ENGINEERING LIBRARY BOUGHT WITH THE INCOME PROM THE SAGE ENDOWMENT FUND THE GIFT OF Menrg W. Sage 1S91 AjsAin . /o/j/Zfox Cornell University Library QE 261.G34 A record of excursions made between 1860 3 1924 004 630 293 Cornell University Library The original of tiiis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004630293 GEOLOGISTS' ASSOCIATION : RECORD OF EXCURSIONS GEOLOGISTS' ASSOCIATION. RECORD OF EXCURSIONS Between i860 anb 1890. EDITED BY THOMAS VINCENT HOLMES, F.G.S., AND C. DAVIES SHERBORN, F.G.S. ^ LONDON : EDWARD STANFORD, 26 & 27, COCKSPUR STREET, CHARING CROSS, S.W. i8gi. PRICE, TWELVE SHILLINGS AND SIXPENCE NET. ^T^iiBL-r : — hf IS-S-c^u^tV HAYMANi CMHISTV AND ULLV, LTD., PRINTKHS, HAVrON WORKS, 113, PAKKINGDON ttOAD, AND 20, 2Z, ST. BILIDE ST., E.C. PREFACE. The task of drawing up a Record of the Excursions of the Asso- ciation was originally entrusted to Mr. Topley, whose many engagements, however, had prevented him from giving it any definite form when it was handed over to me. From him I learned that the excursions were to be arranged and edited so as to form a useful and handy guide to the geology of the places visited. The Record being primarily intended for the use of members (a decided majority of whom have joined the Association during the last ten years), it appeared to me that its character as a chronicle of past work and workers should not be forgotten. Accordingly every excursion down tp the year 1890 has been mentioned separately, and where many reports of visits to the same locality exist I have either suppressed the shorter and retained the fuller, or have given from each account that which is not to be found elsewhere. This course seemed preferable to the compilation of one account from various reports on the following grounds. Visits to the most popular places have been seldom made except at intervals of, at least, five or six years. Conse- quently in their case we have to deal with the work of five or six different directors or reporters, and with descriptions of sections which must have varied very considerably during a qtiarter of a century or more. It seemed better, therefore, to avoid confusion by keeping each report separate, and each reporter responsible for his own account. Indeed, in but few cases is there much repeti- tion, the later reporters usually omitting what has been fully described on some previous occasion. PREFACE. The alterations in the reports as given in the " Proceedings " consist mainly of excisions made in order to reduce the bulk of the Record as much as could be done without injury, the general arrangement and wording remaining unaltered. Of course it by no means follows that the matter excluded is out of place in the original report. Even an after-dinner speech, for example, might have pleasant associations for the partakers of the preceding banquet, though its retention in the Record would certainly be considered useless, if not irritating, by the great majority of readers. It also became obvious during the progress of the work that it would be well to omit reports of excursions of later dates than the year 1884, as during 1885 and since the excursions have been collected together in the November number, instead of being scattered here and there throughout the " Proceedings." But all excursions to the end of 1890 are mentioned, and references to reports of them given. Even without these reports the Record has attained larger dimensions than had been anticipated, partly owing to the addition of many useful illustrations from various sources. It may be worth suggesting that in some cases in which a map or section is not so clear at a glance as could be desired, a little colour will at once give the distinctness needed. Breaks have been made at pp. 224 and 400, so as to allow of binding the voluriie in three parts, convenient for the pocket. Though the Record cannot in itself be considerSci an adequate geological guide even to south-eastern England, it may claim to fill a vacancy hitherto existing in geological literature. Though it will not enable the student to do without Sir A. C. Ramsay's " Geology of Great Britain," Mr. H. B. Woodward's " Geology of England and AVales," or Mr. Harrison's " Geology of the Counties of England and Wales," it occupies ground on which they enter but little. While the writers just named explain the general conformation of a district, or point . out the charac- teristics of its beds as compared with those of equivalent strata elsewhere, in the Record are described many of the spots most important from their geological sections, or for the views they afford of the structure of the surrounding country ; while the intending visitor to any of them may learn from it both how to PREFACE. VII. employ his time most profitably, and how much time will be necessary for his purpose. For the general shape taken by the Record I am wholly responsible. But having brought it to its present form, it became obvious that it would be impossible to send each report to the original reporter for revision. Consequently, I then asked Mr. Whitaker if he would look through the' sheets referring to the country east of a straight line drawn from the Wash to the Isle of Purbeck, and Mr. H. B. Woodward if he \yould examine those dealing with the districts north and west of that line. Both gentlemen, whose special qualifications for the task I need not discuss, kindly complied with my request, and it gives me great pleasure to acknowledge here the valuable services they thus rendered. I am also greatly indebted to Mr. B. B. Woodward and to Mr. F. A. Bather, who have carefully read the proofs. Thanks are likewise Sue to Mr. Worthington Smith, the Geologi- cal Society, the Essex Field Club, and the Herts Nat. Hist. Society for the loan of illustrations. And, lastly, my co-editor, Mr. C. Davies Sherborn, has not only superintended the passage of the Record through the press, but has added References to the end of each chapter, seen to the illustrations, and made the Index. T. V. Holmes. April 20TH, 1891. RECORD OF EXCURSIONS \ MADE BY THE GEOLOGISTS' ASSOCIATION, FROM 1860 TO 1885. SOUTH-EASTERN COUNTIES. k:ent. LEWISHAM, BLACKHEATH, AND CHARLTON. [Thk sections at Lewisham and Charlton have generally been visited on the same day, and may therefore be conveniently grouped together here. The first excursion to Charlton took place on August 13th, i860, and the report of its occurrence occupies four lines in the Proceedings (vol. i. p. 64). The first visit to Loampit Hill, Lewisham, was made in 1868, during the suspension of issue of the- Proceeding^, while excursions were made to Charlton in 1866 and 1869, of which no report ap- peared, The Loampit Hill sections were inspected on May 7th, 1870 (Proc, vol. ii., p. 33), and again on April 25th, 1874, particulars of which follow.] EXCURSION TO LEWISHAM.