' l()t)t) Iti4 ,()N^ UIAN A. Upper Kimmeridgian stratigraphy of Aylesbury, Buckinghamshire forest litter as these wcre the dominant spore- (Westphalian D) of lllinois accords with the producers,at least, of the coal-forming flora (Sctltt, postulated drier, more open country dominatcd by 1979).More than this one cannot say as the ?.(-.till, pteridosperms(l{ichardson, 1956). Michael J. Oales material provides little information on facies The possible palaeodictyopteransare rare and rclationships. poorly preserved(one in sublithologyA and one in OATES, M. J. l[1. Uppcr Kirnmcridgian stratigraphyof Aylcsbury, Buckinghamshire,Proc. ln general,arthropods are lar lessfrequently found B): this accords with their probably having been Geol- Ass., f02(3f l8-s-99. Ficld work carricd out in Aylcsbury in 1987demonstrated that the The associatcclwith pteridospermsor pteridophytes.When washedin to the lake from outsidethe lycopod forest. Uppcr Kimmeridgc Clay attains 3l m thickncssand has a minor non-sequcnceat its.base. gradual thinning southwcstwards,from the relatively thick thcy are associated,there is also ntuch lycopod debris, Non-marine bivalves were fountl predominantly in sequcn"e fits wclfwith ihc trend of of thc wash arca to thc thin scqucncedcpositcd Qver thc oxford shallows. Thc suggcstingdeposition at the forest margin or ntixing of sublithology A/C intermediatescontaining no plant development wcll dcvclopcd sands within thc Pcctiniltus Zonc of thc oxford to swindon areil Arc minimallytransported material from beyond debris. These fine-grainedsediments were probably littcr and rcprescntcdat Aylcsbury only by silty distal intcrcalations in in othcrwisc clay sequence.All a lake (Eager, forthcoming) some thc forcst (cl. Gastaldo, 1987). deposited in the Upper KimmcrirJgiarr anrnronitc-bascdzoDcs' cxccPt thc youngest' were recognlscd' Protorthopterans,whilst commonly associatedwith distance from shore. The Conchostracaoccur irt a two highcst Lowcr Kimnrcridgian zonc.s.but their boundarics could not togethöi with the 'I'he sublithology A and lycopods, have a higher variety of sublithologiesbut are commonest in A, aliays be fixed on anrmonitc cvirlcnce alonc. ammonitc fauna diffcrs from that hitherto percentageoccurrence in sublithology B than other associatedwith abundantlycopod debris, and C which recoided from thc Dorsct succcssiorronly by thc prcscncc of Aulacosteplvmu autissiodorensis determinatearthropods. These sediments,from their lacksplants. They seemedto have lived in a range of (Cotteau) of typicat contioental type, above its coarscr ribbcd cvolutc British variant. Species thc trace-fossils and paucity of plant remains are aquatic habitats which in comparison with extant öt Grauesiq iitp. *ere recordcd from thc uppermost Autissiodorensis Zonc and in the uppcr Kimmcridge Clay, o[ which consideredto representshallow lake deposits(Pollard forms were probably of a temporary nature (Tasch, Elegans-scituluizoncs. Five members arc rccogniscd I{olman.s Bridgc Shale, Watermcad Clay and Elmhurst Silt, arc formally dcscribcd & Ilardy, 1991).The low number of Blattodea and 1964).The presenceof comntinutedexamples suggests thrö, herein. other arthropods in this sublithology suggeststhat that a degree of post-mortem transport, or perhaps predaticln,cannot be excluded. some, if not all, the protorthopterans present had Trefoil Couage, Station Road, Padbury, Buckingham, MKlS2Bl different ecologicalpreferences