils have been obtained from the tertiary clays and sands. -j- Southampton to Ryde. — The steamers from Southampton to the Isle of Wight generally touch at East Cowes, and proceed to Ryde ; those from Portsmouth cross Sjrithead to the latter town, the distance being scarcely five miles. In the former route we pass down Southampton-water, an arm of the sea which extends ten miles inland in a north- westerly direction, and separates the eastern part of the coast of Hampshire from the New Forest on the west. The entrance of Southampton-water is guarded on the west by Calshot Castle, which was erected by Henry VIII. on the narrow slip of land that here advances some little distance from the line of coast* We now obtain a distinct view of the north side of the " beautiful Island ;" and as we approach the land, two parallel chains of hills may be observed, stretching in a direction east and west through the whole extent of the landscape. The nearest range is of moderate height, and slopes towards the shore ; the distant * Portsmouth and Gosport are built on eocene strata ; the wells penetrate the London clay to the depth of from 200 to ouo feet. t Several species of shells, collected by Mr. Holloway, of Portsmouth, are figured in "Sowerby's Mineral Conchology." 90 GEOLOGY OF THE ISLE OF WIGHT. chain, which bounds the horizon on the south', rises with a bolder sweep, and to a much greater elevation, and exhibits the smooth and rounded aspect, and undulated outline, which are so cha- racteristic of the mountain masses of the white chalk, as to indicate their geological character, even when seen from a considerable distance. The first line of hills consists of freshwater strata, which are superimposed on the eocene marine deposits ; the distant range is part of the chain of chalk downs that traverses the island throughout its entire length, forming on the east the promon- tory of Culver-cliff, and on the west that of the Needles (see the map, PL XX.). Geological structure of the Isle of Wight. — Before we land, and proceed to examine par- ticular localities, it will be necessary to take a general view of the distribution of the three formations of which the island consists. It is shown in ligti. 3, (p. 75,) that the Solent and Spit- head occupy a trough or channel from two to seven miles wide-, formed by the London clay and other tertiary deposits which lie upon the chalk. The wells at Southampton, Portsmouth, &c, prove, in the absence of natural sections, that although the strata have undergone great disturbances, the same order of superposition is maintained, as in GEOLOGICAL STRUCTURE OF THE ISLAND. 91 the south-east of England ; and in the southern division of the Isle of Wight, where not only the lowermost cretaceous strata, but even the wealclen, rise to the surface, in consequence of the highly inclined position into which the central mass of rocks has been thrown, the natural order of the deposits is not inverted.* The Isle of Wight is of an irregular rhomboidal form, being in length, from east to west, twenty- three miles, and from north to south, in the widest part, thirteen miles ; the circumference is between seventy and eighty miles. Its surface comprises about 105,000 acres, of which 75,000 acres are under tillage, 20,000 acres are pasturage, and 10,000 acres unproductive heaths and commons. The population is estimated at nearly 45,000. The map, PL XX, shows the range and extent of the respective formations which lie beneath the vegetable soil and superficial loam and gravel. The section in the same plate represents a vertical cut through the island, from Cowes on the north, to the sea-shore beyond St. Catherine's down on the south, and exhibits the relative position and direc- * The Underclitl" presents an apparent exception, for in some instances masses of white chalk are seen covered with beds of firestnne, marl, and gait ; hut these are merely portions of the cliffs that have fallen down in a retroverted position from the encroachments of the sea in comparatively very modern periods. E 92 GEOLOGY OF THE ISLE OF WIGHT. tion of the principal deposits ; these are further exemplified by the instructive diagram, PL VII, p. 94. By a reference to the map it will be seen that the eocene strata which were deposited on the chalk when the latter was in a horizontal position (lign. 2, p. 74), form the northern division of the island ; this tract of country is coloured pink. The other portion (coloured blue) is almost en- tirely composed of the different members of the cretaceous system. The white-chalk forms a range of downs from the eastern to the western extre- mity, and is flanked on the south by the lower beds of this formation. These are succeeded by another group of chalk-hills, that expands into a broad and lofty promontory, in some parts be- tween 800 and 900 feet high, crested by St. Cathe- rine's, Boniface, and Shanklin downs. On the southern escarpment of this chain the inferior deposits of the cretaceous system reappear, and fallen masses of these rocks form the irregular line of terraces which constitute the Undercliff. The downs on the southern coast are separated from those inland by an anticlinal axis which extends through this part of the Island, and is produced by the upheaval of the firestone, gait, and greensand. Tins is shown by the section GEOLOGICAL STRUCTURE OF THE ISLAND. 93 from north to south given in the map (PL XX), in which the different members of the chalk forma- tion are denned by variations in the lines of shading, as explained in the index of colours. The promontory of the Undercliff is flanked both on the east and west by extensive bays, which have been excavated in the clays and sands of the wealden and inferior cretaceous deposits, by the long continued encroachments of the sea. The wealden (coloured sienna on the map) occu- pies an inconsiderable extent of surface ; but in Sandown bay on the east, and in Brixton, Brook, and Compton bays on the west, the cliffs, which are formed of the upper clays and sands of this for- mation, are exposed to unremitting destruction from the action of the waves. The sea-shore is, therefore, strewn with the detritus of these fluvia- tile strata, and the shingle contains innumerable water-worn fragments of the bones of reptiles, and other organic remains. That the general reader may obtain an accurate idea of the phenomena above described, the dia- gram, PL VII, for which I am indebted to my friend Professor John Phillips, is subjoined. In this plan the geographical features of the island are intentionally exaggerated, that the most im- portant physical characters may be clearly under- * a £ O = ,§ J RIVERS AND STREAMS. 95 stood. The northern district, consisting of fresh- water and marine eocene deposits, is marked tertiary. The chalk downs are seen in their full extent from east to west, the dotted lines denoting the inclined direction of the strata as indicated by the layers of flint nodules ; and the lower mem- bers of the cretaceous system occupy the southern portion of the Island ; the principal subdivisions, viz. the firestone (/.), gait (g.), and greensand (g*s.), being marked with letters of reference. The wealden strata (w.) are shown in the bays on the east and west of the Undercliff. The vertical cut or section through jlie island from north to south, explains the position and flexures of the strata, which have given rise to the present geological characters of the surface of the country ; the wealden constituting the foundation and central axis of the Island. Rivers and Streams. — There is a good supply of water, at a moderate depth, throughout,, the greater part of the less elevated districts ; but the rivers and streams are neither numerous nor con- siderable. The drainage of the country is chiefly effected by four or five rivers that flow from the northern flanks of the chalk downs. Of these, the principal is the Medina, which, rising at the north-eastern base of St. Catherine's-hill, meanders 96 GEOLOGY OF THE ISLE OF WIGHT. along the valley that runs to the east of Gat- combe and Mount joy. The river flows on to the east of the town of Newport, and soon expands into a wide estuary, which opens into the sea on the north ; the towns of East and West Cowes being situated on the banks of the embouchure of the river. Between Ryde and Cowes there is an estuary fed by springs that issue from the northern foot of Arreton and Ashey downs, and form a considerable breadth of water at Wooton-bridge, called Wooton-river ; the estuary below the bridge communicates with the sea, and is termed Fish- bourne-creek. The most considerable estuary of the Island is Brading Haven, which covers 800 acres, and at high water has the aspect of a beautiful lake ; but during low water it is a muddy swamp, through which meanders an inconsiderable river, called the Eastern Yar, originating in springs that rise at the foot of the chalk range near Godshill. Newtown Bay, between Cowes and Yarmouth, is the mouth of a small river of the same name, which is mainly fed by a copious stream that rises near Calbourne. The Western Yar has its source from springs that burst forth from the foot of the chalk near FROM COWES TO RYDE. 97 Freshwater, within a short distance of the southern shore, and quickly expands into an estuary that falls into the sea at Yarmouth, the entire length of the river scarcely exceeding three miles. Along the southern shore of the Island there are no streams sufficiently large to deserve the name of rivers ; but the clay beds that in some parts of the cliffs are covered by porous strata many "yards in thickness, give rise to copious rivulets, some of which issue from a great height, and dashing from ledge to ledge, fall into the sea in cascades of considerable picturesque beauty; those of Shanklin and Blackgang Chines {PL XIII.) are well known examples. From Cowes to Ryde. — From the highly cultivated state of that portion of the Island we are approaching, and the luxuriant woods and copses with which it is adorned, its geological structure is almost wholly concealed from view. The water- worn blocks of limestone on the sea-shore, and the layers of tertiary strata exposed in those places where recent encroachments of the sea have undermined the low cliffs which skirt the plantations along the water's edge, afford, how- ever, indications of the nature of the deposits composing this district. As there are no loca- lities of geological interest around Cowes that are 98 GEOLOGY OF THE ISLE OF WIGHT, accessible to strangers, we proceed to Ryde, the quarries at Binstead in the vicinity of that town exhibiting good sections of the freshwater strata, which extend through the island from Headon- hill on the west, to St. Helen's and Bembridge on the east. On landing at Ryde pier, if at the recession of the tide, it will be instructive to notice the appearance of the surface of the sand and silt that extend along the shore, for it is often deeply impressed with ripple-marks produced by the action of the waves ; and similar appearances will be presented to our notice on the slabs of limestone, and laminated clays and shales of the wealden, and other ancient deposits.* The sea-shore at Ryde, during the last century, has undergone a remarkable change in its geolo- gical character, which is worthy of attention. Sir Henry Englefieldf states that, "when Fielding, in the year 1753, was at Ryde, on his voyage to Lisbon, the town was totally inaccessible except On a late visit to Ryde, the wind having ;t few hours previously been exceedingly variable, 1 found the ripple-marks formed on the surface of the muddy dunes by the agitated waters of a very remarkable character, and strikingly resembling the appearance of the limestone covered with fossil fuei. from the Alleghany Mountains: and shortly afterwards 1 obtained from I 111 W I allien at Sandown-bay a slab of shelly marble, with the upper-surface rippled in precisely a similar manner. I " Descriptions of the Picturesqui Bi nth Intiquitie , and Geological Phenomena ol the Isle of Wight," bj Sir Henrj ('. Englefleld, Bart. 18 1C p. 16. THE SEA-SHORE AT RYDE. 99 at or near high water, as the tide on its recession left a vast breadth of mud, which was too soft to bear the lightest weight. But this mud-bank is now almost covered by a layer of fine white sand, which has formed a surface smooth and firm enough to bear wheel-carriages, and which renders bathing at all times safe and agreeable. This bed of sand reaches to Binstead, having, during the last fifty years, covered two miles of the shore ; and it is said to be still extending to the west- ward. To what cause this change is owing it is difficult to explain ; but it is an example of an alternation of deposits from the action of the sea in circumstances apparently unchanged." CHAPTER III. FRESHWATER EOCENE STRATA OF THE ISLE OF WIGHT — QUARRIES AT BINSTEAD — FOSSIL SKULL OF A REIN-DEER — EOCENE STRATA AT BIXSTEAI) — FOSSIL CHARA — FOSSIL LAND AND RIVER SHELLS — FOSSIL TURTLES — FOSSIL REMAINS OF EXTINCT MAMMALIA. Freshwater eocene strata. — The most remark- able peculiarity in the eocene formation of the Isle of Wight as compared with that of London, consists in the lacustrine and fluviatile character of the upper series of deposits, which are super- imposed on marine strata identical with those of the metropolis. For though in some localities clays and sands containing marine and estuary shells, alternate with marls and limestones abound- ing in fluviatile species ; and in others the strata are fluvio-marine, that is, contain an intermixture of marine and freshwater shells ; yet throughout a considerable thickness of deposits the organic remains are entirely fluviatile and terrestrial. In tli is respect the tertiary system of the Island cor- responds with that of the Paris basin, which is characterised by alternations of freshwater marls, FRESHWATER EOCENE STRATA. 101 gypseous limestones, and siliceous millstones, with marine sands and clays. It was from the gypsum quarries of Montmartre that those relics of ex- tinct mammalia were obtained, which the genius of the illustrious Cuvier called forth from their rocky sepulchres, and invested anew with the forms and lineaments of life.* In the Isle of Wight the freshwater series con- sists of marls, limestones, and shelly concretions, with intercalations of clay, marl, and sand; the gypseous marls and limestones, and the siliceous millstones of the Paris group are altogether want- ing. Nevertheless, there is evidence that the two formations were contemporaneous, for the relics of Cuvierian pachydermata have been discovered in the Binstead limestones (see PI. II.). The freshwater eocene strata of the Island, which are spread over the whole of the northern part, are denoted on the map {PI. XX.) by pink on a plain ground ; the marine beds appear on the surface as a narrow band extending along the northern flank of the chalk downs, and are in- dicated by the same colour on a ground shaded with parallel lines. The localities which exhibit the most instructive sections of the marine and freshwater deposits in their natural order of * Wonders of Geology, vol. i. p. 240. 102 GEOLOGY OF THE ISLE OF WIGHT. superposition arc Headon Hill, Alum Bay, and Whitecliff Bay. Binstead quarries.- — The limestones in the vicinity of Hyde have been quarried for many centuries ; the shelly, as well as the compact varieties, having been in great demand during the middle ages for building.* Though the sections exposed in the quarries now open are inconside- rable, they will suffice to illustrate the characters of the strata and the nature of their fossils, and render the interpretation of the phenomena here- after to be examined more easy of comprehension. I would, therefore, first conduct the reader to Binstead, which lies about a mile to the west of Ryde. There are several quarries on both sides of the turnpike road to Newport, and others in a field which lies on the left of the footpath that turns oil" from the main road just beyond a Doric lodge, and leads by copses and hedge-rows to the picturesque hamlet of Binstead, affording here and there glimpses of the most charming rural scenery. The quarries for the extraction of the stone vary in depth from ten to twenty feet, and * A great part of Winchester Cathedra] is built of stone from the old quarries at Binstead. Some- of tin- walls of Lewes Priory were faced with this -lone; and several ancient Sussex churches an- in part constructed of it. ii tj composed of comminuted shells, held together by a sparry calca- reous cement, was extensivel] used; it has been frequently mistaken for Caen stone by our antiquaries. FOSSIL REIN-DEER. 103 appear to have been opened without regard to any regular plan, wherever it was thought a layer of compact stone could be easily reached.* Fossil rein- deer. — Upon entering a quarry at Binstead, the dislocated state of the beds of lime- stone immediately strikes the observer. Vertical and diagonal fissures and chasms, extending in some places to the depth of fifteen feet, are seen traversing the solid rock, and filled with the alluvial loam and clay that form the general sub- soil of this district ; in these deposits bones of a species of horse and ox have been discovered. On a recent visit, I obtained a considerable portion of the skull of a Rein-deer (Cervus tarandus), from clay occupying the bottom of a vertical fissure at the depth of ten feet from the surface. It con- sists of the posterior part of the cranium, and closely resembles a specimen found in a cavern at Berryhead, in Devonshire, and figured by Pro- fessor Owen in British Mammalia ;f the latter is referred by that eminent palaeontologist to the recent species of Rein-deer, chiefly from the proxi- mity of the bases of the antlers to the occipital * Quarr Abbey. — In a sequestered valley, within a short distance of Bin- stead, are a few mouldering walls, the only remains of the once celebrated Quarr Abbey, which are generally visited by the tourist : the beauty of the scenery will amply repay the pedestrian geologist for the extension of his walk to this lovely spot. t " British Fossil Mammals," p. 181, fig. 198. 104 GEOLOGY OF TITE 1*1. F, OF WIGHT. crest. Dr. Falconer, who, with his wonted cour- tesy, obliged me by comparing the Isle of Wight specimen with the skulls of recent deer in the British Museum, agrees with me in the opinion that there is no appreciable difference between the fossil cranium and that of the Rein-deer. Lign. 4,* represents the specimen viewed from LIGN 4. — FOSSIL SKULI. OF A REIN-DKER, FROM A FISSURE IN A QUARRY AT KINSTF.AD a. a. The osseous bases to which the antlers were attached. (One-third linear of the natural tize.) the occipital aspect ; the figure is one-third the size of the original. The skull appears to have belonged to an adult, that had but recently shed its antlers. * Engraved by Mr. Haptr. 6S, Gower Street. EOCENE STRATA OF B1NSTEAD. 105 Eocene strata of Binstead. — The strata in this locality are entirely of freshwater origin, containing no intermixture whatever of marine detritus. This is evident from the fossils, which consist of shells of the common genera of mollusca that inhabit lakes and rivers ; of seed-vessels and stems of aquatic plants ; bones of freshwater tur- tles ; and teeth and bones of land mammalia. An inspection of Plates I. and II. will give an idea of the assemblage of organic remains found in this locality. The layers of stone are commonly broken and dislocated, but not far removed from their original position. On my visit last summer, the following section was exposed in the principal quarry near the road-side ; it presents the usual appearance and arrangement of the upper series of freshwater strata of the Island ; the beds incline slightly to the north. 1. Vegetable mould. 2. Alluvial loam and clay, in which are water- worn blocks of shelly limestone (but ex- tending in fissures tc a depth of 1 5 feet) . 3 feet. 3. Sand, with a layer of shelly limestone, more or less separated into blocks which are waterworn 2 feet. 4. Shelly limestone, in thin layers .... 1 foot. 5. Very tenacious loam and clay, of a dark brown colour, much resembling in appear- ance the dirt-bed of the Isle of Portland . 1 foot. 10G GEOLOGY OF THE ISLE OF WIGHT. G. Fine sand with comminuted sheila . . . 6 feel. 7. Compact grey limestone; termed siliceous limestone by Mr. Webster, from its con- taining a large proportion of sand ; but few fossils were observable 2 feet. 8. Fine sand. "Water issues from this bed, being thrown up (according to the quarry- men) by underlying beds of clay. The upper beds of limestone abound in casts and impressions of shells. No. 3, is full of hollows left by the decay of the shells, and the subsequent separation of the casts of their cavities. This bed appears to have been formed by the infiltration of calcareous matter into a layer of shells, the moulds and casts of which are now cemented together by sparry concretions. A coating of white powder on the casts is almost the only vestige of the con- stituent substance of the shells now observable. In this sparry limestone the minute seed-vessels of charw hereafter described, fragments of bones of turtles, and casts of planorbes (PL I. fig. 1) and limnei (PL I. fig. 3) are abundant. The sand, No. 6, is intimately mingled with comminuted shells, the whole being loosely held together by an infiltration of marl ; the most coherent masses readily crumble into powder between the fingers. I have not succeeded in obtaining a single shell entire; but from a micro- EOCENE STRATA OF BINSTEAD. 107 scopical examination am led to conclude thai the shelly particles are the detritus of the freshwater snails (limnei, and planorbes), so abundant in the limestone ; waterworn bones of turtles occur in this bed. In some of the quarries there is a layer of very hard limestone entirely composed of com- minuted shells cemented together by a crystalline calcareous infiltration ; it contains extremely minute waterworn fragments of turtles' bones, and, very rarely, teeth and bones of mammalia. I be- lieve this bed to be the equivalent of No. 3, from winch it differs simply in its consolidation, and in the absence of sand and marl. This shelly lime- stone is observable in the walls of the most ancient castles and religious edifices in Hampshire and Sussex. The siliceous limestone, or rag as it is locally termed, being very compact and durable, forms an excellent building material. The upper limestones yield stone sufficiently firm for walls, &c, and are extensively quarried in the northern district of the island. The surface of the blocks in newly erected buildings, often exposes such interesting groups of fossil shells, as to present a strong temptation to the geologist to trespass with his hammer. I will now more particularly describe the fossils F 108 GEOLOGY OF THE ISLE OF WIGHT. which occur in these strata. The shells, as we have seen, are very abundant, hut they include only a few genera and species, a circumstance characteristic of fluviatile and lacustrine forma- tions. With the exception of waterworn frag- ments of wood, the Chares are the only fossil vegetables that have come under my notice. The mammalian remains are, at present, of excessive rarity ; but I doubt not diligent research would soon add to the number already known to the palaeontologist.* Fossil Chara. — The aquatic plant termed Chara is, of course, familiar to every one, as it abounds in lakes, streams, and rivulets, throughout the king- dom. The stems are hollow, and composed of tubes filled with a fluid in which green globules circulate. The fruit is a minute spherical body, enclosed in a calcareous integument formed of five spirally-twisted plates, which unite at the sum- mit. -J- These fruits or seed-vessels when first dis- covered in a fossil state were supposed to be the * I would refer the general reader, who is not conversant with the various conditions in which the remains of vegetables and animals occur in the mineral kingdom, according to the circumstances under which they were originally imbedded, and the chemical changes they may have subsequently one, to my remarks "On the Nature of Fossils or Organic Remains," Chap. III. Medals of Creation, vol. i. See also " Instructions for the collecting Of fossils," vol. ii. p. 885. t McdaN of Creation, vol. i. p. 188. FOSSIL CIIAIUR. 109 shells of an unknown species of mollusk, and a genus was formed for their reception, and termed gyrogonites, or twisted stones, a name by which they are still often designated. These fossil bodies, from their extreme minuteness, are likely to elude the observation of the inexperienced col- lector, unless their structure and appearance are particularly noted; but a reference to the figures in lign. 5, will enable the reader easily to dis- tinguish them, with the assistance of a pocket lens. " . ;.£ MV/V-.IR-- I.IGN. 5.— FOSSIL SEED-VESSELS OP CHARGE. (Mr. Lye/1.) Fig. 1. — C/iara medicnginula ; a section showing the nut within the pericarp. 2. — Chara tuberculala ; the pericarp. 3. — Portion of a spiral valve, magnified. 4 and 5. — The natural size of figs. 1 and 2. On breaking the compact limestone, the surface often appears studded with small spherical cavities, and these, with a lens of moderate power, will be f2 110 GEOLOGY OF THE ISLE OF WIGHT. found to present the inner surface of the pericarp or shell of the Chara, the nut or kernel being absent. By a little practice, some of these fossils may be obtained with the external surface ex- posed, and, rarely, with the nut in the shell, as in fig. 1, which is copied from Mr. Lyell's paper in the Geolog. Trans. In the limestone at White- cliff Bay, a species was discovered by Mr. Lyell, having the pericarp composed of nine spiral valves, covered with tubercles (fig. 2). On a recent visit to that locality, there were many blocks of limestone on the sea-shore, in which these bodies were so numerous as to constitute a large proportion of the mass, but I did not succeed in obtaining any specimens with the nut ; the cavity of the pericarp was generally lined with calcareous spar. In some of the sands gyrogonites occur in abundance, and may be detected by examining with a lens a little of the earth spread out on a sheet of paper. Fossil Shells. — The shells at Binstead are chiefly those of univalve gasteropoda, and be- long to genera common in our rivers and lakes. The Planorbis, or discoidal river-snail, I 'I. I. ligs. 1, 2,) may be distinguished by the .shell being involuted or coiled up in a nearly ver- tical plane; five or >i\ specie's have been found. FOSSIL FRESHWATER SHELLS. 1 1 1 The Limneus,* (PL I. figs. 3, 4, 5,) is characterised by its elongated oval form, pointed spire, and deli- cate shell, with an oblique fold on the inner lip of the aperture ; of this genus there are six species in the tertiary strata of the Island. The Bulimus,\ a genus of land snails, is comparatively rare at Binstead; but casts of the large species figured PI. I. fig. 7, are occasionally met with, invested with a white friable coating of the original shell. This species is a reversed shell, that is, the aperture is to the left of the observer, instead of to the rierht. as is most common ; some specimens are two inches in length. There are indications of a sjjecies of Cyclas,% a genus of freshwater bivalves, but the examples met with are not sufficiently perfect to require particular notice. A small species of Unio$ is also sometimes found. Specimens of the Cypris,\\ a small freshwater crustacean, of which several species abound in * Limnei and Planorbes are generally joint inhabitants of our pools and streams. They are pulmoniferous, that is, possess air-breathing organs ; hence they are obliged frequently to rise to the surface of the water to respire. t Bulimus (properly hulinus), a genus of terrestrial pulmoniferous testa- ceous mollusca. These animals are herbivorous, and some of the species that inhabit warm climates are very large, their eggs being equal in size to those of the Wren. X Medals of Creation, p. 411. § Unio, a genus of river mussels, of which a few fossil species have been observed in certain deposits apparently of (luviatile or lacustrine origin. || Medals of Creation, p. 544. 112 GEOLOGY OF THE ISLE OF WIGHT. some of the eocene deposits, occur at Binstead, but I have not observed them in any considerable number. Fossil Turtles. — Waterworn fragments of the bony plates of chelonian reptiles, which, from their granulated or cancellated dermal surface, appear L1GN. ti .— S1XKK.U, PLATE <)l A FRESHWATER TURTLE, FROM BINSTEAn. (One-third linear, the natural size.) The outline, a, represents the corresponding portion of the plastron. to have belonged to the group of soft freshwater tint It's called Trionyx, are often found associated with the shells above described, in the tertiary FOSSIL TURTLES. 113 limestones and sands of the Isle of Wight. It is very rarely, however, that any of the bones are sufficiently perfect to indicate the affinities of the original animal. The most instructive specimen I have obtained is the fossil represented in lign. G ; it is from the bed of sand marked No. 6, in the section p. 106, and when found was so thickly encrusted, that its characters were altogether con- cealed till the investing sand was removed. It is one of the bones (ineso-sternaT) of the plas- tron, or sternum, of a turtle belonging to the predaceous tribe of freshwater chelonians, termed Trionyx, from having three claws. This is evident from the peculiar form of the bone, and the can- cellated outer surface, which is well represented in the lignograph : an outline of the corresponding portion is added to show the position of the bone in the sternum.* That specimens of great interest and beauty may reward more active and judicious research than has hitherto been bestowed on the palasontological treasures of the Island, is manifest from the discovery a few years since, of one of the most remarkable fossil chelonians hitherto found in this country. It was obtained from the tertiary limestone that occurs in a low cliff" near St. * See Medals of Creation, vol. ii. p. 766. 114 GEOLOGY OF THE ISLE OF WIGHT. Helen's, a locality we shall hereafter notice, and was sold to a dealer, who afterwards disposed of it to a casual visitor. It consists of the entire carapace or Luckier of a turtle, apparently of an -T. lign. /. — tortios ok the buckler of a fossil turtle, from st. Helen's. (Size of the original carajiace sixteen inches long, and nine wide.) adult Triowjx. It is sixteen inches in length, and about nine inches in its greatest width ; and is formed of eight pairs of ribs, united by a dorsal series of eight plates. The ribs are of nearly equal breadth throughout their entire length, and have their dermal surface cancellated somewhat after the pattern of the meso-sternal plate figured in lign. 6. The buckler is as convex ;i~- in some of the land tortoises, and therefore differs greatly from the usual form of the carapace in thi' recent Trionyx, which is depressed, and has FOSSIL REMAINS OF EXTINCT .MAMMALIA. 115 a soft flattened margin; a modification of structure enabling these animals to conceal themselves in the mud at the bottoms of rivers and lakes, and seize the mollusca which constitute their principal food.* The only vestige of any other order of reptiles observed in these strata, is a tooth of the croco- dilian type, apparently of the Alligator Hantonien- sis ; a fossil species described by Mr. Searles Wood, from a splendid specimen of the lower jaw and teeth, &c, found in the freshwater beds at Hordwell Cliff, on the Hampshire coast.f FOSSIL REMAINS OF EXTINCT MAMMALIA. From the general correspondence between the tertiary formations of Hampshire and Paris, it is probable that these strata were deposited con- temporaneously, and under very similar con- ditions ; their respective basins being connected with the same sea, and alike characterised by alternations of marine and fluviatile sedimentary detritus. When, therefore, the attention of * I very much regret my inability to give a correct representation of the entire carapace; but having been promised the refusal of the specimen by the dealer, I contented myself with the sketch of the part here figured ; the form of the bones, and the sculpturing of the surface, are correctly shown in the lignograph. t Of this most interesting specimen a beautiful representation is given in the first number of the new periodical,, called " The London Geological Journal, or Record of Discoveries in British and Foreign Palaeontology ." published by Churchill. 116 GEOLOGY OF THE ISLE OF WIGHT. the scientific world was directed to the fossil mammalia found in the gypseous marls of Mont- martre, in consequence of the extraordinary in- terest with which the late Baron Cuvier invested them, British geologists were sanguine in their anticipations of discovering traces of these extinct animals in the freshwater strata of England. But not a relic of this kind was found till some years after the appearance of the " Geograph. Min. des Environs de Paris." The first evidence of the occurrence of the extinct pachyderms of Paris in the British strata was obtained by Mr. Thomas Allan, of Edinburgh, who found a lower molar tooth of an Anoplotherium in a quarry at Binstead.* In 1830 Mr. Pratt discovered teeth and bones of Anoplotheriitm, Palccotherium, and Dichobune, in the same quarries ;-j- up to the present time, eight species, belonging to four genera, have been dis- covered in the strata near Ryde. At Headon Hill a tooth and some bones have been found by Mr. Prestwich ; and from the freshwater beds at Hordwell Cliff, on the Hampshire coast, the re- searches of Mr. Searles Wood have recently * This specimen was figured and described by Dr. Auckland, in the Annals of Philosophy, 1825. | " Remarks on the Existence of the Anoplotherium and Palaeotherium in the Freshwater Formation at Iiit.stead;" by Samuel Peace Pratt, Esq. F.R.8. Trans, vol. iii. New Si FOSSIL REMAINS OF EXTINCT MAMMALIA. 117 brought to light several interesting additions.* The following list comprises the specimens hitherto discovered : — Anoplotiierium commune; teeth (PI. II. fig. 10) and bones; Binstead. secundarium ; teeth and bones ; Seafield.f Ch^ropotamus Cuvieri ; part of the lower jaw with teeth ; Seafield ; by Kev. W. D. Fox. Pal^otherium medium; teeth (PI. II. fig. 11) ; Binstead. • magnum ; a tooth ; Seafield ; by the Kev. W. D. Fox. crassum ; teeth ; Binstead and Seafield. minus; right ramus of the lower jaw with five molar teeth (PL II. fig. 12) ; portions of the skull, radius, and tibia ; Seafield, near Eyde ; by the Eev. W. D. Fox. Dichobune cervinum ; lower jaw and teeth (PL II. fig. 13) ; Binstead ; by Mr. Pratt. All the fossils in the above list are figured and described by Professor Owen in "British Fossil Mammals," J a work of the highest interest, replete with the most profound views of the cor- relation of animal organization, and therefore of inestimable value to the palaeontologist. I have introduced figures of a few teeth in PL II., that * See London Geological Journal, No. 1, pp. 5, 6. t Seafield is a little hamlet to the east of Ryde, but the quarries are not accessible to strangers. t " A History of British Fossil Mammals and Birds. By Richard Owen, F.R.S. &c." 1 vol. 8vo, with numerous Illustrations. Published by Van Voorst, London, 1846. J 18 GEOLOGY OF THE ISLE OF WIGHT. the reader who visits the Binstead quarries may be aware of the appearance and characters of these relics ; the lower jaw of the Palouotherium mi it ax, with five molar teeth {PL II. fig. 12), is a highly instructive specimen.* It is unnecessary to enter at large on the struc- ture and habits of the pachydermata to which these remains belonged ; for even the forms of these extinct beings must be familiar to the reader, as Cuvier's restorations of several species are introduced into every popular work that treats of the ancient inhabitants of our globe, j The Anoplotheria are remarkably distinguished by having feet with but two toes, as in the ruminants, and an uninterrupted dental system; the teeth being placed in a continuous series, as in man, without any interval between them. The A. com- mune was eight feet long, and of the height of a wild boar, but of a more elongated shape ; it had a long and thick tail, which, it is supposed, like that of the Otter, assisted it to swim with facility ; from the structure of the teeth it is inferred that it browsed on grass like the horse. The A.secun- ' Tin Palaeotherium had seven molar teeth on each side the lower jaw ; in figured, three true molars, and two of the premolars, remain , tin- seventh or last molar has three crescent-shaped lulus; the others but ■ ich. I tails ot their anatomical structure are given in Cuvier's '■(>■ I. iii. FOSSIL REMAINS OF EXTINCT MAMMALIA. I If) darium was a smaller species. The Chwropotamw was of the hog tribe, and nearly related to the Peccari, but one-third larger. The Palwotheria resembled the Tapirs in the form of the head, and in having a short proboscis, but their molar teeth were more like those of the Rhinoceros ; their fore-feet had but three toes, instead of four, as in the Tapirs. Upwards of eleven species, varying from the size of the Rhinoceros to that of the Hog, have been discovered in the tertiary strata of France. The P. magnum was of the size of a horse four or five feet high, with a mas- sive head and proboscis, and short extremities. The P. medium was one-sixth smaller than the American Tapir, but had longer and slighter legs and feet. The P. minus was an elegant creature of the size of the Roebuck, with light and slender limbs. The Dichobune is related to the Anoplo- therium, but characterised by the peculiarity of its dental system, which approaches that of the ruminants in the cusps of the molars having a ten- dency to form a double series of crescents. (See PL II. fig. 13.*). We must here terminate our investigation of the strata exposed in the quarries near Ryde, and • In " Brit. Foss. Mam." (p. 440) beautiful figures arc given of portions of a lower jaw with teeth, found at Binstead, by Mr. Pratt. 120 GEOLOGY OF THE ISLE OF WIGHT. proceed to the eastern end of the island, to ex- amine the marine deposits that underlie the flu- viatile and lacustrine strata, to which our attention has hitherto been exclusively directed. CHAPTER IV. FROM RYDE TO CULVER CLIFF — GEOLOGY OF WHITECLIFF BAY STRATA AND ORGANIC REMAINS SANDOWN BAY BONES OF COLOSSAL REPTILES. From Ryde to Culver Cliff. — On the north side of Culver Cliff, the eastern extremity of the chalk downs and of the island, the long-continued action of the sea on the tertiary strata has exca- vated an irregular bay, which is bounded by cliffs that expose a section of the entire series of marine and freshwater eocene deposits. This ex- cavation is called Whitecliff Bay, and is about nine miles from Ryde.* The road from Ryde passes over a country prettily diversified by gentle hills and dales ; but the strata are concealed by pasturage and cul- tivation, and the geological character of the dis- trict can only be traced in the low borders along the sea-shore, and in the pits and quarries opened * See the diagram, PI. VII. p. 94 ; and the Map, PI. XX. The reader will remember that Whitecliff and Alum Bay are natural sections of the vertical and horizontal tertiary strata that extend through the island from east to west, on the north of the chalk downs. 122 GEOLOGY OF THE ISLE OF WIGHT. for the extraction of limestone for economical purposes. The whole of this tract consists of freshwater marls, clays, sands, and limestones, like those of Binstead. As we approach Brading the chalk downs which form the horizon rise up in bold relief, and flank the tertiary strata on the south. On the summit of this line of hills is the signal tower on Ashey Down, which forms a con- spicuous object in the landscape. The picturesque town of Brading, with its ve- nerable church,* stands on a low ridge of chalk ; and in descending the gentle declivity beyond, the highly-inclined position of the chalk may be per- ceived in the bank on the right-hand, the layers of flint being nearly vertical. As we proceed, the marl, firestone, and gait appear, and are succeeded by the ferruginous sands belonging to the lowest group of the cretaceous system, and which continue to the sea-shore at Sandown. But our route lies to the left, and w r e pass by cuttings of chalk and marl, Brading Haven • Brading Church. This interesting edifice is supposed to have been erected soon after tin- Conquest : but, independently of its claims as an object of antiquity, it deserves notice from having been for many years the scene of the pastoral labours of the late Rev. Legh Richmond. The admirers of that interesting Author who visit tin- island, should procure the cheap and elegant littll hand book to the scenes described in the " Annuls uf the Poor," entitled " Th< Lam capi Beauties of tin Isle oj Wight, as described by Iht hiii lie. Legh Richmond; by c,,,,n: Brannon" FROM RYDE TO CULVER CLIFF. 123 being spread out before us on the left, till we approach Yaverland church,* which stands on a little knoll overshadowed by elms, near the foot of Bembridge Downs. From this spot there is ;t narrow road to some fields on the north of the hill, through which a path leads to the brink of the precipitous cliff that overhangs Whitecliff Bay, near the junction of the chalk and eocene strata. Here a very steep foot-track winds down the face of the cliff, which is covered with ferns and brush-wood to the sea-beach. But the main road leads to Bembridge, f and Whitecliff is reached by a walk of nearly two miles along the shore. After much rain, however, the bay is scarcely accessible, for mud and sand-banks * Yaverland church is supposed to have been erected in the twelfth or thir- teenth century. It was in this church that Legh Richmond made his first attempt to preach extempore, and com pletel y failed ; though he was after- wards celebrated for the power and eloquence of his extemporaneous dis- courses. This interesting spot is graphically described by Mr. Richmond in ' • The Dairyman's Daughter." " It is pleasantly situated on a rising bank at the foot of a bold chalk hill, and being surrounded by trees, has a rural and retired appearance. Close to the churchyard stands a large and ancient mansion, which was formerly the residence of an opulent and titled family, but has long been appropriated to the use of the estate as a farm-house. Its outward aspect bears considerable remains of ancient grandeur, and gives a pleasing character to the spot of ground on which the church stands. In every direction the roads that lead to this sacred edifice possess distinct but interesting features. One of them ascends between several rural cottages from the sea-shore, which adjoins the lower part of the village street; another winds round the side of the adjacent hill ; and a third leads to the church by a gently rising approach, between high banks covered with young trees, bushes, ivy, hedge-plants, and wild flowers." t There is a good hotel at Bembridge, and a passage ferry across the mouth of Blading Haven to St. Helen's. G 124 GEOLOGY OF THE ISLE OF WIGHT. obstruct the way, and the slippery state of the ground renders walking most wearisome. Geology of Whitecliff Bay. — From Bern- bridge, the tower of an ancient church painted white, and serving as a land-mark, is seen on the opposite side, on the northern point of the haven ; the pretty village of St. Helen's, embosomed in trees, stands on the brow of the neighbouring hill. A low cliff, composed of freshwater strata, may be observed near its base ; and from this locality the fossil turtle, described in p. 114, was obtained. The cliffs immediately beyond Bembridge are from twenty to thirty feet high, and consist of alluvial gravel and clay, resting upon freshwater strata ; the ledges and rocks on the sea-shore are denuded waterworn masses of the limestone that have fallen from the cliff. After passing the Foreland, and proceeding a few hundred yards along the shore, the tertiary calcareous deposits form the base of the cliffs, and lie in a nearly hori- zontal direction ; but towards the northern ex- tremity of the bay they gradually rise, and at length are bent upwards in a curved position, and rest somewhat unconformably on the almost vertical beds of clay.