— April 25TH, 1874. Director — W. Whitaker, F.R.S. (Proc. Vol. \y. pp. 1 14-15.) On reaching Loampit Hill, where the Woolwich and Reading Series is well displayed, the Director gave a general description of the Series as exhibited in the Woolwich district and in the neigli- bourhood of Reading respectively, and pointed out the special features of the section. The details, taken frorn Whitaker " Geol. London Basin" (1872), p. 127 (Geol. London, 1889, ii., p. 154), arc as follows (Fig. i) : — EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. o H O W o London Clay. Brown • Clay, the lower part roughly- laminated, about IS feet on the north, increasing southwards with the dip (about 3"). Basement Bed. Flint pebbles, with clay and sometimes sand, thickening south- ward from, two inches to a foot or more, resting' evenly on the bed below. Woolwich Beds, about 50 Feet. Light-coloured sand, with partings of clay. At one place a little thin friable buff stone ^ jnst^atnop.' Near the~top a well-marked bed of loose, very light-coloured sand, about 4 inches thick, which makes more plain small faults (from 2 to 9 -inches down-throw) about 10 feet, passing down into Laminated Clay, with partings of sand, and with a little selenite. Near the middle many leaves occur. A little below the leaf-bed there is a 4 or 5-inch layer of small flint-pebbles (a), below this is a lignite-bed (b), 3 to 6 inches thick, some- times with a layer of iron pyrites con- taining casts of shells ; and at one part a sandy lignite at the bottom. Over 10 feet. Brown Sand, about 3 feet. Sandy Clay, about 2 feet. Clay Shell-bed (CyrenaJ, ij feet. Oyster-bed, 2 feet. Clay Shell-bed f CyrenaJ, a few flint pebbles at bottom, Ij feet. Yellowish Clay, with race and soft cal- careous matter, i foot 5 inches (less in parts). Pebble-bed, sandy; the pebbles irregularly arranged (not bedded). t False bedded m parts, red at the top part, over 12 feet. Bottom Bed. Light-coloured sand, with layers of flint pebble?, at the bottom part greenish sandy clay and clayey sand with a few pebbles ; 6 to 8 feet, resting on a worn surface of the next bed. Thanet Sand. i?.'.?-;;'*.-.J[;".V/i'f?.^K":^ 13- Thanet Sand, the uppermost 6 or 8 feet "/:*".~v.v;"*il2J^i yellowish and iron-stained, then 20 feet or more with a pale pinkish grey tint total thickness probably 40 feet. Gretn- coated flints at the bottom, resting regii- larly and conformably on .ti^^^^ss^^^-V- S£;^.«*<- *-a^^* £»«««:»•) ^•^.'•.y-w^ Chalk with Flints. CHARLTON. : ; 3 [Another section is here given, from St. John's, near Charlton, which further illustrates the positions of the deposits in this locality.] Fig, 2. — Section in Chalk Pit near St. John's. I. Upper Chalk. 2. Green-coated Flints. . 3. Thanet Sand. 4. Woolwich and Reading Series. $■ Gravel. EXCURSION TO CHARLTON. [The following is the earliest report of a visit to Charlton that gives any description of the Section.] April 2 6th, 1873. Director — Professor J. Morris, F.G.S.. • (Proc. Vol. iii. /. 205.) The well-known section at Charlton showing the junction of the English Secondaries and Tertiaries was first visited. Professor Morris, after pointing out to the large party assembled around him in the great chalk-pit, the general character of the Chalk and the Lower Eocene beds as they occur in the British Islands, described their foreign equivalents, and the beds which are probably intermediate in age between the Upper Chalk and the Thanet Sands of England. Though we find in our home section that the Thanet Sands appear to he conformably on the Chalk, it is more than probable that we have lost some hundreds of feet of Chalk, either by sub-aerial or marine erosion, or by decom- position after the deposition of the overlying sands. That some of the Chalk has been removed by decomposition is evident from the occurrence of the well-known bed of green-coated flints at the top of the Chalk, which bed must have been formed by the EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. ra.--.-..°A\f.y.°..y.. m quiet and slow removal of the Chalk in which the flints were originally em- bedded. The Thanet Sands and the Wool- wich and Reading Series are both of limited extent in England, the former formation extending only from Pegwell Bay to a httle to the west of London ; yet the Sables de Bracheux and the Argile plastique of the continent of Europe show us that the original exten- sion of these formations was by no means inconsiderable. [The section is taken from Whit- aker, Guide Geol. London (Geol. Survey), 1889, plate.] EXCURSION TO BLACKHEATH AND CHARLTON. July ist, 1876. Director — Professor J. Morris, F.G.S. (Proc, Vol. iv. p. 557.) Leaving Blackheath Station the party- walked across the Heath to the south- east corner of the plateau, and at the edge of one of the gravel-pits gathered round the Director, who explained the geology of the district. After pointing out the characters of the pebbles com- posing the so-called " Oldhaven Beds," on which they stood (Proc. Vol. iv. p. 498), Professor Morris stated that these great accumulations of shingle occupied a large area in Kent, forming the plateau of Fig. 3. — ^Section at Charlton. I. Oldhaven and Blackheath Beds. Flint Pebbles and Sand ; Fossils. 2. Sand and Clay, 3. Clays, somelimes sandy, with Estuarine Shells. 4. Clay, Loam and Sand. 5. Sands, part clayey, with Pebbles. 6. Thanet Sand ; green-coated Flints at bottom. 7. Upper Chalk. i Woolwich and [ Reading Series. CHARLTON, BLACKHEATH AND LEWISHAM. 5 Blackheath, Lessness Heath, and Plumstead Common, as well as the hills of Shirley, and much of the ground about Bromley and Chiselhurst. The great fault running east and west along the southern side of the Thames, where the ground begins to rise from the alluvial flats, throws down the Lower Eocene beds ; and the Chalk (above the river-level at Lewisham and Charlton) is more than 120 feet below the surface of the flat land by the river at the Naval College, Greenwich, and probably correspondingly deep below the marshy land of the northern side of this part of the Thames Valley. The escarpment parallel with the fault is capped for the most part by the Pebble-beds, and is indented by small ravines cut by the water issuing at the junction of these porous beds with the clayey Woolwich Beds below. [No additional details of the Charlton sections are given in any subsequent report, but some are referred to in Dr. Lavis's paper mentioned below.] CHARLTON, BLACKHEATH, AND LEWISHAM. April 30TH, 1881. Director — J. Logan Lobley, F.G.S. (Froc, Vol. vii. p. 142.) After visiting the great pit at Charlton to see the junction of the Chalk and Tertiary Beds, the party proceeded to the almost equally famous section at Hanging-Wood Hill, displaying the Woolwich shell-bed.s. The Upper and Lower Cyren,a beds are very well developed and shells, in good condition, may be obtained in abundance. The shells are Cyrena cuneiformis, C. depredita, and C. cordata. The shell-beds also yield amongst > other species the gasteropods Melania inquinata, and Cerithium funatum in considerable abundance, but the " Ostrea-bed " of the Ballast-pit section thins out at this place. Overlying the shell-beds we find the "Plant-bed," noticed by Dr. H. J. Johnstoti Lavis, in 1876 (Proc, vol. iv. p. 528) containing Dicotyledonous leaves and seed-vessels, but it is not nearly so well developed here as at Lewisham and at Bromley. On reaching Blackheath, the party assembled around the shaft sunk for the purpose of investigating the cause of the subsi- dences which had occasioned so much anxiety and interest amongst the inhabitants of the neighbourhood. The first of these subsidences occurred after an unusually heavy fall of rain on April i2th, 1878 ; but this attracted little attention compared with that caused by two others, which took place in November, 1880. EXCURSIONS OF THE GEOLOGISTS' ASSOCIATlbN. GREElfWI CH ABC: SidsuU^ttx^^.