EXCURSION TO MARLOW. 155

which is met with in wells all over the Isle of Thanet. This risesfrom the shore under Kingsgate Castle.

Passing Joss Stairs, as the next gap is called, we recom­menced collecting. Fossils were not so abundant as in the zoneabove, but we soon found a representative fauna. Micrastercor-anguinum, Parasmilia centralis, Echinoconus conicus, Echino­corys vulgaris (the ovate form, well contrasting with those foundearlier in the day) the characteristic head and columnars ofBourgueticrinus, many spines of Cidaris, Terebratula semiglobosa,and Rhynchonella reedensis.

At four o'clock the signal to return was given. When themembers had assembled at the top of the cliff at Joss Stairs, thePresident tendered the thanks of the Association to Mr. Whitakerand Dr. Rowe for their assistance as Directors, and the cordialityof his remarks was accentuated by the applause of those present.The Directors having responded, the party walked back along thecliff to Margate, a pleasant walk of about four miles. Theweather throughout the day was all that could be desired. Afterdinner at the Hereward the 7.35 train was taken for London.

REFERENCES.

Geological Map, Sheet 3, Drift Edition, Price 8s. 6d.6-inch Ordnance Map, Sheets 25, 26, 37, 38, Price IS. each.RECORD OF EXCURSIONS, pp. 59, 61.1872. WHITAKER, W.-Mem. Geol. Survey, vol. iv, PP' 35, 93-96, 169-171.1887. WOODWARD, H. B.-" Geology of England and Wales," p. 429 et se~.,

and the references there given.1900. ROWE, A. VV·.-" Zones of the White Chalk," Part i, Kent and

Sussex. Proc, Geol. Assoc., vol. xvi, p. 289.

EXCURSION TO MARLOW.

SATURDAY JULY 1ST, 1905,

Directors: Ll. TREACHER, F.G.S., and H. J. OSBORNE WHITE,

F.G.S.

Excursion Secretary: THOS. W. READER, F.G.S.

(Report by THE DIRECTORS.)

ON their arrival at Cookham Station, about 3 o'clock, theparty proceeded to the large gravel pit at Cookham Rise,in which Palseolithic implements have been found in con­siderable numbers for many years past. This gravel belongs to

EXCURSIOK TO MARLOW.

a terrace reaching southward to beyond Maidenhead, at anaverage level of 75ft. abo ve the Thames. On this occasion thepit was not being worked, and only a few flakes and brokenimplements were found, but on the return journey in the eveningsome fairly good specimens were obtained from a workman whomet the train at Cookham Station. From Cookharn Rise thefield-path was followed over the bill to the large chalk quarry onCookbam Dean common. In this pit, which is about 70 ft.deep, small nodular flints occur in regular layers, many of thembeing cavernous and containing " meal " rich in small fossils. Insome places near the bottom the flints are so close together as toform intermittent tabular layers. The chalk itself was found tobe rather poor in fossils, the most abundant being spines ofCidaris clavigera. The Directors considered that, from theposition of the pit, the floor being at least 100 feet abovethe level of the outcrop of the Chalk Rock a short dis­tance to the north, and also from the character of the fossils,the chalk here belonged to the lower part of the zone of Micrastercor-angainum, The following is a list of fossils obtained by theDirectors from this pit, chiefly from the lowest J 0 feet :-

Inoceramus sp, (fragments).Pecten cretosus, Defr.Plicatula sigillina, S. P. Wdw.Kingena lima, Defr.R h.J'1/chondla sp.Berenicea (several species).Clausa francqana, d'Orb.Clinopora lima/a, Beissel.Diastopora sp.Entalophora echinata, Reuss.Entalophora virgu/a, Hag.Pelalopora costata, d'Orb.Spiropora verticil/ata, Goldf.Stomatopora granuiata, Edw.Truncatula sp.Eschara sp.Membranipora 1tIoniliftra,

d'Orb.Membranijora ovalis, d'Orb,

Vincularia sp.Serlmla grm/ulata, Sow..SerjJula ilium, Sow.Serpula turbin el/a, Sow.Cidaris c!avigera, Kcenig.Cidaris perornata, Forbes.Cidaris sceptrifira, Mant.Cidaris serrifera, Forbes.Galerites alboga/erus, Leske.Micraster (fragments) .Asteroid ossicles.Bourgueticritzus dlptfeus,

Miller.Pentaerinus.Parasmiiia centralis, Mant.Porosp/usra globularis, Ph il.Porosphcera patelliformis,

Hinde.Doryderma ramosum, Mant.

The road and footpath were then taken across the QuarryWood ridge, from the top of which fine views were obtained ofthe Thames Valley and the Buckinghamshire hills, and the posi­tion of the now overgrown chalk quarry, which had given itsname to the locality, was pointed out close to the right bank ofthe river. In former times much chalk was quarried here for

EXCURSION TO MARLOW. ]57

building-stone and for lime-burning, the material being exportedby water.

Near the foot of the slope on the northern side of the ridgethe Directors had recently discovered a small exposure of ChalkRock in a road cutting. The characteristic featur es of thisstratum-hard cream-coloured rock with green-coated nodul es­were noted, and a few fossils collected. The following havebeen obtained by the Directors:

Ammonites (Paehydisclls) per­amplus, Mant.