* This is the point of junction * A beautiful sketch of this part of the cliffs is given in PI. XV. ; and of thi Hay, in PI. XVII. No. I, of Sir Henry Englefielu's " Isle of Wight." WHITECLIFF BAY. 125 of the freshwater and marine series of the Isle of Wight eocene deposits. The cliff now entirely consists of the London clay beds, which are ex- posed wherever there is a break or slip in the turf-covered slopes. These strata become more developed towards Culver Cliff, where the lower- most tertiary, and uppermost cretaceous strata, are in juxta-position. The magnificent chalk cliffs of Culver can only be seen to advantage from the sea (see PI. XIV.) ; the dip of the beds is about 70° to the north, and is well defined, even from a distance, by the layers of flints. Most of these siliceous nodules, though imbedded in the chalk, and still retaining their original forms, are splintered to atoms, probably from the concussion produced by the upheaval of the strata ; this phenomenon was first pointed out by Sir Henry Englefield.* Whitecliff Bay, though destitute of those re- markable characters which have rendered Alum Bay so attractive to the tourist, is highly interest- ing to the instructed observer. From the period when Sir H. Englefield and Mr. Webster first directed attention to the phenomena here exhi- bited, this locality has been explored by many * See Linna;an Transactions, vol. vi. p. 108; also, Fossils of the South Downs, p. 151. G 2 12G GEOLOGY OF THE ISLE OF WIGHT, eminent geologists,* and the mineralogica! character, organic remains, and order of succession of the strata, have been accu- rately determined. f But a few months since an elaborate and important memoir, with ample illustrations, and details, was laid before the Geological Society by Mr. Prestwich. % In the present work a concise view of the most interesting facts is alone admis- sible, and which the annexed diagram (lign. 8), from a section exhibited by Mr. Prestwich, will serve to render intelligible. The eocene strata in White- cliff Bay appear in the same order of superposition as at Alum Bay, as we shall point out when we visit that locality ; but the cliffs before us are less * In 1S22 Mr. Lyell made an accurate examina- tion of this cliff, and favoured me with a series of specimens and a detailed section of the strata. + See list of publications relating to the Geology of the Isle of Wight, in the Appendix. i since published in the "Quarterlj Journal of the Geological Society," August, WIIITECLIFF BAY. 127 precipitous than those in the north-west of the Island, and their slopes are covered by debris, and in many places with vegetation, down to the shore. The eocene deposits of the Isle of Wight, ac- cording to the investigations of Mr. Prestwich, may be regarded as forming three principal groups ; viz. the upper freshwater series, and the marine series, which is divisible into the London clay, and the Bognor deposits (see lign. 8).* The strata and organic remains. — If we retrace our steps from Culver Cliff towards the Foreland, we find that the lowermost tertiary strata, those in actual contact with the chalk, consist of mottled plastic clays, in which no ves- tiges of animal remains have been observed. These are followed by a brown sandy clay, with septaria, &c, and a series of sands, sandstones and clays, which abound in species of shells of certain ge- nera, long known to prevail in the strata that emerge along the western coast of Sussex, and * The Bognor fossils were first mentioned by Mr. Webster ; a more extended notice was published in my " Fossils of the South Downs," and "Geology of the South-East of England." "The rocks at Bognor are evidently the ruins of a deposit once very extensive, and which, even within the memory of man, formed a line of low cliffs along the coast; at present a few groups of detached rocks, covered by the sea at high water, alone remain, and the period is not far distant when these will be swept away by the action of the waves. These beds are decidedly analogous to the calcaire grossier of Paris." — Geol. S. E. of England, p. 51. 128 GEOLOGY OF THE ISLE OF WIGHT. particularly at Bognor ; the rocks on the shore at that watering-place consisting of coarse sandstone full of similar fossils. The lowermost or earliest bed of this series, is a layer of brownish clay with green sand (in some parts passing into concre- tionary sandstone) almost made up of the tubular shells of one species of pteropodous mollusk, the Ditrupa plana, formerly called Dentalium planum, (PL III. fig. 3); the Bognor rocks are full of these shells. The clays and sands that succeed swarm with certain marine bivalves (ostrecc, myw, turritellw, pectuncull), which also occur at Bognor. The Panopma intermedia (PI. III. fig. 5), is a very characteristic fossil.* A considerable thickness of variously coloured sands and clays, in which no organic remains have been found, is next in order ; and then the suite of deposits of the London clay teeming with marine exuviae. Among the shells are the species figured in PL III. figs. 1, 2, 4, 6, 7 : the Cardita planicosta (fig. 7), is a strong and thick bivalve that abounds in some of the argillaceous beds, and often attains a large * The position of the strata containing the Ditrupa and the Pun"/,,, a is shown in the diagram, lign. 8. A few weeks since, several blocks of the greenish limestone, covered with Ditrupte, were lying on the beach near the spot indicated. WIIITECLIFF BAY. 129 size.* Shells of the genera Nummulites,f Venus, Ancillaria, Voluta, Cerithia, &c, occur in im- mense numbers ; J and in the greyish blue clay are myriads of minute species. Teeth and bones of fishes, and of reptiles, and remains of crustaceans (crabs, lobsters, &c.) are occasionally found. In the upper beds of the London clay lignite t (carbonized wood), and shells of certain genera which inhabit estuaries (Melanopsis, PI- II. figs. 3, 6,) and some freshwater species are met with, indicating that the strata were de- posited in brackish water. These are the upper- most of the highly inclined marine beds at Whitecliff Bay. * At Bracklesham Bay, on the western coast of Sussex, the clay, at low water, is in many parts literally paved with these shells, and great numbers may be collected in a very short space of time. Bracklesham is also prolific in numerous other fossils of the London clay. In 1821, I made a considerable collection of the organic remains of this part of the Sussex coast, and pub- lished a list of them in the " Fossils of the South Downs," and a more extended one in the " Geology of the South-East of England." But of late years diligent research has brought to light numerous fossils of great interest ; and besides many new species of shells, vertebrae and bones of fishes, ser- pents, turtles, and crocodiles, have been collected. For an excellent notice of this locality by Mr. Bowerbank, see "Medals of Creation," vol.ii. p. 903. Mr. Dixon has a splendid collection of the Bracklesham fossils, comprising several new species of Miliobatis (eagle-ray), A'etobatis, and other genera of the Rays. Spines of these fishes, and of a species of Silurus, have also been discovered. t Nuninutlites, a fossil polythalamian shell, ofadiscoidal flattened form, resembling a coin, hence the name. See " Medals of Creation," p. 242. X A chisel as well as a hammer, and a pickaxe to break up large masses of the stiff clay in which the shells are imbedded, will be required to extract perfect specimens. 130 GEOLOGY OF THE ISLE OF WIGHT. The freshwater series next appears ; but in the lowermost division of this group there is an inter- mixture of estuary and marine shells; these de- posits would, therefore, he more correctly desig- nated flmio-marine. Calcareous marls, sandstones, and limestones, abounding in fluviatile and lacus- trine shells, similar to those of Binstead, form the succeeding portion of the cliff. On a recent visit the fallen masses of rock were full of fossil seed- vessels of chaxae (C. tuberculata, lign. 5, p. 109). Some of the upper strata are of a fluvio-marine character, and within 100 feet of the superior layer, there is a seam of oyster-shells in a bed of marl near the top of the cliff at Bembridge-ledge, which was pointed out by Mr. Lyell in 1824. There are several layers of pebbles in the marine vertical strata ; and in some of the calcareous sandstones of the upper series, pebbles and an- gular fragments of flint are imbedded, alternately with seams of freshwater shells. The total thickness of the eocene strata at Whitecliff Bay is about G50 yards ; * of which, according to the measurements of Mr. Prestwich, the mottled clays are 142 feet; the Bognor series about 300 feet; the London clay 9o0 feet: and * Where the beds are vertical, the horizontal distance of com i tm thickness of the deposits. WHITECLIFF BAY. 131 the fluvio - marine and freshwater group 550 feet. The assemblage of organic remains in these de- posits is regarded by Professor E. Forbes as indi- cating the following sequence of changes in the condition of the basin in which they were formed. " This fauna, which did not begin until after a considerable thickness of mottled clays, in which no traces of animal organization appear, had been deposited upon the chalk, commences by numerous peculiar mya-form shells, pectunculi, ostrege, and their associates, in a series of sands and clays. The earliest fossiliferous bed is a most remarkable one, consisting of a thin stratum, almost entirely composed of the shells of a ptero- podous mollusk (the ditrupa plana, PL III. fig. 3), which appears to have continued but a short specific time in life, and to have entirely disappeared. In the midst of this group, strata charged with myriads of foraminifera (nummulites), probably in- dicating some change in the depth of the sea, appear, and cease. The sudden conversion of the sea into a freshwater lake, denoted by a stratum of paludina clay, its return into a brackish state, and the consequent reappearance of certain marine animals — its reconversion into a freshwater lake thronged with myriads of fluviatile mollusca (plan- 132 GEOLOGY OF THE ISLE OF WIGHT. orbes, llmne'i) — and the almost momentary influx of salt water during that period, which lasted only long enough for a race of oysters to live and die away — all render the tertiary strata in this locality of high interest." * It may assist the collector to state that the ditrupa bed is exposed in the cliff at the distance of from 45 to 50 paces from the junction of the lowermost tertiary clay with the chalk. At 150 paces further, towards Bemb ridge, are green- ish grey sands and clays, in which the cardita planicosta {PI. III. fig. 7), and numerous other marine shells occur ; and about 200 paces onwards similar shells, with large nummulites, volutes, cerithia, &c, are abundant in strata of the same character. -j- Sandown Bay. — To pursue the natural order of our inquiry, we should now retrace our steps to Ryde, and proceeding to the north-western ex- tremity of the Island, examine the corresponding phenomena in Alum Bay. But it may be more convenient to the visitor if we first conduct him to the southern side of Culver Cliff, where a natural section of the strata of the cretaceous * l'aport of the fourteenth meeting of the Brit. Assoc, of Science for 1844. Transactions of the Sections, p. 41. t Sec an interesting paper " On the London and Plastic Clay Formations nf the Isle of Wight," by .!. S. Bowerbank, Esq. F.R.S. Geol. Trans. SANDOWN BAY. 133 system (see table, p. 63), and of the upper Weaklen deposits, constitutes the line of cliffs forming the boundary of Sandown Bay (see the Map, PL XX.). But we shall restrict our remarks to a very general description of the geological structure of these cliffs, and reserve a particular account of the chalk and weaklen formations till we enter upon the examination of the south-western lo- calities of these deposits. From Bembridge we return to the foot of the Downs by Yaverland church,* and thence through the village to the sea-shore, near the centre of Sandown Bay, the distance from Yaverland scarcely exceeding a mile.-f- It is desirable to alight before we reach the Fort, and as near to the coast as possible, and then proceed along the strand to- wards the eastern end of the bay. J The annexed sketch, from the accurate sections of Dr. Fitton, will convey a general idea of the relative position of the strata. * There is a small chalk-pit on the side of the hill worth examination, as it well displays the highly inclined position of the chalk and flint strata. t The stranger must not attempt to go round the headland of Culver Cliff by the strand, even at low water; Sandown Bay can only be safely reached in a boat, except by the road described in the text. t At the village of Sandown there is an inn where refreshment may be obtained for "man and horse." The coach from Ryde to Ventnor stops at the King's Head, near the sea-shore, where the geologist travelling by this conveyance should alight. 134 GEOLOGY OF THE ISLE OF WIGHT. The distance com- prised in the section is between four and five miles ; Slumklin Down forms the western, and Bembridge Down the eastern limit. On the eastern side of the bay the flinty chalk has a total thickness of about 200 feet ; the lower chalk and chalk marl, 200 feet ; the firestone 100 feet; and the gait 50 feet. The greensand beds that follow, correspond with those of Atherfield cliffs, which we shall here- after visit, and contain similar fossils; the low- ermost bed abounding in that remarkable and characteristic shell, the Perm Mulleti (PL IV. fig. 6). The Wealden deposits occupy the mid- dle of the bay ; and on SANDOWN BAY. 135 the west, the sands and clays, of the greensand reappear, and form the cliffs from Sandown to Shanklin, where they are covered by the gait, firestone, chalk-marl, and flinty chalk ; the latter attaining an elevation of nearly 800 feet. Sandown Bay comprises, therefore, a double series of the strata of the cretaceous system, thrown into an anticlinal position by the elevation of the wealden, which constitutes the axis of this line of coast.* Along the middle of the bay opposite the Fort the subsoil, except after very heavy tides, is con- cealed by a thick bed of shingle.-j- Red Cliff. — On proceeding eastward a low bank appears, and the coast gradually rises to the lofty hills of Red Cliff. The strata first acces- sible to observation are the ferruginous sands and mottled clays belonging to the wealden formation, which become more developed as we advance towards the chalk strata that terminate in the * The anticlinal axis and order of superposition of the strata at Sandown Bay, and the correspondence of these deposits with the wealden and cre- taceous systems of Sussex and Surrey, were ascertained more than twenty- four years since by Mr. Lyell, and communicated to me in a letter dated Bartley Lodge, July, 1822, accompanied by a section from Culver Cliff to Shanklin Down, and a suite of specimens comprising examples of all the principal deposits ; this collection is now in the British Museum. + In the section, for the sake of perspicuity, the wealden strata in the middle of the bay are represented more lofty than they actually appear ; for in general the sea-beach extends over the whole surface. But after sweeping spring tides in the early months of the year, the clay and sands are exposed as here represented. 136 GEOLOGY OF THE ISLE OF WIGHT. bold promontory of Culver, which forms a striking object from this part of the bay. In the shingle may be found rolled blocks and pebbles of the wealden shelly limestones ; and of jasper and quartz, with rolled silicified zoophytes that have been washed out of the chalk. In the wealden, bones of large reptiles, and fruits of coniferous plants, have from time to time been discovered; and many colossal bones of the Iguanodon have been obtained from the shingle. Slabs of the paludina-limestone (see PL VI. fig. 3), commonly called Sussex marble, and of indurated shale full of fresh- water bivalves {PL VI. fig. 4), may generally be seen protruding from the clay.* Masses of lig- nite that have fallen out of the cliffs are often found on the beach, and sometimes pebbles of silicified wood. A few hundred yards before we reach the chalk strata, laminated clay and shale appear in the face of the cliff, and the surfaces of most of the lamina? are studded with myriads of the cases of minute freshwater crustaceans, termed cyprides (see lign. 25), belonging to two or three species which are peculiar to the wealden de])osits. * In a late visit to this spot (August 1846) a layer of Sussex marble having a band of fibrous calc-spar an inch thick, above and below, was exposed in the clay near the base of the cliff. SANDOWN BAY. 137 It is only after recent slips of the cliffs from the inroads of the sea, that the beds are clearly exposed, and after heavy rains, that the fossil bones are brought to view by the washing away of the clay in which they are imbedded ; but at all times instructive specimens of the strata, and of the usual species of shells, may be obtained. The greensand and gait are not so prolific in fossils as in some other localities ; but the marl and fire- stone contain many organic remains characteristic of those beds. Bones of the Iguanodon, &c. — The occur- rence in this locality of bones of the Iguanodon and other reptiles whose remains had previously been observed only in the strata of Tilgate Forest, was first made known in 1829 by the pre- sent Dean of Westminster, Dr. Buckland. An enormous toe-bone {metatarsal), weighing six pounds, and measuring six inches in length, and sixteen inches in circumference at its largest ex- tremity, was found in the ledges of ferruginous sand, a little to the east of Sandown Fort.* A considerable number of bones, comprising several gigantic vertebra?, portions of a femur or thigh- bone, fragments of ribs, &c, were discovered near the same spot, at the foot of the low cliff that * Geol. Trans, vol. iii. p 425. 138 GEOLOGY OF THE ISLE OF WIGHT. forms the sea boundary of Yaverland farm. They were observed on the shore after a week of very stormy weather, which had swept away the beach and sand to the depth of two feet, and thus laid bare the fossils, which probably had fallen from the cliffs long previously, and being very heavy, had sunk deep into the shingle, and lain concealed till brought to light by the denuding effects of the storm. In the adjacent cliff of grey sandstone interspersed with clay, several cones of a plant allied to the Zamicc, mixed with fragments of lignite, have been discovered.* We now return to Ryde that we may proceed to the north-western part of the Island, and examine the eocene strata at Alum Bay and Headon Hill. * One of these fossil fruits is figured ami described in "British /'< ii Flora," under the name of Zamia crassa; and in " Medals of Creation,' vol. i. j). 160. CHAPTER V. FROM RYDE TO NEWPORT THE RIVER MEDINA NEWPORT TO C.W.- ' \E AND ALUM BAY — THE COAST FROM RYDE TO ALUM BAY 1IEADON HILL AND ALDM BAY GEOLOGY OF HEADON HILL AND ALUM BAY — SEQUENCE OF GEOLOGICAL CHANGES — ORGANIC REMAINS — YARMOUTH AND LYMINGTON ■ — CHRISTCHURCH BAY STRATA OP IIOKDWELL CLIFFS — HORDWELL FOSSILS. From Ryde, through Newport to Alum Bay. —From Ryde, the journey to Alum bay may be performed either by land or sea. The road passes by Binstead, and through the picturesque village of Wooton-bridge, to Newport, the capital of the Island. In the rooms of the Newport Institution, there is a miscellaneous collection of organic remains; but it is much to be regretted that a complete series of specimens, illustrative of the geology of the Isle of Wight, is not to be met with in this, or any other town, in the Island. Newport is situated on freshwater eocene strata, which are a continuation of those of Headon Hill, and lie in a nearly horizontal position ; the wells in the town are sunk through these beds, to the H 140 GEOLOGY OF THE ISLE OF WIGHT. depth of 200 feet. At Parkhurst barracks, a wel! was dug through 300 feet of London clay, con- taining a few thin seams of shells. On examining the nature of the soil in the tract between the town and the neighbouring chalk hills, the ver- tical marine strata are found occupying the same relative position as at Whitecliff Bay.* In a heap of clay that had recently been dug up from the bottom of a well, Mr. Webster discovered vestiges of coleopterous insects ; and obtained several fossil seed-vessels of a plant related to the Meadow-rue (Thalictrum) ; they consisted of the pericarp, in a carbonized state, filled with clay.-j- The quarries in the neighbouring chalk down of Mountjoy, to the southward of the town, expose some interesting sections of the highly inclined strata of chalk and flint ; and the summit of the hill commands a most extensive and delightful prospect. River Medina. — The Medina river, which rises at the foot of St. Catherine's Down, and divides the Island into two nearly equal portions, called the East and West Medina, flows through * Mr. Webster notices a clay-pit, opened for a brick manufactory, in which were clay and sand strata, in a nearly vertical position, and the upper por- tions contorted .is if from pressure. Sir H. Englefield's " Isle of Wight," pi. xxxiv. fig. 1. t A figure of this fruit (which has been named by M. Adolphe Brongniart, Thalictroide* Weblteri,) is given in the " Medals of Creation," vol. i. p. 190. RIVER 3IEDINA. 141 a transverse valley of the chalk range on the south, and winding round the east end of the town, be- comes navigable for vessels of considerable bur- then, to its entrance into £ 3 the sea at Cowes. The val- g ley of the Medina, like the river valleys of the North and South Downs,* is a transverse £ ■§ dislocation, or rent, across the 5 range of chalk hills, produced » ° by the tension of the strata § 3 I. during their elevation from S | s fo < g a, o the horizontal to their present 8 c 7 nearly vertical position. a ^> I The transverse course of § ! h the Medina through the mid- "f die of the central ridge of > ts chalk, is noticed by Mr. • Hopkins, in his memoir ft. — X z " On the Geological Struc- ture of the Wealden District, T ««. 290. i] u i" those found in the plastic clay at Newhaven, in Sussex, and i Isof th( South Downs, ' /'/. I. HEADON HILL AND ALUM BAY. 149 bers of an undescribed species of Gypris. The lower part of the cliff consists of sand containing freshwater with marine and estuary shells. We next pass Yarmouth, and doubling the headland on which was Worsley's Tower, opposite Hurst Castle, enter Colwell Bay, where the cliffs exhibit alternations of marine and freshwater strata. In the fissure called Bramble Chine a thick bed of oyster shells is exposed, apparently in its original state, the valves being in contact with each other as when living; this appears to be the equivalent of the oyster bed observable at Whitecliff Bay. Many beautiful fossil shells may be collected in this locality. The elegant Cytherea incrassata (PL III. fig. 6), and Neritlna concava (PL II. fig. 5), are found in sandy clay, in as perfect a state as if but recently thrown up by the waves. In Totland, or Tolland's Bay, similar sands, clays, and marls form the cliffs. Headon Hill and Alum Bay. — We now approach Headon Hill and the richly coloured vertical strata of Alum Bay. The picturesque character of the dislocated masses of strata forming the face of the cliffs at Headon Hill is shown in PL IX. The appearance of Alum Bay from the sea is imposing in the extreme, and is thus gra- phically described by Sir Henry Englefield : — 150 GEOLOGY OF THE ISLE OF WIGHT. " The scenery of this bay is very superior in magnificence to that of any other part of the Island. The chalk forms an unbroken face every where nearly perpendicular, and in some parts formidably projecting, and the tenderest stains of ochreous yellow and greenish moist vegetation, vary without breaking its sublime uniformity. This vast wall extends nearly a quarter of a mile, and is more than 400 feet in height ; it terminates by a thin projection, of a bold broken outline, and the wedge-shaped Needle Rocks, rising out of the blue waters, continue the cliff, in idea, beyond its present boundary, and give an awful impression of the stormy ages which have gra- dually devoured its enormous mass. The pearly hue of the chalk under certain conditions of the atmosphere and light is beyond description by words, and probably out of the power oven of the pencil to portray. " The magical repose of this side of the bay is wonderfully contrasted by the torn forms and vivid colouring of the clay cliffs on the opposite side. These do not, as at Whitecliff, present rounded headlands clothed with turf and shrubs, but offer a series of points of a scalloped form, and which are often sharp and pinnacled. Deep rugged chasms divide the si rata in main plans. GEOLOGY OF ALUM BAY. 153 and not a trace of vegetation appears in any part. All is wild ruin ! The tints of the cliffs are so bright and so varied, that they have not the aspect of anything natural. Deep purplish red, dusky blue, bright ochreous yellow, grey, nearly ap- proaching to white, and absolute black, succeed each other, as sharply defined as the stripes in silk ; and after rains, the sun which, from about noon till his setting in summer, illuminates them more and more, gives a brilliancy to some of these nearly as resplendent as the bright lights on real silk. Small vessels often lie in this bay for the purpose of loading chalk and sand, and they serve admirably to show the majestic size of the cliffs under whose shade they lie diminished almost to nothing." * Geology of Alum Bay. — Although the uncon- formable position and dislocated state of the strata at Headon Hill, appear, at first sight, to present but little correspondence with the nearly horizon- tal freshwater deposits at Whitecliff Bay, and the richly-coloured and variegated stripes of sands and clays of the vertical cliffs of Alum Bay, still less to resemble the dull ochreous marine beds ex- posed in the breaks of the turf-covered slopes of that locality — yet a careful examination will soon » Sir H. Englefield's " Isle of Wight," p. 81. 154 GEOLOGY OF THE ISLE OF WIGHT: convince the observer, that the geological charac- ters of this north-western section of the eocene strata, agree in every essential feature with those which engaged his attention at the eastern extre- mity of the Island.* The diagram, lign. 11, will serve to show the close analogy between the de- posits of Whitecliff, and of Alum Bay. This correspondence, and the extension of the same beds throughout the northern portion of the Isle of Wight, were ascertained, and distinctly enun- ciated by Mr. Webster, in his admirable memoir on the " Strata above the Chalk." f From the incessant action of the sea on the base of Headon Hill, large masses of the upper beds are continually falling down ; and the face of the cliff is generally in so ruinous a state, that the true stratigraphical position of the deposits is seldom visible. Repeated observations have, how- ever, ascertained that the superior beds are nearly horizontal, but curve upwards as they approach the vertical strata, in the same manner as the cor- responding layers at Whitecliff. In the sketch, PL IX., the upper masses of marl and limestone * Mr. Prestwich has given accurate and detailed sections of Alum Hay, and Whitecliff, in juxta-position on the same plate, and thus admirably illus- trated the relations of the strata in the two localities, Geol. Journal, No. 7. t On the " Freshwater Formations in the Isle of Wight," (fee. Geol. Trans. vol. ii. p. 161, First Series; l.sl I. ALUM BAY AND HEADON HILL. 155 i -2 ^ ' 55 are lying in this position. The footpath that leads from Grove's hotel, down the chasm by which Headon Hill is sepa- rated from Alum Bay, reaches the sea shore at the point marked b, in lign. 11, and which is indicated by the two upper figures in PL IX. The visitor, therefore, upon arriving on the strand, has the horizon- tal freshwater series on the north, and the vertical marine beds on the south, flanked by the lofty chalk cliffs of High Down, and The Needles. At Alum Bay, as at White- cliff, the lacustrine and fluvia- tile deposits are the upper- most series {lign. 11, a,); the strata most decidedly marine, comprising the London clay, occupy a vertical position, and are the middle series {lign. 11, c,)\ the group denominated the Bognor strata, being the lower- most ; then follow the mottled i 156 GEOLOGY OF THE ISLE OF WIGHT. clays, and these abut against a bed of sandy loam, with pebbles and slightly rolled flints, that is in immediate contact with the chalk; as shown in lign. 11, d. The thickness of the eocene strata, from the chalk to the uppermost bed in Headon Hill, is stated by Mr. Prestwich to be 16G0 feet; which is 300 feet less than the series at Wnitecliff. The surface of the chalk in contact with the tertiary beds is much worn, and covered by a layer of sandy loam, containing pebbles, and rolled flints, which are invested with a coating of green earth ; flints of this kind occur, also, at New- haven, and in the fissures and sand-pipes of the Surrey and Sussex downs. Mottled clays and sand, with traces of lignite, as at Whitecliff, next appear, for a thickness of nearly 100 feet ; and then the brown clay, with layers of septaria, abounding in the ditritpa; this is the lowermost bed of the Bognor rocks.* Beds of sandy clay with seams of pebbles, belonging to the same group, succeed, and in some of the layers marine shells are numerous. A fossil crab, common at Sheppey, * More than twenty species of shells, and some teeth Of sharks, are enume- rated by Mr. Prestwich, from this group. The most characteristic are hiii a], a pin, in, />, riu nciii us brevirostris, Turritella imbricataria, Pholadomya „i,ii-,/iinhii , a, I', nmp, ,u i iili-rnii ilia, and Vrrmi'liia Bognorensit; all well- known Bognor shells, and mentioned in the earliest list of the fossils of that locality. See my " Gi ologj of the South-East of England." STRATA OF ALUM BAY. 157 (Cancer Leachii,) was found in this clay, by Mr. Bowerbank. The variegated and deeply-tinted sands, marls, and clays, which impart so remarkable and bril- liant an aspect to the cliff, are the next in order, and form a total thickness of between 700 and 800 feet. The alternations and variety of the vertical seams, or layers, are almost innumerable ; the sands are of every shade of red, yellow, green, and grey ; some are white, and others almost black : the clays are equally diversified. Mr. Webster remarks, that " the variety of the vertical layers is endless, and may be compared to the vivid stripes of a parti-coloured tulip. On cutting down pieces of the cliff, it is astonishing to see the ex- treme brightness of the colours, and the delicacy and thinness of the several layers of white and red sand, shale and white sand, yellow clay and white and red sand; and, indeed, almost every imagi- nable combination of these materials." In the midst of this series, there are vertical layers of pebbles, and one thick stratum and many seams of lignite ; in some of the clays, dicotyledonous leaves have been discovered, but no animal re- mains. These richly-coloured strata are followed by clays with septaria, seams of pebbles, and a bed i 2 158 GEOLOGY OF THE ISLE OF WIGHT. of green sand ; the whole comprising a thickness of between 200 and 300 feet. In some of these deposits, the usual London clay shells are abun- dant, especially near the spot marked c, in lign. 11.* The dark sandy clay immediately on the north side of the chasm b, is also very prolific, and I have collected from it numerous choice specimens ; nummulites, and other foraminifera, occur in some of the beds.-j- We now arrive at the foot of Headon Hill ; and here the lowermost stratum visible on the beach is a pure white sand, which is largely exported for the glass manufactories ; this is covered by a bed of yellowish clay. A series of variously coloured sands, marls, and clays, with layers of friable limestone succeed. The predominating fossils are species of the freshwater genera, limneus, planorbis, melanopsis, potamides, cyrena, Sec, with which the reader is already familiar. But there are in some of the beds a lew marine and estuary shells, as cytherea, ancUlaria, corbida, &c. ; and a layer of oyster shells occurs, similar to that already noticed in the cliff in Colwell Bay. Within 50 feet of the top of the hill, there is * The two figures in the fore-round, PL IX., are near this locality. t See Mr. Prcstwich's " Memoir," for lists of the characteristic fossils found in each stratum, throughout the entire series of deposits. GEOLOGICAL MUTATIONS. 159 a stratum of reddish brown and mottled clay, with seams of lignite ; and on this i.s superimposed whitish sand and marl, with interstratiiied layers of concretionary limestone, full of freshwater shells. A thick bed of gravel forms the alluvial covering on the summit of the hill. Geological ^mutations. — From this sketch of the lithological characters and organic remains of the strata in this locality, it will be seen that the phenomena under review present a close analogy to those observable in Whitecliff Bay ; the dis- crepancy being inconsiderable, and such as may have resulted from slight changes in the hydro- graphical condition of the district during the accu- mulation of the deposits. In both places there are proofs that the commencement of the eocene formation took place in a wide and open sea; the first accumulation of detritus on the water-worn surface of the chalk, being an argillaceous sedi- ment, in which no animal remains were imbedded. The earliest group of fossils, the Bognor series, comprises the shells of marine mollusks that do not inhabit deep sea-water, but live in depths averaging from ten to twenty fathoms. This depth, as Mr. Prestwich observes, would be ob- viously inadequate to allow of the accumulation of detritus sufficient to form strata, which, when 160 GEOLOGY OF THE ISLE OF WIGHT. desiccated, are from 200 to 300 feet in thickness ; and as the lithological character of the beds denotes a quiet and uniform deposit for a considerable time, and the fossils indicate an unaltered con- dition of animal life throughout the same period, a tranquil and gradual subsidence of the sea- bottom must have taken place. The many hun- dred feet of sedimentary strata which were super- imposed on the Bognor series, denote a subsequent subsidence to a great depth, to allow of the accu- mulation of the London clays, and sands. This epoch was followed by a gradual transition to an estuarine and lacustrine condition, as shown by the layers of fluvio-marine and freshwater shells. But the freshwater lake, or estuary, was subjected to occasional irruptions of the sea ; hence the bids of oysters, and interspersion of a few marine shells. A barrier was at length raised to the influx of sea- water, and the sediments became exclusively of a iluviatilc and lacustrine character ; this is proved by the prevalence of freshwater plants, crustaceans, and mollusks ; and the presence of bones of ter- restrial reptiles, and of mammalia.* Organic remains. — Alum Bay and Headon * This interpretation of the phenomena, is a concise expression of the generalization of Mr. Prestwich, whose admirable Memoir should be carefully studied by those who would enter fully into all the bearings of this infc inquiry. See " Journal of the Gtolog. Sot ii ty," No. 7. ALUM BAY FOSSILS. 1G1 Hill, will afford the visitor an abundant supply of fossil shells, in great perfection and variety. Figures of a few characteristic species, are given in PI. I. and II. Potomomya gregaria, PI. II. fig. 1. Hcadon Hill. Potamides concavus . — _ 2. — !• . — — 8. pilLaLUS . . ventricosus — — 9. — Planorbis euomphalus PL I. — 1. — Limneus fusiform is — — 4. — lnnm«.«t n . — 3. — 6. JOnglSCaullS . Paludina angulosa . . — — Melanopsis fusiform is PI. II. — 3. — bi'evis . . — — 4. — Psammobia solida . . Pllll. — 1. — Cytherea incrassata . . — — 6. — Corbula cuspidata . . — — 2. Alum Bay. Ancillaria subulata . . — — 4. — Neritina concava . . . PI. II. — 5. — Ditrupa plana .... PL III. — 3. — Panoptea intermedia . — — 5. — Cardita planicosta . . — — 7. — Teeth of two species of PalEeotherium (P. cras- sim, and P. medium,) were obtained by Mr. Prest- witli from Headon Hill; and I have seen a block of limestone, in which were imbedded several ribs of a small mammalian, from the same locality. A few species of crustaceans have been collected from the blue London clay, near the footpath. Gyrogonites, and impressions of dicotyledonous 162 GEOLOGY OF THE ISLE OF WIGHT. leaves, and lignite, are the only vegetable remains I have observed. The fluvio-marine and freshwater shells, may be collected in great numbers from the fallen masses of strata that lie on the sea shore. In the marls, the shells of the limnei, planorbes, &c, arc well preserved ; a chisel will be required to extract them. Thousands of the small species of potamides, mdanopsis, &c, will be found on the strand, having been washed out of the clays and sands composing the cliff. Very fine specimens of several species of marine shells may be obtained from the dark clay at the point marked b, in lign. 11. The spot which I have found most prolific, is the base of the cliff at the commence- ment of the footpath, near the sea-shore. Yarmouth and Lymington. — It is unnecessary to extend our remarks on the eocene formations of the Island ; from what has been advanced, the intelligent visitor will readily comprehend the geological phenomena observable in the localities not comprised in our excursions. But before entering upon the examination of the next system, the Chalk, we would recommend a brief sojourn at Yarmouth ; which is a convenient location for the geologist to visit Totland and Colwell Bays, llampstead Cliff, and a few places on the opposite LYMINGTON. 163 coast of Hampshire, which have long been cele- brated for their organic remains. The town of Lymington is situated on the western bank of the river of the same name, about four miles from Yarmouth, across the Solent Sea; to this place there are steam-packets from the Island, several times in the day. The town is spread over a low hill of tertiary strata. Near the brick-kilns on the eastern bank of the river, not far from the toll-gate, a deep excavation has been made in beds of sand and clay, containing fossils.* An alluvial layer of gravel, ten feet deep, lies upon laminated blue and greenish clays, with interspersions of lignite, four feet in thick- ness. The next stratum is fine white sand, like that of Headon Hill, and Hordwell Cliff, six feet ; and beneath is blue (London ?) clay, to an uncer- tain depth. In this clay I found several vertebras and dermal bones of a crocodile, (Crocodilus Spen- ceri,-\) and a few fragments of bones of turtles. I observed no vestiges of shells ; but learnt from the workmen that several kinds were occasionally found, and also many bones, but none had been preserved. \ * This section was open in 1845. t A well-known species of the London clay, at Sheppey. X This brief notice is inserted to direct attention to a locality, hitherto, I believe, unexplored. I recommended the workmen to save every shell, bone, 164 GEOLOGY OF THE ISLE OF WIGHT. Christchurch Bay. — Christchurch Bay is a semi-elliptical excavation, about eleven miles long, formed b) r the action of the sea on the Hampshire coast, which is here composed of an extension of the eocene strata of the north-west part of the Isle of Wight ; the two portions being now separated by the British Channel, which flows into the Solent Sea. The westernmost point of the bay, is Hengisibury Head, near Christchurch ; the easternmost, is the bar of shingle on which Hurst Castle is situated. Along the line of coast bound- ing the bay, there are several places in which sec- tions both of the marine and freshwater strata are exposed ; and Hordle, or Hordwell Cliff, near the little village of that name, has long been known as an inexhaustible mine of fossil relics. So long since as 17(56, a quarto work was published in illustration of the organic remains of this locality, with engravings, which, for accuracy and artistic skill, far surpass most of the modern figures of objects of this kind,* Hordwell is about midway between Lymington and Christchurch ; but from Yarmouth, in fine and tooth, they might meet with; some future visitor will, perhaps, reap the benefit of tin- suggestion. • " Fossilia Hantoniensia collecta et in Musaco Britannioo deposits, a Gustavo Brander, Londini, 1766." " Hampshire Fossils," &c, with nine plates, containing 131 figun CHRISTCHURC1I BAY. 165 weather, a boat offers the most convenient trans- port. Hurst Castle, which guards the narrow part of the Solent Strait, here not a mile across, is built on the extremity of a bar of shingle, that extends nearly two miles from the mainland, on the eastern part of Christchurch Bay. This bank consists of waterworn chalk-flints, and gravel, de- rived from the alluvial drift, which is so largely distributed over the coast district. " It is re- markable," as Sir Henry Englefield observes, " for its uncommon solidity ; for it is merely a submarine cliff of shingle, 200 feet high, the depth of the channel close to the castle being 33 fathoms ; and the tide flows through it with a rapidity which, at certain times, no boat can stem; yet this natural breakwater has remained unmoved for centuries." * At the junction of the bar of Hurst Castle with the mainland, a low bank of gravel extends for about a quarter of a mile, and is succeeded by tertiary sands and clays, which gradually rise into cliffs 200 feet high ; the first mile and a half being Hordwell Cliff, properly so called, which reaches to Long-mead End. From this spot to a ravine formed by a stream at Beacon Bunny, a distance * See Sir H. Englefield's " Isle of Wight," p. 14, for many interesting remarks on the bed of the Solent. 1G6 GEOLOGY OF THE ISLE OF WIGHT. of half a mile, the cliff is named Beacon Cliff. The next two miles and a quarter is Barton Cliff, which is terminated by a stream at Ckerton Bunny ; and the remainder of the line to near Muddiford, is High Cliff.* The alluvial gravel which forms the subsoil of so large a portion of this coast, appears at the top of the cliffs in a bed varying from twenty to fifty feet in thickness. -j: Strata of Hordwell Cliff. — The eocene strata in the coast sections have in no instance a vertical, or even highly inclined position, but gently dip to the east. The Headon Hill series first appears, and constitutes the Hordwell Cliff; and the London clays and sands which rise to the surface at Barton Cliff, form the remaining portion of this line of coast. The strata of Hordwell Cliff consist of alternating beds of marl, sand, and clay, often of a greenish colour, with thin bands of indurated shell-marl full of the usual freshwater species. Mr. Searlcs Wood mentions that a thin seam of sandy clay, abounding in marine shells, is intercalated with these lacustrine strata a few paces ' These localities are accurately described by Mr. Webster, in his second " Memoir," and are here introduced that the visitor may have no difficulty in finding the places hereafter mentioned as yielding certain species of organic remains. t The stratification of the coast, from the west of Christchurch to the chalk at Studland Bay, in Dorsetshire, a distance of seventeen miles, is di by Mr. Lyell, in Geol. Trans, vol. ii. p. 27:>. STRATA OF HORDWELL CLIFF. 167 westward of a ravine that is situated half a mile from the village of Milford. It is about ten or twelve feet above high- water mark, and extends many yards along the cliff.'