^ Almost circular openings in the Heath were formed, of a diameter of seven or eight feet, widening bell-shape fashion below, and having a depth of nearly twenty feet. Arrangements had been courteously made to afford every facility to the Geo- logists by Mr..H. W. Jackson, the Hon. Secretary of the Lewisham and Blackheath Scientific Association, who were trying to explore one of these sinkings." The probable causes of these subsi- * The great expense attending the exploration obliged the .Lewisham and Blackheath Scientific Association to leave off before any decisive results could be attained. A " Report of the Committee for the Exploration of the Subsidences on Blackheath " was published in 1881, drawn up by Mr. J. K. Laughton, M.A., Chairman. To the Report are appended some " Observa- CHARLTON, BLACKHEATH AND LEWISHAM, dences were discussed at the pit's mouth by H. W. Jackson, J. Logan Lobley, and T. V. Holmes. Messrs. Jackson and Lobley were inclined to think them due simply to hydro- geological influences, while Mr. Holmes thought these agents unable to produce these results unless aided by the existence of artificial cavities of the Denebole class ; as the impervious beds of the Wool- wich series would otherwise prevent water that had fallen on the surface of Blackheath from getting lower than the base of the Blackheath Pebble- Beds. tions by T. V. Holmes, F.G.S.," with a geological section across Greenwich and Blackheath, and diagrams to illustrate the way in which — granting the existence of an artificial chamber in the Chalk, with a narrow shaft leading to it — a hollow would naturally be formed th at the base of the Pebble Beds, ■ resulting sooner or later in a sub- ■" sidence. (See Figs, here repro- duced).— {8vo, Blackheath, 30 pp. ; see also Geol. Record, 1880-4,' i- P- 496). EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION, WESTGOMBE PARK, GREENWICH, AND LOAMPIT HILL. WESTCOMBE PARK, GREENWICH, AND LOAMPIT HILL, LEWISHAM.— April 7TH, 1883. Director— 1. V. Holmes, F.G.S. {Report by The Director). Froc, Vol. viii.,/. 112. [The sections at Westcombe Park are described in Proc, vol. viii., 1883, p. 59. The extension of the London and Green- wich Railway to Maze Hill and to Charlton caused the cutting up of Westcombe Park for building purposes. The Lower Tertiary escarpment almost coincides with the northern boundary of Westcombe Park, most of the surface of which consists of the Blackheath Pebble-Beds ; the roads then cut across the brow or along the strike of the Tertiary escarpment affording the sections seen. The letters A B and C on the plan^(Fig. 7) mark the position of the sections shown in Fig. 8. Perhaps it is better (1888) that all the strata above the shell-beds should be classed as Oldhaven or Blackheath. In 1883 it seemed prefer- able to group the sand with clayey partings with the Woolwich Series.] Fig. 7. — Plan of Westcombe Park. w. E. _S2_ 4*0 YAfin-i The two chalk-pits a few yards eastward of the station were first visited. The dip of the Chalk, as indicated by the layers of flint, is,, in this neighbourhood, slight in amount and southerly in ■lO EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. ^ direction, and the same remark applies to the dip of the overlying Lower Tertiary Beds. A little Thanet Sand, however, is seen overlying the Chalk in either pit. After leaving the chalk-pits Westcombe Park was entered from its eastern boundary, and its sections viewed in the order in which they are described in Proc, vol. viii., p. 59- Since their EiG. 8. — Sections in Westcombe Park. a a.'. c\ ou. TilaiMijeaith/ Beds. h.o,d/.e. WbolAvichjSeds. o.SheU/.£eds. Scale — 8 Feet to i Inch, examination by the Director in November, 1882, they had been cut further back and modified in various ways, the result showing the great variability as regards minute detail of the Woolwich ar^d Blackheath Beds. A word of caution may perhaps be useful Fig. 9. — Horizontal Section in Westcombe Park. Thames Vallje\ GrmieL ^■^■^^'^^^"^\^'^^^^^^^^jMM^i^^Bi'«^^<^J'^^Js^ Thanee/Sancb X / iijj^^;^^;^;^^^^^ on the way in which the Blackheath Pebble Beds mask the beds beneath them along the brow of the Lower Tertiary escarpment. WESTCOMBE PARK, GREENWICH AND LOAMPIT HILL. II The. pebbles roll down the hillside in vast numbers, and give the impression that it is entirely made up of pebble-beds, where no road or railway-cutting exists to show the true state of things. Thus in a guide-book to Greenwich and its neighbourhood, pub- lished in 1882, is a remark about "One Tree Hill" in Green- wich Park, to the effect that " owing to a peculiarity of its geo- logical formation it is composed principally of loose pebbles." One Tree Hill is simply a part of the westerly extension of the Westcombe Park escarpment. Leaving Westcombe Park by Foyle Road,, the party, after leaving Greenwich Park by the Blackheath gate, crossed the Heath, and descended the hill towards Lewisham. On reaching the immediate neighbourhood of the Loampit Hill sections, it became evident that great alterations were in progress there. Much building is going on close to the njost easterly pit, that in which the shell-beds of the Woolwich Series and strata immedi- ately below them are displayed. This pit is now enclosed, and used as. a store yard. But as it is, fortunately, nearly semi- circular in shape, a good view of the strata was obtained from the top of the pit. The oyster-bed, 2 feet thick, separating the two Cyrena-beds, was pointed out and contrasted with the mere trace of an oyster-bed at Westcombe Park. Below the shell-beds and that containing " race " and concretions, a thick pebble-bed was seen ; but, above the shell-beds, the thick pebble-beds of West- combe Park were represented at Loampit Hill by a pebble band of 2 to 3 inches at the base of the London Clay. Fortunately at Loampit Hill on this occasion a new and very clear section of the strata between the Woolwich shell-beds and the London Clay was exposed. They consist, as described by Whitaker (Geol. London,' i., 1889, pp. 149, 150), of laminated clay with partings of sand, and sand with partings of clay, having a total thickness of about 25 feet. [On July 7th, 1888, there was an excursion to Loampit Hill, Lewisham, and Westcombe Park, T. V. Holmes, F.G.S., Director , (Proc. Vol. X. p. 501).] EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. EXCURSION TO PLUMSTEAD AND CROSSNESS. July 5, 1873. Direaors—B.F.NRv Walker, F.G.S., W. Whitaker, F.R.S., and Frank E. Houghton. (Report by H. Walker.) {Proc. Vol. iii, /. 265.) On arriving at Abbey Wood the company proceeded across the marches, a distance of two miles, to the ground occupied by the MetropoHtan Main Drainage Works at Crossness, admission having been kindly granted by Mr. J. C. Bazalgette, C.B. By the direction of Mr. Houghton, the marsh had been opened for a depth of eight feet, and in this section the buried land surface was well seen as follows : — ■ Alluvial Deposit ..... 2 feet. Yellow Clay 3 » Blue Silty Clay 3 „ Peat bed, with stools of trees still rooted — The ^succeeding deposits are thus given by Whitaker (Geol. London, 1889, ii. 66), in the details of the Crossness Well-boring in the same marsh : — Peat with remains of trees . . . 6| feet. Dark Grey Silty Clay . . . . i-j „ Thin layers of Peat and Clay, with de- cayed wood full of phosphate of iron \\ „ Dark Grey Silty Clay . . . . 2| „ Silty Sand 2 „ Valley Drift and Oldhaven Beds (?) . 49 ,, Woolwich Beds — Among the stumps and trunks of trees (some of which were of considerable size), the oak and alder were recognised, a catkin of the latter being remarkably well preserved. Mr. Houghton exhibited some articles of furniture made from oak taken out of these marshes during the excavations for the Main Drainage Works. PLUMSTEAD AND CROSSNESS. 