and may have lived lycopod forest. Their chiefly outside the leg ACKNOWLEDGT,MENT morphologysuggested to Bolton (1921)that they were 1. INTRODUCTION (SP823138anrJ822137) (Oates, 1974).A total Upper ground-feeders,possibly at the margins of the coal I would like to thank Ed Jarzcmlrowskifor his great Kirnnreridgian thickncss of about 3l nr was thus 'l'he swamp. diversity and abundanceof protorthop- help and encouragcnrcntin studyingtltc ntatcrialin A general understanding()f the stratiS,raphyof the dctluced(l'ig. 2). terans over blattodeansin the Mazon Creek fauna his care. English KinrmeridgeClay Formation has been greatly Stratigraphicallydiagnostic ammonites were abun- advanced in the last two decades (e.g. Birkelund' dant and, although generally compacted, were of 1983; sufüciently good preservation to allow comparison References Callomon,Clausen, Nohr llansen & Salinas, 1971; Cope, 1967, 1978; Cox' with those collected from other well documented 'Ihe Callomon & Cope, BEALL, U. S. 1991. Writhlington phalangiotarbids: 507- I l. Lott, Thomas & Wilkinson, 1987; Cox & Gallois, sections,particularly Dorset, where Copc (196711978) thcir pafaeobiologicalsignificance. Proc. Geol. Ass. lO2, - 1989. Writhlington Ceological Naturc Rcscrvc. Proc. Gallois& Cox, 1976). establishedthe modern zonal scheme for the Uppcr -68. 1979,1981; t6l Geol. Ass., 100. 219-34. llowever, apart from thc Dorset coastal sections Kimmeridsian. tsOLTON, tl. l92l-22. A monographof thc fossil inscctsof NOR'fH, F. J. l9ll. Insect-lifc in thc coal forcsts, with the'pit dt Westbury, Wiltshire (Fig l)' this The exävation attracted a degree of local interest, the British Coal Measures. Palaeontogr. Soc. (Monogr.), speciaf reference to South Wales. Trons. Cardiff Not. Soc., and boreholcs; large particularly following the discovery of large marine vi +156pp., l0pls. 62,16-44. literature is based mainly on cored 'l'racc remains(e.g. BucksHerakl, 16July 1987).The CARPENIER, F. M. 19{t0. Studics on North American POLLARD, J. E. & P. G. FIARDY. 1991. Fossils temporary exposures in the Kirnmeridge Clay are reptile known ranges and Carbonifcrous insects. 6. Upper Carhoniferous insccls from thc Westphalian D of Writhlingt()n Gcological therefore of considerablcinterest and can potentially site also provided additions to of from Pcnnsylvania.Psyche, Cumb.,87, 107-19. Nature Reserve,near Radstock, Avon. Proc. Geol. Ass., add much to our local knowledgeof thc sequence. transientsof the ammonite fauna from the mid-part CIIALONER, W. G. & M. E. COLLINSON. 1975.An tOz,169-78. Such a temporary exposure was available through- the Kimmeridge Clay Formation, including the only illustratcd kcy to thc c()mrnoner British Uppcr Car- RICHARDSON, E. S. Jr. 1956.Pennsylvanian invcrtcbrates out the sunrmcrof l9tJ7,on the nortlrern outskirts of positiverecord of the AutissiodorensisZonc fronl thc (ieol. lxrnifcrouspliln( conrprcssionfossils. Proc. Ass., 86, of the Mazon Creek area, Illinois. liclliana: Geol., 124' Aylesbury, in an are:r where the stratiSraphyof the line of discontinuous Kimmeridge Cilay outcrop l-44. 3-56. Kimmeridge Clay was notoriously little-known. betweenDorset and the Wash, and scveral recordsof FlSllllR, l). ('. l97ft. Evidcncc for sutracrial activity of SCO'IT, A. C. 1977. A review of the ccology of Uppcr on this sito (SP ti20l55), up to 5 m deep, the rather rare amnronite genus Graucsia. A largc Eupr