* The freshwater beds continue as far as Beacon Bunny, and in the upper part of that ravine, beneath the alluvial gravel, there is a bed of fluvio-marine sand, containing an intermixture of estuary and fluviatile shells, which may be traced to the eastward under the fresh- water marl, to about 300 yards from Mead-end, where it disappears beneath the shingle of the beach.f This is succeeded by fine white siliceous sand, like that at the base of Headon Hill, form- ing a stratum from 60 to 100 feet thick. The London clay series next appears, and extends through Barton and High Cliffs. The upper por- tion of the beds consists of sandy clay of a dark green colour, like that at the base of the cliff in Alum Bay (marked b in lign. 11), and abounds in marine shells ; beneath are layers of septaria. The strata at Hordwell Cliff are regarded by Mr. Lyell as the equivalents of the lacustrine beds which form the coast from Yarmouth to Gurnet Point, where the strata lose the character of an indurated calcareous marl, and are not unfre- * The new " London Journal of Palaeontology and Geology," p. 2. t Mr. Searles Wood, loc. cit. 168 GEOLOGY OF TIIK ISLE OF WIGHT. quently of a bright green colour, like many of the layers of marl and clay at Hordwell. Detailed descriptions of the strata and their fossils are given by this eminent geologist in the second volume of the Geolog. Trans. ; the following sum- mary will be useful to the visitor : — 1. Alluvial gravel, forming the top of the cliff; composed of broken chalk-flints, with interspersions of sand and marl ; thickness from 5 to 50 feet. 2. Fine white sand with greenish marl ; — from 3 to 12 feet. 3. Green marls, with arenaceous clays ; — 16 feet. Contain bituminous wood and seed-vessels, with shells of the genera Helix, Unio, Melanopsis, Planorbis, and other lacustrine species. The lowest stratum is laminated marl, with layers of Cyprides. 4. Sands and clays; — 15 feet. Numerous shells of the mya V' garia. Lignite occurs in a layer of bituminous clay. 5. White calcareous marl, largely constituted of aggregated freshwater shells; contains gyrogonites (see p. 109). It rests on a layer of black carbonaceous clay, with lignite; 1 foot. 6. Green unctuous and arenaceous marls ; the lower portion consists of beds of pure white sand, with argillaceous sands;— 15 feet. Numerous fluviatile shells. The white sand contains abundance of the shells of a small mussel (mya plana) in a very perfect state. 7. Light green calcareous and sandy marls, with layers of a carbonaceous clay containing lignite; — 22 feet. Nu- merous shells; and seed-vessels. 8. Green marl, carbonaceous clay and lignite, ferruginous clay, marl with r<nssions, and green clay; It feet. Freshwater shells, principally two or throe species of bivalves. STRATA OF IIOHDWELL CLIFF. 169 9. White siliceous sand, without shells ; rises near Long-mead End, and extends through Beacon and Barton Cliffs to the middle of High Cliff.* Near Bournemouth, a little watering-place on the Hampshire coast, between Hengistbury Head and Poole Harbour, dicotyledonous leaves, in a carbonized state, of the same species of plants as those found in Alum Bay {ante, p. 162), occur in a sandy marl, which traverses a cliff of firmly aggregated white sand.-)- I am informed by Will tarn Smart, Esq., of Cranbourne (to whom I am indebted for many interesting specimens of these fossil leaves), that the seam of marl is only four inches in thickness, and is limited to a few yards of the cliff, near the base ; it is about mid- way between Bournemouth and Boscombe Chine. In addition to the fossils previously discovered, Mr. Searles Wood has recently obtained the re- mains of five genera of mammalia and of one alligator, consisting of a jaw with all the teeth, of lizards, serpents, and birds. The following remarks on the geological phenomena observable at Hordwell Cliff are too pertinent to be omitted : " From the examination of the various strata * " On the Freshwater Strata of Hordwell, Beacon, and Barton Cliffs, Hampshire," by Charles Lyell, Esq. Geol. Trans, vol. ii. p. 287, Second Scries. t "Medals of Creation," vol. i. p. 193. 170 GEOLOGY OF THE ISLE OF WIGHT. which are exhibited in the beautiful section of Barton and Hordwell Cliffs, and of their peculiar fossils, one may follow in imagination the gradual silting up of an estuary, and its passage east- ward into a pure river deposit. Leaving the regular beds of London clay, which dip gradually to the eastward, and are lost in the beach below Beacon Bunny and Long-mead End, we meet with a stratum of sand in which marine and freshwater shells are intermixed, and one of clay containing leaves and seeds, with an extensive layer of lig- nite. Upon this is a bed whose organic contents display a still nearer approach to freshwater origin by the absence of the more decidedly marine genera, as oliva, natica, &c, and the presence of cyrena, potomomya, &c. in great abundance. Next comes a layer of brown sand, containing rolled fragments of bones of Palcvotherium , Trionyx, &c. y which, from their appearance, may have been transported from a considerable distance. Over this rests a deposit of marl and white sand (No. 6 in Mr. Lyell's section), the latter in the state of an impalpable powder; in this were deposited nearly all the fossils above mentioned. The strata incline to the east at an angle of about 5°. The direction of the stream was no doubt westerly, thai is, toward the marine beds; but at the spot HORDWELL FOSSILS. 171 at which I obtained so many interesting fossils there were indications of a contrary current ; a circum- stance, however, which may very probably have depended upon a sudden bend in the river. The uniformly fine character of the sand, and the con- dition in which it was thrown down, would lead me to infer that the flow of the stream was ex- tremely gentle. The gradual disappearance of marine species, such as are found at Long-mead End, and their replacement, as we proceed east- ward, by species of freshwater origin, is just such a succession as we should expect to meet in tracing the course of a river upwards from its mouth." * Hordwell fossils. — The numerous marine fossil shells which are obtained from this part of the coast of Hampshire are generally known as Hordwell fossils, but it is scarcely necessary to remark, that they almost entirely belong to the London clay strata, and are procured from Barton C'lifis. These fossils are most conveniently ob- tained from the low cliff near Beacon-bunny, and occur in greatest abundance in the upper part of the dark green sandy clay. There are generally blocks of the indurated portions of the strata on the beach, from which fossils may be extracted. * The new "London Geological and Palceontoloyical Journal." loc. cit. K 172 GEOLOGY OF THE ISLE OF WIGHT. It was from Barton Cliff that Brander's fossils* were obtained. Sowerby's "Mineral Conchology" contains figures of numerous species and genera.f The freshwater shells, and the remains of plants and land animals, are to be looked for in Hordwell Cliff, and in the fallen masses lying on the strand. J In conclusion, it may be remarked that shells of those beautiful chambered cephalopoda, the nautili, are seldom, if ever, observed in the eocene strata of these cliffs, or in those of the Island; though the nautilus imperialis is not uncommon in the septaria on the western coast of Sussex, and in the London clay at Sheppey. * Fossilia Hantoniensia. + A collection of Hordwell fossils, consisting of teeth of several species of sharks and rays, hones of turtles, and a great variety of shells, may be purchased at a reasonahle price of Jane Webber, dealer in fossils, Barton Cliff, near Christchurch. % The highly interesting specimens which have rewarded the recent inves- tigations of Mr. Searlcs Wood, will douhtless induce many a collector to visit the spot. The lower jaw of the Alligator Bantoniensis, a coloured plate of which embellishes the first numher of the new "London GeologicalJournal,'' is one of themost splendid British fossils hitherto discovered. Plate 2 of the same work contains figures of some of the mammalian remains discovered at Hordwell by Mr. S. Wood. CHAPTER VI. THE CHALK FORMATION — SUBDIVISIONS OF THE CRETACEOUS SYSTEM — RANGE OF THE CHALK IN THE ISLE OF WIGHT — THE UPPER AND LOWER CHALK CHALK AND FLINT — SILICIFIED FOSSILS OF THE I'll VI.K — THE FIRESTONE THE GALT THE GREENSAND — SUMMARY. The Chalk formation. — The different mem- bers of the Cretaceous system, though presenting considerable variety of lithological character, are yet essentially of the same type, and are linked together by a peculiar fauna, indicating the pre- valence of a similar oceanic condition, throughout the vast period of time comprised in this geolo- gical epoch. The features of a chalk district are so well known, that a brief notice of the physical geo- graphy of that part of the Island which is com- posed of the cretaceous strata, will suffice for our present purpose ; and a reference to the map, PL XX., will render local details unnecessary. The rounded summits of the hills covered with short verdant turf — the smooth undulated out- line of the downs, unbroken save by the sepulchral v o 174 GEOLOGY OF THE ISLE OF WIGHT. mounds of the early inhabitants of the country — the coombes and furrows ramifying and extending into the dee]) valleys which abruptly terminate at the base of the hills, and appear like dried up channels of rivulets and streams, though free from all traces of alluvial debris — thus bearing the impress of physical operations of which the agents that produced them have long since passed away — are phenomena familiar to every one who has travelled over the downs of the south- east of England, and are displayed in striking characters in the chalk districts of the " beau- tiful Island." These features are restricted to the hilly districts of the white-chalk, and have resulted from the peculiar nature of the sedimen- tary detritus of which the strata comprised in the upper division of the cretaceous system are com- posed. For in the lower groups, clays, marls, sands, and sandstones prevail, and where these deposits approach the surface and form the sub- soil, the country is broken and diversified, and the landscape presents a striking contrast with the down scenery ; as may be observed in the picturesque district which flanks the escarpment of the chalk hills. It may perhaps be necessary to remind the unscientific observer that these strata are but SUBDIVISIONS OF TUE CRETACEOUS SYSTEM. 175 an insulated portion of an ancient sea-bottom, or in other words a mass of consolidated sedi- ments formed in the profound depths of the ocean, in a very remote period of the earth's physical history. This detritus is made up of inorganic and organic materials : the former con- sist of the debris of the cliffs and shores which encompassed the ancient sea ; of the spoils of islands and continents brought into the ocean by freshwater currents ; and of chemical deposits thrown down from mineral solutions. The or- ganic substances are the durable remains of animals and plants which lived and died in the ocean, and of fluviatile and terrestrial species that were transported from the land by rivers and their tributaries ; the whole forming such an assemblage of sedimentary deposits as would pro- bably be presented to observation, if a mass of the bed of the Atlantic 2000 feet in thickness were elevated above the waters, and became dry land. Subdivisions of the Cretaceous system. — The nomenclature of the chalk formation has undergone so many alterations, that to avoid con- fusion, it is necessary to define the precise mean- ing which the terms employed in the following pages are intended to convey. 176 GEOLOGY OF THE ISLE OF WIGHT. Chalk formation, and Cretaceous system, are syno- nymous terms, and designate the entire series of deposits between the Wealden and the lowermost eocene stratum. The Chalk— signifies the white chalk, including 1. the upper or flinty chalk ; and 2. the lower or hard chalk, in •which hut few, if any, flints occur. TnE Firestone or Glauconite — comprises the chalk- marl, without any intermixture of green particles, as well as the limestone called in Sussex malm-rock ; and the sands and arenaceous marls and limestones full of green particles of silicate of iron, and termed by geologists the upper-green-sand and firestone. This group is the Glauconie crayeuse, of the French geologists. The Galt — a deposit of stiff blue clay underlying the firestone, and characterised by particular species of organic remains : called also Folkstone marl, and Blue chalk-marl. The Greensanh — designates the scries of clays, sands, sand-tones, and arenaceous limestones; comprising the Iron-sand of Mr. Webster, the Lowcr-greensand of Dr. Fitton (and of tbc map PI. XX.) ; the Shank- Hit sands of the author; and tbc lower argillaceous group, termed the Neocomian or Aiherfield deposits. Range of the Chalk formation m the Island. — The various members of the cretaceous system, as previously stated, constitute the southern half of the Island ; a range of chalk hills, broken through by the transverse valley of the Medina, extending from east to west, and RANGE OF THE CHALK FORMATION. 177 separating the northern and southern districts. At Sandown Bay, we have seen the lower divi- sions of the formation successively appearing in the cliffs, in the anticlinal axis formed by the elevation of the Weal den strata ; and in Compton Bay a like elevation of these deposits in a similar anticlinal system. At Culver Cliff, and from High Down to Comp- ton Bay, the chalk downs, consisting of highly inclined strata, form the sea-boundary ; but in the middle of the Island, this chain is flanked on the south by a denuded district of the lower strata, which expands several miles, and is succeeded by another system of downs formed of horizontal beds of chalk. This range extends from St. Catharine's to Shanklin Down, a distance of six miles, (see the Map and section, PI. XX.). Thus in travelling from the northern part of the Island to the southern shore — as for ex- ample from Ryde to Sandown, or from Calbourne to Brixton — vertical and highly-inclined strata of the flinty chalk are first passed over, and then the firestone, gait, and greensand deposits ; the latter composing the sea-cliffs from Sandown to Ather- field, except where the fallen masses of the upper beds strewn along the Undcrcliff conceal them from observation. But in crossing the central district 178 GEOLOGY OF THE ISLE OF WIGHT. the chalk range is first traversed, and on the southern flank of the hills the firestone, gait, and greensand appear, and the latter extend south- ward several miles, and dip beneath another chain of hills capped with white-chalk strata ; and on the south of this second range, the firestone, gait, and greensand again emerge and contribute to form the picturesque region of the Undercliff. The Upper and Lower Chalk. — In pur- suing tlus inquiry, I propose, before conducting the reader to the most interesting localities, to explain more fully the inorganic and organic com- position of the principal deposits of the chalk formation ; and thus afford a general view of the mineral characters and organic remains, of the strata that will come under review, in our excur- sions along the southern coast. The superior group of the cretaceous system consists of white limestone disposed in strata, which vary in thickness from a few inches to several feet. In the Upper Chalk there are nume- rous parallel rows of siliceous nodules that occur at irregular distances from each other; and in some places there are sheets of flint (called tabular flint) between the layers of chalk, which extend over considerable areas. The cretaceous strata arc also traversed by vertical and diagonal CHALK AND FLINT. 179 veins of the same substance. In the Lower Chalk of England, flints are of very rare occurrence, and in general are altogether absent. The greatest total thickness of the white chalk strata is esti- mated at 1000 feet. The only metallic substances observable are oxide of manganese in the state of dendriditieal or arborescent markings in the chalk and flints, and sulphurets and oxides of iron. The most common form is the sulphuret of iron, or pyrites, in spherical nodules beset with crystals, which radiate from the centre, and when broken a shell or other foreign substance is very com- monly found to be the nucleus. This substance often forms the casts of echinites, terebratulse, and other shells, the surface of the mineral retain- ing sharp imprints of the original. The bones and scales of fishes and other animals imbedded in chalk, have invariably a ferruginous stain. Chalk and flint. — The pure white chalk is composed of lime and carbonic acid ; it dissolves rapidly in hydrochloric acid, and leaves only a slight residuum, consisting of silex and organic matter. A microscopical analysis shows it to be a mere aggregation of shells and corals, so minute that upwards of a million are contained in a cubic inch of chalk; the amorphous particles appear to be the detritus of similar structures. These organisms, 180 GEOLOGY OF THE ISLE OF WIGHT. for the most part, are the calcareous shields and chambered shells of the animalcules termed foraminifera ; which swarm in inconceivable num- bers in our present seas, and are daily and hourly contributing to the amount of sediment now forming in the bed of the ocean.* The nodules and veins of flint that are so abun- dant in the upper chalk, have probably been produced by the agency of heated waters and vapours. The perfect fluidity of the siliceous matter before its consolidation, is proved not only by the sharp moulds and impressions of shells, &c. retained by the flints, but also by the presence of numerous organic bodies in the substance of the nodular masses, and the silicified condition of the sponges and other zoophytes which swarm in some of the cretaceous strata. Although silex or the earth of flint is insoluble in water of the ordinary temperature, its solution readily takes place in vapour heated a little above that of fused cast-iron, as has been proved by direct experiment ;-j- and similar effects are being produced at the present moment by na- tural causes. The siliceous deposits formed by the * See " Medals of Creation," Article " Fossil animalcules," p. 21"). t An account of Mr. JeflVrcy's important experiments will be found in the •' Reports of the British Association," for 1840. SILICIFIED FOSSILS OF THE CHALK. 181 intermittent boiling fountains, called the Geysers, in Iceland, are well known ;* and in New Zealand this phenomenon is exhibited on a still grander scale. From the crater of the volcanic mountain of Tongariro, which has an elevation of 6,200 feet above the level of the sea, jets of vapour and streams of boiling water highly charged with silex are continually issuing forth, and dashing down the flanks of the volcano in cascades and torrents, empty themselves into the lakes at its base. As the temperature of the water diminishes, siliceous sinter is deposited in vast sheets, and incrustations of flint are thrown down on the extraneous sub- stances lying in the course of these thermal streams. Silex is also precipitated by the boiling waters, in the state of stalagmitic concretions, and in nodules resembling in colour and solidity the flints of the English chalk.f The complete impregna- tion, and silicification (i. e. transmutation into flint) of organic bodies is referable to an agency of this kind, as the eminent American mineralogist, Mr. Dana, has clearly shown.;}; SiLICIFIED FOSSILS OF THE CHALK. 111 many instances the organic remains in chalk flints, are * " Wonders of Geology," vol. i. p. 84. t Dr. Dieffenbuch's " New Zealand." t " American Journal of Science," for January 1845. See also, " Notes of a Microscopical Examination of Chalk and Flint," by the Author. Annuls Nat. Hi.it. 1845. 182 GEOLOGY OF THE ISLE OF WIGHT. simply incrusted by silex : such is the state of numerous sponges which are as it were invested by the flint, and have their pores and tubes filled by the same material ; the original tissue appear- ing as a brown earth. In other examples the sponge has been envelo|)ed by a mass of liquid silex and has subsequently perished ; in this man- ner have been formed those hollow nodules, which on being broken present a cavity containing only a little white powder, or some fragments of sili- cified sponge : while in other instances the cavity is lined with quartz or chalcedony. It frequently happens that part of the zoophyte only is per- meated by silex, while the other portion is a friable calcareous substance imbedded in the chalk. Certain zoophytes (Ventriculites, see *' Medals of Creation," vol. i. p. 274,) are often found in this state ; hence the protean forms of the flints that have been moulded on portions of these organisms. But there are innumerable flint nodules which exhibit no traces of spongcous structure ; and veins, dikes, and sheets of tabular flint that may be regarded as pure, and free from organic remains, excepting such as must inevitably have become entangled and imbedded in a stream of mineral matter flowing over a sea-bottom. FOSSIL ANIMALCULES. 183 A sponge or other organic body often forms the nucleus of the flint nodules, and the original substance of the fossil is generally transformed into silex, and yet the most delicate structure preserved. In other examples the organisms en- closed in the flint have undergone no change, but appear as if immersed and preserved in a semi- transparent medium. Such is the state in which the foraminiferous shells (rotalice, textilarice, " Medals of Creation," p. 232), and minute corals, often occur.* Fossil animalcules. — For the most part the microscopic shells in chalk and flint are filled with amorphous mineral matter ; but recent observa- tions have shown, that in numerous examples the shell contains the body of the animal, in some instances silicified, but in others in the state of a dried animal substance, like the ink-bag of the cuttle- fish in lias,j- the soft parts of cephalopoda in clay,;}; and the capsule of the eye and the mem- branes of the stomach of certain fishes, in chalk. § * An exquisite example of this kind was discovered liy the Marquess of Northampton in a chalk flint from Brighton In a polished slice of this specimen, presented to me by his Lordship, there are branches of several deli- cate corals (pustulopora, relepora, idmonea, "Medals," p. 284,) and forami- nifera, as perfect, and unaltered in appearance, as if immersed in glass. t Dr. Buckland, " Bridgwater Treatise." % Professor Owen on the Belemnite. § " Wonders of Geology." 184 GEOLOGY OF THE ISLE OF WIGHT. In Hint, such specimens are by no means rare, and from the semi-transparency of that mineral are easily detected. The annexed figure (lign. 12) represents the body of a rotalia in its shell (highly magnified) imbedded in an atom of flint, in which there is another example, and some other organ- isms. The shells of Rotaliee in the chalk also >?- 'ih ;,-. THE SHKll OF A ROTALIA; Containing the fossilized remains of the body of the animal ; in flint; highly magnified,'' contain the body of the animal ; and by dissolving the chalk and the shell in weak hydrochloric acid, * Specimens of the Rotaliae, Xanthidia, and other minute fossil organisms ef the chalk and flint may he obtained of Mr. Topping, the well-known microscopic artist. No. I, York Place, Pentouville Hill, London. See "Medals of Creation," vol. i. pp. 78, 244, lor instructions how to prepare fossils for the microscope. THE FIRESTONE. 185 and immersing the residue in a transparent medium (Canada balsam), the soft parts are as distinctly seen, as in a recent dead specimen.* So little attention has been paid to the white chalk fossils of the Island, that a few of the common species of terebratula, spondylus, and echini ; teeth of sharks; ventriculites, choanites, and other zoophytes, comprise almost all the specimens I have observed in private collections ; but there can be no doubt that were the quarries and natural sections diligently examined, an interest- ing series might be obtained.-j- The Firestone. £ — The lower white chalk, in some places, as at Dover, gradually passes down into a bluish-grey chalk, and the latter into an argillaceous limestone, well known by the name of chalk-marl. In other localities the chalk maintains its purity to its junction with the marl. An intermixture of green sand charac- terises the latter in many districts, and this * A Memoir on this subject, by the author, will appear in the third Part of the Philosophical Transactions for 1846. t Figures and descriptions of British chalk fossils are given in my "Fossils of the South Downs," "Wonders of Geology," and "Medals of Creation," and "Geology of the South-Eastof England;" in Sowerby's "Mineral Con- chology," Mr. Lyell's " Elements of Geology," and in Parkinson's " Organic Remains of a Former World." t The name Upper-green-sand, generally given to these arenaceous marl beds of the chalk formation, has been productive of so much confusion, that the provincial term, Firestone, however inapplicable as a descriptive term, seems preferable. 186 GEOLOGY OF THE ISLE OF WIGHT. variety passes into a hard calcareous sandstone, termed in Surrey Firestone. Deposits of green sand, with layers and concretions of chert, and seams and nodules of coarse chalcedony, charac- terise this group in some districts, and are largely developed in the Undercliff. The bands of sili- ceous limestones and calcareous sandstones, with veins and nodules of chert which appear in the inland cliff of that district, belong to this division of the cretaceous system. NAUTILUS ELEGAXS. From the Chalk-marl, near Ventnor. The chalk-marl in most localities abounds in fossils ; it contains numerous species of Ammonites, Nauti- lus, Turrilites, and other cephalopoda, which are cither of excessive rarity, or altogether absent in t lie upper chalk strata. The Nautilus and Ammonites i II \I.K-MARL FOSSILS, 181 figured in the subjoined lignographs, 13, 14, 15, are characteristic species of the chalk-marl. The AMMONITES VARIANS. From the Chalk-marl, near Bonchurch. LIGH. I... AMMONITES M.VNTELLI. From the Chalk-marl, near Bonchurch. specimen of Nautilus elegans, UgnAS, is a young shell: this species is often two feet in circumference. 188 GEOLOGY OF THE ISLE OF WIGHT. Some localities of the Island are extremely prolific in organic remains, and have yielded to the researches of Capt. Ibbetson an interesting- series.* J. M. Saxby, Esq. of Bellevue House, has recently collected many species from Bon- church and Ventnor. A list of the fossils obtained by Dr. Fitton from these strata, chiefly from the cliff at Western Lines, is given in Geol. Trans, vol. iv. p. 202. The galt. — This is a deposit of very dark blue marl, having an average thickness of 100 feet ; the clay in many places has a large inter- mixture of green sand, and is traversed by thin layers of red marl. It presents no distinctive mineral aspect, but is characterised by the abun- dance, peculiarity, and state of preservation of its fossils. Numerous species of Ammonites, Hamites, and other cephalopoda, with their nacreous shells entire, and bivalves and gasteropodous univalves seldom, if ever, found in the strata above or below, may be collected from most localities where the Gait is exposed in natural or artificial sections of any considerable extent. This deposit is seen on each side of the anticlina.s on the southern coast, and in some parts of the Undercliff, near Ventnor * There is a pood suite of marl fossils belonging to this gentleman exhi- bited in the Isle or Wight model-room of the Polytechnic Institution of London. THE GREENSAND. 189 and Bonchurcli ; I believe only a few fossils have been observed. The greensand. — This division of the creta- ceous s} r stem comprises numerous alternations of argillaceous and arenaceous strata of great thick- ness and extent, constituting an important group, which is well defined by the fossil remains. It consists of cherty and calcareous sandstones, and sands of various colours, white, green, grey, red, brown, fawn, yellow, and ferruginous : the predominance of the green sands in some districts having suggested the term now employed to de- signate the group. It was called the iron-sand where the ferruginous character predominated, as in the Isle of Wight.* Thick beds of sandy and ferruginous clay, are intercalated with the arena- ceous strata. The Greensand is separable into three divisions, as was first shown by Dr. Fitton, whose indefatigable and successful labours have so largely contributed to the elucidation of the characters and relations of the deposits between the chalk and oolite in England. In the upper or Shanklin sand series, the strata * The whole series is described by Mr. Webster, as the Iron-Sand, in his various memoirs on the geology of the Isle of Wight; and the unfortunate application of this term to the sands of the Wealden districts of Surrey, Kent, and Sussex, retarded, for a long period, the true exposition of the nature and relation of those deposits. l2 190 GEOLOGY OF THE ISLE OF WIGHT. arc chiefly ferruginous sands with iron-stone and concretions of chert, with dark clays in the lower part. The middle group is marked by the preva- lence of green and grey sand with beds of calca- reous sandstones, and cherty limestone called Bcvrgate-stone in Surrey, and Rag in Kent. In the lowermost or Atherfield series, the argillaceous character predominates. The beds of sand abound in peculiar fossils, and the concre- tionary limestones and sandstones contain charac- teristic organic remains. This general notice will suffice, as the details of the sections exposed along the southern coast of the Island, have been worked out by Mr. Webster, Dr. Fitton, Capt. Ibbetson, Professor Forbes, and other eminent observers, and are published in the Transactions and Journal of the Geological Society. The following species of shells from the Green- sand of the Isle of Wight, are figured in Plates IV. and V. Corbis corrugata, PI. IV. fig. 1. This and the following figure represent but one side of the bivalves, and therefore do not convey an idea of the form of the entire shell ; but the markings on the surface are distinctly given, as afford ing the easiest comparison for the inexperienced collector. Trigonia caudata, PI. IV. fig. 2. This shell is so remark- aide lioth in its form and sculpture, as to be easily iden tified. OervUlia anceps, PI. IV. fig. 3. Entire beds "I' this shell GREENSAND FOSSILS. 191 occur in some of the sands at Atherfield. The species is generally more elongated than in the individual figured. Venus striato-costata, PL IV. fig. 4. A small and easily recognised shell. Venus parva, PL IV. fig. 7. In iron-stone nodules in Shank lin cliff. Area raulini, PL IV. fig. 5. Perna mulleti, PI. IV. fig. 6. This large and remarkable bivalve, occurs in great numbers in a thick layer imme- diately above the junction of the greensand with the wealden, at Atherfield and Sandown-bay. The prolonged hinge-line is commonly broken off in extracting the shells from their matrix, unless due care is taken. Thetis minor, PL V. figs. 1, 2. These are only casts in ironstone, the shell having perished. They are abundant in the concretions from the ferruginous sand on the top of the cliff at Dunnose Point, that have fallen on the shore. Gryphea sinuata, PL V. fig. 3. This shell attains a large size ; specimens are numerous along the shores at Shank- lin, Ventnor, and in Compton-bay ; being washed out of the cliffs of greensand. Terebratula sella, PL V. fig. 5. This shell in a very perfect state is found by hundreds in the greensand at Atherfield, &c. It occurs in great numbers in the greensand-pits at Faringdon in Berkshire. Nucula scajrfia, PL V. fig. 6. This and the following small shells abound in the Atherfield Crackers-rock. Tornatella albensis, PL V. fig. 4. Xalicarotundata, PL V. fig. 7. Pterocera retusa, PL V. fig. 8. Eostellaria robaldina, PL V. fig. 9. Cerithium turriculatum, PL V. fig. 10. Scaphites gigas, PL V. fig. 11. This shell attains a large size ; specimens two feet long are sometimes found. The collections of Capt. Ibbetson and Mr. Bowerbank contain splendid examples. Imperfect specimens of the spiral part have been described under different generic names. 192 GEOLOGY OF THE ISLE OF WIGHT. Summary.— The character of the cretaceous system, as shown by these investigations, is that of an ocean-bed formed in a vast basin by successive accumulations of sedimentary detritus, transported by currents, and thrown down in the tranquil depths of the sea ; arenaceous and argillaceous deposits prevailing in the lower, and cretaceous in the upper division of the series ; periodical intru- sions of heated fluids charged with silex having taken place at uncertain intervals. The fossils prove that the ocean swarmed with innumerable beings of the usual orders of vertebrate and inver- tebrate marine organisms, belonging for the most part to species and genera now unknown ; and in the chalk are seen for the last time that numerous tribe of cephalopoda, the Ammonites, of which not a single species is known either in the tertiary strata, or in any more recent deposits : so far as our knowledge at present extends, with the chalk the whole race of Ammonites disappeared. With regard to the vegetable kingdom of the cretaceous period, the presence of numerous fuci attests the nature of the marine flora; and the fragments of drifted coniferous wood, fir-cones, stems and leaves, which are found in the flint and chalk in some localities, prove that the dry land was clothed with pine-forests, and cycadeous StTMMARY. 193 plants. The occasional discovery of bones and teeth of reptiles, shows that the islands and conti- nents were tenanted by oviparous quadrupeds.* Of birds and mammalia not a vestige has been dis- covered. * It is worthy of remark, that fossils and fragments of other rocks are very rarely found in the white chalk. Pebbles of quartz and sandstone are the only extraneous minerals of frequent occurrence. A solitary instance of fragments of green chlorite schist, in chalk marl, near Lewes, was discovered by myself some twenty-five years ago. My friend, Henry Carr, Esq. C E., has recently found some water-worn pieces of fossil wood imbedded in while chalk, from the cutting of the railway he is constructing between Epsom and Croydon. This wood, in its mineralogical character and organic structure, is unquestionably identical with the well-known fossil wood of the Portland oolite, and I have no doubt is a portion of a mass that was drifted into the bed of the cretaceous ocean. CHAPTER VII. PROM YARMOUTH TO FRESHWATER-GATE SCRATCHELLS -BAY VER- TICAL CHALK STRATA — SHATTERED FLINTS — THE CHALK DOWNS — CAUSES OF THE PRESENT CONFIGURATION OF THE CHALK HILLS FROM FRESHWATER-GATE To COMPTON-BAf — GEOLOGICAL SECTIONS OF THE SOUTHERN COAST PEBBLES AND SHINGLE. From Yarmouth to Freshwater-gate. — In resuming our survey of the geological phenomena of the Isle of Wight, we proceed from Yarmouth to Freshwater-gate, on the south-western shore. In a direct line, through the transverse valley of the river Yar, which rises from the northern foot of the downs, the distance hut little exceeds two miles and a half ; but the road makes a consider- able detour to the left, round the eastern border of the estuary. Passing over a gently undulated country of the fluvio-marine eocene strata, and ascending a steep acclivity of tertiary sands, we cross the narrow tract of highly inclined chalk which unites Alton-Downs on the east with High y „ ;i " YARMOUTH TO FRESHWATER-GATE. 197 Down on the west, and. reach the southern coast by an opening in the chalk cliffs that extend from Compton Bay to The Needles. Immediately on our left are some detached pinnacles of chalk, jutting into the sea, and on the right the fine section of highly inclined strata of chalk and flint represented in PI. X. At the base of this headland is the entrance to a considerable excavation in the cliff, produced by the erosive action of the waves on the lower beds of chalk ; some perpendicular masses of the harder portions of the rock worn into irregular columns support this natural archway, which is known to tourists as " The Cave." It extends 120 feet into the cliff, and is between thirty and forty feet high ;* it is well deserving the notice of the geologist, for the displacement the strata have undergone is here strikingly displayed. From Freshwater-gate to the Needles, a dis- tance of three miles, the cliffs present a succession of mural precipices of chalk, from 400 to up- wards of 600 feet in height. The face of these cliffs when seen from the sea at a short distance * The description and beautiful illustrations of the picturesque features of the scenery along this part of the coast, in Sir H. Englefield's ' ' Isle of Wight," render it unnecessary to dwell upon this inviting subject. Some of Mr. Bartlett's views of these chalk cliffs, in Barber's " Illustrations," are very accurate and effective. 198 GEOLOGY OF THE ISLE OF WIGHT. has a remarkable appearance, from the rows of flints, which score the surface of the white rock with fine dark parallel lines, running in an oblique direction from the top to the bottom of the section. In some places the lines are undulated, in others arched, and near the summit of the cliff towards Alum Bay, they are very fiexuous, and bent down, as if a heavy mass above had pressed upon the upper ends of the layers of flints, while the chalk was in a plastic state. The general inclina- tion of the beds of this part of the range is nearly vertical on the north, with a gradually decreasing angle towards the south. Scratchell's Bay. — The most stupendous line of chalk cliffs is that termed the Main-bench ; and beyond is ScratcheWs Bay, which is bounded by the Needles. The aspect of the scene in this bay is romantic in the extreme ; in the face of the cliff, from the destruction of the lower beds of the bent strata, a magnificent arch «300 feet high has been produced, and forms an alcove that overhangs the beach 150 feet.* The well-known pinnacles of chalk, called The Needles, are isolated masses of the extreme western * In calm weather Scratchell's Bay and the Needles may he safely visited in the pleasure-boats to In- hired at Freshwater-gate; parties generally land cm this strip of shingle to view the stupendous arch above. A splendid \ lev baj li) Mr. Webster is given in PL 2. r >, of Sir H. Englefield's work. scratchell's-bay. 199 point of the middle range of Downs, which have been produced by the decomposition and wearing away of the rock in the direction of the joints or fissures, with which the strata are tra- versed. The angular or wedge-shaped form of these rocks, has resulted from the highly inclined northward dip of the beds of which they are composed. Vertical chalk strata. — To the late Sir Henry Englefield belongs the merit of having first observed and directed attention, to the highly interesting phenomena, occasioned by the disrup- tion and elevation of the eocene and cretaceous formations, which are so remarkably displayed in the Isle of Wight ; namely, the vertical position of the strata, and the shattered condition of the flint nodules, though still imbedded in the solid rock. These appearances may be conveniently examined in the cliffs before us. The chalk forms parallel beds or strata vary- ing from two to five feet in thickness, which are commonly separated by layers of flint no- dules imbedded at irregular distances from each other; there are also a few nodules dispersed indiscriminately in the mass. The dip of the inclined strata as previously stated is in general from 70° to 80° : but many beds throughout a con- 200 GEOLOGY OF THE ISLE OF WIGHT. siderable extent are quite vertical (see PI. XIII.). The parallelism of the cretaceous strata, and the absence of sand, gravel, and other coarse detritus, denote that the deposition of these calcareous sedi- ments took place in tranquil water, and remote from sea-cliffs and shores. Where a large extent of the cliff is exposed, the face of the chalk is seen to be traversed by fissures or joints at right angles to the planes of stratification ; some are vertical, others diagonal, and crossing in various directions, divide the entire mass into irregular portions ; in some localities these partake of a rhomboidal form.* These fissures have evidently been pro- duced after the consolidation of the strata in which they occur, for where they traverse the horizontal layers of flint nodules, some of the latter are often displaced ; and very commonly a fault, or inter- ruption of the parallelism of the opposite sides of the chasm, has taken place, either from the elevation or the subsidence of one of the separated masses. In many instances the fissures are filled up with flint, which occupies the crevice wholly, or partially, throughout its whole extent, forming large sheets of pure silex, varying in thickness from that of * Mr. Webster particularizes the large chalk-pit on the south side of Arre- ton Down near the top, not far from Ryde. In this quarry the Btrata are inclined at an angle of 80 deg. ; and both the tabular flints and the nodules are completely shivered. VERTICAL CHALK-STRATA. 201 pasteboard, to two or three inches. These sili- ceous veins often consist of two plates with loose calcareous detritus between them, as if the flint had flowed down or oozed from the sides of the fissures ; and this detritus is frequently composed of shells of microscopic foraminifera. In other cases the cavities are filled with marly and soft chalk ; and in many instances they are empty, but their sides are lined with crystallized carbonate of lime. These fissures are evidently referable to a period long antecedent to the elevatory movements which broke up the chalk strata, and hurled them into their present posi- tion, for they traverse the horizontal layers ; and the subsequent introduction of flint, proves that they were the effect of submarine movements, which took place while the physical condition of the bed of the cretaceous ocean remained un- changed. This fact also corroborates the inference, that the eruptions of steam or vapour charged with silex into the chalk, occurred periodically, and sometimes at long intervals. But there are numerous chasms and fissures in the strata which clearly belong to a very dif- ferent epoch ; to a period geologically recent, when the now upper surface of the chalk was rent by earthquakes, and the mountain 202 GEOLOGY OF THE ISLE OF WIGHT. masses of the cretaceous system acquired their present position and configuration. For these fissures are invariably connected with the surface, and are more or less filled with clay, sand, gravel, and waterworn flints, from the alluvial debris that forms the subsoil of the country. These appear- ances may be observed in the chalk underlying the bed of gravel and clay, on which the Albion Hotel at Freshwater-gate is situated. Shattered flints. — Upon carefully extracting a flint nodule from this cliff, it retains its original form ; but upon examination it will be found " shattered in every direction and broken into pieces, varying in size from three inches in diameter down to the minutest fragment, and even into an impalpable powder. The flints thus shivered, as if by a blow of inconceivable force, retain their form and position in the bed. The chalk closely invests them on every side, and till removed, nothing different from other flints can be perceived, excepting fine lines indicating the fracture, as in broken glass ; but when moved, 'In \ fall at once to pieces. The fragments are as sharp as possible, and quite irregular, being cer- tainly not the effect of any peculiar crystallization or internal arrangement of the material, but solely attributable to external violence." Such is the SHATTERED FLINTS. 203 description of this remarkable phenomenon given by Sir H. Englefield thirty years since.