1 3 This forest-bed has a considerable range. From the bed of the river (in which the peat is found by soundings) the forest passes under the marshes of Kent on the one side, and Essex on the other, where it is concealed by the overlying alluvium, and is only revealed by excavations. The same forest was found under the alluvium in excavating the docks in and near the Isle of Dogs, and in excavations in Lambeth and Wandsworth Marshes. During the excavations in Plumstead Marshes for the Southern Outfall Sewer, in 1862-3, the forest-bed was well exposed. The Crossness Boring was then visited. [The details of this boring, as given in the report of this excursion, are necessarily incomplete, but may be seen in full in Whitaker's Gaol. London, ii., 1889, pp. 66, 67. As this is one of the deep borings ending in " red-rocks " of Old or New Red Sandstone age, it is thought that the vertical sections of these and other deep borings of S.E. England, given below, will be found useful to those who wish to see their general results at a glance. They are from a Presidential Address to the Essex Field Club, by T. V. Holmes, on " The Subterranean Geology of South-Eastern England " (Essex Naturalist, Vol. ii., Nos. 9 and 10, Sept. and Oct., 1888). The deep boring at Streatham has also ended in rocks of Old or New Red Sandstone age.] The next visit of the Association to Plumstead was paid in 1887 to the Lower Tertiary escarpment, not the marshes. The Director was J. G. Goodchild, F.G.S., and a report was printed m Proc, vol. x., No. 4, p. 191.] References. Maps. — Ordnance Survey. Geological, Quarter Sheets, i S. W. , I S.E. 3.?. each. NewOrdnance Survey. Sheets 270, 271. \s. each. Stanford's Geological Map of London. <,s. Books. — -W. Whitaker, " Geology of London and Part of the Thames Valley." 8vo. 'Z^«(f(?re (Geol. Survey), 2 vols. 1889. 115. [For literature.] W. Whitaker, " Guide to the Geology of London." 8vo. London (Geol. Survey). 5 Edit. 1889. \s. 14 EXCURSIONS OF THE GEOLOGISTS'" ASSOCIATION. Fig. io. — Deep Borings of S.E. England. (Thicknesses from H. B. Woodward's Geology of England and Wales.) By permission of the Essex Field Club. index to numbers, showing the relative ages of the various beds. 1. Alluvium ;~raade ground, etc. 2. Tertiary Beds. 3. Chalk. 4. Upper Greensand. 5. Gault. 6. Lower Greensand. 7. Purbeck Beds. ' 8. Portland Beds. 9. Kimeridge Clay. 10. Corallran Bfeds. 11. Oxford Clay. 12. Great Oolite. • ., 13. Lower Carboniferous Beds. 14. Devonian and Old Red Sandstone. 14a. Beds of doubtful age. Old Red 01 15. Upper Silurian Beds. New Red Sandstone. PLUMSTEAD AND CROSSNESS. IS- ?'a ^ •'- • ^•t^ " ■* ?i^ .''• rt rt f 1 i-H '"z: ■■Q O M '■' ■'o.'- -i3 ■>'- s EO ^ rt o o 13 a ^'^ rt a frf S^£ ^- 0) +j rt ;3 -r OJ -=H O o li, at/^O] s ;- rt j:: J< ■»-' C/i 'o m >> s .^ 1 s fL, ^ ■3 'S o be ^^ S ^ ^.s ^1 rt 3 g U) 05 ,;g & S a C o S 13 •5 3 'S •^ .s c« o J=~ a s 11 ^fs QJ c/j pa Q ERITH AND CRAYFORD. 19 00 Q Bi u 5 pq « o b . <; JS fe r K ^ > ffi G E-i M T3 C! Iz; hJ w F-! a s H >< tT n lU J4 a J ^ IS ^ c« s £5 i t^ 13 t3 V -4-1 w M 'E ex Di ilr'il i '«=> (U 3' J r^ rt ^ «r 3 K G J3 ^ ,i3 ""^ J2 — , _- t>. a . a> _ (u -ja 3 o !y -2 jeqa3PQ&HpLieQ. a 1» p. Rl ja 1 1 13 c EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. H S W 5 o H O c mmmifiifi/r-U The bottom of the pit is about two feet above the top of the Chalk, which underlies the whole, and is seen at one or two small wells. Wells of little depth in this area furnish water in abundance. The proximity of the Thames, and the slight difference of level between the bottom of the Ballast Pit and high- water mark, cause here an unlimited supply of water in the bed of Chalk immediately underlying the Bui'. Head bed, the whole of the Chalk below being filled to saturation. As may be expected, the water falls and rises in these wells with the ebb and flow of the tide in the adjacent river. The sides of the pit reach a height of sixty or seventy feet, and are (1872) formed almost exclusively of the , Thanet Sands, the only ex- ception being a small capping of the Woolwich and Reading Series at one place, that at which the side of the pit is highest. Leaving the Ballast Pit the hill on the south was ascended, and ex- posures inspected of the Woolwich and Reading Series and of the Old- haven Beds, which latter consist in this place of a great accumulation of pebbles. The extensive excavation known as White's Pit was next visited. At this place an interesting section of the old river-bank is capped by a Oldhaven and Blackheath Beds Sand and Clay. Clays, sometimes sandy, with estuarine Shells. I Woolwich and Crimson-mottled sandy Clay. j Ro!./i:n™ c— Sand, partly clayey, with Flint Pebbles. J Thanet Sand, with green-coated Flints at base. Upper Chalk. ' Flint Pebbles and Sand ; Fossils. Reading Series. ERITH AND CRAYFORD. 21 great deposit of Pleistocene sands and brick-earth. The Thanet Sands, which, at the Ballast Pit, about half a mile distant, are sixty feet thick, are here only fifteen ; they rest on the Chalk, and form the summit of what was a steep river-bank. OS Id ■X) « -i < The Pleistocene deposits yield Corbicula [Cyrena] fluminalis^ Valvata fiscinalis, Pisidium amnicum, Bythinia tentaculata, &c., and from them have also been derived remains of several 2 2 EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. species of Mammalia, including, according to Boyd Dawkins, Bos primigenius, Canis lupus, Elephas antiquus, E. primigenius, Equus fossilis (= caballus), and Eelis spelcea. Leaving White's Pit the great excavation at Crayford was reached. The sections exposed here are very varied, and display some remarkable features of the ancient Chalk river-banks, which have been preserved from destruction or even injury by the enveloping Pleistocene deposits. The fauna is, as might be expected, similar to that of the Erith Pit, but the remains of Mammalia found at Crayford give us a list of species much longer than those from Erith. Fig. 20.— Section in Crayford Pit. [Reprinted, by permission of the Council, from the Quart, ^cmrn. Geol. Soc, vol. XXV.] C. Brick-earih. B. Thanet Sand. A. Chalk. Fig. 21.— Section at Stoneham's Pit, Crayford. [Reprinted from the Quart. Journ. Geol. Soc, vol. xxiii.] ■ 8. Surface-soil, from I to 2 feet. ;;. Irregular bed of reddish Sand, with Flints and Quartz Pebbles, 4 feet. — 6. Fine stratified Sands, 8 feet. — 5. Loamy, chocolate-coloured Brick-earth, 5 feet. — 4. Gravel, from I inch to 2 feet. 3. Sandy grey and reddish Brick-earth, 2 feet 6 inches. ■- 2. Irregular layer of Pebbles, from I to 2 feet. gj^4 — ' I. Red and grey loam, 10 feet. -■■ Thanet Sand. , -Chalk. ERITH AND CRAVFORD. 23 FIG 22.-SECTION OF PART OF THE "CoRBICULA" BED, CrAYFORD [Reprinted, by permission of the Council, from Quart. Journ.Geol Soc.,^o\. xxv. J .. Laminated Brick-earth, Gravel, and Loam, 25 feet, passing into Coriic.la i Pe^bble; from Woolwich Series, Brick-earth and Clay, 6 feet. 't Slaminaffirick-earth, 6 feet. .. Sands. 4 feet. FIG. 23.-N0N-MARINE M0..USCA -O- --,.l:n°rrd.] (With the exception of 6), extinct in Britain. L^eni oy ^^ 1. ' ~^" '• \ Unio littoiraliSjErith. 5. Pisidium astartoides. Crayford. 6. Pisidium amnicum. „ 7 Helia fruticum. Ilford 3' I Corbicula fluminalis. Crayford. g' Hydrobia marginata. N.E. London .4- ( 24 EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. Fig. 24. — Section in Crayford Pit. [Reprinted, by permission of the Council, from Quart. Jaurn, Geol. vol. XXV.] Soc, « ^ffi^H^K^^^^""^ Length of Section, 150 feet ; Height 30! feet. To show variation in the Pebble Beds C. F. Covering b?d [Trail ?] (without Shells). D. P'alse-bedded Sand cor6ku/a-hed, from 4 to 5 feet. B, C, and E. Beds with Shells. A. [Not defined.] [Excursions to £rM and Crayford were made on June 26th, 1875 (J. Logan Lobley again acting as Director), and on April 6th, 1879, under the leadership of Prof. J. Morris. The reports of both are extremely brief, and contain nothino- new. They may be found in Proc. Geol. Assoc, vol. iv., p. 323, and vol. vi., p. 174. On June 13th, 1885, the Erith and Crayford pits were again visited, F. C. J. Spurrell directing. A full report of this excursion is given in Proc, vol. ix., pp. 213-16, by F. C. J. Spurrell and J. G. Goodchild, with a section of a cliff near Crayford (Fig. 25), and references to writers on the formations seen in this neighbourhood. The latest visit of the ERITH AND CRAYFORD. 