Seaphites Geinitzi, d'Orb,Pieurotamaria p erspectiva,

Mant.Turbo gemmatus, Sow.Troehus beroesdrensts, WoodsCardium sp.Inoceramus sp.

Nucula sp.Rhynehone//a p /ieati/is, Sow.Terebratula semigl()bosa, Sow.Terebratula carnea, Sow.Serpula sp.Mieraster eor-bovis, Forbes.*Mieraster sp.Parasmilia centralis, Mant,

Crossing the river by Marlow Bridge and passing through thetown, the party continued their walk up Oxford Lane, where arecent widening of the roadway at the first bend has exposed agood section, some ten feet in depth, of rath er coarse flint andquartzite gravel, with a loamy matri x and seams of chalky matter,belonging to an obscure river-terrace about ] 00 ft. above theThames. A little farther up the lane older cuttings show a moreclayey drift , containing angular flints and chalk rubble, andpossessing a rude stratification obviously due to the creep andwash of the material down the slope in which th is part of the roadis sunk.

At a point nearly opposite the entrance to the Waterworks, thetopmost layer of the Chalk Ro ck, with its characteristic green­coated nodules and a few fossils, app ears in a small excavationjust above the level of the road and about 100 feet higher thanthe similar section ment ioned above in Quarry Wood, a mile anda-half to the south-east.

Having examined these sections the memb ers ent ered theWaterworks quarry, the floor of which in part coincides with thetop of the Chalk Ro ck. The face of the pit shows about 60 ft.of chalk; white, with frequent bands of nodular and tabular flintin the upper two-thirds; greyish, lumpy, and containin g smallscattered flints and a few tabular seams in the lower third. Oneconspicuous band of tabular flint occurs about ]0 ft, up andforms a useful datum line.

The beds in this section have been assigned both to the lower]

• A small form. com mon. but see n only in sect ion .t ..Geology of London," Mlm. Clot. Survey. vol. I, p. 76.

EXC UR SION TO MARLOW.

and to the upper" portions of the zone of AIicraster cor­testudin arimn, but actually belong partly to that zon e and partlyto the zone below.

Owing to the comparative scarcity of di stin ctive organicremains, and to the fact that the higher parts of the section aregenerally inaccessible, the exact position of the junction of theH olaster planus-and M. cor-testudin nrium-zcnes has not yet beendetermined. A fa ir num ber of fossils are obtain ed by the quarry­men, but a rath er close sea rch is necessary for the detection of th eall-important Aficraster and its associate guide fossils, ill sitti,The specimen s of M. p necursor so far forth comin g from the baseof the section are all of the H. planus-zon e types, with sutured,or feebly-inflated-areas and tho se found a littl e higher up, butstill below the tabular band ab ove referred to, have moderately,to distinctly, inflated areas. From I to 3 ft . ab ove th e tabularflint band a few tests with areas of the strongly inflat ed type havebeen found by th e Directors, while from the higher beds thequarry-men have obtained examples with the subdivided a mbul acraand other essential features of the M. cor-testudinariton -rotv: typ es,including the name fossil. The gibbous form of Echinocory sscutatus is very common in the H. planus beds, and H olasterplacC1lta scarcely less so, but .H. p lanus itself has not beenobs erved. The following is a list of fossils either found by theDirecto rs themselves or ob tained from the workm en who collectunder their instru ction s. All of them come from the lower two­thirds of th e sect ion, th e upp er third not having been workedfor many years.

Lamna sp.Ptychodus latissimus, Ag.Inoceramus sp. (v.c.),Spondylus sp inosus, Sow (v.e.).Crania egnabergensis , Retz.Terebratula semigiooosa, Sow

(v.c.) .Terebratula atrnea, Sow.Terebratulina striata, Wahl ,Berenicea sp.Proboscina sp.Stomatopora granulata, Edw.Meticeritites Lonsdaiei, Greg .

Membranipora (Hippothoa)elegans, d'Orb.

Enoploclytia L eachi, Mant,Serpula cineta, Goldf (c).Serpula sp. (?)E chinocorys scutatus, Leske.Infulaster excentricus, Rose

(v.c.).Micraster cor-testudiuariu m,

Goldf.Micraster prrecursor, Rowe (c).Holaster placenta, Ag, (c).Cidaris sceptrifera, Mant.

The lower beds contain also many sponges, chiefly in theform of ferruginous casts.

When the members had satisfied thems elves as to theH. planus-age of the lowest beds here, and had awarded a vote

• " Cretaceous Rocks of Britain," litem. Gcol. SUrlJ~'y, vol. iii, p, 2 11.

EXCURSION TO MARLOW. 159

of thanks to the Directors on the proposition of Mr. E. T.Newton, F.R.S., they returned to Marlow for tea, and left by the7.30 train.

REFERENCES.

Geological Survey Map, Sheet 7 (Old Series).Ordnance Survey Map (r inch) (New Series), Sheet 225.r864. WHITAKER, W.-" Geology of Parts of Middlesex," etc. Mem. Ceol.

Sun'ey, pp. 7 and 82.r889. WHITAKER, W.-" Geology of London." Mem. Ceol. Survey, vol. i,

pp. 76 and 390.r897. TREACHER, LL.-" Excursion to Cookham." Proc, Geot. Assoc.,

vol. xv, p. ror.r904. JUKES-BROWNE, A. J.-" Cretacous Rocks of Britain." Mem. Ceol.

Survey, vol. iii, p. 217, 221-222.