* The tabu- lar and plated flint in the fissures is also shattered in a similar manner. The nodules in the regular layers are invariably in this state, in every locality of the vertical and highly inclined chalk ; but the separate nodules in the middle of the strata are entire ; and in the horizontal beds, as for ex- ample, on St. Catherine's, Boniface, and Shanklin Downs, all the flints are unbroken. This shattered condition of the flints has doubtless arisen, as Sir Henry Englefield suggested, from the con- cussion caused by the upheaval and disruption of the once horizontal cretaceous deposits. The disturbing force, though in many instances pro- ducing flexures in the strata, was clearly exerted violently and suddenly, and in such manner as to shatter the flints without dislodging them from the chalk. From the insulated nodules being generally entire, it would seem that the greatest violence * Sir H. Englefield's "Isle of Wight," pp.20, 21. The following places are enumerated as exhibiting this phenomenon very distinctly : — Alum Bay — Pit south of Carisbrook Castle, and near Carisbrook town — Arreton-pit — Brading- Down-pit — BradingShute — Culver Cliff. Shattered flints are occasionally met with in some parts of the Sussex and Surrey chalk. My attention was first directed to the subject in 1S20, by a paper of Sir H. Englefield in the •' Linnean Transactions;" and a chalk-pit on the top of North-street, Brighton, now filled up, and the area built over, presented a fine example, for every flint, though retaining its form, was reduced to fragments. See the " Fossils of the South Downs," p. 152. M 204 GEOLOGY OF THE ISLE OF WIGHT. of the shock was exerted in the direction of the lines of stratification. Mr. Webster, in describing the shivered Hints in the chalk at Handfast-point, on the Dorsetshire coast, remarks that the nodules are not only much shattered, bu1 appear as if they had been re- duced to atoms while the rock was yet in a soft state, for the fragments are in general separated from each other, with chalk between them ; and the broken pieces of flint are at such distances, that it is impossible to conceive by what means they could have been so far separated, had the chalk been solid at the moment of their fracture. The bent condition of the strata at Handfast-point, which will be described in a future page, attests the plastic state of the chalk at the period when its upheaval took place. The Chalk downs. — We now leave the sea- shore to ascend the hill, and proceed along- the foot of Alton Down to Compton Bay, which is about a mile distant. The western part of the central range of downs extends from the Needles Cliff to Motteston Down, which is 700 feet high, and is a narrow ridge nine miles in length, with steep declivities on each side; that on the north arises from the highly-inclined dip of the strata; thai on ih. south is produced by the precipitous THE CHALK DOWNS. 205 escarpment formed by the sudden termination of the cretaceous beds where they rise to the sur- face. The summits of this range command views of great extent and picturesque beauty, for both the northern and southern shores are distinctly visible.* From the Needles Down, may be seen on the north Tollands, Colwell, and Yarmouth Bays ; and on the south, Freshwater and Compton Bays, and the di tant line of coast. The eastern portion of this chalk range, from Arreton Down to Culver Cliff, a distance of seven miles, is of the same character, f * A graphic description of the scenery from this range of hills is given by Sir H. Englefield, chap. iii. The view from Buccomb Down, looking over Carisbrook Castle and Newport in the vale beneath, is very splendid ; that from Arreton Down is equally fine. t The view from Ashey sea-mark, which is situated on this part of the chalk-hills between Arreton and Brading Down, is thus described by the Rev. Legh Richmond : — "Southward the view is terminated by a long range of hills (Shanklin, Wroxall, and Appuldurcom.be,) at about six miles distant. They meet to the westward another chain of hills, of which the one whereon I sit forms a link, and the whole together nearly encompass a rich and fruitful valley, filled with corn-fields and pastures. Through this vale winds a small stream for many miles ; here and there lesser eminences arise in the valley, some covered with wood, others with corn or grass, and a few with heath or fern. One of these hills is distinguished by a church (New church) at the top, presenting a striking feature in the landscape. Villages, churches, country seats, farm-houses, and cottages, are scattered over part of the southern valley. In this direction also appears an ancient mansion (Knighton), embellished with woods, groves, and gardens. South-eastward is a broad expanse of ocean, bounded only by the horizon. More to the east, in con- tinuation of the chain of hills on which I am sitting (Ashey) rise two downs (Brading and Yaverland hills), one beyond the other; both are covered with sheep, and the sea is just visible over the furthest hill, as a terminating boundary. In this point are seen ships, some of which are sailing, and M 2 206 GEOLOGY OF THE ISLE OF WIGHT. Ascending Afton Down, the summit of which is crowned Avith a group of tumuli, the views along the southern coast are lovely in the extreme. When almost half way up the acclivity, the land- scape to the west displays a magnificent coup d'ce'd of the romantic scenery of Freshwater and Scratchell's Bays, and The Needles ; and that to the east affords a view of Compton Bay, Brook Bay, and the coast, till it is lost in the remote distance. Cause of the configuration of chalk downs. — From what has been stated as to the compo- sition of the white chalk, and the formation of the strata, the cause of the external configuration of the verdant downs we are now traversing appears sufficiently obvious. If we examine the spots where the turf has been removed by the flint- diggers, we perceive immediately beneath the others lying at anchor. On the north the sea appears like a noble river (the Solent), varying from three to seven miles in breadth, between the banks of the opposite coast and those of the island. Immediately underneath me is a fine woody district, diversified by many pleasing objects. Distant towns Portsmouth and Gosport) are visible on the opposite coast; and numbers of ships occupy the sheltered station which this northern channel affords them. Westward, the hills follow each other, forming several intermediate and partial valleys, in undulations like the waves of the sea, and bending to the south, complete the boundary of the larger valley I have described, to the southward of the hill on which 1 sit. One hill alone (St. Catherine's), the highest in elevation, and about ten miles to the south-westward, is enveloped in a cloud, which just permits a dim and hazy sight of a signal-post, a light ind an ancient chantry, on its summit." — Annals of the Poor, lnj tin- tut* Rev. Legh Richmond. THE CHALK DOWNS. 207 vegetable mould a thick layer of loose nodules but slightly abraded, and in no instance worn into the state of boulders, pebbles, or gravel. The surface of the chalk covered by the flints is fur- rowed and waterworn, like that of the exposed chalk along the coast. From the state of the loose flints, it is evident, that although they must have been washed out of pre-existing strata, they have not been subjected to the action of the waves for any considerable period, like the materials of the existing sea-beach. For when masses of the chalk cliffs fall within reach of the billows, the exposed portions of the flints are com- pletely rounded before the nodules are loosened and detached from the parent rock ; and so soon as the flints are liberated by the wearing away of the surrounding chalk, they are quickly driven against each other and broken, and the fragments ground into pebbles, gravel, &c. ; in this man- ner are formed the shingle and sands that accumu- late along the sea-shore. From the state of the down-flints, it is there- fore obvious that the deposits whence they were derived, must have been less consolidated than the present chalk, and have admitted of the removal of the calcareous materials, and the consequent extrication of the siliceous nodules from the rock, 208 GEOLOGY OF THE ISLE OF WIGHT. in a comparatively short space of time ; and the disengaged flints, after a very brief exposure to attrition, must have been transported beyond the reach of the waves. From the organic composition of the chalk {ante, p. 1 80), it is manifest that when first deposited at the bottom of the ocean, it was a fine white detritus or mud, resembling in its nature and ap- pearance the chalk now in progress of formation, along the coasts of the Bermuda Islands ;* some layers of which are as rich in microscopic shells as any of the cretaceous strata. The veins and beds of flint, as we have previously explained, probably originated from the periodical introduc- tion of thermal waters highly charged with silica, into the calcareous sediment. The subsequent conversion of the incoherent detritus into compact limestone, may have resulted in part from pressure, but principally from the slow infiltration of crys- talline carbonate of lime ; a process which has so rapidly converted the mud of the Bermudas into a rock fit for building, that the imbedded shells in many instances retain their natural colour and polish. It may therefore with great probability be as- sumed, that at the period when the cretaceous ■ Wonders of Geology, vol, i. p. (>9. THE CHALK DOWNS. 209 strata were subjected to those elevatory move- ments which ultimately raised enormous moun- tain-masses of chalk, together with the wealden deposits on which they rest, above the level of the sea, the last formed, uppermost, and of course least coherent beds, would be the first exposed to the action of the waves ; and if the elevation were gradual,* successive layers would be subjected to the same agency, until the fragments of the ancient ocean-bed, now the Downs, were lifted above the reach of further destruction. The drainings of the elevated portions of the soft calcareous rock would then commence, and give rise to streams and rills, by which the surface would be worn into furrows and channels. Funnel-like cavities, and deep and narrow cylindrical and tubular hollows, would be formed by the gyratory action of eddies or whirlpools, induced by opposing currents ; such effects may be observed on the muddy dunes of an estuary during the reces- sion of the tide. The beds of loose and but slightly water-worn flints — the undulated and unbroken contour of the gently swelling hills — and the smooth basin-shaped coombes, and valleys of chalk districts — characters which are strikingly * See Mr. Lyell on the elevation and denudation of the wealden districts ; " Elements of Geology," vol. ii. 210 GEOLOGY OF TUE ISLE OF WIGHT. exemplified in the hills before us, would be the natural result of such operations. From Freshwater-Gate to Compton Bay. — The road to Compton Bay sweeps round the southern slope of Afton Down ; the pedestrian should take the path along the edge of the cliff to Compton Chine, where a narrow track leads to the sea-shore. As we approach this spot a fine view is obtained of the line of coast from the bay to beyond Brook Point, as is shown in the slight sketch, PL XI. The foreground is part of the southern slope of Afton Down, consisting of flinty chalk ; and the foot-track to the Chine is seen crossing it on the right. The cliffs in this view are composed of the clays, shales, and sands of the Wealden, which continue to near Atherfield Point. The nearest headland is Brook Point, the western boundary of Brook Bay ; and the one im- mediately beyond is the eastern limit of the same. The ledges of rock extending from the foot of Brook Point into the sea, are chiefly composed of petrified trees. The most distant cape is part of the greensand cliffs, near Blackgang Chine; and the lofty range on the horizon is St. Catherines mu. Compton Chine is a deep chasm worn in the ferruginous sands by a stream that falls from COMPTON BAY. 213 the summit of the cliff; it is situated to the west of the Blockade-station. The footpath to the shore slopes along the face of the crumbling cliffs of greensand strata, which rise from beneath the upper divisions of the creta- ceous system, as is shown in lign. 16. The succes- sion of the beds from Freshwater to Compton Bay, i. e. from west to east, is as follows : — 1 . Upper or flinty chalk. 2. Lower chalk. 3. Firestone, comprising the chalk marl. 4. Gait. 5. Greensand, consisting of beds of ferruginous saDds, clays, sandstones, and layers of very compact ironstone grit. 6. AVealden clays, sands, shales, and limestones. Geological sections of the southern coast. — The strata incline to the west, as is shown in lign. 16, to beyond Brook Chine, where the eastern side of the anticlinal axis begins, and the dip is to the east, as represented in the continuation of the coast, in lign. 17. This line of cliffs is, in fact, the counterpart of that of Sandown Bay {ante, p. 134, lign. 9) ; but the wealden deposits are here more developed, and extend between six and seven miles along the shore. As these cliffs consist of clays, sandy marls, shales, and other materials that offer 214 GEOLOGY OF THE ISLE OF WIGHT. but feeble resistance to the action of the waves, the destruction effected by the sea during the winter and early spring, when the highest tides prevail, is very great; and the wealden fossils washed out of the cliffs and strewn along these shores are so numerous, that the strand between Compton Bay and Atherfield has yielded a greater number of fossil bones of colossal reptiles than any other part of the Island. In short, these strata and their organic remains impart to this portion of the southern shore so much interest, that it is desirable to postpone a particular account of the wealden deposits for a special excursion to Brook Bay. We will therefore continue our sur- vey of the greensand by proceeding from Compton to Atherfield, and along the Undercliff to San- down Bay, where our investigation of the south coast commenced.* The chalk, firestone, and gait of Compton Bay, are not very prolific in fossil remains ; but the greensand yields ammonites, trigoniw, pemce, &c. ; and numerous specimens of the large oyster-like gryphea sinuata, (PL V. fig. 3,) are generally scattered on the sands and shingle at the foot of the cliffs. At the point where the " The visitor who would find it more convenient to continue liis observa tions along the cliff to Brook Chine, should refer to chapter ix. K5CJ l-B cqai 216 GEOLOGY OF THE ISLE OF WIGHT. lowermost bed of the greensand is in contact with the wealden clays, the distinctive characters of the marine and freshwater deposits may sometimes be observed in a mass of the stratum but a few inches thick ; marine shells appearing imbedded in the upper layers, and freshwater shells in the lower portion. Pebbles and shingle. — Before we ascend the cliff to pursue our excursion towards Atherfield, I would offer a few remarks on the sea-beach. The beds of shingle along this coast, consist in a great measure of chalk flints that have been broken and rounded by attrition into boulders, pebbles, and gravel. This is evident from the peculiar aspect and fracture of the stones, and the nature of their organic remains, of which some traces are generally manifest. The clear transparent pebbles, with bands and veins of quartz and chal- cedony, which in some specimens are as clear as crystal, and in others of a bright yellow, amber, dark brown, and bluish-black colour, have a similar origin. The moss-agates,* as they are called by the lapidaries, are silicified chalk sponges ; and the beautiful fossils {Choanites)-\ commonly known as " petrified sea-anemones,' 1 '' are • Not the German moss-agates exhibited in the shops as the genuine pro- ductions of the Island. Sec note In page 18. I " Thoughts on a Pebble," pi. 1 and 2. PEBBLES AND SHINGLE. 217 characteristic zoophytes of the white chalk. Small pebbles of pure transparent quartz or rock-crystal, are often found in the shingle in Compton and Sandown ; these have probably been washed out of the wealden strata, for pebbles identical in mineral ogical character occur in the grits of Tilgate Forest and Tunbridge Wells. But the shingle contains other siliceous pebbles which essentially differ from those of the chalk- flints. Some of these are composed of a dark brown mottled jasper, and when cut and polished resemble the well-known Egyptian pebbles ; others are of an opaque white jasper, veined with black dendritical or arborescent figures, or marked with zones of rich brown tints. Some have a concentric arrangement of bands of silex of various shades of colour, and resemble agates ; others assume the character of botroidal and mammillated chalcedony. The differences observable in the materials com- posing the shingle, did not escape the notice of Mr. Webster, who describes some of the principal varieties of the pebbles, and suggests that those which are not waterworn chalk-flints, may have been derived from veins or nodular masses of silex, in tertiary strata now destroyed. A polished slice of silicified wood found in the shincde of 218 GEOLOGY OF THE ISLE OF WIGHT. Sandown Bay, was presented to me by Mr. Fowl- stone, of Ryde. I believe specimens of this kind are very rare in the Island ; but on the western coast of Sussex, waterworn fragments of silicified monocotyledonous wood are occasionally met with. Boulders and pebbles of petrified bone and wood, and of shelly limestone, are common on the beach in Compton and Sandown Bays ; they are from the wealden beds, and will be more par- ticularly noticed in a subsequent chapter. CHAPTER VIII. FROM COHPTON BAY TO ATHERFIELD POINT — ATHERFIELD CLIFFS — GREENSAND SERIES — NEOCOMIAN OR ATHERFIELD STRATA GREEN- SAND FOSSILS — CLIFFS AT BLACKGANG CHINE — THE UNDERCLIFF — GI-OLOGICAL STRUCTURE OF THE UNDERCLIFF FOSSILS OF THE FIRESTONE — SOUTHERN RANGE OF CHALK DOWNS COAST OF THE UNDERCLIFF — FROM VENTNOR TO SANDOWN BAT. From Compton Bay to Atherfield Point. — The road from Compton Chine to the coast-guard station at Atherfield Point, runs along the southern flank of Shalcomb and Mottestone Downs. As we pass Brook Manor-house the ferruginous beds of greensand may be traced in the banks on the road-side ; and Brook church is seen standing high up the hill on a terrace of those deposits. The relative positions of the strata in this district are displayed in the cuttings on the sides of the road from Shalcomb Down through the village of Brook to the sea-shore ; as shown in lign. 18. If we proceed from the coast at Brook Chine through the village, and ascend the road by the church, and over Shalcomb Down, we pass in suc- cession, 1, the Wealden ; 2, the Greensand ; 3, the N 220 GEOLOGY OF THE ISLE OF WIGHT. Gait ; 4, the Firestone ; and then cross the ridge formed by the highly inclined strata of the White- chalk. Shalcomb Down. Brook Puint H. Fossil Trees. wealden. -6, LIGN. 18. — SECTION FROM BROOK-POINT TO SH ALCOMB-DOWN ; 1$ MILE. The turnpike-road leads through the villages of Mottestone* and Brixton, to Shorwell, where it divides, and sends off a branch to Newport on the north-east, and another on the south-east, through Kingston and Chale to Blaekgang Chine. About midway between Brixton and Shorwell a tenantry road turns off to the right, and admits a carriage to within a few hundred yards of the cliff, near the Atherfield Coast-guard Station. This is the most convenient place to alight, and reach the sea-shore near the junction of the Greensand and Wealden formations. The path down the preci- pitous face of the cliff lies a little to the east of the * On an eminence overlooking the village of Mottestone is a rude pillar of ferruginous sandstone called the "Long-Stone," and which was probably erected ..* a landmark or boundary stone, at a very remote period. It is twelve feet high ami of an irregular quadrangular form. ATHERFIELD CLIFF8. 221 Station ; it is a mere foot-track worn in the rock by the sailors and fishermen.* At a moderate distance westward of the spot where the path reaches the shore, is the headland called Ather- field Point, on which stands the Station-house ; and at its foot, a ledge of rocks extends into the sea. Near this place after recent slips of the cliff, and the removal of the fallen debris by the waves, the uppermost of the Wealden deposits, and the lowermost of the Greensand may be seen in juxta-position; in other words, the line of de- marcation between the accumulated sediments of a mighty river — some primeval Nile or Ganges, teeming with the spoils of the land and the ex- uviae of extinct terrestrial and fluviatile animals and plants — and the bed of a vast ocean, loaded with the debris of marine organisms, of genera and species unknown in the present seas. Atherfield Cliffs. — These cliffs are about 150 feet high, and, with the exception of a few feet of Wealden clay forming the base of the headland above mentioned, entirely consist of the green- sand strata, which extend eastward as far as the * This path is too precipitous and inconvenient to be attempted without risk by ladies or invalids. I have always visited the spot by this route, and am not aware of there being a more easy descent to the beach, except at a long distance from the most interesting part of the cliffs. N 2 222 GEOLOGY OF THE ISLE OF WIGHT. eye can reach. The total thickness of the series is upwards of 800 feet ; but the section exposed, though vertical, is in an oblique direction to the planes of stratification, and from the slight angle at which the strata dip to the north-east, the cliffs as far as Blackgang Chine are composed of the greensand deposits. To the eastward these strata are concealed by the upper cretaceous group along the Undercliff, reappear at Bon- church Cove, and continue to Sandown, extend- ing as far as the anticlinal axis of the Wealden in the bay. The lowermost bed which rests on the Wealden at the base of Atherfield Point, is but a few feet above the beach ; the uppermost strata first ap- pear on the shore to the east of Rocken-end ; between these two points the cliffs are made up of sands and argillaceous deposits of various colours, composition, and thickness, containing particular collocations of organic remains. The importance of the Atherfield section as elucidating the nature and relations of the lower group of the cretaceous system, was but little regarded till the appearance of Dr. Fitton's memoir " On the Strata between the < '/"(Hi and Oolite" * Since that time this locality lias acquired additional interest from its affording Geol. Trans, vol, iv. L8S6. GREENSAND OF ATHERFIELD CLIFFS. 223 a solution of the geological problem, to which we shall hereafter briefly advert. The subsequent me- moirs by the same author,* Captain Ibbetson, Pro- fessor Edward Forbes,-j~ and Mr. Simms,J contain an elaborate account of these deposits, and of the nature and distribution of the fossils they contain. The limits necessarily assigned to the present volume, will only admit of a concise notice of the facts detailed in those publications, and a general view of the geological phenomena presented to observation in a stroll along the shore, from Ather- field Point to Blackgang Chine. Greensand series. — There are 63 distinct beds between the Wealden at Atherfield Point, and the upper stratum of Greensand which is in contact with the Gait near Blackgang Chine ; the total thickness being 843 feet.§ These deposits have been variously grouped and named by different observers; but the most practically useful ar- rangement to the investigator on the spot, is that which especially relates to the organic remains. 1 1 We will now briefly notice the prin- cipal subdivisions in an ascending order; that is, from the Wealden at Atherfield Point, * Geol. Journal, vol. i. p. 179. t Ibid. p. 190. I Ibid. p. 76. § Captain Ibbetson. || A list of the strata, and a table of the distribution of the fossils, are given in " Geol. Journal," vol. i. p. 195. 224 GEOLOGY OF THE ISLE OF WIGHT. to the junction of the greensand with the gait {lign. 17.). The Wealden clay, as previously stated, first appears in a bed five or six feet thick, at the foot of Atherfield Point ; the upper layers are shaly, and contain freshwater shells (cyclas, paludina, potamides,* PL VI.) similar to those we observed at Sandown Bay.f The Wealden clay in the upper part is intermixed with grey and green sand ; and two or three inches above there is a stratum of sandy clay containing marine shells. The distance between the layers of fluviatile and marine shells is therefore but a few inches ; so that, as Dr. Fitton remarks, portable masses containing characteristic .shells of both formations may be extracted. I have not been so fortunate as to visit Atherfield Point when the line of junction at the base of the cliff, and to the westward, was exposed to any considerable extent. But sometimes, from a con- junction of favourable circumstances, the strata are laid bare for several hundred yards. This happens * Potamides are spiral fresh-water shells, -which much resemble in form those belonging to a marine genus termed Cerithium; the Cerilhia men- tion il by Dr. Fitton as occurring in the Weald clay at Atherfield, may pos- sibly be Potamides. 1 have never observed any vestiges of Cerithia in the Wealden deposits. t A few small thin-shelled oysters were observed by Dr. Fitton in this bed. "These fossils occur within a very few inches from the junction with the bovi thi Wealden. " — Proceedings, Geol. Soc. GREENSAND OF ATHERFIELD CLIFFS. 225 after heavy gales and high tides, which sweep away both the fallen masses of rock and the sea- beach, and expose a large surface of the ad- jacent strata washed clean, and visible at low water.* 1. Lowest Greensand clay.f — A bed of brown clay with marine shells : 3 feet thick. In the lowermost layers, near the Wealden shale and clay, are seams of minute fish- bones. 2. Perna Mulleti band. — A stratum two feet thick, of a very firm sand-rock, characterised by numerous shells, and especially by a layer of the Perna Mulleti (PL IV. fig. 6) ; which also occurs in the same relative stratigraphical position in Compton and Sandown Bays. 3. Lower Lobster clay-bed. — Clay strata, with numerous fos- sils in the lower, and but few in the middle beds. The upper layers are remarkable for the abundance of a small species of lobster (Astacus), which occurs in a beautiful state of perfection, imbedded in blue saponaceous clay ap- proaching to fuller's earth. The specimen figured in the Vignette of the title-page of this work, is from this stratum. Total thickness 100 feet. 4. The Cracker's rock.% — Sandy clay with two bands of nodular or concretionary masses of very hard calciferous sandstone : 18 feet. These beds are highly interesting for the abundance and variety of their organic remains. The nodules consist of very compact rock, and contain innu" merable shells in a perfect state, of which many species * Such was the state of the cliff when visited by Dr. Fitton in 1843. Proc. Genl. Sue. vol. iv. part 1. t The names adopted are those employed by Captain Ibbetson and Pro- fessor E. Forbes. Gcol. Journal, vol. i. p. J90. I This local name is said to be derived from the noise made by the breakers when dashing over the rocks and ledges of this concretionary sand-rock. 226 GEOLOGY OF THE ISLE OF WIGHT. do not occur in any other strata. The Gervillia anceps (PL IV. fig. 3) is crowded together in groups of hun- dreds, and the shells are as perfect as if lying in their native bed. Several small shells from the Cracker's rock are figured in PI. V. (figs 4, 6, 7, 8, 9, 10). These fossils occur in such numbers and variety, that almost every considerable fragment of the rock will be found to contain several species. 5. Upper Lobster clay.— A deposit of saponaceous clay, similar to No. 3 ; and abounding in the same kind of fos- sil lobsters as that bed. It also contains ammonites and other shells : total thickness 20 feet. 6. Zone of Terebratulce. — Clays full of fossils, 20 feet : above which is a bed of dark sand, 22 feet in thickness, enclosing immense numbers of Terebratulm (PI. V. fig. 5), and Serpulai. 7. Zones of Gryphem and Scaphites. — A series of sands and clays, including layers of QrypJiecR (the large bivalve figured in PI. V. fig. 3), imbedded in dark sand, and alternating with bands of nodules which contain gigantic Scaphites (PI. V. fig. 1\), ammonites, and numerous other fossils : total thickness 155 feet. S. Upper zone of Terebratodce. — A bed of sand 30 feet thick, full of layers of Tercbratulae (chiefly of Terebratula biplicata) : above which is a stratum of dark sand, 24 feet thick, with a band of Grypheae as in No. 7, but with- out the Scaphite nodules. 9. Ferruginous sands. — Sands highly ferruginous, with layers of dark blue clay, and bands of ironstone nodules full of casts of shells (PI. IV. fig. 7, PI. V. fig. 1), of the genera Venus, Thetis, Trigonia, &c. Seams of lignite are dis- seminated through the lower beds in undulated laminae ; and thin layers of ironstone grit without fossils, occur in the upper part of the series. The beds in contact with the Gait are generally of this character. NEOCOMIAN OR ATHERFIELD STRATA. 227 In the upper 250 feet of the greensancl but few organic remains are met with, and the strata are more or less highly charged with peroxide of iron. " Every thing," says Professor E. Forbes, " in this stage, appears to indicate a shallow and barren sea, probably from an elevation of the sea-bottom, pre- vious to a new state of things, when a fresh series of clays, forming the Gait, being deposited, the majority of the animal forms which characterise the clays of the greensand disappear, and are replaced by distinct species, representative in time." * Neocomian or Atherfield strata. — The in- ferior portion of greensand at Atherfield, from the lowest bed to the Crackers inclusive, abounds in fossils which are either very rare, or altogether absent in the upper part of the series. A group of subcretaceous deposits near Neufchatel, in Switzerland, having lately been found to con- tain many species of shells not previously known in other parts of the cretaceous system, has, in consequence, been described by some emi- nent French geologists as a distinct formation, belonging to a period antecedent to the de- position of the Greensand, and synchronic with the Wealden ; and they have designated the * Geol. Journal, 1845. 228 GEOLOGY OF THE ISLE OF WIGHT. group " Terrain Neocomien." But Dr. Fitton has shown, by a careful comparison of a large number of the French fossils with those from Atherfield, that so close an agreement exists in the organic remains, as to leave no reasonable doubt that the so-called Neocomian strata are but the equivalents of the lower series of the English greensand system.* In a Report read before the British Association of Science, at Southampton,!" Dr. Fitton gave a table of 150 species of shells, the stratigraphical position of which has been accurately deter- mined. From this it appears that 130 species occur in the lowermost 150 feet of strata; and that in the upper beds, comprising a thickness of nearly 700 feet, but twenty additional species are met with ; the absolute number of fossils also rapidly diminishes, but few, if any, organic remains appearing in the uppermost layers. But throughout this period of consecutive deposition, one series of fossils only is indicated, bounded by the Wealden below and the Gait above. It is the lowermost part of the Atherfield section which is regarded as the equivalent of the remarkable * The name Neocomian is introduced in the section, liy/i. 17, p. 215, to ate these remarks, t In September, !MG. GREENSAND FOSSILS. 229 fossiliferous group of Neufchatel. The principal difference between the continental and English greensand fauna, is stated by Professor E. Forbes to consist in the abundance of gasteropoda and cephalopoda in the former, and of acephalous bi- valves in the latter. Greensand fossils.* — The organic remains of the greensand to be met with along this coast are almost exclusively shells ; but few traces of the higher orders of animals, or of plants, have hitherto been observed. It should, however, be borne in mind, that remains of land reptiles, and trees, and plants, have been found in strata of this forma- tion in Kent ; similar relics may therefore occur in the same deposits in the Isle of Wight.-f- Of the vegetable kingdom but few vestiges have been discovered. The laminae of lignite in the upper ferruginous beds, and obscure traces of fuci in some of the lower sandstones, are the only in- dications of the flora of this geological epoch that have come under my notice. But remains of the * The finest collection of the organic remains of the greensand of the Isle of Wight is, I believe, that made by Captain Ibbetson, and now exhibited in the Polytechnic Institution of London. The Geological Society has the most complete series of the shells, principally contributed by Dr. Fitton, and named by Professor Forbes. Figures of most of the species will be found in " Mineral Conchology," Dr. Fitton's "Memoir," and in the "Geological Journal," vol. i. t See " Wonders of Geology," vol. i. p. 394. 230 GEOLOGY OF THE ISLE OF WIGHT. foliage of a fern that abounds in the Wealden {Lonchopteris Mantelli, lign. til), were discovered by Mr. Morris in many of the strata at Atherfield ; and the Messrs. Gladstone have since found several leaflets of the same species associated with trigonise, &c. in ironstone nodules at the foot of Shanklin Cliff. This interesting fact we shall have occasion to notice in a subsequent chapter. Of the poriferae and corals but few species occur. Traces of bulbiform Siphonia, (apparently S. pyri- formis, Dr. Fittoris Memoir, PL XV.), are some- times displayed on the waterworn surface of fallen blocks of sandstone. A small elegant coral, a species of Astrea, is not uncommon in the Cracker's Rock at Atherfield. The lowermost beds at Atherfield Point being very fossiliferous, the collector will have but little trouble in obtaining good specimens of the shells distributed in those strata : the perna mulleti {PL IV. fig. 6) may generally be extracted toler- ably perfect.* From the nodular masses of the Crackers with which the shore at low water is often thickly strewn, an abundance and variety of shells may be procured ; and that part of the • It is necessary that the geologist should so arrange the time of his visit to this coast, as to arrive at Atherfield at the beginning of the ebh of the tide, that be ma) be able to examine the cliffs and collect specimens at leisure. GREENSAND FOSSILS. 281 cliff, where the two parallel layers of these con- cretionary masses are within reach, (almost half a mile to the east of Atherfield Point), will afford specimens at all times. The large gryphea sinuata (PL V. fig. 3), may be found everywhere along the shore ; the shell being sufficiently strong to resist for a time the action of the waves, clean and perfect examples often occur imbedded in the sand. Beneath Walpen High-cliff, and at Whale's Chine, the gryphea bed may be examined in situ ; the terebratula sella (PLY. fig. 5), maybe obtained from the loose green sand (No. 6, p. 226), in great perfection and variety. The magnificent cephalopodous shell, the Sca- phites grandis, * (8. gigas of our Pl.V. fig. 11), is most likely to be met with near the base of the same part of the cliffs. Some fine specimens have been found along the shore near Ladder Chine; and very large ammonites and nautili occur in the same locality. On the shore, not far from the base of Blackgang Chine, nodules with scaphites * This shell has been described under different names, as Crioceras Bower- banksii, Scaphites gigas, &c; the latter name is given in the description of PI. V., but Professor E. Forbes has adopted that originally affixed to this gigantic cephalopod by Mr. Sowerby. Scaphites are distinguished from Ammonites by the disunion of the whorls, and from Hamites, by the spiral arrangement of the posterior volutions. A very small species of Scaphite (not exceeding an inch in length) is frequent in the chalk marl. See " Medals of Creation," vol. ii. for an account of fossil Cephalopoda. 232 GEOLOGY OF THE ISLE OF WIGHT. may be observed above a bed of sand full of terebratulae. The fossil lobsters, the most beautiful of the Atherfield fossils, may generally be met with after recent slips of the cliff involving masses of the strata (Nos. 3 and 5, pp. 225, 226,) in which they occur. The vignette of this volume {engraved by Mr. Lee from a drawing by Mr. J. Dinkel) repre- sents an exquisite specimen from a fallen block lying near the pathway at the foot of Atherfield Cliff. Minute bones of fishes in the lowermost clay, and a few teeth of the Shark family, are the only remains of vertebrate animals I have observed ; but Capt. Ibbetson has obtained from these cliffs a specimen of extraordinary interest. It is a considerable portion of the skull, with the bones of the face and the jaws and teeth attached, of a species of Hybodus; a genus of fishes of the shark tribe, having teeth of a transversely elongated form, with a series of compressed conical cusps, of which the middle one is the longest.* In this remarkable fossil the mouth is open, and forms a semilunar aperture six inches wide. The upper jaw has twenty-four teeth, and the lower nineteen, in their natural position ; two rows of * Medals of Creation, vol. ii. p. 622. CLIFFS AT BLACKGANG CHINE. 233 successional teeth are traceable behind the ante- rior series. These teeth, as shown in Ugn. 19, have a central cusp rather hooked, and two lesser points on each side. LIGN. 19. — FIVE TEETH ATTACHED TO A PORTION OF THE JAW OF A FISH OF THE SHAUK FAMILY; FROM ATHERF1ELD. (Hybodus bassanus, of Sir P. Egerton. Geol. Journal, vol. i. pi. iv.) The Hybodonts, like other fishes of this family, were armed with strong dorsal spines, which are often found in the lias, oolite, and wealden strata ; and rarely, in the chalk.* The Cliffs at Blackgang Chine. — Proceed- ing from Atherfield Cliffs eastward, the first inter- esting point is Blackgang Chine ; a spot well known to every tourist who visits the Undercliff. Viewed from the sea-shore at low water, especially when the springs which feed the waterfall have been swollen by heavy rains, the effect is highly * Capt. Ibbetson's specimen is in the Polytechnic Institution on a pedestal at the entrance of the Isle of Wight model-room. It is figured and described by Sir Philip Egerton in " Geol. Journal," vol. i. p. 197. Unfortunately, the drawing was made before the bones of the face and jaws were cleared of the adherent stone, and it therefore represents only the margin of the jaws with the teeth, surrounded by a shapeless mass. 234 GEOLOGY OF THE ISLE Oh WIGHT. picturesque. The cascade falls in a perpendi- cular column from a ledge 70 feet high, down the midst of a deep chasm formed in dark ferrugi- nous clays and sands, and surmounted by broken cliffs 400 feet high ; and towering above all is the majestic escarpment of Saint Catherine's-hill, rising to an altitude of between eight and nine hundred feet. The sketch in PL XII. shows the section exhibited in the face of the cliffs. The bands of greenish-grey sand and sandstone which alternate with ferruginous clays in this division of the greensand system, appear very prominent, owing to the wearing away of the soft and friable intermediate beds. As the face of the sandstone, after long exposure to the atmosphere, separates into square blocks, the appearance of the projecting bands of stone, which are from ten to fifteen feet thick, is very singular, and is not unaptly compared by Sir H. Englefield to courses of masonry built up at dif- ferent heights to sustain the mouldering cliffs. The thin layer of ironstone grit which, as we have previously remarked, is very constantly found in this division of the greensand, constituting as it were a line of demarcation between the upper arenaceous deposits and the lower more argilla- ceous group, intercepts the water that percolates THE UNDERCLIFF. 237 through the upper porous strata, and projecting in a ledge forms the bed of the stream that falls in a cascade over the face of the cliff. In reference to the springs along this coast it may here be remarked, that no less than ten copious streams issue from the strata on the south side of the range of hills facing the Undercliff, and run directly into the sea ; most of those which flow from the greensand are chalybeate. At Sandrock, near Blackgang, is a celebrated alumi- nous chalybeate spring, of which an analysis was published by Dr. Marcet in Geol. Trans, vol. i. This water is highly charged with sulphate of iron and alumina ; it rises from a bed of sand within fifty feet of the gait. The Undercliff. — We have now arrived at the western extremity of that interesting and pic- turesque region known as the Undercliff of the Isle of Wight ; and which may be described geologi- cally, as a miscellaneous accumulation of debris, principally composed of fallen masses of the upper cretaceous strata, occasioned by the encroachments of the sea on the lower argillaceous and sandy de- posits that form the base of this line of coast. The Undercliff consists of an irregular terrace, sloping towards the south, from a quarter to half a mile in breadth, and six miles in length ; its elevation o2 238 GEOLOGY OF THE ISLE OF WIGHT. above the sea is from 100 to 400 feet. It is pro- tected on the north by the escarpment of the southern chain of hills, which forms a line of vertical cliffs, from 200 to 400 feet high, and extends from St. Catherine's to Shanklin Down. There is perhaps no tract of such limited ex- tent, that affords so remarkable an instance of the modification of climate induced by geologi- cal structure and physical configuration, as the Undercliff. Completely sheltered on the north by the range of chalk cliffs — elevated above the in- fluence of the mists and fogs of the sea-shore — possessing a soil composed of the detritus of chalk and sandstone, which rapidly absorbs and carries off superfluous moisture, yet supports a luxuriant vegetation — with an undulated and varied surface enjoying throughout its whole extent a southern aspect — and fanned only by breezes which invigo- rate but do not chill — this fairy region well merits the high encomium of the medical philosopher. It is indeed, what Sir James Clark, in his invaluable work on Climate, has described it to be — " a lofty natural terrace backed by a mountainous wall on the north, and open on the south to the full in- fluence of the sun from his rising to his going down, during that season when his influence is THE UNDERCLIFF. 239 most wanted in a northern country. The climate is remarkably equable as well as mild and dry, and there are not many days during the winter on which the invalid cannot take some exercise in the open air. The mildness and dryness of the climate during the winter months, may be in some degree estimated by the circumstance of myrtles, gera- niums, and various tender greenhouse plants usually withstanding the winter in the open flower borders. The absorption of heat by the almost perpendicular cliffs of the Undercliff, exposed as they are to the rays of the sun during the whole day, must be considerable, even in winter ; and the radiation of this heat during the night no doubt tends to equalize the temperature. To the invalid who has a taste for natural history, this sheltered district and neighbourhood possesses an additional advantage. It is rich in varied and interesting plants ; indeed the specimens of natural history with which it abounds offer abundant in- ducements to exercise, and healthful mental oc- cupation, to the cultivators of this delightful science."'* How great will be my reward, should these humble pages open a new source of intel- lectual enjoyment, to any of those who may repair * The Sanative Influence of Climate ; by Sir James Clark, Bart. m.d. iic. Fourth edition. London, 1846. 240 GEOLOGY OF THE ISLE OF WIGHT. to this favoured spot, for the restoration of health, or the alleviation of mental affliction. Geological structure of the Undercliff. — The structure of this district will be readily un- derstood by an examination of the western extre- mity of the Undercliff. The diagram, Ugn. 17, (p. 215), illustrates the position of the several groups of the cretaceous beds at St. Catherine's Down, which is 830 feet in height ; the strata are nearly horizontal. The greensand series reaches to the top of the cliff at Blackgang, upwards of 400 feet high ; the gait lies above it, and forms a bed more than 100 feet thick. The marls, sands, and cal- careous sandstones, comprised under the name of Jirestone, in thickness about 100 feet, next appear, and rise into a vertical inland cliff, half a mile from the shore. Strata of white chalk form the summit of St. Catherine's Down, the total thickness amounting, in some places, to 250 feet ; but on the south-western brow of the hill these beds thin out, and form a mere capping over the firestone.* The Gait is seen at the top of the ravine west of Blackgang hotel, resting upon the greensand which " -Mr. Lowry, the eminent engraver, informs me that the firestone reaches id within 133 feel of the beacon on St. Catherine's Down, as he ascertained by barometrical observation in 1837. STRUCTURE OF THE UNDERCLIFF. 