25 Association to Crayford was on May 3rd, 1890, the Directors being F. C. J. Spurrell and E. T. Newton. On Saturday, May 17th, 1890, there was an excursion to Swanscombe under the direction of F. C. J. Spurrell. The party alighted at Northfleet and returned from Greenhithe. Near Crayford, but a little higher up the the valley of the Cray, is Bexley. The most important sections visible in this neighbourhood are those seen during descents of the deneholes, which abound in Jorden's Wood.] -l,*>> — Tj^'-Si Fig. 25. — Section of Cliff near Crayford. e physical and topographical features immediately west- ward were first explained, Keston, Knockholt Beeches, and the long dry valley of the upper Cray being notable objects in the c 34 EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. view. Skid Hill itself (capped with gravel) is but a portion of the interesting outlier of Thanet Sands and Woolwich Clay which at ^Vell Hill— a mile further along the same elevation — has a still larger capping of gravel, of great age and singular interest. At length the higher ground, more than 600 feet above Ordnance Datum, was reached, and the Well-Hill gravel sections confronted the visitors. Here, above the Thanet Sands and the Woolwich Beds, were large rolled flints, highly fossil- iferous, in a reddish, unstratified sandy matrix. A closer search discovered fragments of chert and ragstone. These Prof. Prest- wich referred to the Lower Greensand beds at the Sevenoaks Range, some six miles further south, and sedarated from Well Hill by the deep and broad vale of Holmesdale. The Well Hill gravel, according to Prestwich, is a solitary patch of marine gravel, of Glacial age, which once stretched over Kent, and is altogether an unique geological monument in the county. Before leaving the spot the following orchids were gathered on the damp parts of the heath about Well Hill — Orchis maculata, Habenaria bifolia, and Listera ovaia, and close at hand under the trees Ophrys muscifera. The following objects, to which Prof. Prestwich called attention on the arrival at Shoreham may also be mentioned : — Some notable sand-pipes in the Chalk, by the side of the high road to Sevenoaks, between the eighteenth and nineteenth milestones ; a very fossiliferous bed of Chalk with Inoceramus, near the first shaft at the north entrance to Halstead Tunnel ; and a dry upper valley of the Chalk (south branch of the Timberden valley) with six feet thickness or more of flints, the water standing at a level below the valley fully 100 feet deeper than it once stood. Lastly, the visitors viewed from the hill near Darent Holme, the trumpet- mouthed valley of the Darent, opening out into the Weald, but draining in the opposite direction into the Thames. References. Maps. — Ordnance Survey. Geological — Sheet 6. 8j. 6d. New Ordnance Survey — Sheet 271, is. Book. — Whitaker, Geol. London. 1889. 2 vols. ixs. [The five excursions which follow were arranged for the purpose of enabling the members of the Association to make themselves acquainted with the Physiography and the Geology of the country between the London Tertiary Basin and the summit of the Weald.] ORPINGTON AND KNOCKHOLT. 35 EXCURSION TO ORPINGTON AND KNOCKHOLT. Saturday, May ioth, 1879. (First of the Weald Series). Director — J. Logan Lobley, F.G.S. {Report by — W. Fawcett, B.Sc.) {Proc. Vol. vi. /. 189). At Orpington, on the edge of the London Tertiary Basin, just outside the station, Mr. Lobley pointed out an exposure of Thanet Sands, the lowest member of the English Tertiaries, and, at a little distance, a good section of the Chalk, the uppermost of the English Secondaries. The presence of Chalk is clearly indicated by the altered character of the country from this point to Knockholt. The bottoms of the Chalk valleys are here covered by ten or twelve feet of gravel and "wash of Pleistocene age, seen on this occasion in an excavation for new wells for the Kent Water Company close to the railway bridge. The road now runs along the bottom of the valley which is but a continuation inland of that of the Cray, but streamiess from the absorbent character of the Chalk. Arriving at Green Street Green, a fine section of Valley Gravels was pointed out, showing an increased thickness of this deposit, fully twenty feet being here exposed. After passing through the village, the ascent of the Downs was commenced; and the party speedily reached higher ground commanding a view over a large area. Mr. Lobley remarked that, instead of the ordinary appearance of sheep-walks in a Chalk country, we here meet with woods and cultivated fields. This is due to the presence of superficial deposits of clays and gravels, the remains of the Tertiary beds once covering the Chalk. After passing High Elms, the road led over the upland towards Cudham. On the right is a beautiful example of a Chalk valley, with its steeply sloping sides and streamiess bottom. From Cudham the Downs were crossed, by Lutt's Green, to Knockholt village. From Knockholt Beeches, 783 feet, there is a most extensive vjew. Looking towards London, the Crystal Palace was visible on the high ground of the London Clay ; to the south-east, the range of Lower Greensand hills on which Seven- oaks is built ; and, further on, the hills of Hastings Sands. c 2 36 EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. EXCURSION TO KNOCKHOLT AND SEVENOAKS. Saturday, May 24TH, 1879. (Second of the Weald Series). Director — J. Logan Lobley, F.G.S. {Report by — W. Fawoett, B.Sc.) {Proc. Vol. y'\. p. 194). Starting from Halstead Station, the route lay through Halstead Place Park, by Knockholt Beeches, through Chevening Park, Chevening, Chipstead, Riverhead, and Sevenoaks. At Halstead Mr. Lobley showed how much more complete had been the: denudation than about Cudham ; here there is but little soil, or valley gravel. The Chalk has bands of flints, characterising it as Upper Chalk. From Knockholt Beeches there is an easy descent through the woods of Chevening Park, down the Chalk escarpment. At Chipstead Tile- yard. Pleistocene Brick-earths are seen over- lying the Gault clay. They are both worked and often mixed. Here in the Gault are found Ammonites interruptus, A. auritus, A. lautus, Belemnites minimus, and Inoceramus concentricus ; but Am. splendens was not seen, though it is a characteristic fossil of the Gault elsewhere. From the blue Gault clay are made red bricks and dark tiles. The redness is due to the peroxidation of the iron of the clay by the burning, and the dark colour is produced by the oxide of manganese being mixed with the clay. Iron com- pounds are plentiful in the Upper and Lower Greensand and Gault, chiefly in the form of sulphuret or iron-pyrites, but not in the Chalk. From the tile-yard the way lay across the bottom of the valley, and over the infant Darent to Chipstead village, where the Lower Greensand, which forms the hilly and beautiful ground to the south, begins to rise and form the southern side of the valley. In half-a-mile the village of Riverhead is reached. At Riverhead the Folkestone Beds of the Lower Greensand (of a foxy-brown colour) are exposed ; but they are better seen in the quarry at the Bat and Ball Station, Sevenoaks. In this latter place the sand is loose, the grains only being cemented together here and there in thin irregular layers of ferruginous sandstone. These layers at first sight give the appearance of false bedding, but Mr. Lobley was of opinion that they were not due to that cause. He pointed out the " Box-stones," large irregular ferruginous SEVENOAKS AND TONBRIDGE. 