241 extends in a terrace beyond it : some of the fossils peculiar to this deposit (Inoceramus sulcatus, and /. concentrlcus) have been obtained from this place. This bed also appears beneath the firestone on the face of the cliff east of the Sandrock spring, above the road leading to Ventnor. The Firestone in the southern face of St. Cathe- rine's hill, above the road from Niton, presents the usual characters of this group as they appear in a succession of terraces along the Undercliff.* The chalk-marl forms the upper part of the series, and passes downwards into greenish grey sands and calcareous strata, in which are layers of bluish marl rock. Strata of cherty sandstone, alternating with layers of sandy marl, occur in the lower part ; and from the disintegration and removal of the intermediate earthy beds, the chert appears in projecting ledges along the face of the southern escarpment of the downs, through a considerable extent of the Undercliff. This circumstance im- parts a peculiar feature to the landscape, and, under certain combinations of rock and vegetation, * The firestone strata in the Isle of Wight arc more numerous and diversified than in Kent and the south-east of Sussex, and resemble the equi- valent deposits in the western district of Sussex and Hampshire, so ably elucidated by Sir Roderick Murchison, in his first contribution to that department of natural philosophy, the boundaries of which his genius and important researches have since so largely contributed to extend. (See Geol. Trans, vol. li. Second series. 1826.) 242 GEOLOGY OF THE ISLE OF WIGHT. contributes greatly to the picturesque character of the local scenery.* The layers and concretionary masses of chert are principally distributed in the upper part of the series ; and beneath them are sands, and a bed of sandstone from two to four feet thick, which, though soft when first extracted, hardens by expo- sure to the air, and becomes an excellent building material. The ancient churches on the south side of the Island have been constructed of this stone, and it is being largely quarried for the edifices now in progress of erection. Fossils of the Firestone strata. — The fossils of the arenaceous and cherty strata of the firestone group, comprise many species which also occur in the uppermost deposit, the chalk marl; and like- wise several that have either not been observed, or are very rare in the other strata. They consist of several kinds of Ammonites, Nautili, Hamites, Scaphites, and other cephalopoda; numerous bi- valves, especially pectens, terebratulae, trigoniw, * Captain Ibbetson, whose beautiful and accurate models of the Undercliff are exhibited in the Polytechnic nstitution, subdivides the firestone group into the following : — 1. Upper greensand ; 2. Chloriticmarl ; ','>. Second bed of eenBand; 1. Fossiliferous war!, in which large scaphites occur; 5. Two alternations of malm and rag: the term malm is applied to a firm argillaceous rock, and raff, to the cherty sandstone that alternates with the former. A very large collection, comprising numerous species of shells, zoophytes, &c, i Obtained from these strata, and especially from the fossiliferous marl. FOSSILS OF THE FIRESTONE. 243 &c, and of a few genera of simple univalves, as Cirrus, Trochus, Awllana, &c. The bare enumer- ation of the species would occupy a considerable space, and be unintelligible, except to the scientific reader, without the aid of figures. There is, however, one fossil which it is neces- sary to describe, from the abundance of its remains which meet the eye in almost every block of fire- stone. It is a species of Siphonia (S.'Websteri), a zoophyte resembling the sponge in its porous structure, but possessing numerous tubular channels that permeate the general mass, and communicate by openings into a central cavity.* This species is in the form of an oblong bulb with a shallow opening, supported upon a long slender stem, * Mr.Webster on some new varieties of fossil Alcyonia, Geol. Trans, vol. ii. First series, p. 37C. Mr. Webster mentions that the first specimens showing the connexion of the stems and bulbous part, were observed on some " stupendous and difficultly-accessible masses of rock lying under the ro- mantic cliffs of Western-lines." The branches vary in size from half an inch to three inches in diameter, and from six to eighteen inches in length ; they terminate above in a bulb or head, somewhat resembling in form a closed tulip, and from one to six inches long; the other extremity branches into root-like fibres, by which these bodies, when living, were attached to rocks or stones. If the stems and bulbs are broken transversely, they are found to consist of bundles of longitudinal tubes ; and this internal structure is generally silicified, so that polished sections are very interesting. I need scarcely remind the reader that these bodies have no relation to the Alcyonia, which are polypiferous zoophytes; whereas these fossils are simply a con- geries of tubes and pores, like certain sponges. The fossil that is figured in my "Medals of Creation" (vol. i. p. 259), as Siphonia Websteri, is not that species, but S. piriformis of Goldfuss, which generally occurs in the green sand, but is occasionally met with in the firestone, and in the grey chalk, associated with another common fossil sponge, the Scyphia meandrina. 244 GEOLOGY OF THE ISLE OF WIGHT. having a root-like base by which the original was attached to the rock. This fossil was first figured and described by Mr. Webster, under the name of tulip alcyonium. The bulbs and steins are often disposed in relief on blocks that have been wea- thered, or washed by the sea ; for the fossils, being harder than the surrounding stone, more effectually resist abrasion, and large surfaces of firestone are therefore covered with their remains, which, being whiter than the rock, are very con- spicuous. Fossil Cycadeous plant. — But the fossiliferous marl (as Captain Ibbetson designates the bed most prolific in organic remains) has lately been found to contain relics of a higher order than any previously known to occur in the cretaceous strata of the Isle of Wight. In the collection deposited in the Poly- technic Institution, there is a specimen from the marl near Ventnor, that several years ago attracted my attention, but which I was unable to obtain an opportunity of examining till a few weeks since, when Captain Ibbetson, with great liberality, per- mitted me to inspect and figure it for this work. It proved to be, as I had conjectured, the summit of a stem, surrounded by the petioles, or leaf stalks, the leaves themselves having either been shed or decayed, of the Clathraria Lyettii, a FOSSIL REPTILE. 245 cycadeous plant, hitherto only known in the Wealden formation. A figure {Ugn. 23) and de- scription of this most interesting relic, will be given in the account of the organic remains of the Wealden in Chap. X. Fossil femur of a reptile. (?) — Another discovery, not less important, has recently been made in the easternmost quarry, above Bonchurch, and was communicated to me by S. M. Saxby, Esq. of Bellevue House, Ventnor; a gentleman to whom I am indebted for many interesting local details relating to the strata and fossils of the Undercliff. The specimen referred to is either the humerus (arm -bone) or femur (thigh-bone) of a terrestrial animal, probably of a gigantic lizard. It is broken transversely, and some two or three inches of the middle portion of the shaft are missing, but the articulating ex- tremities are in excellent preservation. So far as a hasty inspection would enable me to form a conjecture of the affinity of this bone to recent types, it appears to approach nearest to the femur of the Monitor or Iguana ; most certainly it bears no resemblance to the corresponding bone of any of the Wealden reptiles that have come under my notice. The lower portion is 9 inches in length, and terminates at its distal extremity in two large 246 GEOLOGY OF THE ISLE OF WIGHT. laterally compressed condyles, having a very wide popliteal space between them ; the anterior or patellar aspect is smooth, and but little depressed. The transverse diameter of the bone at the con- dyles is 6h inches; the upper and fractured end of the shaft is o\ inches in diameter in the same direction. The proximal extremity, or head of the bone, is somewhat compressed, and its cha- racters are concealed by adherent firestone; it is 7 inches wide in the transverse and longest dia- meter. This portion of the bone is one foot in length ; the transverse diameter of the inferior and fractured end is 4 inches ; and as the correspond- ing part of the shaft of the distal portion is 3j inches, it is obvious that the lost intervening piece of bone must have gradually diminished in circumference 2\ inches, from above down- wards. The shaft in the transverse diameter measures 4 inches; in the antero-posterior, only o inches. But the most remarkable character of this bone is the relatively enormous size of the medullary cavity, which is 3 inches by 2; the walls of the bony cylinder at the fractured part being only half an inch thick. I have not been able to procure a fragment for microscopical exa- mination, by which its reptilian or mammalian affinitymight be determined : but for the courtesy FOSSIL FUCI. 247 of Mr. Saxby, even these brief details could not have been obtained.* Fossil ftjci. — White ramose and meandering- lines are not uncommon on the surface of the sandstone : these are probably vestiges of fuci or other marine plants. A well-known delicate species, the Fucoicles Targionii,-\ that abounds in the malm- rock of Bignor, in Sussex, occurs sparingly at Ventnor. Some very curious trifid impressions are sometimes observable on the surface of waterworn blocks of sand-rock, and are possibly referable either to this tribe of plants, or to some kind of siphonia. Some of these imprints so closely re- semble, both in form and in their arrangement on the surface of the slabs, the supposed Ornithicnites, or footsteps of birds, that occur in such perplexing abundance and variety in certain ancient secondary rocks of the United States^ that Mr. Saxby, who first observed these fossils, was at infinite pains to ascertain their nature. The examples hitherto obtained, though very specious in appear- ance, cannot, I conceive, be regarded as the im- prints of the feet of any animal : unequivocal * Mr. Saxby has kindly informed me, that the quarry at Bonchurch is pre- cisely at the commencement of the land-slip by the turnpike road, and the layer in which the bone was found is three or four feet above the firestone. + Medals of Creation, vol. i. p. 105. I Ibid. vol. ii. p. S10. 248 GEOLOGY OF THE ISLE OF WIGHT. evidence as to the origin of these problematical objects is still desirable. Molluskite. — The soft bodies of the testaceous mollusca often occur in a fossil state, changed into a brown carbonaceous substance, which I have proposed to distinguish by the term molluskite.* When empty shells are found enclosed in rocks, the mineral matter generally fills up the cavity and forms a cast of the interior; but if the animal occupied the shell at the time it was imbedded, the soft parts appear to have become changed into a brown or black substance, which in some instances retains the form of the original, but in general occurs as an amorphous mass, con- taining a large proportion of animal carbon. In the greyish green sands of the firestone of Kent and Sussex this substance often occurs, and it is equally abundant in some of the sandstones of the Uridercliff. The brown spots dispersed through the stone forming the mouldings and mullions of the new church at Ventnor, are composed of molluskite. In recently extracted stone at Ventnor, I have ob- served shells of trigoniae, rostellaria?, and cucullea, filled with this carbonaceous matter. The shelly limestones of the Wealden, called Sussex and Pur- beci marbles, are mottled with black molluskite, * Medals of Creation, vol. i. p. 431. MOLT.USK1TE. 249 consisting of the carbonized remains of the river snails of which the limestones are composed. Southern range of Chalk Downs. — From this digression on the zoological characters of the middle system of the chalk formation, we resume our geological survey of the southern coast. Before we climb St. Catherine's-hill, let the observer for a moment take another glance at the view commanded by the terrace in front of the Black- gang hotel, which affords a coup oVoeil of the south- western shores. Looking down the ravine im- mediately at our feet, the aspect of the scene is singularly wild and dreary, from the sombre colours and fantastic masses of the broken walls of the chine, and the gloomy shade thrown athwart the chasm by the projecting cliffs. On the coast, the greensand strata are seen stretching on to Atherfield Point ; and beyond may be distinguished Brook Point, which from this elevated spot appears as a low promontory; and farther west are the chalk cliffs, gradually vanishing away towards The Needles. Ascending St. Catherine's-hill, a magnificent panoramic view bursts upon the sight. From the summit, a height of between eight and nine hundred feet, when the atmosphere is clear, the eye commands at one glance the grand features of 250 GEOLOGY OF THE ISLE OF WIGHT. the physical geography of the Island, and the range and extent of the principal groups of strata. We are now on the western extremity of the southern range of chalk downs which, as previously explained {ante, p. 177), is separated by a con- siderable district of greensand from the central chain of hills.* This system of chalk downs varies in breadth from half a mile to three miles, and extends six miles in a direction E.N.E. and W.S.W. from St. Catherine's-hill to Dunnose, its eastern termination, which is nearly 800 feet high. The intermediate parts of the range maintain an elevation of from 650 to 800 feet, with the excep- tion of a deep valley on the east of St. Catherine's, through which the road to Niton passes ; and another at Steephill called the Shute or Shoot, above Ventnor, traversed by the road to Appul- durcombe and Newport. A marl bank on the side of the Shute abounds in fossils.-f- The strata of these hills are nearly horizontal, having only a slight inclination to the south-east. From Ventnor to St. Boniface Down, above Bon- church,^ a distance of three quarters of a mile, the Refer to tin' diagram. /'/. vu. and the map, /'/. XX. t Mr. S,i\hy informs me that In.' lias obtained from this locality turrUitet U , nautili, belemnites, and many other marl fossils. t High up on the slope of tin- hill bursts forth a spring called SI. Boniface's I snds have attached much veneration. COAST OF THE UNDERCLIFF. 251 usual smooth verdant character of the chalk is resumed, and the hills rise to the height of 800 feet, sending oft' to the northward the lofty range of Shanklin Down, and terminating in Dunnose Point.* The siliceous nodules in the&e strata are always found entire ; presenting in this respect a striking contrast to the shattered flints in the ver- tical strata that form the opposite range at Brading Down (see PL XIII.). Coast of the Undercliff. — The district of the Undercliff, from the western extremity of St. Catherine 's-hill to Bonchurch, is about six miles ; and the road from the west passes along an irre- * Deviation of the plumb-line at Shanklin Doivn. — During the progress of the Ordnance survey, a deviation of the plumb-line from its mean direction was observed in the neighbourhood of Shanklin Down, by Col. Colby, the Director of the Trigonometrical Survey; a considerable attraction of the plumb-line to the south of the Dunnose station having been unequivocally determined, and which is supposed to depend on the intensity of the attrac- tion of the hill. In alluding to this remarkable phenomenon Sir Roderick Murchison (in his address at the meeting of the British Association of Science at Southampton, September 184C) observed, " that it is a matter of surprise that this, comparatively, low chalk range in the Isle of Wight should attract, in one parallel at least, with more than half the intensity of the high and crystalline mountain of Schehallien in the Highlands of Scotland. a Can this be explained by the peculiar structure and distribution of the ridge of upheaved strata which runs as a back-bone from east to west through the Island? or is it to be referred to the effect of dense masses of plutonic rock ranging beneath the surface along the line of displacement of the deposits ?" a In the year 1774, from astronomical observations made on the mountain of Schehallien by Dr. Maskelyne, it was proved that a sensible disturbance was produced in the direction of the plumh-line by the attraction of the dense masses of granular quartz and limestone, and mica and hornblend slate, of which that mountain is composed. P 252 GEOLOGY OF THE ISLE OF WIGHT. gular terrace composed of fallen masses of chalk, marl, and firestone, which in the lapse of cen- turies have accumulated in a talus on the southern escarpment of the Downs. Although subsidences are occasionally taking place, and within the last hundred years, from eighty to ninety acres of the upper cliff sunk down at one time, the greater part of this singularly picturesque and lovely region has undergone no material change since the Con- quest. This is evident from the ancient churches of St. Lawrence, and St. Boniface, which are referred by antiquaries to the eleventh or twelfth cen- tury.* In travelling from Blackgang to Ventnor, the firestone cliffs are the most important geolo- gical feature. Here and there on the road side are seen accumulations of debris, and projecting crags of chert and sandstone, which from their superior hardness have for years resisted the dis- integrating effect of the elements. From the in- termixture of calcareous and argillaceous earth resulting from the decomposition of the strata, a soil has been produced which supports a luxuriant vegetation. Even the refractory siliceous rocks are more or less clothed with foliage, for the ivy has insinuated itself into every cranny, and hangs in festoons of verdant tapestry over the cherty peaks. * Sir Henry Englefield ; Isle of Wight. COAST OF THE UNDERCLIFF. 255 In many places the fallen blocks of sandstone are covered in relief with stems and bulbs of the Siphonia Webster i (ante, p. 243), and contain nume- rous shells. At Ventnor there are (or were) some bold vertical sections of the firestone ; and an enormous mass of rock overhangs the road east of the Marine hotel. The calcareous sandstone here abounds in shells and molluskite. The terrace and sea-cliffs that form the southern boundary of this rapidly increasing town, are entirely composed of fallen masses of the upper groups of the creta- ceous strata. In many instances huge fragments of white chalk appear imbedded in the green sand of the firestone ; and I observed (in 1844) a series of chalk strata forty feet in thickness, surmounted by many feet of marl and firestone, forming a low headland on the sea-shore ; the entire mass having been retroverted in its fall from the heights above. The diagram in lign. 20, p. 256, will serve to elucidate the above remarks. The vicinity of Ventnor is rich in the shells and zoophytes of the cretaceous system. The follow- ing localities have been pointed out to me by Mr. Saxby :— The bank on the roadside at the Shute above Ventnor, abounds in Chalk-marl fossils. Horse-shoe Bay, in black malm rock ; many shell;-;. Under the cliiT to the cast, called Highrport, at low water, nodules 256 GEOLOGY OF THE ISLE OF WIGHT. of pyrites, generally having a tercbratula or other shell as the nucleus. East of ( 'olin's Point and Mill Bay ; the gait is visible and contains shells. In a highly inclined fallen mass of sand- stone, sharks' teeth, coprolites, molluskite, and many shells. Firestone with fossils occurs on the shore, east- ward of the Parsonage. In the gravel-pits on "Little-town Down," above Ventnor, the Hints abound in sponges. They sometimes contain a sharp conical body fixed by its base and projecting into an elongated fusiform cavity. This appearance has been produced by a belemnite, of which the large cavity is the impression, and the conical body the cast of the phrag- mocone, or chambered shell of this curious cephalopod.* LIGN. 20. — SECTION or THE UNDERCLIFF. NEAR VENTNOR. In the chalk marl above Bonchurch nume- rous fossils, comprising turrilites, scaphites, am- monites, incocerami, &c. have been found. The bone of a reptile (p. 245), and the stem of Cla- thraria, previously described {ante, p. 244), were obtained from this locality. * Sec Medals of Creation, vol. ii. p I S 9 ventnor to sandown bay. 257 The coast from Ventnor to Sandown Bay. — From Rocken-end, east of Blackgang Chine, to Bonchurch, the sea-cliffs, in consequence of the displacements which have produced the Undercliff, present no continuous sections of the strata, of sufficient importance to require especial notice. It may be briefly stated, that after passing along that ruinous district, and arriving at the eastern termination of the promontory formed by the southern chalk downs, a repetition of the section observable at St. Catherine's-hill on the western extremity, is presented to view on the east of Bonchurch Cove, at Dunnose Point and Shanklin Down. This section of the nearly horizontal strata of chalk, firestone, gait, and greensand, is shown in the diagram, lign. 9, p. 134. The white chalk forms the upper series of deposits ; of the fire- stone, which varies in total thickness from 70 to 100 feet, a good section is seen above the ravine at Luccomb, between Bonchurch and Shanklin. The gait underlies the firestone as at Sandrock, near Blackgang ; and beneath are the ferruginous sands and dark clays of the greensand • the layer of ironstone nodules full of casts of shells (see ante, p. 226) extends through the upper part of the cliff at Dunnose ; but the pema mulleti bed has not been observed along this part of the coast. 258 GEOLOGY OF THE ISLE OF WIGHT". Luccomb Chine, which lies between Chine-head and Dunnose Point, is an extensive gnlly like that of Blackgang, formed by springs derived from the high land on the north-west, and which falling over a perpendicular cliff of sand and clay, have worn a deep ravine that is slowly receding from the shore. The celebrated chine of Shanklin is of the same character ; the cliff here is 230 feet high, and the chasm extends 150 yards from the shore, being 300 feet wide at the top, and narrowing down to the bed of the torrent. The steep sides of the ravine are clothed with verdure, and over- shadowed by underwood, except where bare masses of rock protrude, and contribute to the picturesque effect of this romantic glen. The character of the scenery around Shanklin so entirely depends on the geological structure of the country, that I am led to transcribe the follow- ing vivid description of this part of the Island by Sir II. Englefield: — "As we approach the village of Shanklin, its appearance is equally singular and interesting. It is seated in a small vale hanging towards the sea, at a great height above that level; the houses are detached from each other, and almost buried in groves of elms ; and every cottager, however humble, being in the habit of letting Lodgings in the summer season, surrounds bis I3HANKLIN CHINE. '2~)9 dwelling with a garden full of flowering shrubs. The whole spot has a most cheerful and uncommon character. The little church, which is of a pretty form, stands on a broken knoll open to a beautiful pasture, with groups of elms carelessly disposed about it; and it is backed by the high hill of Dunnose, whose lower part is covered with thickets and groves hanging down its steep sides. From among these in one part a range of rocks starts out; the northern face of the same great stratum to which the Undercliff owes its exist- ence and its beauty. The route from Shanklin church, by the road which winds through the open groves up the flank of Dunnose is eminently beautiful, affording, as we ascend, the most lovely views. The village with its groves forms a charm- ing first distance — the bay of Sandown with the Culver Cliffs present a noble winding shore — and beyond the low land of Sandown, in the direction of Brading Haven, a part of the anchorage of Portsmouth with its shipping is visible. From the top of the ascent, the elevation of the ground is so much greater than the chalk hills of Yaver- land, that the sea is visible over them ; and the distant blue heights of Hampshire and Sussex form an uninterrupted line, till to the eastward they are blended with the horizon of the sea ; 260 GEOLOGY OF THE ISLE OF WIGHT. emerging out of whose waters the white cliffs from Brighthelmston quite to Beachy-head, are distinctly visible, though from forty to sixty miles distant." * The western cliff of Shanklin Chine consists of an alternating series of clays and sands. The upper part is greenish-white sand, resting on a bed of dark-blue clay ; beneath this is another stratum of sand, and a second bed of clay lying on a deposit of greenish-grey sand, with bands of sand- stone. ' The lower part consists of ferruginous sands, with concretionary layers of green sand full of terebratulse. The argillaceous partings have given rise to narrow ledges, which are verdant from a covering of rank grass ; but slips are con- tinually taking place from the wasting away of the sand, by the oozing of the water arrested in its descent from the porous strata above, by these beds of clay. Along this shore numerous specimens of the gryphea sinuata are generally to be met with loose in the sea-sand, as at Atherfield; and iron- stone concretions full of shells, that have fallen from the cliffs: in these nodules, leaflets of the Wealden fern (Ugn. 21) are sometimes found asso- ciated with trigonise, terebratula?, &c. * Sir H. Engelfield's Isle of Wight, p. 70. VENTNOR TO SANDOWN BAY. 261 At the foot of the cliff near Shanklin Chine, the lower series of greensand strata emerge, and gradually rising to the surface, form the western coast of Sandown Bay. The view of the bay from Shanklin is extremely interesting, for the white chalk strata of Culver form the eastern promon- tory, and the gait, firestone, and greensands of Redcliff, succeeded by the low Wealden cliffs, may be distinctly traced. Beyond the cliffs at Sandown is the vale of Newchurch, a low alluvial plain, protected from the inroads of the sea only by a thick bed of shingle ; beneath which, at low water, the Wealden clay may be seen extending under the green- sand strata on the east and west. The little Inn on the shore, and the Fort, now appear, and we reach the spot where our examination of the eastern side of Sandown Bay terminated. Our excursions have now extended round the Island, and embraced the whole series of coast sections, with the exception of the Wealden cliffs that intervene between Compton Bay and Ather- field Point. A visit to Brook Bay will enable us to complete our survey, by an investigation of those highly interesting natural records, of one of the most remarkable epochs in the physical history of our globe. CHAPTER IX. THE WEALDEN FORMATION NATURE OF RIVER DEPOSITS WEALDEN STRATA OF THE ISLE OF WIGHT EXCURSION TO BROOK BAY — CLIFFS FROM COMPTON CHINE TO BROOK POINT BROOK POINT — PETRIFIED TREES — STRUCTURE OF THE FOSSIL WOOD. The Wealden formation. — The lacustrine and fiuviatile origin of the strata spread over the northern part of the Island, was clearly denoted by the prevalence of land and freshwater shells, and the remains of aquatic and terrestrial plants; and by the presence of bones of mammalia re- lated to the Tapir, Peccari, &c, but referable to extinct species and genera ; while the marine and estuary shells, and other exuviae, in the de- posits on which the freshwater beds were super- imposed, afforded conclusive evidence that these strata were formed in the basin of a comparatively shallow sea. The cretaceous system, which so long engaged our attention, displayed, on the contrary, an as- semblage of sedimentary deposits that had been accumulated in the profound depths of the ocean, THE WEAEDEN FORMATION. 263 in a period of unfathomable antiquity and of long- duration. The innumerable relics of marine or- ganisms showed that then, as now, the sea was teeming with life ; while a few vestiges of ter- restrial plants and animals attested the existence of dry land, inhabited by oviparous quadrupeds and clothed with vegetation, during the formation of this series of oceanic deposits. The natural records of an antecedent epoch are now before us, and we proceed to examine an assemblage of strata, not of marine, but of fresh- water origin, that was deposited ere the formation of the cretaceous rocks commenced ; for these fluviatile sediments constituted the sea-bottom, over which was spread the first layer of the green- sand (see p. 221). From the extension of these deposits over the wealds of the south-east of England, and from their fluviatile characters having in the first instance been determined by observa- tions on the strata and organic remains discovered in those districts, the formation has received the name of The Wealden. Before entering upon the examination of the cliffs in Brook Bay, which will form the principal object of the present excursion, a few general ob- servations on river deposits, and on the information to be derived from their investigation, as to the 264 GEOLOGY OF THE ISLE OF WIGHT. nature of the laud, and its fauna and flora, may be necessary to enable the unscientific reader justly to appreciate the geological interest of the pheno- mena that will demand his notice — phenomena which, if rightly interpreted, will reveal a former condition of the earth's surface, more marvellous than any which even the wildest imagination has ventured to portray. Nature of river deposits. — The torrents that rush down the mountains' sides, and the streams and rivulets that meander through the plains, are more or less charged with earthy particles, worn from the rocks and strata over which the waters flow ; and the united streams, in their progress to- wards the rivers, become more and more loaded with adventitious matter, and a great quantity of de- tritus is mechanically suspended in the water, and carried towards the sea. If the current is feeble, and the inclination of the ground but slight, a large proportion of the mud, pebbles, and gravel, subsides in the bed of the river ; but the greater part is transported to the mouth of the stream, and accumulating in the bays and creeks, and around the embouchure of the river, gives rise to those deposits of alluvial debris termed deltas and estuaries. But the finest particles of the detritus are carried far out to sea, by the NATURE OF RIVER DEPOSITS. 265 currents, and finally sink down, and form layers of mud in the profound depths of the ocean. Rivers, however, convey not only the in- organic materials of the countries through which they flow, but also the leaves, branches, and trunks of trees, and other vegetable remains, and the car- cases of land animals that fall into the streams, and terrestrial, lacustrine, and fluviatile shells. The remains of man and works of art are also occasionally transported to the delta, and en- gulphed in the mud, silt, and sand ; and relics of this kind are sometimes drifted out to sea, and deposited in the bed of the ocean. In the rivers of India and of America these operations are in daily progress on an immense scale. In the Mississippi rafts formed of prostrate forests are transported to the delta of that mighty stream, and become buried in the freshwater deposits which are there rapidly accumulating. In these sediments the remains of the animals as well as plants of the new world, are en- gulphed. It is evident that should deposits of this nature become dry land, the naturalist, by an examination of the imbedded organic remains, may with cer- tainty determine the characters of the fauna and flora of the country whence these fluviatile sediments 2G6 GEOLOGY OF THE ISLE OF WIGHT. were derived. Thus in the delta of the Thames he would find the bones and antlers of the deer, horse, dog, and other domesticated animals, with the leaves and branches of the elm, oak, ash and other trees and plants of our Island, with human bones, fragments of pottery and other works of art; while in that of the Ganges or the Nile, the remains of the animals and plants of India, or of Egypt would be discovered.* To apply these data to the elucidation of the present argument. Let us suppose that the river has disappeared, that the sea also has left its place, and that the delta has become dry land; that towns and villages have been built upon the con- solidated mud and sand, and that the surface of the country is either covered with woods and forests, or under cultivation. If in natural or artificial sections of these deposits, the bones of men and animals, with works of art, and the remains of plants and river shells, should be found in the clays or sands, such appearances would excite in us no surprise, because we are acquainted with the pro- cesses by which the strata were accumulated ; and should an inhabitant of the new country express his astonishment how fragile shells, and delicate Por .n more extended view of this subject sec Wonders of Geolopy. vol. i. p. 12. NATURE OF RIVER DEPOSITS. 267 leaves, and bones of animals, became enclosed in the solid rock, and refusing assent to our interpre- tation, attribute their presence to the effect of a deluge which softened the crust of the earth, and imbedded in the sediments of its waters the remains of animated nature — our reply would be that such a catastrophe must inevitably have intermingled the relics of the animals and plants of the land, the rivers, and the ocean, and that the regular stratification of the materials, and the exclusively fluviatile and ter- restrial character of the fossil remains, are fatal to such a hypothesis, and confirmatory of our ex- planation of the phenomena. It was by such a train of reasoning that the fluviatile origin of the Wealden deposits was established. The strata composing the Wealden formation of the south-east of England, admit of the subdivisions given in the tabular arrangement, p. 63. Alter- nating layers of clays, sands, and limestones almost wholly composed of freshwater univalves, and of small bivalves with minute crustaceans, form the upper series. Sand and sandstones, with bands of arenaceous limestones or calciferous grits, wdth shells and lignite, prevail in the middle group ; while in the lowermost, sands, clays and argillaceous shelly limestones again appear; and Q 268 GEOLOGY OF THE ISLE OF WIGHT. buried beneath the whole is a petrified forest of pine-trees with cycadeous plants, still erect in the soil in which they grew ; and in all these deposits bones of colossal terrestrial reptiles are more or less abundant. The upper clays and limestones oc- cupy the valleys of the Wealden districts that skirt the inner escarpments of the chalk downs in Surrey, Kent, and Sussex ; the middle group of sands and sandstones constitutes the Forest-ridge of those counties ; and the lower series appears in the deep valleys in the east of Sussex, around Battel, Bright- ling, Burwash, and Ashburnham. The Purbeck strata, which are characterised by thick beds of shelly limestone principally formed of a small species of paludina, appear on the coast of Dor- setshire, in the Island, or more properly the Penin- sula, whence the name is derived. The Wealden presents the most perfect example of an ancient delta hitherto discovered ; in the numerous for- mations comprised in the systems of Geology, there is no other instance of so well defined and extensive a group of fluviatile deposits.* * Scarcely twenty-five years ago, though the Wealden districts were traversed daily by hundreds of intelligent persons in their journeyings to and from London and Brighton, their freshwater origin was unsuspected; the whole group being considered by Geologists as identical with the sands, clays, &c. of the chalk formation. For though the shells forming the Sussex marble of the weald clay, were supposed, so long since as Woodward's time, to be fluviatile species, yet this point was controverted by some able eonchologista ; and but lew if any other organic remains bad been obtained THE WEALDEN STRATA. 269 The total thickness of the Wealden (inclusive of the Purbeck beds) is estimated at upwards of 1,500 feet, being equal to three times that of the delta of the Mississippi."* Wealden strata of the Isle of Wight. — In the Isle of Wight but a small portion of the upper series of clays, sands, and sandstones is ex- posed to view. These deposits constitute the line of coast already noticed, in San down Bay, and the range of cliffs from near Atherfield Point to Compton Bay. The section exposed in the cliff's on the south-western coast, is shown in lign. 16, from the strata of the Weald. Having for several years diligently collected the fossils of the south-east of Sussex, and separately arranged the specimens from different localities, I was struck with the want of accordance between the organic remains from the chalk, gall, hrestone, &c. and those which I had obtained from the quarries and wells, opened or sunk in the Wealden district , and by degrees, the freshwater character of the area between the green sands of Sussex, Kent, and Surrey, became manifest. The absence of ammonites, echinites,terebratulas, corals, and otiier common and characteristic fossiis of the chalk, in my wealden collection, was a circumstance that could not fail to arrest attention; and the discovery of the bones of large reptiles, witli the leaves and stems of ferns, cycadeous plants, &c. in the strata of 'lilgate Forest, of which there were not the slightest traces in the cretaceous deposits, corro- borated the inferences suggested by my previous observations. In 1S22 the Tilgate strata were first described, and their freshwater origin pointed out in " The Fossils of the South Downs." In June 1822, I communicated to the Geological Society of London an account of the extension of these strata over Sussex, being the result of my own and Mr. Lyell's observations. In 1827, "The Fossils of Tilgate Forest," containing nearly 200 figures of wealden fossils, was published. See Dr. Fitton's charming little work ; "A Geological Sketch of the vicinity of Hastings." London, 1832. p. 13. * The delta of the Mississippi is computed by Mr. Lyell to be 528 feet, or about the tenth of a mile in depth; the area it covers 13, COO square statute miles ; the solid matter annually added 3 billions 700 millions cubic feet ; and the period required for its formation, many thousand years. q2 270 GEOLOGY OF THE ISLE OF WIGHT. (p. 215), from Dr. Fitton's Memoir; to which reference must be made for details, which though of great value in a scientific point of view, possess but little interest for the general observer.* The Wealden strata forming this line of coast, consist of laminated clays, shales, and loosely coherent sands, full of freshwater shells and crus- taceans, with lignite, and in some strata abundance of pyrites ; layers, a few inches in thickness, of tough bluish argillaceous shelly limestones, some being composed chiefly of bivalves, and others of univalves ; sands, with concretionary nodules of calcareous compact grit and sand-rock ; and varie- gated clays, mottled with different shades of red, yellow, blue, green, and grey; waterworn bones of reptiles occur throughout. But the subdi- visions of the Wealden are in a great measure arbitrary, for the same fossils, and the same litho- logical characters, pervade the entire series. Beds of sands, clays, and argillaceous limestones, and calciferous grits, almost identical in mineral composition, and containing similar organic re- mains, are found alike in the upper and lower part of the series; indicating a similar condition of the land and water throughout the Wealden epoch. In that part of Sussex over which my <•> "I. Trans, vol. iv. second series, p. 197 — 220. EXCURSION TO BROOK RAY. 271 earliest researches extended, the univalve lime- stones {Sussex marble) and shales, predominate in the upper series ; sands and calciferous grits alternating with clays in the middle ; and bivalve limestones and clays in the lower division. But in the Isle of Wight, the clays and limestones with bivalves, are as abundant as those with univalves ; and slabs from San down and Compton Bays, could not be distinguished from the shelly limestones of Ashburnham and Battel in Sussex.* Excursion to Brook Bay. — The Wealden strata extend between six and seven miles along the coast ; we have ah'eady noticed their emer- gence from beneath the greensand at Ather- neld Point (ante, p. 224), and at Compton Bay (p. 216). From Compton Chine to Brook Chine, a distance of but little more than two miles and a half, the most interesting phenomena may be examined in a stroll along the beach, which should be undertaken at the ebb of the tide, to allow of suf- ficient time for the collection of specimens. If a brief visit only be contemplated, the tourist should drive to Brook, and within a short distance of the * It may be worth inquiry whether the Wealden strata of the Isle of Wight really belong to the upper division — whether they may not be referable to a lower group, and the superior beds have been destroyed by the incursions of the sea, before the delta subsided and the greensand was deposited upon the now uppermost bed of clay ? 272 GEOLOGY OF THE ISLE OF WIGHT. chine,* and he may alight within a few hundred yards of the most interesting spot — the fossil forest at Brook Point. The most favourable season for a geological examination of this part of the coast is the early spring — the latter end of March or the beginning of April — for at low water a great extent of sand is laid bare, and reefs of Wealden sand-rock are seen stretching far out to sea ; and the high tides often sweep away the shingle from the base of the cliffs, and the lowermost visible strata are exposed. The chance of obtaining fossil bones is also greater at this period of the year than at any other, owing to the inroads of the sea on the clay cliffs, and the consequent dislodgment of any bones they may contain ; and as these relics are very heavy from an impregnation of pyrites, they fall on the shingle, and are left by the retiring waves. We shall commence our ramble at the foot of Compton Chine, near which place fossils of the Greensand and of the Wealden alike abound. Cliffs from Compton Chine to Brook Point. — The description of the coast as seen from the foot of Afton Down, given on our previous visit to Compton Bay (p. 210, PL XL), and a reference to the sections in lign. 16 and 17, * There is no Inn near the spot, hut accommodation for horses may be obtained at a neighbouring farm-house or cottage. COMPTON CHINE TO BROOK POINT. 273 p. 215, and to the map (PL XX.), will afford the necessary information as to the geological relations of the strata we are about to examine. As we descend to the sea-shore near Compton Chine, the top of the cliff, to the depth of ten or twelve feet, is seen to be composed of drifted gravel, clay, and loam ; and this alluvial covering- continues for several miles along the coast, forming, as shown in the annexed sketch (PL XIV. p. 274), a horizontal bed upon the edges of the inclined strata of which the lower part of the cliff consists. In this accumulation of drifted materials are numerous trunks of trees and quantities of hazel- nuts, in the usual condition of peat or bog-wood. The trunks are several feet in length, and a foot or more in diameter ; the ligneous substance is very black and soft when first extracted, but hardens after exposure to the air, and some of the wood is so firm in texture as to be employed for various domestic purposes. I could not learn that any bones had been found in this subterranean forest, but I picked up, on a bank hard by, teeth of the horse and deer, which were deeply stained with phosphate of iron, and probably belonged to this alluvial deposit. The Wealden strata to the east of their junction with the greensand, principally consist of clays, 274 GEOLOGY OF THE ISLE OF WIGHT. with seams of shale and sand, and layers of shelly limestone ; the appearance of the face of the cliff formed hy these strata is shown in PI. XIV. In this view the nearest headland is Bullface Ledge ; that beyond, which extends far out to sea, is Brook Point, the western extremity of the Bay ; that in the far distance is the eastern boundary of the same. The view of Brook Point from Afton Down (PL XL p. 210), shows the conti- nuance of the cliffs from beyond Bullface Ledge and Brook Bay to Blackgang Chine. Masses of the Wealden clay with freshwater shells, in connexion with the greensand containing marine shells, should be the first objects of re- search. Mr. Morris was so fortunate as to obtain from this spot, a mass in which specimens of a very characteristic univalve (Potamides carbonarius, PL VI. fig. 5) were imbedded. Waterworn blocks of the shelly limestones (PL VI. figs. 2, S, 4), and rolled fragments of bones washed out of the cliffs, will be found in abundance in the shingle. Slabs of the freshwater limestones may be observed in the cliffs at an accessible height ; and specimens of the shale covered with cyprides and shells, ma\ be obtained from the fallen masses on the shore. The laminated clays and shales are succeeded, as we advance eastward, by mottled plastic clayi , BROOK FOINT. 