37 concretions, or rather shells with loose light-coloured sand in the middle, many of them being of very considerable size. They are very dark in colour, and so hard that they are used for road-metal. [On June ist, 1889, some gravels at and vi&zx Ighthani -vext. visited, Prof. Prestwich and W. Topley being directors. See Proc, vol. xi., p. Ixvi. ; and Prestwich, Quart. Journ. Geol. Soc, vol. xlv. (1889), p. 270.] EXCURSION TO SEVENOAKS AND TONBRIDGE.— Saturday, June 14TH, 1879.* (Third of the Weald Series). Director — J. Logan Lobley, F.G.S. (^Report by W. Fawcett, B.Sc.) (Proc. Vol. vi. /. 202). Members left the train at Dunton Green to inspect the excava- tions in the extensive Brick-yards of Mr. W. J. Hooker, who courteously gave every facility for the observation of the sections and the collection of fossils. These excavations well show the Gault ; it extends E. and W. for many miles along the base of the escarpment of the North Downs, forming the beautiful Vale of Westerham. Both the Gault and the Pleistocene Brick-earths which cover the Gault in places along the valley, afford here materials for bricks and tiles. After crossing the alluvium of the Darent Valley, and the stream itself, the Folkestone Beds of the Lower Greensand were found exposed in a field near Riverhead, through which village the party then proceeded to the Tub's Hill (Sevenoaks) Station. Between the station and the tunnel there is a fine section, about 90ft. high, showing the Hythe Beds of the Lower Greensand, and yielding abundance of Gryphcea sinuata. F. Drew, in Topley, (Geology of the Weald, p. 116), gives the following description of the beds on the coast of Kent : — " The Hythe beds are interstratifi- * Sevenoaks was also visited by the Association in 1864. and 1866. In Proc. vol. i., p. 390, about a dozen lines are given by Caleb Evans to the details of the excursion of 1864, followed by a paper on the Geology of the district The excursion was especially undertaken to inspect the Geology of the extensive rai Iway- works carried on by the South-Eastern Railway at that time, and the paper may be consulted with advantage. The excursion of l866 took place while no Proceedings were published. 38 EXCURSIONS OF THE GEOLOGISTS* ASSOCIATION. cations in about equal proportions of limestone and sand. The former is close in texture, has a grayish blue colour, and contains fine grains of quartz ; the latter is for the most part drab-coloured, impure, rather clayey, and somewhat calcareous ; the stone goes by the name of ' rag,' while the intermediate sandy beds are called ' hassock.' " At Sevenoaks the distinction is not so great ; the hassock is harder, is in a larger proportion than the rag, and both are used for building. The Sandgate Beds, intermediate between the Folkestone and Hythe Beds, are here wanting, whereas at Folkestone all three are developed. A good example of a fault, and a remarkable anticlinal, were noted near the entrance to the tunnel. The Folkestone Beds cover the Hythe Beds, and form the high ground on which the town of Sevenoaks stands. The junction was seen as the party ascended from the railway cutting and made their way to Sevenoaks. A brief visit was paid to Knole Park, in which the beautiful country formed by the Lower Greensand of Kent is well shown. Proceeding along the road to River Hill, on the escarpment of the Lower Greensand, a fine view over the second of the great east and west valleys was obtained. At the bottom of the hill is the Atherfield Clay, then the broad expanse of Weald Clay, with the Medway meandering through it. The road through Hildenborough was taken, and after a brisk walk across the Weald Clay vale, rich with hop-gardens and orchards, Tonbridge was reached, standing close to the Alluvium of the Medway. EXCURSION TO TONBRIDGE AND TUNBRIDGE Wells. — Saturday, June zSth, 1879. (Fourth of the Weald Series.) Director — J. Logan Lobley, F.G.S. {Report by W. Fawcett, B.Sc.) (Proc. Vol. vi. /. 204.) The members of the Association met at Tonbridge to inspect the country from Tonbridge to Tunbridge Wells. Tonbridge Station is on the Tunbridge Wells Sand ; and at the Hastings Road is first seen the Wadhurst Clay, which extends to Quarry HiU. The Ashdown Sand at Quarry Hill, thrown up by a fault, is interesting, as it is the lowest member of the Wealden group. A short distance after passing Mabledon Lodge TONBRIDGE AND TUNBRIDGE WELLS. 39 we again come upon the Wadhurst Clay, succeeded at the Pens- hurst Road by the Tunbridge Wells Sand, which extends beyond Tunbridge Wells, with outliers here and there of the Weald Clay. At one of those points on the road from which a view may be had of the valley of the Medway, Prof. Morris spoke of the origin of the Medway Gravels. These gravels occur at various heights above the present bed of the river, up to as high as 300 feet. It is remarkable that in no part of the Weald are gravels found at any great distance from the margins of streams ; and hence it is inferred that they have been laid down by rivers actually running in the same courses as at present. The gravels along the upper stream of the Medway consist only of Wealden pebbles ; but, on the banks of the Eden, the western tributary of the Medway, they also contain flints and flint pebbles from Tertiary Beds. The Eden joins the Medway at Penshurst ; from that point, onwards, the gravels combine the characters of the Upper Medway Gravels and the Eden Gravels, until the Medway has passed well ©ut of the Weald country, and then the Wealden pebbles disappear. Again, the gravels of the Beult and Teise, the eastern tributaries, joining the Medway at Yalding, are composed of Wealden pebbles. Now when it is seen that the Upper Medway, the Beult, and Teise, and their feeders, drain Hastings Beds, and that the Eden runs down from the Chalk escarpment, it appears difficult to explain the composition of the gravels on any other hypothesis than that adopted by the Geological Survey, that the gravels were formed by rivers running in the same courses, and (contrary to the theory of S. V. Wood, junr.*) in the same direction as at present. One difficulty at first sight is that the Wealden pebbles disappear in gravels near the mouth of the Medway ; but this is explained if the debris of the Wealden Beds, either entirely disappear almost as soon as formed, as in the case of the calcareous " Rag,'' or are of a character so soft in comparison with flints and Tertiary pebbles, that they soon wear down from pebbles into sand. There appears, then, to he proof that rivers have excavated valleys to the depth of at least 300 feet. It is impossible to say how much more river-erosion had taken place before these highest gravels were deposited ; but, if it was as much as 300 feet, that amount would account for the whole of the subsequent denudation of the original plain of marine denudation- — that is to say, all the present features of the * Quart. Journ. Geol. Soc, vol. xxvii,, 1871, pp. 3-2/. 