277 containing bands of reddish and yellow sand, and hard grit or sand-rock ; and the strata gradually decline till we reach Brook Bay, where they are nearly horizontal. From Bullface Ledge we perceive the low pro- montory of Brook Point that forms the eastern boundary of Compton Bay, and at its base a reef of rocks extending seaward to a considerable distance. If the tide is very low, a succession of ledges of this kind are visible along the shore, stretching out to the distance of half a mile or more from the land, and indicating the former extent of the southern coast of the Island, at a comparatively very modern period. These reefs and rocks consist of the harder masses of the Wealden sandstone, which have resisted the de- structive effects of the waves, after the clays, sands, and softer materials, have been swept away. Brook Point. — As we approach Brook Point, the variegated sands and grit which lie beneath the clays, become more developed ; and large waterworn blocks of sandstone appear here and there on the shore. The ledge at the base of the cliff, which formed so prominent a feature of this part of the coast when seen from a dis- tance, consists of indurated sandstone inclosing 278 GEOLOGY OF THE ISLE OF WIGHT. trunks and branches of large trees completely petrified, many of which are strewn along the strand, and half buried in the sand and shingle. The projecting masses at the foot of the cliff are the broken edges of the strata, and the trunks of fossil trees ; the upper and less coherent deposits having been washed away. The cliff is between thirty and forty feet high, and is capped by the bed of loam and gravel pre- viously noticed at Compton Chine. Beneath this alluvial covering are laminated clays and shales, and sand and friable sandstone, abounding in masses and layers of lignite; and minute particles of the same substance are disseminated through- out the strata. Pyrites occurs abundantly in small nodules and spheroidal masses ; and this mineral generally pervades the lignite and wood. Towards the base of the cliff, are the beds of sand and sandstone with hard concretionary grit, containing the fossil trees ; and beneath these are seen, at low water, compact variegated sands, which are the lowermost deposits in the Island. East of the Point is Brook Chine, a deep fissure or chasm that has been worn in the softer strata by the long continued erosion of a stream, which gushes out from beneath the sand beds inland, and (lowing through the alluvial PETRIFIED TREES. 279 gravel to the top of the cliff, falls in a cascade to the sea-shore. Petrified Trees. — The prostrate fossil trees at Brook Point were first noticed by Mr. Webster thirty years ago.* After describing the clays and sandstones of the cliff, Mr. Webster states that he " observed many masses of a coaly blackness, bear- ing the exact form and resemblance of trunks of trees that had been charred, lying on the beach, and imbedded in the clay-cliffs, and also in the rock. In some parts the ligneous fibre was still evident ; in others the wood had been converted into a substance much resembling jet, its black- ness being intense, its cross fracture conchoidal, and its lustre very great. Other parts of the trees were entirely penetrated by pyrites, and groups of crystals of this substance were frequently attached to the outside. On lifting up some of the sea-weed, that grew upon the shore between high and low water-mark, I was astonished to find almost all the rocks below them composed of pe- trified trees which still retained their original forms. The knotty bark and ligneous fibre were very distinct ; and trunks and branches were fre- quently imbedded in masses of clay now indurated and in the state of argillaceous rock." * Sir H. Englefield's Isle of Wight, p. 153. 280 GEOLOGY OF THE ISLE OF WIGHT. Upon first reading the above description, my curi- osity was strongly excited, and when in the course of my researches in the strata of the wealds of Sussex, the nuviatile origin of those deposits be- came evident, I felt an irresistible desire to visit Brook Point, in the expectation of beholding a petrified forest of the country that had been in- habited by the colossal reptiles, of which so many remains had been discovered in Tilgate Forest. Nor was my expectation disappointed ; I have visited this coast many times, and always with increased interest — an interest which I hope to excite in some of my intelligent readers, and induce them to repair to the spot, and investigate the phenomena, of which these pages can present but a feeble outline.* The trees are all lying prostrate and » In June 1823, my friend Mr. Lyell visited Compton Bay for the purpose of ascertaining more clearly the relations between the ironsand of Mr. Webster, and the strata of Tilgate Forest, of which an account had appeared in my "Fossils of the South Downs." In a letter detailing the result of his investigation, Mr. Lyell remarks : — " At Compton Chine I found in Webster's blue marl, several small Inocerami (I. sulcalus) and some other characteristic shel.s, so that I believe the identity of this bed with the Folkestone gait might be made out by further research. The section from Compton Chine to Brook is superb; we see there at one view the whole Geology of your district, from the Chalk with Hints down to the Battel beds, and all within an hour's walk. — This is so beautiful a key, that 1 am at a loss to conceive how so much confusion has arisen. — The softness of the weald clay has caused a ruinous state of the cliff just where the Sussex marble ought to be. Soon after this, layers of limestone with bivalves appear; then some mottled beds; then pyritous coal (lignite) like that at Bexhill 1 presume. In Sandown Bay I picked up a block of Petworth marble two feet in diameter, of which and the other rocks I will send you • ii.-.." PETRIFIED TREES. 281 confusedly intermingled. There are no erect trunks, nor any other indications that the forest was submerged with its native soil, like that of the Isle of Portland.* On the contrary, this accu- mulation of fossil trees resembles the rafts, as they are termed, that are annually brought down from the interior of the country by the tributary streams of the great rivers of North America, and which, hurried along by those vast floods, entangle in their course the remains of animals and plants that may happen to lie in the beds of the rivers, or be floating in the waters. These rafts are at length drifted out of the course of the currents, and becoming loaded with mud, sand, and other extraneous matter, sink down, and are engulphed in the bed of the delta.-j- The fossil trees at Brook Point appear to have been submerged when arrived at maturity, and while fresh and vigorous ; for the trunks before removed from the sandstone, are invariably covered by the bark in the state of lignite. This cortical investment quickly disappears when the stems are exposed to the action of the waves ; but the ligneous structure, which is converted into a very hard calcareous stone, for a long while resists * Wonders of Geology, vol. i. p. 362. t Ibid. vol. ii. p. 667. 282 GEOLOGY OF THE ISLE OF WIGHT. destruction. Trunks and branches, from a few inches to three feet in diameter, and many feet in length, are in general to be seen lying on the shore between high and low water mark ; and in these specimens the texture of the wood, and the annular lines of growth on the waterworn transverse frac- tures, are strongly defined. On a late visit there were two stems which could be traced to a length of twenty feet ; and they were of such a mag- nitude as to indicate the height of the trees when living at from forty to fifty feet. Many stems are concealed and protected by the fuci, corallines, and zoophytes, which here thrive luxuriantly, and occupy the place of the lichens and other para- sitical plants, with which the now petrified trees were doubtless invested when flourishing in their native forests, and affording shelter to the Iguan- odon and other gigantic reptiles. Structure of the Fossil wood. — These fossil trees are calcareous, not siliceous like those of Portland. The wood is more or less traversed by veins and filaments of pyrites, which impart a beautiful appearance to polished specimens of the steins. Slices rendered transparent by Canada balsam, exhibit under the microscope, in the transverse sections, the cellular tissue as a reticulation of polygonal meshes; and in the radial, FOSSIL WOOD. 283 the ducts or glands characteristic of the Coniferae, and arranged in alternate rows as in the Araucaria or Norfolk Island Pine.* The annular lines of growth are often very distinct ; I have traced from thirty to forty on some of the stems. These circles are of unequal thickness, and therefore in- dicate a variation from year to year in the climate of the country in which they grew. They are, too, as small as in the slow growing pines and firs of England. Many of the stems exhibit an obli- quity in the annular lines, proving that they grew in situations which exposed the trees to prevailing currents of wind from a particular quarter, and caused them to incline in the opposite direction. I have discovered no vestiges either of the foliage or fruit. It is remarkable that coniferous wood occurs but sparingly, if at all, in the Wealden deposits of the south-east of England ; but drifted stems and branches of pines of the araucarian type, are common in some of the upper beds of the greensand, and are occasionally met with in chalk flints.j- Such is a brief description of the accumu- lation of fossil trees at Brook Point, which evi- dently originated in a raft composed of a prostrate * See Medals of Creation, vol. i. p. 71. t Medals, vol. i. p. 168. 284 GEOLOGY OF THE ISLE OF WIGHT. pine-forest, transported from a distance by the river which flowed through the country whence the Wealden deposits were derived, and became sub- merged in the sand and mud of the delta, burying with it the bones of reptiles, mussel-shells, and other extraneous bodies it had gathered in its course. In the strata that overlie the fossil forest, thin interrupted seams of lignite,* and masses of the same substance invested with crystals of brilliant pyrites, are every where abundant ; and beautiful and instructive specimens may be obtained. f In the clays for several hundred yards both to the east and west of Brook Point, bones of the Wealden reptiles are numerous ; with these are associated large mussel-shells {PL VI. fig. 1), and lignite. To the east of Brook Bay is Brixton Bay; and along this line of coast, as far as Ather- field, similar organic remains art' continually met with after the high tides of the early spring. I have not examined the cliffs further to the eastward, and must refer to Dr. Fitton's Memoir for a particular enumeration of every important * Lignite, &c— for an account of the changes by which vegetable sub- stances are converted into lignite, coal, &c, see Medals of Creation, vol. i chap .">. t Unfortunately these specimens generally fall to pieces after a few months, in consequence of the decomposition of the pyrites with which they are permi WEALDEN STRATA. 285 stratum, along the southern coast of the Isle of Wight. My attention has always been so much engrossed by the interesting phenomena observ- able in Brook Bay, which is at all times easy of access, that I have had neither leisure nor incli- nation to extend my researches to the east of the point above mentioned. Dr. Fitton states that in the cliff at " Tiepit and thence to Shepherd's Chine, and within that chine and Cowlease Chine, the Wealden clay and its passage to the sands beneath, are better displayed than in any other localities."* * Geol. Trans, vol. iv. p. 19S CHAPTER X. ORGANIC REMAINS OF THE WEALDEN FOSSIL VEGETABLES ENDO- GENITES EROSA CYCAHEOUS PLANTS CLATHRARIA LYELLII FOSSIL SHELLS — TTNIO VALDENSIS FOSSIL CYPRIDES — FOSSIL FISHES. Fossils of the Wealden. — The Wealclen strata of the Isle of Wight have afforded examples of the most characteristic organic remains that have been discovered in this formation in other parts of Eng- land. They have yielded five or more genera of terrestrial plants ; of which one belongs to the Pines, several to the Cycadeas, and two or three to the Ferns : several species of river-shells, of the genera Unio, Paludina, Potamides, Cyclas, &c. ; and of the small crustaceans, the C[iprides. Fishes allied to the Bony-pike and the Sharks occur, and bones of seven or eight species of terrestrial saurian reptiles, and of two or three genera of Chelonians, Fossil vegetables. — Our description of the fossil forest of Brook Point entered so fully into the character of the coniferous trees of the Wealden, that it is unnecessary to enlarge upon FOSSIL FEEiNS. 287 that subject. A great proportion of the lignite in the laminated sands and clays forming those cliffs, is undoubtedly the bark of the mature trees, and the wood of the young plants, in a carbonized state. But the coaly particles disseminated through the strata have probably, in a great measure, lign. 21. — a fossil fern (Loncliopteris Mantelli) from the weald CLAY ; BROOK POINT. Fig. 1. — Portion of three leaflets, magnified, to show the reticulations of the veins. 2. — Part of a stem, with leaves. originated from the foliage of two elegant extinct species of ferns, that abound in some parts of the Wealden of Sussex, and of which a few recog- 288 GEOLOGY OF THE ISLE OF WIGHT. nisable specimens have been discovered in the Isle of Wight. Fossil Ferns. — Entire layers of the sandstone, grit, and shale, in Tilgate Forest, are so full of carbonaceous matter as to acquire a dark mottled colour, and this detritus is composed of minute particles of the leaves and steins of ferns, that have been ground to pieces by agitation in water loaded with sand and mud. One of these plants (Sphe- nopteris Mantelli, "Wonders of Geology," p. 370) is characterised by its slender wedge-shaped leaf- lets. The other fern (Lonchopteris Mantelli, lign. 21 ) is the species already mentioned as occurring in the greensand of Atherfield and Shanklin. It is distinguished by its long and many-times pinnated leaves, and the reticulated disposition of the secondary veins that spring from the mid-rib of the leaflets. Endogenites erosa. — In the strata of Tilgate Forest, and in the sands at Hastings, numerous frag- ments of the stems of a remarkable monocotyledon- ous (?) plant occur, and are mentioned in my Fos- sils of the South Downs, and figured in the Fossils of Tilgate Forest, &c. These steins are of various forms; some are cylindrical, and tapering at both ends; and others are flattened, and of a clavated shape, like some of the Cacti and Euphorbia ; the ENDOGENITES EROSA. 289 specimens are from a few inches to seven or eight feet long, and the largest from twenty to thirty inches in circumference. When imbedded in the strata, a thick coat of lignite surrounds the stem ; but this soon becomes friable, and falls off after exposure to the air. The constituent substance of the stems is a grey, compact, subcrystalline sand- stone, and the external surface is traversed by fine semicircular grooves and deep tubular furrows, lined with minute quartz crystals ; a transverse section exhibits the surface covered by small pores, and a few large openings, the sections of the tubes. From the eroded appearance of the surface of the specimens, when deprived of their carbonaceous investment, the name Endogenites erosa was given to this fossil plant by Messrs. Stokes and Webb, who described it from my specimens, in the Geological Transactions, vol. i. second series. Dr. Fitton * subsequently described and figured a series of interesting specimens ob- served by him in the strata at Hastings. In trans- verse slices of these fossils, obscure indications of circular bundles of vascular tissue were detected, but (as in all my specimens from Tilgate Forest) very few vestiges of organic structure were appa- rent; the cavities exposed in the sections being * Geol. Twins, vol.iv. p. 172. 290 GEOLOGY OF THE ISLE OF WIGHT. not the vessels themselves, but the hollows left by their decay.* The occurrence of this fossil plant in the Wealden of the Isle of Wight has only recently been discovered. Among the waterworn fossils which I collected from the shingle, on my last visit to Brook Point, was a rounded, sub- cylindrical block of sandstone, very smooth, and marked externally with small crescent -shaped spots, which are the terminations of bundles of vascular tissue. A transverse section of this fossil proved it to be a portion of the stem of the Endogenites erosa, in a better state of preservation than any example pre- viously obtained. The openings, instead of being empty, are for the most part occupied by the vessels ; and an external band, or zone, of vascular tissue, disposed somewhat in festoons, is tolerably well preserved. Very thin slices, immersed in Canada balsam, to render them as transparent as the dull siliceous substance of which they are composed will admit of, examined under the microscope, indicate, in the opinion of Dr. Robert Brown, a nearer approach to the Cycadeae than to the Endo- genous tribes. Fossil cycadeous plants. — Among the coni- ferae, or cone-bearing plants, the Cycadecc and " Dr. FittOI) has given magnified figures of the sections in Ills pi, xx. FOSSIL CYCADEOUS PLANTS. 291 Zamite are remarkably distinguished by the pecu- liarity of their fructification, their seeds being exposed; hence the name of the order in which these plants are arranged — gymnospermous, i. e. naked seeds : the organization of their stems is also different from that of the other coniferae.* As several species of Zamia and Cycas are cul- tivated in our greenhouses, their general aspect, which approaches that of the palms, must be familiar to the reader. Most of the Zamiae are short plants, with stout cylindrical stems, beset with thick scales, which are the petioles, or leaf stalks, left after the leaves have fallen off. On the summit of the stem is a crown of elegant pinnated leaves, with simple veins. The fruit bears some resemblance to the cones of the pines, but the seeds are not enclosed in receptacles. The Cycadece resemble the Zamice, but the trunk is in general longer ; one species, Cycas circinnalis, attains a height of thirty feet. The stem is in most species simple, but in some it is dichotomous, dividing into two or more branches ; the leaves are tough, and in the young state coiled up like a crosier, as in the ferns. These plants are inhabitants of hot and humid climates, and abound in the West Indies, Molucca Isles, &c. A few plants of this order * See Dr. Buekland's Bridgwater Essay, p. 490. 292 GEOLOGY OF THE ISLE OF WIGHT. have been detected in the carboniferous strata ; and in the Lias and Oolite they appear in immense numbers; several species have been found in the Wealden, and cretaceous formations. The discovery of cones of a species of Zamia (Z. crassa, "Medals of Creation," p. 160), associated with bones of the iguanodon, in the Wealden strata in Sandown Bay, has already been mentioned (p. 138). Clathraria Lyellii. — But the most interest- ing fossil plant belonging to this tribe of coniferae, of which any remains have been found in the Wealden, is that discovered by me in Sussex, and described in 1822; and subsequently in "The Fossils of Tilgate Forest," under the name of Clathraria Lyellii. * This plant was formerly classed with the Lilia- cew, by that eminent botanist M. Adolphe Brong- niart ; but the discovery of more illustrative specimens than those first obtained, indicate its affinity to theCycadeae, with which M. Brongniart has some years since arranged it. The stem of the Clathrariaf is composed of an axis having the sur- face covered with reticulated fibres, and of a false bark produced by the union of the consolidated * Fossils of Tilgate Forest, Plates I. M. III., and doin-y of tin- South East of England, PI. I. I Clathraria, or latticed stem ; so named from the scorings left on the stem by the • thi petioles. CLAT1IRARIA LYELLII. 293 bases of the petioles, the insertions of which are rhomboidal and transverse. The external surface of the stem is in consequence covered with lozenge- shaped elevated scars, separated by lateral depres- sions, which are surrounded by a parallel band of a fibrous appearance (see lign. 2 C £). This outer portion is sometimes consolidated into a compact cylinder of stone, which will separate from the central axis LIGN. 22. WATERWOllN STEM OF THE CLATHRARIA LYELLII. From the shingle in Brook Bay. [One-third linear, nat. size.) (Foss. Tilg. Forest, PI. II.) : the latter is solid, and strongly marked externally with reticulated interrupted ridges. This surface has generally patches of vascular tissue adhering to it, but these are in so friable a condition, that microscopical 294 GEOLOGY OF THE ISLE OF WIGHT. examination has thrown no light upon their struc- ture.* On some parts of the internal axis there are deep pits, indicating the lacunae in which a resinous secretion w r as contained. The waterworn portion of a stem, figured in lign. 22, which I picked up on the sea-beach in Brook Bay, is the only specimen of the Clathraria 1 have seen from the Wealden of the Isle of Wight. This fragment is highly interesting, for the calcareo-siliceous earth of which the stem now consists, is of a finer texture than in any of the Tilgate Forest specimens, and trans- verse sections display under the microscope more satisfactory indications of the organization of the original. Without many figures, and more length- ened descriptions than our space will admit of, the peculiarities of structure exhibited in these slices, could not be demonstrated ; it must there- fore suffice to state, that the organization, so far as it can be determined, shows a near approach to that of the Cycadeae. But additional and most important informa- tion as to the external form of the Clathraria, has been afforded by the splendid specimen from • For other details I must refer to the " Medals of Creation," vol. i. p. 182. All the specimens (inured in my previous works are in the Hritish Museum, in the room appropriated to fossil vegetables. CLATHRARIA LYELLII. 295 the chalk marl cf the Undercliff, mentioned in a previous chapter (Chap. VIII. p. 244), as having been discovered by Captain Ibbetson, and now exhibited in his collection of Isle of Wight fossils, in the Polytechnic Institution. This invaluable relic is admirably represented by Mr. Dinkel,* and engraved by Mr. Lee, in lign. 23, p. 297. This specimen consists of the summit of the stem, and is fifteen inches in length ; the appear- ance of the lower end shows that some portion has been broken off and lost. The stem is com- pressed into an elliptical form ; the figure exhibits the longest diameter, and the side on which the characters of the plant are best preserved. On the upper 10| inches, this trunk is covered by the petioles or leaf-stalks ; and these appendages re- main on one side almost to the lower extremity. The surface of the inferior portion, to the extent of four inches, is marked with transverse lozenge- shaped scars, produced by the separation of the petioles ; the internal axis appears at the fractured end: see lign. 23, a. The leaf-stalks are from * This eminent artist now permanently resides in London ; being engaged at the British Museum by Dr. Falconer, on the illustrations for the impor- tant work on the Sub-Himalayan Fossils, which is now in progress of pub- lication. For subjects requiring talent, accuracy, and knowledge of animal and vegetable organization, for their successful delineation, the pencil of Mr. Dinkel will be found invaluable. 296 GEOLOGY OF THE ISLE OF WIGHT. one to two inches wide, rounded above, and con- tracted below, as shown in the detached petiole figured in lign. ~1< ; they are traversed by fine and nearly parallel longitudinal veins. The sum- LIGN. 24. A PETIOLE OF CLATHRAR1A LYELLII, SEPARATED FROM THE STEM. a, the external aspect ; b, the internal surface ; c, the vascular markings left on the summit of the petiole by the separation of the leaf. mits of those petioles from which the leaves appear to have been shed, not broken off, arc marked by vascular pits disposed with great regularity, as shown at c, lign. 24 ; a structure which M. Adolphe Brongniart informs me partakes more of the character of the Ferns, than of the Cycadeae. The substance of this fossil is a sandy marl, and probably does not retain any traces of the internal structure of the original ; still it is desirable that sections of the petioles, and of the stem, should be microscopically examined. M. Adolplic Brongniartj to whom 1 transmitted CLATHRARIA LYELLII. 297 GN. IS. CLATHRARIA LYELLII; From the Chalk-marl at Bench urch, Isle of Wight; discovered by Captain Ibeetson. This fossil is the summit of a stem garnished with petioles or leaf- stalks on the upper part : from the lower portion the petioles have been removed. The internal axis is seen at a. The original is fifteen inches in length; and eleven and a half in the widest transverse diameter. 298 GEOLOGY OF THE ISLE OF WIGHT. a sketch of this specimen of the natural size, immediately favoured me with his remarks on this interesting fossil. He considers the speci- men to be the upper termination of a stem of the Clathraria, garnished with persistent leaf-stalks ; and that some of the uppermost petioles were broken off accidentally while the leaves were alive ; but that in the lower ones which possess vascular markings on their summits, the leaves were detached naturally, and these petioles remained, probably for some years, as is the case in the existing Cycadeae. The petioles having fallen from the exposed part of the stem, the surface is left bare, and is marked by lozenge-shaped cica- trices or scars, which are the points of attachment of the bases of the leaf-stalks. On the other side of the specimen there appeared to me indications of the foliage, but M. Brong- niart suggests it as more probable, that they are only elongated and flattened petioles. The occurrence of this very characteristic plant of the Wealden high up in the chalk formation, is in accordance with the discovery of the bones of the Iguanodon in the greensand of Kent.'* In the strata of Tilgate Forest the remains of the C'lathrariae are invariably associated with water- * Wonders of Geology, vol. i. p. 394. FOSSIL SHELLS OF THE WEALDEN. 299 worn bones of reptiles, and pebbles, gravel, and other drift, and are often imbedded in the fluviatile conglomerate which occurs in some parts of the Wealden.* They appear to have floated down the river with the carcases and limbs of the rep- tiles, and at length to have sunk to the bottom and become imbedded in the mud and sand of the delta. Fossil shells. — The shells of the Wealden of the Isle of Wight belong to the same genera and species of fluviatile mollusca, as those in the contemporaneous deposits of the south-east of England : and though spread over areas of con- siderable extent, and through deposits of great thickness, they comprise but a few species — a characteristic feature of the fauna of all rivers. The substance of the shells in the limestones is for the most part changed into carbonate of lime ; but the shells in the argillaceous strata are often but little altered, and sometimes occur in as perfect a state as in very recent deposits ; the epider- mis and even the horny ligament being preserved. In the coarse limestones the shells have generally perished, and casts only remain. Sussex and Petworth marble. — The most * See remarks on the " Discovery of the Hylaeosaurus," in Wonders of Geology, vol. i. p. 401. S 300 GEOLOGY OF THE ISLE OF WIGHT. abundant univalve shells are four or five kinds of Paludina ; a common river snail, of which there are species in the tertiary freshwater strata of Headon Hill and Calbourne (see PL I. fig. 6). Numerous beds of marble, coarse limestone, clays and shales, abound in, or are wholly made up of paludinae, and minute crustaceans. The compact Sussex limestone, which from its taking a good polish, is called marble, principally consists of the shells of one large species, the Paludina flwiorum {PL VI. fig. 3), held together by an infiltration of crystallized carbonate of lime ; the cavities of the shells, and the interstices between them, being often filled with white calc-spar. Upon examin- ing thin slices of this marble under the microscope, the shells are found to contain myriads of the cases of Cj/prides (Jign. 25). The Purbeck marble differs from the above in being composed of a much smaller species — the Paludina elongata {PL VI. fig. 2). These marbles were in great repute with the architects of the middle ages, and there are but few of our cathedrals and ancient churches which do not still contain examples of both varieties, either in their columns, sepulchral monuments, or pave- ments. The polished cl nster-eolunuis of the Tei 1 1 ] > 1 1 • Church in London, and ninny of the monuments SUSSEX AND PETWORTH MARBLE. 301 in Westminster Abbey, are of Purbeck marble ; in other words, they are composed of the petrified shells of snails, that lived and died in the rivers which flowed through the country inhabited by the extinct colossal reptiles. The dark masses and veins so common in these marbles, are the remains of the bodies of the mollusca, changed into the car- bonaceous substance termed molluskite (see ante, p. 248). The shells which were empty at the period of their becoming imbedded, had their cavities filled with the mud, silt, &c. which are now clay, marl, and limestone ; but in the shells containing the animals, the gelatinous parts were converted into molluskite. In polished sections of the marbles this substance appears either within the shells, or in black or dark brown masses, and veins : the most beautiful slabs of Sussex marble owe their variegated markings to the contrast produced by the black molluskite with the white calcareous spar. Potamides. — Some species of the elongated, spiral, freshwater univalves, termed Potamides, of which several occur in profusion in the strata at Headon Hill (see PL II. figs. 2, 8, 9), are found in the Wealden. A very characteristic shell, the Potamides carbonarius, is figured in PL VI. fig. 5 : this species was first discovered in the weald clay s 2 302 GEOLOGY OF THE ISLE OF WIGHT. at Pounceford in Sussex.* It also occurs in Hanover, in the clays intercalated with beds of coal, belonging to the Wealden formation. Fossil freshwater bivalves. — Many of the bluish grey argillaceous limestones, as we have before remarked, are chiefly composed of five or six species of bivalves of the genera Gyclas and Cyrena ; a small slab with several shells in relief, is represented PL VI. fig. 4. Large blocks covered with shells of this kind, are commonly to be found along the base of the cliffs, at Brook, Compton, and Sandown bays ; and in the clays, there are numerous seams of crushed shells of these genera. The hard grits often abound in casts of Cyclades, associated with a small species of river-mussel ( Unio) ; and some layers of Sussex marble contain an intermixture of these shells with the paludinae. Unio Valdensis. PL VI. fig. 1. — The only other bivalves which occur in any considerable number in the Wealden, are the mussels termed Unio?iidce ; a family of testaceous mollusca contain- ing several genera, and comprising many species of considerable magnitude. These animals have a solid pearly shell, with two principal and two Lateral teeth on the hinge. Tn number, variety, and internal lustre, the Uniones of the large • Wonik-rs of Geology, j>. 350 ; it is there named Melanopsii. UNIO VALDENSIS. 30.3 rivers of North America, present a striking con- trast with the few and homely British species. In a fossil state Uniones are rare ; a few occur in the carboniferous strata, and these with eight or nine small species from the Wealden, figured by Dr. Fitton and myself, comprise all that are known in our secondary strata. Many of the slabs of limestone procured from Sandown Bay, and used in the pavements at Brading, Ryde, &c. display sections of a species of Unio, which is common in some of the Pet- worth and Purbeck beds. On a visit to Brook Point in 1843, I discovered a remarkably fine and large species of Unio in the cliff above the petri- fied trees, and have since collected many specimens of this interesting fossil, which I have proposed to distinguish by the name of Unio Valdensis, or Wealden river-mussel. A small and young example is figured in PL VI. fig. 1 ; the hinge, and the an- terior muscular imprints, are shown in the upper figure. The specimens obtained from the cliffs are in an excellent state of preservation ; the sur- face of the shell, which is but little worn, is of a tawny-red colour, like some of the recent Ohio species. Even the horny ligament with its trans- verse rugae remains ; and in some instances the shell is occupied by the body of the animal in the 304 GEOLOGY OF THE ISLE OF WIGHT. state of molluskite. The constituent substance of the shell is occasionally changed into calcareous spar, and admits of a fine polish ; nodules of crystallized sulphate of barytes of a pink colour, are not un- common within the shells. Some examples which I extracted from the bed containing the fossil trees, are partially invested with lignite. One pair of valves has been separated, and the hard grit with which they were filled cleared away, so as to deve- lop the characters of the hinge, &c. The shell is of an ovate form, from four to six inches long three inches in altitude, and two inches in thickness or dia- meter; the weight of a pair of valves cleared from extraneous matter is eleven ounces. The shell is equivalved, sub-equilateral, the posterior half one-fifth longer than the anterior, and com- pressed along the margin of the anterior slope. It is very thick and strong, and marked externally with longitudinal stria'. The summit is rounded, antero-dorsal, and slightly inclined forward ; the umhoncs are decorticated, as in most of the shells of the Unionidaj. The ligament is external, post-apicial, and marked with transverse rugae. The base or circumference of the shell is entire ; the margin or internal lip is thick and flat. The inner surface is smooth, with the exception of a few irregular projections of nacreous deposit. The hinge is dorsal, the hinge-plate very thick with a deep fosse beneath the lamellar portion. The cardinal teeth of the right valve are two; the anterior one is the largest, and bifurcated ; the lamellar tooth-plate is broad. The anterior muscular im- print is in front of the large cardinal tooth, and immediately d this impression is the indentation left by the attachment of the retractor muscles of the foot. The posterior muscular imprint i- placed ;it the extremity of the lamellar topth-platc. FOSSIL CYPRIDES. 305 The palleal impression extends from one muscular imprint to the other, running parallel with the margin of the base. There is a considerable difference observable in the width of the pos- terior part of the shell in a series of specimens, which appears to be sexual ; for a similar variation occurs in the male and female shells of the recent species from the Ohio. The collocation of these large mussels with drifted trees and bones of land reptiles, in clays and sands so manifestly of fluviatile origin, com- pletes the analogy between the rafts imbedded in the delta of the Wealden, and those which float down, and become engulfed in the mud and silt of the Mississippi. Fossil Cyprides. — The minute crustaceous ani- mals termed Cyprides, of which the shells or cases of several species are so abundant in the Wealden strata, were brought under the notice of the reader in our examination of the tertiary strata at White- cliff Bay and Headon Hill ; and in the clays and shales of Sandown Bay (p. 136). These animals have the body enclosed in a horny case, consist- ing of two pieces united by a hinge line. They have one compound eye, and four feet, and two straight simple antennae with a tuft of cilia at the extremities. They swim with rapidity, and may be seen actively pursuing the minuter animals on which they prey. Like other crustaceans, they frequently shed their cases, and the surface of the o06 GEOLOGY OF THE ISLE OF WIGHT. mud spread over the bottom of still lakes is covered with their exuviae. The largest living Cypris, does not exceed one-sixth of an inch in length. In a fossil state these cases appear like minute, white, elliptical, or reniform scales, on the surfaces of the recently separated laminae of clay, shale, and limestone. After exposure to the weather the cases decompose, and leave the surface of the stone covered with their casts, which appear as minute polished tubercles ; some layers of the compact ironstone have a granulated appearance from the abundance of these remains. Three species of the Wealden Cyprides are represented in lign. 25. The immense accumulation of the remains of these crustaceans in the Sussex marble is quite surprising; some slabs which I have examined under the microscope, have the shells and their interstices literally crammed with whole and broken cases. As the recent species inhabit either still lakes or gently flowing streams, and not the tur- bulent waters of estuaries, it follows that sediments largely charged with the exuviae of cyprides must have been deposited in lakes, or bays, or in tran- quil streams, communicating with the flood of waters which transported to their present situation the bones of terrestrial animals and plants. These beds of fluviatile shells and cyprides, with scarcely FOSSIL FISHES. 307 any intermixture of other organic remains, which are spread over such wide areas of the Wealden formation, afford, therefore, decisive proofs of tranquil subsidence in freshwater. .-,;' % ' •'?- LIGN. 2o. FOSSIL CYPRIDES; FROM BROOK BAY. Fig. 1. Cypris spinigera ; the small figure shows the natural size. 2. Cypris granulosa. 3. — Valdensis. 4. Clay, with numerous cases of the species represented fig. I, of the natural size. Fossil fishes. — But few remains of fishes have been found in the Wealden of the Island ; those which have come under my notice are some small teeth, and a fin-bone, of a species of Hy~ bodus (see p. 233) ; and several teeth and scales of the Lepidotus, a genus of extinct freshwater fishes, with very thick, enamelled, rhomboidal scales, and obtuse hemispherical teeth ; the latter 308 GEOLOGY OF THE ISLE OF WIGHT. arc called fishes' eyes by the peasants who collect fossils from these shores.* Detached scales and teeth of two species of Lepidotus occur in most localities of the Wealden deposits. -j- I found a portion of an intermaxillary bone with several teeth, and a group of ten scales of the Lepidotus Fittoni, in the cliff to the east of Brook Chine. * Figures of the scales and teeth of one species of Lepidotus of the Wealden are given in Medals of Creation, p. 438, PI. VI. fig. 10. t It is rare to meet with any considerable number of scales in contact; but a few specimens were discovered in Tilgate Forest, exhibiting part of the cranium, the opercula of the gills, the pectoral and dorsal fins, and large masses of scales. These are now in the British Museum, in the room appro- priated to Fossil Fishes. CHAPTER XL FOSSIL BONES OF REPTILES — THE IGUANODON — HYL.EOSAURUS — MBGA- LOSAURUS CETIOSAURUS STREPTOSPONDYLUS — PLESIOSAURUS — TURTLES — IMPRINTS ON SANDSTONE — RIPPLE-MARKS — SUMMARY — THE COUNTRY OF THE IGUANODON — VOYAGE ROUND THE ISLE OF WIGHT. Fossil bones of reptiles. — The occurrence of bones and teeth of gigantic terrestrial reptiles in the beds beneath the chalk of the south-east of England, was first announced in the " Fossils of the South Downs," in which many remains of oviparous quadrupeds from the strata of Tilgate Forest are described. Relics of this kind have subsequently been discovered in numerous loca- lities of the Wealden, and nowhere more abun- dantly than in the Isle of Wight ; although search for these highly interesting remains has not hitherto been very actively or judiciously pursued. The bones are washed out of the cliffs by the inroads of the sea, and strewn on the shore, where they become exposed to the action of the waves, and are soon abraded and deprived of any pro- cesses, or other anatomical characters, they may 310 GEOLOGY OK THE ISLE OF WIGHT. have retained after their original exposure to attrition, in the river by which they were trans- ported and imbedded in the strata. Thus those parts which would afford the most valuable infor- mation to the anatomist become entirely defaced, and the specimens are for the most part water- worn masses of bone, indicating only the enormous magnitude of the animals to which they belonged. The bones even when imbedded in the sandstone and sand, are in general abraded, from having been transported by water from a considerable distance ; those in the clays are commonly less injured, from the plastic material with which they were enveloped having, apparently, afforded some protection. The bones are coloured and strongly impregnated with iron ; especially those in Brook Bay, which are permeated throughout with py- rites; groups of brilliant crystals of this mineral often invest the outer surface. The medullary cavities are occasionally found lined with white calcareous spar, and the cancellated structure of the bone is often filled with this substance.* The quantity of bones collected from the sea- shore in Sandown, Brixton, Brook, and Compton • Some of these osseous boulders and pebbles afford interesting sections for the microscope. Slices from specimens presented to me by the Rev. Charles Pritchard, of Clapham Common, beautifully display the canci Uab d structure ol thi bone, with the rolls lined with pyrites and calcareous •-par. FOSSIL BONES OF REPTILES. 311 Bays, during the last few years, is very consi- derable ; the examples which I have seen at various times, and in the possession of different persons, must have belonged to between 150 and 200 indi- viduals. And though from their abraded and mutilated condition, but few of the specimens were instructive, yet so large a number proves that the country from which the Wealden deposits were derived, must have teemed with colossal oviparous quadrupeds. Some of the rolled bones indicate more gigantic animals than even the largest from Tilgate Forest, and now in the British Museum. The Rev. Gerard Smith, in 1825, obtained seve- ral fragments of bones of reptiles from Sandown Bay; and in 1829 a considerable number was found by Mr. James Vine, near Bull-face Ledge ; the latter are now in the collection of the Geological Society of London. In 1884 Mr. John Smith, of Yaverland Farm, collected several large vertebrae of the Iguanodon, portions of two thigh bones, and many fragments of smaller bones : these relics were presented to the Oxford Museum.* It must be borne in mind that these fossils have, for the most part, been picked up by persons * See a Memoir, by the Rev. Dr. Bucldand, on " Bones of the Iguanodon from the Isle of Wight," Geol. Trans, vol.iii. New Series. 312 GEOLOGY OF THE ISLE OF WIGHT. wholly uninstructed as to the characters which alone render such specimens interesting. What the waves cast up on the strand, the fishermen gather together, the casual visitor selects such as please his fancy, and the remainder are thrown away, or employed to pave the footpath, or surround the flower-border, of the cottager's dwelling.