40 EXCURSIONS OF THE, GEOLOGISTS ASSOCIATION. country, the hills and valleys, are due to the action of rain and rivers only. Certainly there is no evidence of any other agency ; there are no raised beaches, the result of marine denudation, no drifts left by tidal erosion, and no moraines left by glaciers. After a visit to Pennington Lane, which affords a grand view over the Medway valley and some of the richh -wooded lateral vaJleys, the party proceeded towards Tunbridge Wells. On the way, Mr. Lobley pointed out an outlier of the Weald Clay at Mrs. Newnham's brickfields. Arriving by Mount Ephrajm on the famous and beautiful Common, the higher valleys of the district were seen, and the summit of the Weald, Crowborough Beacon, at length bounded the view. The Tunbridge Wells Sand is conspicuously displayed in the picturesque " rocks " which stud the higher parts of the Common near Mount Ephraim. The sand is so well compacted that soft sandstone is the result, and, where it is harder than elsewhere, greater resistance to weathering has given outstanding masses, some most grotesque in form and appearance. Permission was kindly, given to visit the charming grounds of the Spa Hydropathic Establishment, which fronts Bishop's Down at the ea.stern extremity of the Common. In the grounds may be .seen a good specimen of the beautiful litlle valleys which abound in the neighbourhood, and which, with the fine timber adorning both hills and valleys, render this district so attractive. A little further to the east the Tunbridge Wells Sand is again characteristically seen on Rusthall Common, where the rocks are still more striking than at Mount Ephraim. One of these masses has received the name of the Toad Rock, from its resemblance to that animal, and others, too, are known by distinct names. They, are fine examples of rocks of various degrees of hardness, acted upon by atmospheric agencies. Leaving Rusthall Common the Wadhurst Clay was seen, occupying the bottom of the Happy Valley, and the well-known High Rocks again showed Tunbridge AVells Sand, here thrown up by a fault. After inspecting these huge masses of soft sand- stone, with their remarkable clefts, members made their way by the narrow valley along which runs one of the feeders of the Medway, the boundary between Kent and Sussex, to Tunbridge Wells Station, for the return to London. TUNBRIDGE WELLS AND CROWBOROUGH BEACON. 4 1 EXCURSION TO TUNBRIDGE WELLS AND CROWBOROUGH BEACON.* Monday, July i2TH, 1879. (Fifth of the Weald Series.) Director — J. Logan Lobley, F.G.S. (Report by W. Fawcett, B.Sc.) Proc. Vol. y\. J>. 230. On alighting at Tunbridge Wells the members proceeded to the Parade, the Pump Room, and, after crossing the boundary of Kent and Sussex, to Broadwater Down. Here, with almost the whole of Tunbridge Wells in view, Mr. Lobley pointed out that the town was built at the junction of two valleys. The higher ground is Tunbridge Wells Sand, with outlying patches on Rust- hall Common and elsewhere of Weald Clay, while in the valleys Wadhurst Clay occurs. The Marquis of Abergavenny had invited Mr. I.obley to conduct the members through Eridge Park to the Castle, and had kindly instructed Mr. Rush, of Eridge, to accompany the party, and point out everything of interest in the magnificent domain, one of the oldest enclosed parks in the kingdom. At Eridge Castle two iron cannon balls were exhibited, the first made in England. Prof. Morris referred their manufacture to the year 1543, when the first cannon of English make was produced at the then famous Sussex furnaces. A hundred years later, during the Civil War, many of the furnaces >vqre destroyed, and from that time the gradual extinction of the old forest of the Weald, and the conse- quent loss of fuel, led to the decline and ultimate cessation, in the beginning of the present century, of the Wealden iron-furnaces. But the loss has only been a local and a temporary one. Some three or four of the ironmastei-s of Sussex, finding fuel growing scarce in their own country, established themselves in Wales, and were the first promoters of the iron-trade of Merthyr Tydvil and Aberdare. From the lawn in front of the Castle there is a good view of the well-wooded Wadhurst Clay Valley, which forms a large portion of the grand old park. The Eridge Rocks in another i \ — ; ' * As this excursion is the last pf .the " Weald " series, it is here included among^ Kentis'i excursions, though itself mainly in Sussex. Tunbridge Wells is on the Kentish s-ide of the border. • 42 EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. portion of the park were examined, and compared in many points with the Toad and High Rocks. The position of the Bridge Rocks, inasmuch as they are in a sheltered position, seems to, militate against a theory of Sir A. Ramsay, who endeavoured to account for the peculiar undercutting by pointing out the enormous force with which the wind files away at the base of the rocks by means of the sand — a natural emery powder. A dis- cussion arose with regard to the origin of the hemispherical markings. Mr. Lobley suggested that they were structural, and compared them with the " box-stones " of the Sevenoaks Quar- ries. Professor Morris pointed out that they followed the lines of false bedding. This false bedding proves the existence of varying currents in the great riVer which laid down the Tunbridge Wells Sand as part of its delta. Attention was called to a very " clean " cleft. It is remarkable that these "clefts" run parallel in a direction nearly N.W. and S.E. The party left Bridge and followed the road to Uckfield. Gradually ascending, they soon found themselves on ground commanding most extensive views, as well over the cultivated region as over the wild expanse of Ashdown Forest, stretching away to the west. Still ascending, Crowborough was at length reached, and standing on the summit Mr. Lobley reminded the members that they had now arrived at the anticlinal axis of the Weald, from which the beds dipped north and south ;, that they had traversed first the lorig northern slope of the Chalk ridge of the North Downs, had then descended its steep escarpment on the southern side, crossed the Gault vale, and, at Sevenoaks, the Lower Greensand ridge, and then the Weald Clay valley of the Medway, followed by the Tunbridge Wells Sand ridge and the Wadhurst Clay vale, from which they had ascended the great swelling mass of Ashdown Sands, on which they now stood. The parallel ridge and valley character of the country had been well seen ; the long slopes and the escarpments, the varying character and appearance of the country, and the change of vegetation following the change of formation had been noted. Professor Morris remarked on the absence generally of gravel beds in the Wealden area, and said that where these did occur they went to prove that the direction of the rivers had Always been the same, though S. V. Wood, jun., maintained that the contrary was the case in the north, from the existence of trumpet-shaped gorges in the North Downs. He showed that if the Chalk had covered the Beacon, we should have to account for the denudation ,of "^ V3 O g TUNBRIDGE WELLS AND CROWBOROUGH BEACON. .^ •UODBSg qSnoJOqMOJQ I 43 t Clay. Sand. Beds. 15 O U 1 < ■siFAv ; ^■s^ « 33puqunj_ V K^ b 1 «:<£ a o 5 - ' -^ D / o 4J \ 9 c. c o o rt '— ' c +j^ fc o Tj 'p cl ^ «XI o o uy *_] S %: v^ oi J2 ?■§ 'c/5 - bocOo tn St ^ ^ 1^ 44 EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. some 3,000 feet, but it was quite possible that Crowborough Beacon forined a bank in the Cretacepus sea.* References. Maps. — Ordnance Survey. Geological, Sheet 6. &s. 6d. New Ordnance Survey. Sheets 287 and 303. is. Books. — W. Topley, The Geology of the Weald, etc. 8vo. London (Geol. Survey), 1875. 