* The remains hitherto found, are separate bones belonging to the well-known Wealden reptiles, viz. the Iguanodon, Hylceosaurus, Megalosaurns, and Streptospondylus ; and the Cetiosaurus, Plesio- saurus,-f and two or more kinds of turtles. I have seen but two teeth ; a fragment of one belonging to the Megalosaurus, and the specimen figured in lign. 27. The Iguanodon. — Of this most gigantic of terrestrial reptiles, which, when living, must have more nearly resembled in its magnitude and huge proportions, the largest of our living pachvder- mata, than any of the saurian order to which it belongs, many vertebra?, portions of ribs, and bones of the extremities, have been discovered in * The largest toe-hone of the Iguanodon now in ray possession was obtained from a row of stones placed round the flower-plot of a cottage near Brixton. I much regret that my professional engagements have rendered it impossible for me to attempt to remedy the evil mentioned in the text. t Having given a concise exposition of the OSteological characters of these extraordinary beings in the " Medals of Creation" (vol. ii. p. 684, ch. xvii. and xviii.), with full instructions for the collection of their remains; to that Work refer the reader desirous of pursuing these inquiries. THE IGUANODON. 313 the Wealden at Sandown Bay, and at Brook and Brixton. The vertebrae are invariably deprived of their processes ; even the neural arch is in general destroyed, and the waterworn body, or cen- trum of the bone, alone remains.* The specimens are commonly permeated with pyrites, and, in consequence, are of great weight. The long bones of the limbs are for the most part mutilated, and but seldom have an articulating extremity so perfect as to indicate the individual bone. Some of the fragments, however, retain characters suffi- ciently recognizable, and have unquestionably be- longed to reptiles of enormous size. I obtained from Sandown Bay the lower half of a tibia (large bone of the leg), having the extremity that articu- lates with the foot perfect ; the circumference of this bone is four times that of a perfect tibia of a young Iguanodon, which is one foot long : when entire, its length must therefore have been nearly four feet. The corresponding thigh-bone, estimated from the relative proportions of a femur and tibia in juxtaposition, would be a foot longer: the entire length of the leg and thigh to which the Sandown fossil belonged, must consequently have been upwards of nine feet. * As shown in lign.ISS, fig. 8, p. 697, "Medals of Creation," vol. ii. The perfect form of a caudal vertebra of the Iguanodon is represented in fig. 3 of the same lignogiaph. 314 GEOLOGY OF THE ISLE OF WIGHT. The most perfect femur, or thigh-bone, collected in the Isle of Wight, was dug out piecemeal from a fallen mass of the cliff in Brook Bay : it evi- dently belonged to an aged individual, and though squeezed and somewhat distorted by pressure while softened by long immersion in the clay in which it was imbedded, well displays the pecu- liar characters of this part of the skeleton of the Iguanodon. It is 3 feet 4 inches in length. The figure in lign. 26 is a representation of this specimen, as it would appear if uncompressed. The femur of the Iguanodon is so remarkable, that even fragments may readily be distinguished ; and as portions of this bone are not unfrequently to be met with in the clay cliffs or on the shore, I subjoin the following description. The head is hemispherical, and projects in- wards ; a laterally flattened process, or trochanter {lign. 26, a), forms the external boundary of the neck of the bone, from which it is separated by a deep and very narrow vertical fissure. The shaft is sub-quadrangular ; a slightly elevated ridge, produced by the union of two broad, flat, longitudinal surfaces, extends down the middle of the anterior face, and diverging towards the inner condyle, gradually disappears. The shaft termi- nates below in two large rounded, and laterally THE IGUANODON. 315 compressed condyles (c,d), which are sejDarated in front and behind by a deep groove (e). Near the middle of the shaft, the mesial, or inner edge, forms a compressed ridge, which extends into an angular projection, or inner trochanter (b). Thus the upper part of the femur may be known by the presence of the upper trochanter (a) ; and if that process is broken away, the fractured surface in- dicating its position will be detected. If a frag- ment of the middle part of the shaft only is found, the flattened angular spaces, and the submedian tro- chanter (b), or the mark libs.jb.-iot FE»m or an- f i ts attachment, will iguanodon. From Brook Hay. (The original, 40 inches in length.) identify it. The loW T er a, Upper trochanter. 6. Middle trochanter. extremity of the femur c, Inner, rf, outer condyle. . , . . . Groove between the condyles. may be distinguished bv 316 GEOLOGY OF THE ISLE OF WIGHT. the deep groove (e) between the condyles, both in front and behind. The long bones of the Iguanodon have a large medullary cavity.* Several bones of the feet and toes have been found in this locality. Dr. Buckland obtained a toe-bone of enormous size from Sandown Bay ; it is six inches long and fifteen inches in circum- ference, at the largest extremity. f The metatarsal and phalangeal bones of the Iguanodon are short and thick, and so much resemble those of the Hippopotamus, that Baron Cuvier at first supposed the specimens from Tilgate Forest belonged to that animal. Tooth of the Iguanodon. — With the thigh-bone above described were found several dorsal and caudal vertebrae, many fragments of ribs, and the only tooth of the Iguanodon I have obtained from the Island. It evidently, like the femur, belonged to an adult, and very probably to the same indi- vidual. The crown is worn down almost to the neck of the tooth, and shows the remarkable cha- racter imparted to the teeth of this herbivorous reptile, by the trituration of its food, — a character in which they differ from the teeth of any other known reptile, either living or extinct ; for all * Medals of Creation, vol. ii. p. 7 18. 1 Geol. Trans, vol. iii. pi. II. TOOTH OF THE IGUANODON. 317 other herbivorous reptiles chip off and swallow their food whole, the construction of their jaws not admitting of a grinding motion.* From this condition of the crown, as shown in the tooth figured below, it is obvious that the Iguanodon fed on vegetables, and masticated its food like the is**'' LIGN. 2(. TOOTH OF AN IGUANODOK. From the Weaklen, Brook Bay. horse and other herbivorous mammalia : while the base shows the imprint of the successional tooth, which, by its pressure, occasioned the absorption of the fang of the old one. In the perfect tooth, the crown is of a prismatic form, * For an account of the development of the teeth of the Iguanodon, see " Fossils of Tilgate Forest," p. "2; and " Wonders of Geology," p. 390. T 2 318 GEOLOGY OF THE ISLE OF WIGHT. with, three or four longitudinal ridges down the front, and a broad denticulated margin on each side.* The resemblance between the unworn teeth of the Iguanodon and those of the Iguana, a herbivorous lizard of the West Indies, suggested the name of this colossal extinct reptile ; but the teeth of the Iguana are very small, not exceeding in size those of the mouse. Sections of the teeth are beautiful objects under the microscope, and show that the structure of the dentine, or tooth-ivory, is coarser than in other reptiles, and resembles that which charac- terises the teeth of the Sloth tribe. The crown of the tooth is incrusted with an external coating of enamel, which is thick in front, and thin on the inner surface. In consequence of this disposition, and of the dentine being hardest in the anterior part, the grinding surface of the tooth is always worn away obliquely, and a sharp cutting front edge of enamel maintained in every stage. if Sacrum of the Iguanodon. — A very remarkable peculiarity in the anatomical structure of the Iguanodon, and of the Hyheosaurus and Megalo- saurus, consists in the sacrum being composed of five vertebrae an chylosed, or fixed together, into a solid * Medals of Creation, \>. 741. t Wonders of Geology, veil. i. p. 390. SACRUM OF THE IGUANODON. 319 column ; whereas in all living saurians the sacrum consists of but two vertebrae. The neural arches of the vertebrae are shifted to the interspaces be- tween the bodies of those bones, by which more solidity is given to the pelvic arch. Professor Owen (who first pointed out these modifications of structure) states, that the sacrum of the Ostrich presents the same characters, and in the young bird the individual vertebrae, and the remarkable change in the relative position of the vertebral elements, may be clearly traced. Though these details are of the greatest interest to the comparative anatomist, I should not have dwelt upon them in the present work, were it not probable that specimens of this part of the ske- leton will come under the notice of the visitor, and would, perhaps, from their unsightliness, be re- jected. I have obtained from Brook Bay several waterworn portions of the sacrum, consisting of two or three anchylosed vertebrae; the finest ex- ample of the entire series belonging to a large individual, was found on this coast.* Form of the Iguanodon. — From the numerous detached bones that have been collected from * This fossil is in the interesting museum of W. D. Saull, Esq., of 15, Aldersgate Street, City, to which visitors are, with great liberality, admitted every Thursday at 12. Mr. Saull's collection of organic remains contains many specimens from the Isle of Wight. 320 GEOLOGY OF THE ISLE OF WIGHT. various localities of the Wealden, and with the aid of the few specimens in which several are collo- cated in the same block of stone, the size and proportions of the body and limbs of the Iguanodon may be determined ; yet but a vague idea of the form and appearance of the original animal can be derived from the relics hitherto discovered. For the great discrepancy between the known parts of the skeleton, and the corresponding bones in the largest existing saurians, renders it vain to attempt the restoration of the form of this colossal reptile, till the skull, jaws, &c. are known. In all proba- bility the entire or a considerable portion of the skeleton of a young Iguanodon, will sooner or later be brought to light, and yield the information necessary to enable the palaeontologist to recon- struct the skeleton, and delineate the form of the living original. In the present state of our knowledge we may, however, safely conclude, that the body of the Iguanodon was equal in magnitude to that of the elephant, and as massive in its proportions ; for be- ing a vegetable feeder, a large development of the abdominal region may be inferred. Its limbs must have been of a proportionate size to sustain so enormous a bulk; one of the thigh-bones (in the British Museum) if covered with muscles and THE IGUANODON. 321 integuments of suitable proportions, would form a limb seven feet in circumference. The hinder extremities, in all probability, presented the un- wieldy contour of those of the hippopotamus or rhinoceros, and were supported by a very strong short foot, the toes of which were armed with claws Like those of certain turtles.* The forelegs appear to have been less bulky, and furnished with hooked claws resembling the ungueal phalanges of the Iguana. The teeth demonstrate the nature of the food required for the support of this her- bivorous reptile, and the power of mastication it enjoyed. The palms, ferns, cycadeous plants, and coniferous trees, with which its remains are asso- ciated, indicate the flora adapted for its suste- nance. But the physiognomy of this creature, from the form of the skull and jaws, constructed as the latter must have been to give support to the powerful muscles necessary for the tritura- tion of tough vegetable substances, must have remarkably differed from that of all known saurians. The length of the Iguanodon has been variously estimated, the difference in the computation de- pending chiefly on the length assigned to the tail, which in the Iguana and many other lizards is * Wonders of Geology, PI. III. 322 GEOLOGY OF THE ISLE OF WIGHT. much longer than the body. If the tail of the fossil reptile was slender, and of the same relative proportions as in the Iguana, the largest individual would be fifty or sixty feet long ; but it is more probable, and in fact almost certain from the short- ness of the bodies of the caudal vertebrae, that the tail was short, and flattened in a vertical direc- tion, as in certain living reptiles — for example, the Doryphorus ; the length, therefore, would be re- duced to little more than thirty feet.* From what has been advanced we may conclude, that the Iguanodon was a gigantic but inoffensive herbivorous reptile, which lived on the ferns, cycadeae, palms, and coniferae that constituted the flora of the country of which it appears to have been the principal inhabitant. Hylzeosaurus, or Wealden Lizard. — This is another reptile of the Wealden, possessing the same remarkable conformation of the sacrum as the Iguanodon. It is distinguished by a peculiar modification of the bones composing the sternal arch, and by its osseous dermal appendages : like the bones of the former reptile, its remains were first observed in the strata of Tilgate Forest. The scapula is like that of the crocodiles, while the coracoid bone is of the lacertian type. The ribs * Medals of Creation, p. 751. THE HYLiEOSAURUi?. 323 have the bilobed head, as in the crocodiles, asso- ciated with the arched and rounded process of the lizards, and an enormous expansion of the bone at its spinal curvature. This reptile possessed a very formidable dermal covering : it had rows of ellip- tical and circular dermal bones along each side of the vertebral column, and appears to have been armed with a series of angular spines of great size, arranged along the middle of the back ; in the same manner as the dorsal fringe of the Iguana. The' structure of the bone composing these dermal processes, closely resembles that of the ligamentous fibres of the corium, or skin, and seems to have resulted from an ossified condition of the dermal integument. A few detached vertebra? of the Hylasosaurus, recognisable by their perfectly cir- cular and nearly flat extremities, have been found in the Weald clay at Brixton.* Megalosaurus.-J- — This name was given by Dr. Buckland to an enormous reptile, of which teeth and bones were first observed in the oolitic lime- stone of Stonesfield, near Oxford, and afterwards in the Wealden strata. The teeth present a striking contrast to those of the Iguanodon ; they * See " Medals of Creation," p. 734, and " Memoirs on the Fossil Reptiles discovered in Tilgate Forest." Philos. Trans. Part II. for the year 1841. t See Dr. Buckland's Bridgewater Essay. 324 GEOLOGY OF THE ISLE OF WIGHT. are sabre-shaped, with trenchant serrated edges. The original was probably carnivorous, and nearly thirty feet in length. As it was contemporary with the Iguanodon and several other large sau- rians, it may have preyed on their young and on the lesser reptiles. Many teeth, vertebras, and por- tions of the femur of this animal, have been found in the Island. The vertebrae are not subquadrangular like those of the Iguanodon, but are cylindrical at the ends and contracted in the middle, and have a very smooth surface. The femur is nearly cylin- drical and slightly bowed ; it has two large rounded prominences, or trochanters of nearly ecpual size, below the head of the bone ; it may therefore easily be distinguished from the thigh-bone of the Iguanodon. Cetiosaurus. — This extinct reptile, as its name imports, bore some resemblance to the Ceta- ceans. The vertebrae are almost circular at the ends, and have a very short body ; the front arti- culating surface is nearly flat, and the other concave, in the dorsal vertebra?, but in the caudal both ends are deeply hollowed ; they are very large, often eight inches in diameter. By these cha- racters the vetebrae of the Cetiosaurus may easily be recognised. I have obtained several from the weald clay at Sandown and Brook. The original CETIOSAURTJS. 325 animals are supposed to have been of aquatic, and probably of marine, habits, on the evidence of the sub-biconcave structure of the vertebra?, and of the coarse cancellous tissue of the long bones, which are destitute of a medullary cavity. They must have rivalled the whales in bulk, for some remains indicate a length of forty or fifty feet.* Streptospondylus. — Among the large verte- brae washed up on the shore in Brixton Bay, I found several with one end convex and the other concave ; these belong to the extinct crocodilian reptile called Streptospondylus (meaning reversed- spine), because these vertebrae are arranged in the spinal column in a position the reverse of that which obtains in all other reptiles of the same osteological type ; for the convexity or ball of the vertebrae is placed anteriorly, whereas in the cro- codile, &c. it is in the opposite direction. f The original, in its form and habits, probably bore a general relation to the crocodiles. Plesiosaurus. — The splendid collection in the British Museum, which contains several perfect skeletons of different species of this genus of ex- tinct marine reptiles, must be too well known to render any description necessary of the osteological * Medals of Creation, vol. ii. p. /26. t Cuvier's Reckercltes stir les Ossemens Fossiles. Tom. V. pi. 6. 326 GEOLOGY OF THE ISLE OF WIGHT. characters of the Plesiosauri and Ichthyosauri. A few vertebrae of Plesiosauri are the only remains of these animals I have obtained from the Island. Fossil Turtles. — Of che Ionian reptiles, water- worn fragments of bones are the only vestiges that have come under my notice. Some of these fragments in all probability belong to the Trionyx Bakewelli, a species which occurs in the Wealden strata of Tilgate Forest,* and is characterised by the granulated surface of the costal plates, and a dermal covering of tortoise-shell, as is shown by the imprints of the scales left on the bones. Except in possessing a defensive integument of this kind, this extinct chelonian must have re- sembled the existing predaceous soft turtles ; and doubtless like them inhabited the mud-banks of rivers, and preyed upon the eggs and young of the larger reptiles, and on the uniones and other mollusca, the shells of which are often found asso- ciated with its remains. Imprints on sandstone. — We must here con- clude our description of the fossils that have been discovered in the Wealden strata of the Isle of Wight ; to attempt a full exposition of the characters and relations of these organic remains, * Geology of the S.E. of England, p, 235. Medals of Creation, p. 778. IMPRINTS ON SANDSTONE. 327 would requii-e a volume expressly devoted to the subject. A few additional remarks are, however, necessary on some anomalous appearances in the sandstone of Brixton Bay, that have recently come under my notice. The occurrence of im- prints resembling the foot-tracks of birds and reptiles, on the surface of slabs of sandstone of very ancient formations, must be known to the well-informed reader, from the lucid illustration of the subject, in Dr. Buckland's Bridgewater Essay. Among those supposed foot-prints are several of large dimensions, described under the name of Chirotherium, which are conjectured to have been made by some enormous three-toed reptile, passing over the stone when it was in a soft state. Others equally colossal, from the arrangement of the markings on the slabs indica- ting the progressive footsteps of bipeds, have been ascribed to gigantic extinct birds.* The layer of clay, or sandstone, overlying these imprints, gene- rally retains casts of them, which appear in relief on the surface of the slabs when removed ; in other instances the cast of a single mould alone remains, and being more consolidated than the matrix, is often extracted whole. Several large sandstone casts of this kind were dis- * Medals of Creation, p. 708. 328 GEOLOGY OF THE ISLE OF AVIGHT. covered last year in the Wealden sands at Has- tings, and sent up to the Geological Society. A similar cast has been obtained from the Wealden sand in the cliff in Brixton Bay, and is in my pos- session. This specimen is a solid tripartite mass of fawn-coloured sandstone ; the middle process is fifteen inches, and the two lateral projections are twelve inches in length ; the greatest thickness is six inches ; the processes are laterally compressed and rounded at the extremities, and united to one common base. As the origin of these singular concretions is very problematical, every specimen should be preserved ; and if several occur on the same bed of sand, their relative position should be carefully ascertained.* Ancient ripple-marks. — Connected with this subject are the ripple-marks so often pervading extensive surfaces of sands, sandstones, and clays, in sedimentary deposits that have been formed on sea-shores, or along the banks of rivers, or in * The method adopted to obtain impressions from engraved monumental brasses, namely, the placing of tough thin paper over the surface of the in- scription or effigies, and rubbing it freely with the black composition termed " heel hull," which adheres to the parts in relief, but leaves the cavities white, will be found convenient for obtaining an accurate plan and outline of the imprints on the sandstone. This process is also applicable to anj fossil that lias a surface flat and firm enough to bear the friction when covered by the paper. I have often taken in a few minutes, imprints of the plates of turtles, scales of fishes, &c. sufficiently distinct to exhibit the general cha- racters of the surface of the specimens. ANCIENT RIPPLE-MARKS. 329 bays, deltas, lakes, and estuaries, in comparatively shallow water. In many parts of the Wealden formation these appearances are very striking ; especially in the vicinity of Horsham,* and in the quarries in Tilgate Forest in Sussex, j- The slabs of limestone, clay, and sandstone, exposed in recent falls of the cliffs along the southern shores of the Island, are frequently covered with ripple- marks. Every one must have noticed when walking by the side of a river at low water, or on the sands of the seashore, that if the water has been agitated by the wind, the surface of the mud or sand is fur- rowed more or less deeply by the rippling of the waves ; the markings presenting various appear- ances according to the force and direction of the wind and currents. The undulations on the sur- face of the sandstone have arisen from similar operations. In many instances the stone is so rough as to be employed in stable-yards, where an uneven surface is required to prevent horses from slipping as they pass over. Sometimes the fur- * These were first noticed by Mr. Lyell in 1822, and described in a letter addressed to the author. t It is singular that although Professor Playfair mentions the cause of this appearance as undoubted, yet so little attention or credit was given to the statement, that my description of the phenomenon was received with much hesitation. 330 GEOLOGY OF THE ISLE OF WIGHT. rows are deep, denoting that the water was much agitated, and the ripple strong ; in other instances the undulations are shallow, and intersected by cross-ripples, indicating a change in the direction of the waves. Some slabs are covered by slightly elevated, broad ridges of sand, made up of gentle risings disposed in a crescent shape ; these have been produced by rills flowing into the river, during the recession of the tide. The rippled surfaces often bear traces of the trails of mol- lusca, and annelides, and in some strata, im- prints of the claws of crustaceans, of the pectoral fins of certain fishes, and of feet of reptiles have been observed.* But I have never detected un- equivocal evidence of footmarks of any kind in the Wealden strata. Impressions of vegetables, several of which appear to have been produced by grasses, were abundant on some recently exposed slabs near Brook Point, on my late visit ; the vegetable matter had evidently been changed to carbon, which was in a great measure washed away, but enough remained to point out the origin of the markings. 1 have observed similar appearances on slabs of sandstones and clays lying on the embankments of the recently con- structed Tonbridge Wells Railway. * Set Dr. Buckland's Bridgewater Essay. summary. s;n Summary. — And now, ere we depart from these shores, and bid farewell to scenes so fraught with interest and instruction, I would detain the reader a brief space, and while the data are before us, endeavour to interpret the nature of those physical revolutions of which they afford such unequivocal evidence. It appears, indeed, scarcely possible for the most incurious observer while sitting on these rocks of petrified trees, and surrounded by fossil bones of enormous reptiles, and heaps of river-shells obtained from the neighbouring cliffs, not to speculate on the causes which have given rise to these extraordinary results. For as a profound thinker has justly remarked, " when any natural phenomena are for the first time ob- served, a tendency immediately develops itself in the mind to refer them to something previously known, and bring them within the range of ac- knowledged sequences."* It was with a view of inducing a train of thought which should lead the intelligent stranger, un- familiar with the nature of geological evidence, to attempt the interpretation of the appearances pre- sented to his notice, that this excursion was intro- duced by some general remarks on the changes * "On the Correlation of Physical Force*;" by W. K. Grove, Esq. M.A. F.R.S. &c London. 1846. 332 GEOLOGY OF THE ISLE OF WIGHT. effected on the surface of the land, by the agency of streams and rivers. Let us test the facts before us by the principles enunciated in those remarks. We have here strata of great thickness, made up of laminated detritus, identical in appearance and composition with the consolidated mud-banks of rivers and deltas — we have rafts of drifted pine-trees, and the remains of cycadeous plants, and arborescent ferns — innumerable layers of freshwater shells and crus- taceans, with large mussels resembling the unio- nidas of the rivers of America — heaps of waterworn bones of colossal oviparous quadrupeds, which com- parative anatomy instructs us belong to types of organization long since extinct — in fine, an accu- mulation of transported materials teeming with the spoils of some unknown region, associated with fluviatile mollusks and crustaceans, without any intermixture of marine exuvia?. What is the obvious inference — what the unavoidable conclu- sion at which we must arrive ? Unquestionably, that these deposits were the delta of a river, which flowed through a country possessing a fauna and flora of a tropical character, and essentially dis- tinct from any now known to exist. The country of the Iguanodon. — We have here then data from which, by the method of COUNTRY OF THE IGUANODON. 333 induction previously explained, we may restore, as it were, the region whence the Wealden strata were derived, the animals by which it was inha- bited, and the vegetables that clothed its surface. Whether that country was an island or a con- tinent cannot, perhaps, be determined ; but that it was diversified by hills and valleys, and irrigated by streams and rivers, and enjoyed a climate of a higher temperature than any part of modern Europe, is most evident. Arborescent ferns, palms, coniferous trees, and cycadeous plants, constituted its groves and forests, and delicate ferns the vege- table clothing of its soil; and in its fens and marshes the equiseta, and plants of a like nature, prevailed. Its principal herbivorous quadruped was the enormous lizard, the Iguanodon ; its carnivora, the Megalosaurus and other predaceous reptiles; crocodiles and turtles frequented its rivers, and deposited their eggs on the banks and shoals; and its waters teemed with fishes, mol- lusca and crustaceans. That the soil was of a sandy nature on the hills and plains, and argil- laceous in the lowlands and marshes, may be inferred from the vegetable remains, and the litho- logical character of the strata in which they are 'imbedded. Some inferences relating to the pre- vailing atmospheric condition of the country may u 2 334 GEOLOGY OF THE ISLE OF WIGHT. also be drawn, from the undulated surfaces of the sandstones, and from the fossil trees. In the former we have proof, that when the land of reptiles existed, the water was rippled by the breezes, which then, as now, varied in intensity and direction in a brief space of time ; by the latter, that in certain situations the wind blew from a particular quarter for a great part of the year, and that the mean annual temperature was as variable as in modern times. From what has been advanced, it must not, however, be supposed, that the country of the Iguanodon occupied the site of the south-east of England ; and that the animals and terrestrial plants of the Wealden, lived and died near the spot where their relics are entombed. For with the exception of the shells and crustaceans, which probably inhabited the delta, all the fossil remains bear marks of having been transported from a great distance. But though three-fourths of the bones we discover have been broken and rolled,- — the teeth detached from their sockets, — the vertebras and bones of the extremities, with but very few ex- ceptions, disjointed, and scattered here and there, — the stems and branches of the trees torn to pieces, and deprived of their foliage--— there is no* intermixture of sea-shells, nor of beach or shingle ; COUNTRY OF THE IGUANODON. 335 these remains have been subjected to abrasion from river currents, but not to attrition from the waves of the ocean. The gigantic limbs of the large reptiles could not have been dissevered from their sockets without great violence, except by the decom- position of their tendons from long maceration in water ; and if the latter had been the sole cause, we should not find the bones broken and sepa- rated, but lying more or less in juxtaposition, like the skeletons of the Plesiosauri in the Lias. The condition in which these fossils occur, proves that they were floated down the river with the rafts of trees, and other spoils of the land, till, arrested in their progress, they sank down, and became imbedded. The phenomena here con- templated cannot, I conceive, be satisfactorily explained upon any other grounds ; and the source of the mighty stream which flowed through the country of the Iguanodon, must therefore, like that of the Mississippi, have been hundreds, perhaps thousands, of miles distant, from the delta accumulated in the course of ages at its mouth. Voyage round the Isle of Wight. — As during the summer months, excursions round the Island are almost daily made by the steamers, an opportunity is afforded of obtaining a general view of the geology of the coast in the course of a few 336 GEOLOGY OF THE ISLE OF WIGHT. hours. To a person acquainted with the physical structure of the country, such a voyage is alike agreeable and instructive, and the reader will find a day well spent in taking a rapid survey of the most important geological sections which the coast scenery exhibits. The steamers leave Cowes or Ryde, and take an easterly or westerly course, according to the state of the tide. In the following brief notice, the localities most worthy of remark, in a geological point of view, are described in the order they will appear, if the former route be pursued. Proceeding from Ryde to the eastward, we coast along the northern shore of the Island, which is almost everywhere covered with vegetation to the water's edge ; a low bank, or cliff, of the fresh- water eocene marls and limestones, being the only indication of its geological structure. St. Clare, the charming seat of Col. Vernon Harcourt, stands on an eminence of these deposits. Doubling the eastern point of St. Helen's, Bembridge Foreland appears, surmounted by the range of chalk hills that terminates at Culver Cliff, We cross the mouth of Brading Haven ; the little town of Blading is seen nestling in a grove of elms at the foot of the chalk downs, which form the western boundary of the view. The upper horizontal .-..: VOYAGE ROUND THE ISLE OF WIGHT. 339 freshwater strata on the northern extremity of Whitecliff Bay (see p. 127) next appear, and a good view is soon obtained of the bay, bounded on the south by the magnificent chalk cliffs of the Culvers. On reaching the extremity of Whitecliff Bay, the vertical section of the highly inclined chalk strata, which forms the eastern promontory of the Island, is finely displayed (see PL XV.). The dip of the strata, varying from 50° to 70° towards the north, is clearly marked by the layers of flint nodules, which are distinguishable a quarter of a mile from the shore. Culver Cliffs, which the reader will remember, are the eastern termination of Bembridge Downs (see lign. 8, p. 126), are be- tween 300 and 400 feet high, and about a quarter of a mile in breadth. When off the promontory, a very interesting geological view is obtained ; at one glance we see the nearly vertical chalk, bounded on the right {north) by the eocene strata of Whitecliff, and on the left (south) by the green- sand of Redcliff. Upon doubling the headland, we enter Sandown .Bay (see the section, lign. 9, p. 134) ; the lower chalk, firestone, gait, and greensand, appearing in succession, like sloping bands of yellowish white, green, blue, and deep red; the latter denoting the 340 GEOLOGY OF THE ISLE OF WIGHT. ferruginous sands of the lower group. Sandowri Fort is now visible, and marks the low tract con- sisting of the Weald clay (p. 133). The new church and little town of Sandown, are seen on the brow of the sand cliffs which form the western side of the bay, and extend toward Shanklin, retaining the same dark red ferruginous colour as those at Redcliff. The eastern termination of the southern range of chalk, forming the lofty downs above Shanklin, next appears, and seaward, the high but subordinate cliff of greensand at Dunnose Point. The dip of the strata in the cliffs on each side of Sandown Bay, and the anticlinal axis formed by the elevation of the Wealden, may be distin- guished by means of a good telescope. Off Dunnose, we lose sight of the inner range of chalk downs, and gain the region of the Undercliff, which from the sea presents, in the foreground, a line of fallen masses of rock and strata scattered along the sea-shore ; and above, a verdant terrace covered with trees and shrubs, with here and there houses peering out from amid the foliage — the barrier of firestone capped with chalk, surmounting the terrace on the north, and hounding the view for a distance of six miles (see p. 251). The ledges of cherty firestone pro- jecting like lines of masonry along the face of VOYAGE ROUND THE ISLE OF WIGHT. 341 this inland cliff, may be distinguished, if the steamer keeps within the usual distance of the shore. Nearing Blackgang, St. Catherine's appears towering above the western termination of the Undercliff. The Sandrock hotel is seen standing on a ledge high up the precipitous escarpment of the greensand, which here forms the sea-cliff (see p. 234), near the foot of the inland cliff of fire- stone ; the latter rises to within 200 feet of the summit, which is nearly 800 feet above the level of the sea. The ruins of the tower of St. Catherine surmount the whole. The white chalk is seen forming the top of the downs, and appearing from the sea as an inconsiderable layer, immediately over Blackgang. From Blackgang to Atherfield the cliffs are entirely composed of the greensand, and the general direction of the beds from east to west may be easily traced (see lign. 17, p. 215). The clays and sands along this part of the coast present a very curious appearance. The lower strata are generally dark, indeed, almost black, but the up- permost are of a light ferruginous colour ; and wherever springs are thrown out by the clay part- ings, the cliffs are stained with broad streams of ochreous yellow. This appearance is cor- 342 GEOLOGY OF THE ISLE OF WIGHT. rectly attributed by Sir Henry Englefield, to the action of the water that percolates from the surface of the soil through these strata, and issues out on the face of the cliff; the oxidation of the sands and clays is the result of the decomposition of the sulphuret into peroxide of iron. This change is often accompanied by the formation of crystals of sulphate of lime or selenite.* The abundance of nodules of pyrites in these clay cliffs, as well as in those of the Wealden, is so great, that consider- able quantities of this mineral are collected on the shore by the cottagers, for sale to the copperas manufacturers. Approaching Atherfield, the undulated outline of the distant horizon on the north, denotes the re-appearance of the central range of chalk downs, which we lost sight of behind Dunnose Point, and is here seen extending in a south-westerly direction towards the southern shore. The station- house on Atherfield Point marks the locality where the junction takes place between the Wealden and the greensand (p. 221). The next interesting geological features of this coast, are the cliffs at Brook Point, but the steamers pass at so great a distance from * A similar result has taken place in some of the railway clay embank- ments, ami been productive of considerable injury to the woikd. VOYAGE ROUND THE ISLE OF WIGHT. 343 the shore, that the general bearing of the strata only can be distinguished. In the long sweep ex- posed in these bays (p. 210), the greatly elongated arch, formed by the anticlinal axis of the Wealden (p. 214), may be distinctly made out in a clear state of the atmosphere. Shalcomb Down (p. 220), now forms the inland distance on the north ; and as we near Compton Bay, the middle chalk range is seen extending to the shore, and the sea washes the base of the magnificent line of chalk hills from Afton Down to the Needles. The position of the greensand, gait, and fire- stone, beneath the white chalk, in the cliffs west of Compton Chine, may be distinguished from a dis- tance, owing to the contrast of colour presented by the upper and lower groups ; as in RedclifF in Sandown Bay. Freshwater Bay (p. 195) is now gained, and the cliffs of the Mainbench, and of Scratchell's Bay, and the Needles, stand forth in all their sublimity (see p. 197). There is one point in Scratchell's Bay in which a magical effect is produced, by the sudden appearance of the richly coloured cliffs in Alum Bay, between the pure white pinnacles of chalk. As we sail round the Needles, the distant Isle of Portland is seen on the western horizon, and on the north are the shores of Hampshire (p. 16*4). 344 GEOLOGY OF THE ISLE OF WIGHT. The vertical strata of Alum Bay (p. 146), and the freshwater series at Headon Hill (p. 151), are now on our right ; and we perceive that the structure of this north-western extremity of the Island, is the counterpart of the north-eastern promontory at Culver Cliff and Whitecliff Bay, which we sailed by in the earlier part of our voyage. Col- well and Thorness Bays are next passed, and we land at Yarmouth to prepare for our excursion to the Dorsetshire coast. CHAPTER XII. GEOLOGICAL EXCURSIONS ALONG PART OF THE SOUTHERN COAST OF DORSETSHIRE. VOYAGE FROM YARMOUTH TO SWANAGE — SWANAGE BAY — THE PUR- BECK STRATA FOSSILS OF THE PURBECK STRATA THE PORTLAND- OOLITE GEOGRAPHICAL DISTRIBUTION OF THE STRATA THE SOUTH-EASTERN COAST OF PURBECK — THE SOUTH-WESTERN COAST WORBARROW BAZ LULWORTH COVE — FOSSIL TREES — DURDLE COVE CHALDON DOWNS — RINGSTEAD BAY — THE ISLE OF PORTLAND — PETRIFIED PINE-FOREST — FOSSILS OF PORTLAND AND WEYMOUTH RETROSPECT — COROLLARY. Voyage from Yarmouth to Swanage. — At the distance of about fifteen miles across the chan- nel, from the western extremity of the Isle of Wight, the south-eastern part of the county of Dorsetshire forms a peninsula, which is called the Isle of Purbeck. This district is of an irregular oval form, its greatest length from east to west is between thirteen and fourteen miles, and its average breadth from north to south, seven miles. It is composed of cretaceous, wealden, and oolitic deposits, and a brief notice of its geology will form an interesting and highly instructive sequel, to our survey of the corresponding strata in the " beautiful Island." 346 GEOLOGY OF THE ISLE OF PURBECK. At Yarmouth a cutter may be engaged to con- vey the visitor to Swanage, a little town on the eastern coast, situated near the once celebrated quarries of Purbeck marble. But during a great part of the year, steam-packets ply twice or thrice weekly from Portsmouth and Southampton, to Poole, and Swanage, calling for passengers at Ryde, Cowes, and Yarmouth ; so that the Isle of Purbeck may be included in our geological ex- cursions with but little inconvenience. This short voyage is very delightful in fine weather, for with a telescope the principal lines of strata may be traced along the distant coasts, and a comprehen- sive view obtained of the relations, and original continuity, of the now dissevered masses which form the dry land. In sailing from Yarmouth towards the Isle of Purbeck, our course, after passing by the Needles, is to the west, and the chalk dill's of Dorsetshire soon become distinctly visible ; and we at once perceive, that if the vertical chalk range we are leaving behind were prolonged in a direct line to the west, it woidd unite with that towards which we are steering our little bark. Mr. Webster has graphically described the most striking features of the varied landscapes which successively appeal- in this voyage: "The Island we had just left assumed FROM YARMOUTH TO SVVANAGE. 347 a very interesting- appearance. The gradual rise of the northern side above the sea — the coloured strata of Alum Bay — those singular masses of rock the Needles — with the majestic chalk cliffs behind them of the most dazzling whiteness — and the precipitous face of the southern side of the Downs above Freshwater — composed altogether a picture of the most romantic character. On the north lay the coast of Hampshire (see p. 164), consisting of tertiary clay cliffs, above which were seen the town of Christchurch, and several lesser places. As we approached the Dorsetshire side, I perceived that the chalk cliffs were of great height, forming the eastern end of the promontory called Handfast Point ; on the north side of which lay Studland Bay, and on the south Swanage Bay. In these cliffs, which present a vertical section of the Isle of Purbeck from north to south, were seen, while we were yet some miles distant, several very large caverns ; and towards the north end four or five detached masses of rock rising out of the sea ; these were evidently isolated portions of the chalk, which like the Needles had resisted longer than the rest of the cliff, the destroying effects of the waves. When sufficiently near, I made the vessel lay to, that I might examine the stratification by a telescope ; and I was surprised and delighted to 348 GEOLOGY OF THE ISLE OF PURBECK. «so ' find the south end composed of strata of chalk and flint quite vertical."* Swanage Bay. — We land at the little town of Swanwich, or Swanage, where excellent ac- commodation may be obtained, and vehicles and boats hired for excursions by land or water. The exportation of stone is still so considerable as to give the place an aspect of cheerful activity. The cliffs that extend across Swanage Bay, expose a trans- verse vertical section of the strata from north to south, and afford a key to the geological structure of the Island ; as shown in lign. 28. In this line of coast, the entire scries of deposits from the Chalk at Ballard Downs, to the Portland oolite at Durl- stone Head, is displayed in the natural order of succes- sion. This section will remind li B< Id's [sle of Wight, p. 164. 3S SWAN AGE BAY. 349 the reader of that from Shalcomb to Brook Point (lign. 13, p. 220) ; but in the latter, only the upper wealden beds appear on the south, the lower group not being exposed to view. The general dip of the strata is to the north, but the angle of inclination is not uniform, and some of the cretaceous and wealden deposits present flexures and contortions of a very remarkable cha- racter. Before we stroll along the shore to collect specimens, and examine the strata in detail, it is desirable to engage a boat, and sail across the bay, that we may obtain a general idea of the geologi- cal structure of the country. From Swanage the cape or headland of Handfast Point, a chalk cliff 350 feet high, appears on the north ; and to this spot we will direct our course. Doubling this promontory we enter Studland Bay,* and perceive that the coast is formed of the upper chalk, which emerges from beneath the eocene strata on the north at a very low angle, and continues round the ex- treme point of the cape, where several pinnacles, that may be regarded as representative of the Needles, guard the coast. A little to the south of this point, the layers of chalk and flint, which are as strongly defined as in Culver Cliff (p. 336), * If the section, lign. 28, were prolonged, Studland Bay would appear on the north of Ballard Downs. x 2 350 GEOLOGY OF THE ISLE OF PURBECK. suddenly turn upwards in a curve, forming nearly a quarter of a circle, and abut against vertical strata of the same kind ; " the vertical layers of flints meeting the bent part of the chalk, as so many ordinates would meet a curve, and decreas- ing in height as they get more under it."* (See lign. 28. Handfast Point). This appearance, as Mr. Conybeare has clearly shown, is attributable to a fault or dislocation, which in part of its course coincides with the lines of stratification. The chalk in the curved and vertical strata is extremely indurated, but in the horizontal, is of its usual consistence. The vertical flints, like those in the Isle of Wight, are, for the most part, shattered {ante, p. 202), and the fragments separated from each other by the chalk. These flints do not fall to pieces in the hand, like those of Freshwater, Culver, &c. because the severed portions are firmly held together by the chalk in which they are imbedded ; but there is the same variety in the size and form of the fragments, from large angular pieces to fine powder.f * Geology of England and Wales, p. 110. t These appearances were first pointed out by Mr. Webster, whose de- scriptions will be found as faithful as they are lucid, by those who visit the scenes he has so exquisitively portrayed in the beautiful illustrations of Sir Henry Englefleld'a work. These phenomena may be most easily examined on the south side of the cliff at Handfast Point, where the shore is gener- ally strewn v. itli large masses of fallen chalk. SWANAGE BAY. 351 Southward of Handfast Point, near the foot of Ballard Down, there is a small cove or recess termed Punjield, in which strata of Firestone, Gait, Greensand and Wealden clay, are seen in a highly inclined position. The middle series of the Wealden deposits, the Hastings Sands, which are not visible in the Isle of Wight, form the line of cliffs from Punfield to Swanage. These beds consist of sands, clays, and calcareous grits, enclosing seams and disseminated masses of lignite, and containing bones of reptiles, &c. The sea-shore, as in Brook and Sandown Bays, is often strewn with fossil trees, and rolled bones of the Iguanodon and other animals, that have been washed out of fallen masses of the strata. The tract on which the town of Swanage stands, is on the line of junction between the Hastings beds, and the Purbeck group ; the latter comprises clays, sands, and limestones, with bands of shelly marbles, calcareous shales, and coarse limestones, full of small paludinos, cyclades, and other fresh- water shells. The spaces respectively occupied by these de- posits as measured along the foot of the cliff, are given by Dr. Fitton as follow : — Firestone 250 paces. Gait 200 — 352 GEOLOGY OF THE ISLE OF PURBECK. Greensand 240 paces. Weald clay 46 — Hastings sands 3500 — Interval between the sand cliffs and the rise of the Purbeck strata 200 — * The cliffs in Durlstone Bay are entirely com- posed of the Purbeck strata ; those in the middle are much bent and undulated, but in the southern part, the arrangement of the beds is well displayed. The termination of this coast at Durlstone Head, consists of the marine strata called the Portland oolite, which are seen to emerge from beneath the Purbeck hills (see lign. 28). In the coast section thus briefly described we have, therefore, the following series : — I. The Cretaceous System, comprising the upper and lower white chalk, firestone, gait, and greensand. II. The Wealden, including the Weald clays, the Hastings beds, and the Purbeck. III. The Oolite, of which the upper, or Portland group, is alone visible. Of these, the Purbeck and Portland strata are for the first time brought under the observation of the reader, and will therefore require more particular notice. * Geological Transactions, vol, iv. p. 207. THE PURBECK STRATA. 353 The Purbeck strata. — The uppermost Pur- beck bed is a green, calcareous, and for the most part friable, deposit, containing shells of a small species of Unio ; beneath this is a stratum of the well-known marble, composed of an aggre- gation of the small river snail -shells already de- scribed (Paludina elongata, P/.VI. fig. 2); a polished slice of this marble is figured in lign. 29. Some of I.1GN. 2'J. POLISHED SLAB OF PURBECK MARBLE. ( Composed of petrified river snail-shells. ) the layers contain interspersions of the large palu- dinae (P. jltiviorum, PL VI. fig. 3) of the Sussex marble, and also a few small river-mussels. I have seen polished slabs of this kind, in which sections of bivalves (Uniones) formed the princi- pal markings ; these shells were associated with cyprides and very small fragments of bones, and vegetable detritus. The white and cream-coloured 354 GEOLOGY OF THE ISLE OF PURBECK. slates and coarser limestones, or Purbeck stone, as they are termed, are also shelly conglomerates, the prevailing shells being small species of the genera Cyclas, Cyrena, &c* The stone now quarried is in the upper part of the series of shales, clays, and limestones. Mr. Webster states, that in the thickness of 125 feet, there are more than fifty layers of useful stone ; these include a remarkable deposit, 12 feet thick, termed "Cinder" by the workmen, and which consists of a regular oyster-bed. The lower 150 feet are made up of shales, clays, and shelly limestones, too friable to be of any value in an economical point of view. The total thickness, from the uppermost bed to the Portland marine limestone, is about 275 feet.f Fibrous carbonate of lime, in layers two inches thick, is often found adhering to the bands of marble, as in the in- stance observed in Sandown Bay (p. 136). Fossils of the Purbeck strata. — From what has been stated, the reader will be aware that the fossils of the Purbeck strata are identical in their general character, with those of the upper divi- * Some of the most ancient pavement in Ely Cathedral consists of slabs of the Purbeck bivalve limestone. * Mr Webster, in Geol. Trans, vol.ii. new series. Mr. Webster mentions having found some nodular concretions of chert, containing silicified fresh- water shells in the state of chalcedony ; I have not obtained any specimens of • Mis kind. FOSSILS OF THE PURBECK STRATA. 355 sions of the Wealden, described in the pre- vious chapters. They consist of river shells, drifted land plants, bones of saurian and chelo- nian reptiles, with the remains of fishes, and crustaceans ; the absence of ammonites, echinites, zoophytes, &c. being as complete as in the Sussex wealden. Many bones of reptiles have been procured from Swanage cliffs,* and from the quarries in the neighbourhood; but the most remarkable fossil of this kind hitherto discovered, I had the good fortune to obtain, through the intelligence and liberality of Robert Trotter, Esq. F. G. S., of Sussex. The Swanage fossil Crocodile. — In the summer of 1837, the workmen employed in one of the quarries near Swanage, had occasion to split asunder a large slab of the fawn-coloured lime- stone, when, to their great astonishment, they perceived many bones and teeth imbedded on each of the exposed surfaces. As this was no ordinary occurrence, — for though scales of fishes, shells, and fragments of bones, were frequently met with, an assemblage of bones had never been * A description of some bones of the Iguanodon, found on the shore, half a mile north of Swanage, is given by Dr. Buckland in Geol. Trans, vol. iii. p. 429, new series. 356 GEOLOGY OF THE ISLE OF PURBECK. observed before, — both slabs were preserved; and Mr. Trotter, who casually visited the place, pur- chased them, and presented them to me. These slabs measure 3 feet 10 inches by 3 feet, and are a few inches in thickness. Many of the bones were split asunder in separating the stone, others were deeply imbedded, and of a few, imprints alone remained. Much labour and care were required to unite the severed parts of the bones, to develop the others, and bring the specimens into the state in which they now appear. On one slab, a considerable portion of the left side of the lower jaw, with two teeth, is preserved; and several teeth, and numerous dermal or skin-bones, of a very peculiar form, are dispersed about the stone.* The bones of the pelvis, and some of those belonging to the extremities, with many caudal and dorsal vertebrae, and chevron bones, are im- bedded in the same slab. The corresponding piece of stone bears the impression of the portion of jaw, and contains numerous dermal bones, vertebra?, &cf Teeth and dermal bones of this reptile were among my earliest discoveries in * These dermal bones are figured in Medals of Creation, vol. ii. p. 702. t The .slab first described is figured in the Wonder* < if Geology, vol. i. pi. i. Botb specimens are now placed in an upright glass case against the wall, near the doorway of the room containing the remains of the Iguanodon and other Sauriaus, in the Gallery of Organic Remains, in the British Museum. SWAN AGE FOSSIL CROCODILE. 357 Tilgate Forest ; several teeth are figured by Baron Cuvier, in Oss. Foss. torn, v., and in my " Fossils of Tilgate Forest." In the latter work portions of dermal bones, or scutes, are repre- sented, and described as belonging to the fresh- water turtles called Trionyces ; and it was not until I discovered more perfect specimens, that the true nature of these bones was apparent. The gigantic Gavial of the Ganges, has rows of osseous scutes, which are deeply pitted on the external surface. Those of the Swan- age Crocodile are distinguished by a lateral conical projection, which fits into a corresponding depression on the under sur- face of the opposite angle of the adjoining plate. Nume- rous hexagonal and pentagonal scutes, articulated together by marginal sutures, also entered into the composition of the cui- rass of this reptile, which there- fore, must have constituted a flexible and impenetrable coat of armour, capable of resisting the attack of the most formidable assailant. The teeth of the Goniopholis (lign. 80) resemble in form those of the crocodile, LIGN. 30. — TOOTH OP THE SWANAGE CROCODILE. (Goniopholis crassidens.) 358 GEOLOGY OF THE ISLE OF PURBECK. but the crown is strongly marked with numerous sharp, well-defined, longitudinal striae, and there is a prominent ridge down the middle of each side. The successional teeth are often found in the base of the perfect old teeth, as in the crocodile. Some specimens from Tilgate Forest are two inches long, and half an inch in diameter at the base.* The vertebrae are biconcave, and have an irregular medullary cavity in the centre of the bone ; the chevron bones resemble those of the crocodile. Fossil Turtles. — Waterworn bones of turtles are very common in the Purbeck strata, and several almost perfect examples of the carapace, or buckler, and of the plastron, or sternal-plates, have been discovered ; a remarkably fine specimen from Purbeck, was exhibited many years since in Mr. Bullock's museum, in Piccadilly. Fossil Fishes. — Detached angular scales of the well-known Wealden fish, the Lepidotus, are often met with in the clays and limestones ; and many specimens of the entire fish, of a smaller species of the same genus (Lepidotus minor), have been obtained. The small hemispherical teeth, termed by the quarry-men fishes' eyes, are of very frequent " See Fossils of Tilgate Forest, PI. V. figs. 1, 2, 9. THE PORTLAND OOLITE. 359 occurrence in many of the beds. The slabs con- taining the Goniopholis, previously described, have numerous teeth and scales of the Lepidotus minor scattered among the bones. The Portland Oolite.* — The series of sedi- mentary deposits, termed the Oolite formation by English geologists, and known as the Jura lime- stone on the Continent, from the mountain-range in which it is so largely developed, consists of Limestones, sands, and clays of great thickness and extent, which abound in marine shells, corals, crinoidea, articulata, and fishes — terrestrial and marine reptiles, insects, and land plants — and two or three genera of very small mammalia, referable to the marsupialia and insectivora. In this formation there are several local intercalations of fluviatile deposits, resembling the Wealclen in the presence of terrestrial animals and plants, and freshwater shells. -j- Certain beds of the Oolite (called the Stonesfield slate) contain organic remains, which, with the exception of trigoniae and other marine shells, correspond with those of the Tilgate cal- ciferous grits. The collocation of teeth and bones * The term Oolite, or egg-stone, is derived from many of the limestones being composed of an aggregation of very small grains or spherules, which bear some resemblance to clusters of small eggs, or to the roe of a fish ; this structure is merely concretional. t See Wonders of Geology, vol. ii. p. 436. 360 GEOLOGY OF THE ISLE OF PURBECK. of the Megalosaurus, Lepidotus, &c, with stems and fruits of cycadeous plants, presented so striking an analogy, that it led me, on my first discovery of similar fossils in the Tilgate strata, to seek for the equivalent of the latter in the Stonesfield oolite.* In the Isle of Purbeck, the uppermost group of the Oolite only appears; it is denominated "the Portland Oolite" from the island in which the limestone has for centuries been extensively quarried. This group is separated into three divisions ; viz. 1 , the Portland limestones ; 2, the Portland sands ; and, 3, the Kimmeridge clays, so called, from the bay of Kimmeridge, where these beds are well displayed. 1. Portland limestones. — Oolitic limestone, abounding in trigoniw, ammonites, pernxc, pluro- tomariw, and other marine shells ; layers and nodular masses of chert and flint; total thickness, from 30 to 40 feet. 2. Portland sands, — Beds of white and green sand and sandstone, with concretionary masses of grit; the lower strata argillaceous ; total thick- ness, about 130 feet. 3. Kimmeridge clay. — Dark blue clay, with ' see The Fossils of the South Downs, 1S22, " On the analogy betfreen the organic remains of the Tilgate beds and those of Stonesfield, near Oxford," p. O'J. GEOGRAPHY OF THE STRATA. 361 septaria, and bands of sandy concretions ; beds of lignite, and highly bituminous shales and clays; marine shells are very numerous ; total thick- ness, 800 feet. One species of oyster, the Ostrea deltoidea, is characteristic of this group, and occurs abundantly in every locality.* Geographical distribution of the strata. — The White chalk forms a narrow but lofty chain of hills, that ranges inland across the Island, from Handfast Point (section, lign. 28), to the cliff called Bats-corner, on the south-western shore. The lower cretaceous deposits appear along the southern escarpment of the downs ; the chalk is also exposed to the east of Bats-corner, in Wor- barrow, or Worthbarrow Bay, and in several lesser bays or coves, that have been excavated, by the long-continued action of the waves, in the Purbeck and Wealden deposits, that form the southern cliffs. The height of this chain of downs is from 500 to between 600 and 700 feet. Ballard Hill, over Handfast Point, is 584 feet, and Ninebarrow Down, 642 feet high. A line of chalk cliffs forms the coast from Bats-corner to Whitenore (see lign. 36), where the cretaceous ♦ Sowerby's " Mineral Conchology " contains figures of many of the shells of the Portland Oolite ; and in Dr. Fitton's Memoir, plates xxii. and xxiii., several species are figured and described. 362 GEOLOGY OF THE ISLE OF PURBECK. beds trend inland, and the cliffs beyond consist of the strata below the chalk. The Wealden and Hastings deposits extend entirely across the penin- sula, from Swanage Bay to the southern shore at Worbarrow Bay, and form a valley, diversified with heaths and cultivated tracts, between the chalk escarpment and the next range. The Purbeck beds run in a nearly parallel direction with the Wealden, from the hills above Swanage, spreading out to the north as far as the village of Worth, and westward four or five miles, to the seashore on the south of Worbarrow Bay, and the adjacent coves. The Portland group appears on the south-east, beneath the Purbeck at Durlstone-head, and continues along the coast to Gad-cliff, consti- tuting the irregular tract that forms the south- eastern part of the Isle of Purbeck. Southern coast of Purbeck. — We must now take a rapid view of the most important features of the coast, from Durlstone-head to the western extremity of this interesting district. Swanage will be the most convenient place for the visitor desirous of exploring the geological phenomena of the eastern part of Purbeck ; the numerous quarries in the vicinity, and the coast sections, being rich in organic remains. East and West SOUTHERN COAST OF PURBECK. 363 Lulwortb, two little villages near Worbarrow Bay, are the best halting-places for a survey of the south-western shores ; and if the observer be tempted to extend his tour to the Isle of Port- land, Weymouth, of course, will be the place of sojourn. As the general dip of the strata is to the north, the lower beds are displayed along the southern coast; and we will now point out the most in- structive localities, in proceeding from the south- eastern corner of the Isle of Purbeck, to the west. Contorted Purbeck strata. — The strata in the middle and on the south side of Durlstone Bay, are very remarkable for their broken and con- torted condition, which was evidently produced when the beds were in a plastic state. Septaria, veins of calcareous spar, and crystals of gypsum, occur in some of the clays ; there are also masses of breccia, or conglomerate, composed of fragments of the undulated layers, cemented together into a firm rock.* To the west of Durlstone Head, the Portland oolite appears ; and at Tillyichim ilign. 28) there are quarries for the extraction of the fine white limestone, here called Purbeck stone. These strata * Mr. Webster has figured a mass of this kind in pi. xxxi. Sir II. Engk- field's Isle of Wight. 364 GEOLOGY OF THE ISLE OF PURBECK. contain ammonites, trigoniae, and the usual Port- land shells, and veins and nodular masses of chert. A bed of oyster shells, which an infiltration of calcareous matter has converted into a hard shelly conglomerate, like that of Bromley, in Kent,* occurs in the upper part of the series. The quarries at Tillywhim are generally visited by parties in the summer, on account of the romantic character of the scenery, and the delicious cool retreat afforded by the caverns or excavations ; these are reached by a path that winds through a deep valley, strewn with masses of stone, and the descent is by steps cut in the rock.-j- To the eastward there are similar caves, formed by the extraction of the layers of limestone : fine specimens of the oyster-shell conglomerate may be obtained from near the summit of the cliffs. Lofty perpendicular cliffs of oolite, capped with Purbeck strata, continue along the coast to the west; and at the distance of about three miles from Tillywhim, the Portland stone is worked in Windspit quarries,! which are excavations in the cliff, like those at the former place. About a mile to the west of Windspit quarries, * See Medals of Creation, vol. i. p. 385. t A view of the cliff at Tillywhim is given by Mr. Webster, in Sir II Bnglefield's Me of Wight, pi. xxxiii. ■ .iton, 241. O. Osborne, 145. Osmington Cliff, 393, 401. Parkhurst Barracks. 140. Portland, Isle of, 393. Purbeek, Isle of, 345. Q. Quarr Abbey, 103. K. Redcliff, 135, 3 Ringstead Hay, 390,401. Hookley, 142. R,yde, 18, 98. S. Saint Adhelm'a Head, 365. ■ Boniface Down, 250. Catherine's Down, 240, 249. Clare, 236. Helen's, ill. 124, 336. Sandown Bay, 132, 261, 339. i :., 237. Schehallien, 251. Scratchell's Bay, 198. Seafleld, 117. Shalcomb Down, 219, 343. Shalfleet, 142. Shanklin, 258. ■ ■ Chine, 258. Down, 251, 257. Shepherd's Chine, 285. Southampton, 86. Spithead, 90. Stare Cove, 386. Stone, Bucks, 400. Stubbington, 89. Studland Bay, 349. Swanage, 346. ■ Bay, 348. Swindon, 399. Swine's Back, 369. T. Thame, 399. Thornev Bay, 146. Tiepit, 2S5. Tilly-whim Quarries, 363. Tolland's Bay, 149. Tongariro, 181. U. Undercliff, 93, 237, 251. V. Vauxhall Station, 17. Ventnor, 248, 255. Shute, 250. W. Walpen Chine, 231. Wandsworth Station, 83. Wardour, Vale of, 31)9. West Lulworth, 29, 376. Weybridge Station, 84. Weymouth, 391. 401. Whale Chine, 231. WhitecliffBay, 124, 339. Whitenore Point, 390, 401. Winchester. 86. Windspit Quarries, 364. Wingfield Station, 85'. Woking Common, 84. Wooton-bridge, 19, 139, — river, 96. Worbarrow Bav. 28, 370, 375. Knob, 367. Var, River, 96. Yarmouth, 19, 162, 194, 345. Yaverland, 123,311. GENERAL INDEX. Afton Down, views from, 25, 206. Alligator, fossil remains of, 169. Hantoniensis, 169. Alum Bay, View of, 24, 147. , fossils of, 161. , geology of, 152. , section of, 155. Ammonites giganteus, 400 Mantelli, 187. varians, 187. Animalcules, fossil in flint, 184. — j so f t p ar ts, 184. Anoplotherium commune, 117, 118. secundarium, 117, 118. Anticlinal axis of Sandown Bay, 135. Araucaria excelsa, 398. Area raulini, 191. Artesian wells, 81, 87. well of Crenelle, 82. Ashey Down, 122. sea-mark, view from, 205. Atherfield Cliffs, 221. fossils, 225, 239. -, greensand series, 223, 225, 227. -, road to, 220. - Station, 20, 221. -, view of, from the sea, II. Bagshot sands, 78. Bar of shingle off Hurst Castle, 165. Barber's Isle of Wight, 17. Barn-door Cove, 386. Basingstoke, 85. , ruins of a chapel at, S5. Bats-corner, 390. Bern bridge, 124. Binstead, IS, 105. , fossils, 103, 107, 110. , limestone, 107. , quarries, 102. Blackgang Chine, view of, 26, 233. , strata of, 233. , from the sea, 341. Bognor rocks, 127. Bog-wood, 273. Bonchurch, 245. , fossils from, 245. Bones of reptiles, 137, 312, 355. in firestone, 245. Botanic Garden, fossil trees in, 397. Bowerbank, J. S. Esq., on Alum Bay, 13. , on Sandown Bay, 132. Bracklesham fossils, 129. Brading Church, 122. Down, vertical strata on. 26, 252. Haven, 96. Brander's Hampshire fossils, 164. Brannon's Map of the Isle of Wight, 17. British Museum, fossils in, 356, 398. Brodie, Rev. P. B., on Fossil Insects, 400. Brongniart, Ad. M., on Fossil Plants, 257, 397. Brook Bay, Excursion to, 271. Point, view of, 25, 277, 342. to Shalcomb, 220. , from the sea, 342. Brown, Dr. Robt., on Fossil Plants. 290, 398. Buckland, Rev. Dr. (Dean of West- minster) Bridgevater Essay, 323, 330. on Geology of Weymouth, 381. Wells, 82. on Artesian 422 GENERAL INDEX. Buckland,Rev.Dr. on fossil Cycadea, 398. reptiles, 137, 311, 323. Bulimus, fossil, 111. Bullface Ledge, 274, 277. Butler, Mr., of Yarmouth, 19. Calbourne, 142. to Alum Bay, 143. , fossil shells, 142 Calshot Castle, 89. Cardita planieosta, 128. Carisbrook, 142. Carr, Henry, Esq., fossil wood in chalk, 193. Cave in chalk cliff, 197. Cerithium turriculatum, 191. Cetiosaurus, 324. Chaeropotamus, 117, 119. Chalk cliffs at Freshwater-gate, 24, 195. in Purbeck, 349. composition of, 175, 205. Downs, 173, 204, 206. formation, 61, 66, 173, 178. fossils, 185. subdivisions of, 176. — vertical strata of, 199, 253. — at Handfast Point, 349. ■ marl, 176. Chara?, fossil, 108, 130. Chert of the Undercliff, 211. Chesil-bank, 391, 393. Chesilton, 401. Chilley pitch-stone, 368. Choanites, 216. Christchuroh Bay, 164. Clark, Sir James, on Climate, 238. Clathraria Lyellii. 244, 292. , specimen of Capt. Ibbeson, 295. Cliffs at Alum Bay, 155. at Blackgang Chine, 233. — — in Compton Bay, 272, 274. Culver, 27, 125, 339. Climate of the Undercliff 238. Coal, Kimmeridge, 367. Coast, eastern, Isle of Wight, 124. -, northern, Isle of Wight, 89, 145. Coast of the Isle of Purbeck, 348. 370. Colby, Col. on the Plumb-line, 251. Colwell Bay, 149. Compton Bay, 25, 27, 214, 274, 343. , Mr. Lyell on, 280. ■ Chine, 273. Coniferous fossil wood, 252. Contorted .strata, 363. Conybeare. Rev.W. D., on Handfast Point, 350. the Coves in Purbeck, 374. Corlns corrugata, 190. Corollary, 409 Country of the Iguanodon, 332. Coves of Dorsetshire, 28, 29, 369, 376. Cowes, 18, 97, 146. Crackers rocks, 225. Cretaceous system, 175, 192. Crocodile, fossil, 163. of Swanage, 355. " Crows' Nests," 398. Culver Cliffs, 27, 125. Cycadeous plants, 291 ■ — fossil, 288, 395. Cyprides, fossil, 111, 136, 305, 307 Cytherea incrassata, 149. Damon, Mr., fossils collected by, 401. Notes by, 401. Dean of Westminster. See Dr. Buckland. De la Becbe, Sir Henry, on the Geo- logy of Weymouth, 384. Description of the plates. 23. Dichobune cervinum, 117, 119. Dinkel, Mr. Joseph, drawings by, 295. Dirt-bed of the Isle of Portland, 395. . in Lulworth Cliff, 384. Ditrupa plana, 128. Dodspit, tosails at, 143. Dorsetshire Coast, view of, 28. Coves on, 28, 374. Downs, Afton, 204, 206. St. Boniface, 250. Catherine, 240. Chaldon, 369, 389. ■ Needles, 205. -. southern, Isle of Wight, 213, . western, Isle of Wight, 155. of tin- Undercliff, 251. — Hampshire, 163. — Shanklin, 251, 257. • southern range of, 249. Drift, or alluvium, 60. Dunnose Point, 257. from the sea, 310. Durdle Cove. 29, 385 GENERAL INDEX. 423 Durlstone Bay, 351. Head, 352, oolite of, 303. E. Endogenites erosa, 288. Engleficld, Sir Henry, work on the Isle of Wight, 98. • quoted, 14!), 165, 199,202,258. Esher, strata at, 84. Excursion to Atherfield, 218. Brook Bay, 271. — from Compton Bay to Atherfield, 220. toChristchurch Bay, 164. Fossils, vegetable, 108, 161, 244, 247. of the eocene strata, 110, 161. firestone, 242. greensand, 229, 260. Portland oolite, 400. Wealden, 286, 299, 354. wood, in chalk, 193. — of the Wealden, 279. oolite, 40n. Fowlstone, Mr. ofRyde, fossils by, 18. silicified D. fossils found by, wood, 218. Fox, Rev. W. 117. Freshwater eocene strata, 100, \r6. Bay, 343. Gate, cave at, 197. cliffs at, 19, 24, 195. Fuci, fossil, 247 Fault in Ringstead Bay, 391. Femur of Iguanodon, 314. unknown reptile, 245. Ferruginous sand-cliffs, 341. Firestone strata, 176, 1S5, 241, 242. Fishes, fossil, 307. Fissures, or joints, in chalk, 200. Fition, Dr. on the Atherfield strata, 222, 228. Portland strata,390. Wealden, 270, 289, 351. — Worbarrow Bay, 375. ■ sections by, 134, 215, 375, 3S0. Flint, formation of, 1 79. layers and nodules, 180. veins, 200. shattered, 202, 350. Footsteps, supposed, 247. Forbes, Prof. E. quoted, 131, 223, 227. Forest, petrified, of Portland, 395. Fossil alligator, 172. animalcules, 183. crocodile of Lymington, 163. cycadeae in chalk-marl, 244. fishes, 232, 307. fuci. 249. lobsters, 232. ■ mammalia, 115. reptiles, 245, 309. sponges, 183. turtles, 326, 358. Fossils, cretaceous, 181. of Alum Bay, 161. Barton, 172. Hordwell, 171. Gad Cliff, 366. Gait, 176. of the Undercliff, 240. Geology of Alum Bay, 153, 159. Brook Bay, 272. Compton Bay, 210. Headon Hill, 158. ■ Hordwell Cliff, 166. Isle of Wight, 90. Portland, 393. Purbeck, 361. Sandown Bay, 132. the S. E. of England, 69. Whitecliff Bay, 124. Geological mutations, 74. ■ principles, 56. Gervillia anceps, 190. Gladstone, Messrs. fossils collected by, 230. ■ ■ geological tour by, 20. Glauconite, 176. Goldsworth Hill, 84. Goniopholis, 357. Gosport Railway, 88. Greensand, 176, 189, 223. Upper, or Firestone, 185. fossils, 190, 229. in Polytechnic In- stitution, 229. — group, 189. of Atherfield, 221, 223, 225. Neufchatel, 227. Grenelle, Artesian well of, 82. 424 Grey Wethers, 80, Grove's Hotel, 144. Gryphea sinuata, 191, 231. Gurnet Bay, 146. Gyrogonites, 109. Hampstead Cliffs, 146. Handfast Point, 349. , vertical strata of,350. Hastings, Geology of, by Dr. Fitton, 269. — — sands, 351. Headon Hill, 24, 161. . fossils of, 161. - strata of, 158. GENERAL INDEX. — view of, 24. PI. IX. Geological 151. Hengisbury Head, 1G4 Hopkins, — , Esq. o Structure, 141, 392. Hordwell, 164. ■ Cliffs, 166. fossils of, 169, 171 strata of, 166. Hurst Castle, 165. Hybodus fossil, 232. Hylaeosaurus, 322. Ibbetson.Capt.Clathraria discovered by, 295. , , ," -fossils collected by, 229, 232. on the Firestone, 242. , . Greensand, 223. — models of the Isle of Wight, by, vi. Iguanodon, 312, 321. bones of, found in San- down Bay, 137. Swanage Bay, 35 J country of the, 332. femur of, 314. sacrum of, 318. teeth of, 316. Impressions of fossils, method of taking, 328. Imprints on sandstone, 326, 328. Insects, fossil, 1 10 of the Wealden, 400. Brodie,Rev. P. B. , on, 400. Iron-sand of Mr. Webster, 189. Isle of Portland, 393. — petrified iorest of, 395. 185. of, 91. - Purbeck, 345. - Wight, cretaceous fossils of, - eocene, 108. 127. - form of, 91. - geological structure 91. 190. map of, — greensand fossils of, 286. Itchin, river, 86. - models of, vi. - plan of, 94. - rivers of, 95. - Undercliff of, 93. - voyage round, 335. - Wealden fossils of, J. .lasper pebbles, 217 K. Kimmeridge Bay, 366. -clay, 360, 390. coal, 367. coal-money, 368. Lepidotus, 307. Lignite in greensand, 323. . wealden, 284. Limneus, 111. Lobster, fossil, 232. bed of, 225. Lonchopteris in greensand strata, 230. Mantelli, 288. London and Brighton railway, 72. London basin, 60, 78. clay, 80. eocene formation. 66. Long-mead End, 165. Long-stone, 220. Luccomb Chine, 256. Lulwortb Cove, 376. - strata of, 379. view of, 28. GENERAL INDEX. 425 Lyell, Charles, Esq., on Compton Bay, 280. -the Ham li- the Mis- Sandown Whitecliff shire coast, 167. sissippi, 269. Bay, 280. Bay, 126, 130, 146. Lymington, fossils from, 163. Mammalia, fossil, 24, 115, 117. from Hordwell, 169. Mantellia;, 398. Map, geological, of the Isle of Wight, 30, 92, 430. Meadow-rue, fossil, 140. Medina river, 9f>, 140. Megalosaurus, 323. Mineral spring at Sandrock, 237. Mississippi, delta of, 269. Molluskite, 248. Morris, John, Esq. , fossils discovered by, 230, 274. Mountjoy Downs, 140. Murchison, Sir R., on the deviation of the plumb line, 251. firestone strata, 241. ■ South- ampton well, 88. Mussel-shells, fossil, of the Wealden, 302. N, Natica rotundata, 190. Nautilus elegans, 186. Needles, the, 198, 343. Neocomian strata, 227. Neritina concava, 149. Neufchatel, greensand of, 227. Newchurch Vale, 261. Newport, 139. to Calbourne, 142. Newtcwn Bay, 96, 146. Nodules of flint, 180 Northampton, the Marquess of, fos- sils discovered by, 1S3. Nucula scapha, 191. Nummulites, 129. Oolite, meaning of, 359. Portland, 359. Order of superposition of the strata, 65. Organic remains of the chalk, 181. eocene stra- ta, 151. 242. 190, 229. beds, 400. beds, 354. 286. ■ firestone, • gait, 240. ■ greensand, ■ Portland ■ Purbeck Wealden, Osborne, strata on the coast of, 145. Osmington Cliff, 393. Owen, Professor, British mammals by, 117. on the sacrum of reptiles, 318. Oxford clay, 393. oolite, 367, 391. Oyster - shells, fossil, in Purbeck strata, 224, 354. tertiary strata, 130, 149, 158. Palseontological Journal, 171, lis. Palaeotherium crassum, 117. magnum, 117. — medium, 117, 119. — minus, 117. from Hordwell, 170. Paludinae, fossil, of the Wealden, 300. PanopEea intermedia, 128. Parkhurst barracks, well at, 140. Pebbles, 18, 216. Pedestrian tour round the Isle of Wight, 20 Perna mulleti, 191. Petrified forest, 395. trees, 279. wood, 282. Petworth marble, 299. Phillips, John, Professor, plan of the Geology of the Isle of Wight, 94. Planorbis, fossil, 111. Plesiosaurus, 325. Polytechnic Institution, models and fossils in, 188, 229, 232, 245. GENERAL INDEX. 426 Portland, Isle of, 394. limestone, 360. oolite, 359. petrified forest of, 395. quarries, 396. . — sand, 360. Potamides of the Wealden, 224, 301. Pratt, S. P. Esq., fossils discovered °y> 116 - ., B Prestwich, J. Esq., on Alum Bay, 154 ' 15 !: Whitecliff Bay, 126. Pristis (saw-fish) fossil, 84. Pritchard, Rev. Charles, fossils by, 310. Pseudo-volcano, 394. Pterocera retusa, 191. Purbeck, Isle of, 345, 361. . . fossils of, 354. strata of, 353, 363. ._^__ views in, 28. . marble, 353. Pyrites, 278. Q. Quarr abbey, ruins of, 103. Quarries at. Binstead, 102. . Portland, 395. , Purbeck, 354. . Tillywhim, 363. ■ Windspit, 364. R. Raft, fossil, in Brook Bay, 279. Railway sections, 83. Range of the Isle of Wight chalk hills, 176. Red-cliff, 135. Rein-deer, fossil, 103. Reptiles, fossil remains of, 24.,, 309. . ■— femur of, 245. _, . of the Wealden, 309. Retrospect, 403. Richmond, Rev. Legh, quoted, 122, 123, 205. Ringstead Bay, 390. fl_l_ .- fault in, 391, Rippled sandstone, 328. River Medina, 140. Rivers, nature of deposits, 264. , of the Isle of Wight, 95. , Wealden, 332. " Roach," limestone so called, 402. Rock, arched, in Durdle Cove, 386. Rock-crystal pebbles, 217. Hoitellaria robaldina, 191. Rotaliae, fossil, 184. soft parts of, 1R4. Ryde, 18, 98. quarries near, 102. seashore of, 98. to Alum Bay, 145. Culver Cliff, 121. Newport, 139. S. Sacrum of the Iguanodon, 318. St. Adhelm's-Head, 365. chauntry, 365. St. Boniface's Down, 250. well, 250. St. Catherine's Down, 240. St. Cross, hospital of, 86. St. Lawrence's church, 252. SandownBay, 132,261,339. . section of, 134. Sandrock mineral spring, 237. Sandstone, rippled, 326. unknown imprints on, 326. Saw-fish, fossil teeth of, 84. Saxby, J. M. Esq., fossils by, 188, 255. Scaphites grandis. 19, 231. Schehallien, mountain of, 251, Scratchell's Bay, 198. Sections, geological, from Alum Bay to Headon Hill, 155. - Brook to Shalcomb, 220. London to Brighton, 72. London to the Isle of Wight, 71, 75. of Chaldon Downs, 390. — Compton Bay, 213. — Durdle Cove, 385. Cove, 376. — Sandown Bay, 134. — Whitecliff Bay, 126. Worbarrow Bay, 375. coast, by Mr. Ly — theHampshire ell, 168. — southern coast of the Isle of Wight, 213. -Underdid, 256. , ... Sedgwick, Professor, quoted, 40J. Septaria, 402. GENERAL INDEX. 427 Shalcomb Down, 220. Shalfleet, fossils from, Ml'. Shanklin, 258. Chine, 258. Down, 251. sand-strata, 189. Shark, fossil skull of, 232. Shattered flints, 202, 251, 350. Shells, fossil, of the cretaceous strata, 185. eocene freshwater strata, 24, 110. marine stra- ta, 24, 161. — firestone, 242. — greensand,24,229. — Portland strata, — Purbeck strata, — Wealden strata, 299. Shingle, pebbles composing it, 216. Silicified chalk fossils, 186. Siphonia, 230, 243. Smart, W.Esq., fossils from Bourne- mouth, by, 169. Smith, Rev. Gerard, fossils by, 311. Soft parts of animalcules in chalk, 184. Southampton Artesian wells, 87. station, 86. to Ryde, 89. water, S9. South-East of England, Geology of, 59, 69. Southern coast of the Isle of Wight, sections of, 213. South-west coast of Dorsetshire, 368. South-western railway, 77. Steamers to the Isle of Wight, 89. Lymington, 163. Swanage, 346. Steam-voyage round the I. of Wight, 335. Stonesfield fossils, 359. Strata, arrangement of, 63. chalk, vertical, 199. Streptospondylus, 325. Stutchbury, Mr. Henry, dealer in. fossils, 401. Subsidences of the TJndercliff, 252. Sugar-candy spar, 395. Summary of the geological pheno- mena of the Wealden, 331. Superposition of the strata, 65. Surrey, geology of, 78, 83. Sussex marble, 249. Swanage Bay, 348, 352, 363. fossil crocodile, 355. T. Tabular arrangement of the strati, 63. Teeth, fossil, of Goniopholis, 357. Hybodus, 232. Iguanodon, 316. Tennant, Mr., fossils of, 100. Terebratulae, 226. Terebratula sella, 191. Terrain Neocomien, 228. Tertiary strata, 60. of Alum Bay, 24. Hampshire, 169. Headon Hill, 24. - Hordwell, 166. the London basin, 60, 63, 66. 124. Lymington, 163. Whitecliff Bay, Thalictrum, fossil, 140. Thetis minor, 191. Tilgate Forest, fossils of, 269. Tillywhim quarries, 363. Tolland's, or Totness Bay, 149. Tongariro, mountain of, 181. Topping, Mr., microscopical artist, 184. Tornatella afbensis, 191. Tour of the Isle of Wight, 20. Trees, fossil, in Brook Bay, 279. Lulworth Cliff, 383. — the Isle of Portland, 395. the Regent's Park, 397. Trigonia caudata, 190. Trionyx Bakewelli, 326. fossil, 112, 114. of Hordwell, 169. the Wealden, 326. Trotter, Robert, Esq., fossil reptile found by, 355. Turtle, fossil, ol Binstead, 112. Purbeck, 35S. St. Helen's, 114. the Wealden, 326. U. Undercliff, the, 237, 340. coast of, 251. geology of, 240. Unio Valdensis, 302. Valley of the Medina, 111. Variegated strata of Alum Bay, 157. Vauxhall station, 77. c c 428 GENERAL INDEX. Ventnor, fossils from, 255. Shute, fossils from, 250. stiata around, 255, to Sandown Bay, 257. Venus parva, 191. striato-costata, 191. Vertical chalk strata, 199. at Handfaot Point, 349. the Needles, 155. -onBrading Down, 251. Vine, J. Esq., fossils found by, 311. Voj age from Yarmouth to Swanage, 345. round the Isle of Wight, 335. W. Wealden clay of Atherfield, 224. cyprides, 305. fishes, 307. formation, 62, 68, 262. character of, 268. of the Isle of Purbeck, 353. Isle of Wight, 269. Sandown Bay, 136. — Sussex, 267. fossils of. 286. 2S8. reptiles of, 309. shells, 299. unionidae, 302. Webber, Mrs. Jane, of Barton, dealer in Hordwell fossils, 172. Webster, Thos. Esq., on the Geology of the Isle of Wight, 127, 140, 145, 154, 157. Brook Point, 279. shire coast, 346. tered, 204. strata, 368. land, 394. strata, 354. -the Dorset- - flints, shat- -Kimmeridge -pebbles, 217. - Portland ls- - Purbeck - Siphonice, Wells, 83, 87, 90. ■ at Southampton, 87. WestLulworth, 29. Weybiidge, 84. Weymouth, memoir on the geology of, 384. organic remains from, 401. Whitecliff Bay, 124. — Forbes, Prof, on, 131. Prestwich, Mr., on, 126. section of, 126. Whitenore chalk cliffs, 390. Winchester station, 85. Windspit quarries, 354. Wingfleld station, 86. Woking Common, 84. Wood, Searles. Esq., on Hordwell Cliff, 115, 167, 169. Wood, coniferous fossil, 252. in chalk, 193. of Portland, 395. Woodward, Professor, drawings by, 30. Wooton-bridge, 19. river, 96. Worbarrow Bay, 28, 370, 375. Yar, river, 194. Yarmouth, 19, 163. to Freshwater Gate, 194. Hordwell, 164. Lymington, 162. Swanage, 346. Yaverland, 123. Zamia, fossil, 13S, 291. — crassa, 138. Zoophytes of the chalk, 182. F I N 1 S. WORKS BY DR. MANTELL. I. THE FOSSILS OF THE SOUTH DOWN'S; or. Rlus trations of the Geology of Sussex. 1 vol. royal 4to, with 42 Plates, containing several hundred figures of Fossils ; Map, &c. (London, 1822).— Mr. Bohn has a copy of this Work; 21. 2s. II. THE FOSSILS OF TILGATE FOREST ; or, Illustrations of the Geology of the South-East of England. 1 vol. royal 4 to, with a Map, Sections, and 20 Plates, comprising nearly 200 figures of Wealden fossils. (London, 1827). Out of print. III. THE GEOLOGY OF THE SOUTH-EAST OF ENG- LAND. 1 vol. 8vo, with Map, Plates, and numerous Figures. Price 11. Is. (Published by Messrs. Longman, of whom a copy may be obtained.) " The straitness of our limits prevents us from indulging in any quotations from this original and scientific work, which is distinguished hy a correctness of arrangement, an accuracy of description, an acuteness of deduction, a comprehensiveness of theory, a perspicuity of style, and an excellence of graphic illustration, which reflect infinite credit upon the zeal and industry of the author, who, though most extensively engaged in the practice of his profession, has devoted his leisure to such noble purposes as the researches commemorated in this book. The successful handling of such subjects requires an exact and extensive knowledge of chemistry, and comparative and human anatomy, and botany, and a general acquaintance with all the natural sciences ; this knowledge is possessed in a high degree by Dr. Mantell, whose numerous discoveries in fossil botany and anatomy not only evince the solidity of his knowledge, but place in a strong light his industry, perseverance, and patience, in overcoming the difficulties and evading the obstacles which the pursuit of his arduous profession presents. Dr. Mantell affords an example worthy the imitation of all his medical brethren, and furnishes a signal proof that active professional occupation, is not incompatible with a deep devotion to the most profound philosophical investigations which can engage the mind of man." — Lancet, March, 1834. IV. THE WONDERS OF GEOLOGY; or, A Familiar Expo- sition of Geological Phenomena. In 2 vols, foolscap 8vo, with coloured Plates and numerous Illustrations. Fifth Edition, with an Introduction by Professor Silliman. (London, 1844. H. G. Bohn). Price 14s. " Dr. Mantell's Wonders of Geolugy must continue to be a favourite work, equally in the geological schools, in the private study, and in the family circle. It may be read and understood by any intelligent and educated individual; its exact science, sound logic, and dignity of style, ensure its acceptance with the learned; its elegance and perspicuity, with the polite and refined ; and its comprehensive brevity, with the student of the elements of Geology. It realizes, indeed, our beau-idea! of a familiar, yet dignified, philosophical style ; being alike condensed and luminous, possessing a graceful and flowing eloquence, and rising, as the subject may require, into the sublime as well as the beautiful. We are not aware of the existence of any work, in any department ef science, which has higher claims at once to a place in the library of a philosopher, and on the table of a refined family. " — American Journal of Science. Review of Ike Fourth London, and First American Edition of the Wonders of Geology. "Dr. Mantell's eloquent and delightful work, the Wonders of Geology." — Sir E. Bulwer Lytlon's " Zanoni." 430 WORKS BY DR. BCANTELI* V. THE MEDALS OF CREATION; or, First Less< - G ■!>! and in thi Study of Orga s. In -2 vols, foolscap Sro, in cloth, elegant : with coloured Plates, and several hundred Figures ■ Remains. (London: H. G. Bohn. Ills. " Dr. Maxiiii's 'Medals re among the chef-d'ceucres of the art of book-making in the best understanding of the term : we mean technically and mechanically, as well as intellectually. The two volumes are elegantly bound, and. being of a portable size, will and must take their place as the companion, not only of the geologist in his study, but also in the :. while they must also accompany the intelligent travellers of both s?xe- rnost instructive and delightful Mentors in their journeyings among the grand and beautiful scenes of our globe. The work is. indeed, a classic of high excellence, of great research, and formidable labour." — American Journal of Science for January, 1S45. - f * The " Wonders of Geology," and the ' ; Medals of Creation." are trans- lated into German, and copies may be obtained through the foreign booksellers. VI. THOUGHTS OX A PEBBLE: or. A Fin til. The Seventh Edition, witi Iditional Illus- trations. In purple cloth, silt. \ Reeves Brothers. King William- street. Strand. 1846). Pri - VII. THOUGHTS ON ANIMALCULES; or, A Oli flit Invisible World of Being revealed by the Microscope. 1 vol. square >vo. with 12 coloured Plates, and Wood Engravings. \Mr. Murray. London. lS-to). Price 10s. 6d. ■ Dr. Mantell, in the T has presented a vast deal of information on the most interesting species of ! - thed it with that fascinating - - ,uence, with which he has been ever wont to impart knowledge. — Dr. Mantell was one of the very first philo- sopher* wh« - ■ theory of the ' Vestiges of Creation : ' and in the work before us he has again advened to it, and. in our opinion, has clearly exposed the error that pervades it." — Westminster Review, No. XC. VIII. A DAY'S RAMBLE IX AND ABOUT THE ANCIENT TOWN OF LEWES; illustrative of the ohj - of Geological and Antiquarian interest. 1 vol. with Plates. (H. G. Bohn, London. 1846). P, ••A charming guide to a charming spot, rich in picturesque scei histori ss ons of the highest interest. — A day's ramble, which even one who vi> - - sure, will not fail to undertake, with so instructive and delightful a companion." — Bri__ i3irparu:g for ^ubliralion. THE PHENOMENA OF THE XET. - STSTE3 A Pa miliar - v - : being the substance of a course of popular Lectures. In one volume, with numerous Illustrations. R. CLAY. PRINTER. BKEAP STREET Hltt. University of California SOUTHERN REGIONAL LIBRARY FACILITY 405 Hilgard Avenue, Los Angeles, CA 90024-1388 Return this material!* the l.brary from which it was borrowed. Ql OCT 16 1995 RECEIVED OCT 1 6 1995| ARTS LIBRAI UC SOUTHERN REGIONAL LIBRARY FACILITY A 000 049 524 2 BOUND BY WESTLEYS & CLARK . LONDON. ,