2is. W. Whitaker, The Geology of London, etc. 8vo. London (Geol. Survey), 2 vols. 1889. lu. SHEPPEY. \Sheppey was first visited by the Association in 1861. (Proc, vol. i. p. 166.) The next excursion there took place in 1868, while the publication of Proceedings was suspended. The third excur- sion, on June 7th, 1875, is reported at some length (Proc, vol. iv. p. 320.) A fourth visit was made on May 23rd, 1881, and a short account of it appears in Proc, vol. vii. p. 149. Sheppey was also the scene of another excursion in 1887, a record of which appears in the excursion, or November, number for that year. The following account is derived from the reports of the visits in 1875 ^"^ 1881.] EXCURSION TO THE ISLE OF SHEPPEY. June 7TH, 1875. Directors — W. Carruthers, F.R.S. ; Major F. Duncan, R.A., and W. H. Shrubsole, F.G.S. {Proc. Vol. iv. /. 320.) On arriving at Queensborough, the members were met by Major Duncan and Mr. Shrubsole. Carriages were taken in the direction of Warden Point, at the extreme eastern end of Sheppey. The lower road, through Eastchurch, was chosen, and after a pleasant drive over a country at first somewhat unattractive and bare, but afterwards pretty and well timbered, with fertile vales and swelling elevations, affording glimpses of the sea to the north, the vehicles arrived at Warden Court, where, through the kindness" of Mr. C. * Sheet 77 of the Horizontal Sections of the Geological Survey, from Newhaven to the North Downs two miles S.E. of Farningham, in Kent, crosses Crowborough Beacon and Knole Park. ISLE OF ^HEPPEY. 45 Payne, Major Duncan was enabled to give his guests a hospitable welcome. A large collection of the fossils so abundant in Sheppey, pyritized palm-fruits (Nipadites), stems, chelonian and fish remains, together with coprolites and crystals of selenite, exhibited by Messrs. Boughey, Hall, and Atkins, of Sheppey, invited the attention of the party before the road was taken to the cliffs. On the brink of the cliff stand the ruins of a little church, that, not very long ago, was considered to*ciccupy a secure position, but which now, so rapid is the destruction of the land by the sea^ and so near is the church to the edge of the cliff, it cannot be long before the whole structure is destroyed. [See next report.] Close to the ruins, and with a commanding view of the crumbling masses of London Clay forming the seaward face of Sheppey, the visitors assembled to listen to the President'si account of the Flora of the London Clay of Sheppey. {See Proc, vol. iv. p. 318.) Following Mr. Carruthers, Mr. W. H. Shrubsole, who has been resident in the island for twenty years, informed the visitors that the stems, as well as the fruits of plants, were often found. Landslips here were frequent, and were sometimes extensive, as much as five acres of land having given way at one time. There was a terrace, or lower cliff, which formed, as it were, a buttress to the upper, and, while this endured, the upper cliff remained ; but when this support was destroyed by the waves, the upper cliff gave way, and so another undercliff was formed. The rapidity of the destruction of the cliffs is such, that no less than 800 tons of iron-pyrites, derived from the clay washed away by the sea, had been shipped in three months. Septaria are also numerous, and these calcareous masses being washed out like the pyrites, were collected on the beach,, and used for the manufacture of cement. A path along the edge of the cliff led to the course of a stream, by means of which the shore was gained, and the mem- bers were enabled to examine the rugged face of the clay, which was well searched for fossil fruits. These, however, did not ' present themselves in great numbers, but specimens of pyrites, frequently encrusting portions of stems, were very common. Some chelonian remains were also fo\ind. The London Clay of Sheppey has been estimated by Prest- wich to have a maximum thickness of about 480 feet, and is similar in lithological character to the formation in the London Basin generally. Its dissimilarity palaeontologiciUy is, however, very remarkable. The extraordinary number of plant remains 46 EXCURSIONS OF THE GEOLOGISTS' ASSOCIATION. which it contains has been dilated upon by Carruthers, and affords ground for concluding that near here a river emptied itself into the London Clay sea. This evidence of the proximity of land is in accordance with the fact tiiat in the Sheppey area remains of turtles * are found in abundance, while they are wanting in the London Clay of Middlesex and of Surrey. Again following the path on the top of the cliff, the site of a Roman pottery-kiln was reached. Mr. George Dowker con- sidered it to have been a " smoulder-kiln," in which clay vessels were placed with charcoal, and the fire sustained by a current of air passing through a channel dug in the earth. At Hensbrook a second descent to the shore was made, and the face of the cliff was then observed for a long distance to the west. Mr. Carruthers described and explained the plants met with, one of which, the Orchis mascula, was in full flower, growing luxuriantly in a sheltered spot, and so afforded an illustration of the peculiarity of its reproductive organs. Sheppey is mainly, though not altogether, composed of London Clay, for, in a few places, as at- Minster, East Church, and at East End, a capping of sands has been observed, and these sands have been mapped by the Survey as the Lower Bag- shot Sands, which, in other localities, overlie the London Clay. Perhaps the best exposure of these arenaceous beds in the island is the cliff-section near the end of East-End Lane, where they are seen overlying the London Clay, and have a thickness of about twenty-five feet. EXCURSION TO SHEPPEY.— Monday, May 23RT), 1881. Director — W. H. Shrubsole, F.G.S. (Proc. Vol. vii. /. 149.) The members were met at Sheerness station by the Director. After a pleasant drive of about nine miles, via Minster and Eastchurch, the cliff edge at Warden Point was reached. Six years before, when the Association visited this spot [see preced- ing report], the church was standing in dangerous proximity to the cliff. Since then it has been pulled down, and the materials have been removed to prevent them descending to the shore. The Director, in the course of a short address, spoke of the extensive waste of land that had occurred during the thirty years he had known the locality. He also called attention to the * Woodward and Sherborn, Cat;il. Brit. Foss. Vert,, 1890. SHKPPEY. 47 fact that whilst the fruits of endogens were very abundant, the fossil wood that came from the clay was exogenous. The absence of the endogenous wood might be accounted for by its incoherent fibrous structure, which probably caused it to float until dicom- position took place. Getting down to the foot of the cliffy fossils were eagerly looked for amongst the shingle, pyrites, and fragrrients of septaria scattered on the beach and foreshore. Wood bored by Teredo was observed to be in abundance, and shark's teeth, crabs, and fruits were found. The best specimen was a fairly good chelonian. After a rough and slippery walk of five miles, the cliff-top was regained near East End Lane, where a good section of the Lower Bagshot Sand was examined ; the junction with the London Clay below was found to be quite sharp and well-defined. Here, also, the changes that had taken place between the two visits of the Association pointed to the conclusion that the land-area of Sheppey had, even in these six years, been con-, siderably lessened. o -f c o k: ^ (u o a* p B t