I tr5 HIGHSTREET Ml( l l^lil, J. ()A l l:s sP 823r38 I irt I f::.:ri:n tot I t'.'.'.'.'.1 liffiupperLydireBed T ll l$l:-'.:l I l l lEI -i--l | ffi ll>l El+-:_:--] I '-'.t=rArsrrroc@ussondvERrrcaL ll lpl--.I-l I scalE' ; '"1'J" *o.ror'rsrREEr lEArs,,toc@6si,t- l=l'l| | I l::-::Jl;-=J |i l- Avl€sburv I ol --lI I l:;,+=i I sP82rr34 [r | | luL::-=-:J I f------l croY I o,,";b>' l-1..1: ffi I .-==- LlProstrc l. I l-l G l=:i=:l poilosioideszonel-:--:_-:- 1 le | | l
l,l.lEEEEl wreorrejensisr:i : ll lg'l I E€l : ll'l+äl f -[ t== HARTWELL I I Fäl Eresons-sciiuluszl-]f\ : ------F'.r- + ET-n aurissiodoFnsisZ.-! i \.--.-.--.--.-..-----..-.--.-.-..--.--_- lül,l| I il \ I I Itrldl I | ; rl setionreporr.dinI I l=1..,1 l | : ll srlesurveyr&ords l>löl I EudoirusZ.I r' \ (b) l'lEl I | \ ('. 'l'emporary Fig. l. (a) Kimmcridge Clay outcrop in Soutlr€fn England, highlighting localities cited in thc text (b) l:lEl| \ll 'i KinrnrcritlgcClay cxposurcsin thc Aylesbury area. läl:l I \ll - ' l'lhl I li :i |lil I ll llllr.ir Fig. 2. Corrclation of thc thrcc tcnrlxlrary scctions uscd to compilc a cornplctc UJrpcr Kinttllcridgc ('lry scqucncc llr Aylcsbury Lithostratigraphyatrd atrtmottitczoncs arc indicatcd. I utl Ml( llAlir. .r. ()A'ilis -:-=---:-l (pors) Tenrporary excavationsfrlr the M40 motorway l0 km Stewkley, the Kinrnrcridge Clay is ovcrsteppctl by the -:_-:- -:{ ELMHURSTSILT MBR. east 0f oxford near watcrstock (sP 62uu9- Aptian Lower Crcensand. No signilicant cxposurc lras a ,: SP625{)47)(Cox, llorton & Sunrbler,1990) in early existed recently between this point and Ely, f (P. pectinatus -(Cl: :--:-:1p. ) aff. o P. (V. ) grandis 1990 pnrvided the details necessary to complete Cambridgeshire. ;rdcquately the correlation with former sections at The publication of the results of'IJCS borcholcs at o c Whcatlcy(Arkell, 1947). Brill (SP65701412) and llartwcll (sl'79761221) c (*EMBER (l) Although having no formal lithostratigraphicstatus, (resumds of which appear in Galkris & Worss;rrn, 'l-ower 'Upper the terms Kimmeridge CIay' and 1983; tsritish Geological Survey, l9tltl; and (irx & P. (V. ) c-lave-lJi trans. (lirla ()ur I 1 q, Kinrmeridge Clay' have been historically used for Sunrbler, l9tt9) will add uscful l)()ints t() smednorens is convenience (Upper Kimmeridge Clay equating to knowledge of the Kinrmcridge ('lay irr lluckirrghlrrr- o post AutissiodorensisZone sedimentsor beds atrove shire, proving the naturc and thickrrcss of thc Lowcr (L l o :/ I Bed 35 of Cox & Gallois, 1979). This boundary Kinrmeridge Clay, and dcnrorlslrating thc latcral ) cornutifer coincideswith the base of the Upper Kimmeridgian variation, of the Uppcr Kinrrncrirlgc ('lay. c) +=F Substagesensu anglico. 3 3. Lt't'ilos't RA't't(;RAPilY lr,, = 2. KIMMERIDGE CLAY RECORDS TN THE Five distinct lithostrirtigr:rphic:rlurrils ;rrc rccogrrirctl ,n., donovani o c Ce 6 3 AREA in the Uppcr Kirnnrcritlgc ('l;ry irr tlris ;rrc:r. I hcy ;uc lr. P. (V, ) decorosus (fronr abovc): o 6 about here The nearest comparablesections to that exposed at P. (v.) donovani -llxrtwcll Sill Mcrrrbcr .; Watermead were at Rid's ltill Brickpit (SP664l5l), P. (A. -Swindon (llay Ca 6 ) hudLestoni Brill (abandonedin l9l1) and the Wheatley Brickpit Mcnrbcr U' -E,lmhurst (rrcw (SP589054)at Littleworth, near Oxford. Rid's tlill pit Sil( Mcnrhcr rrrnrc; lyl)c scc{i()n: I Walk)n Slrcct, Aylcsbur y) was worked mainly for the Lower Kimmeridge Clay, o q -Watcrntc:ttl ( (rrcw o and no more than 2.5 m (8 feet) of Upper liry Mcnrlrcr rurrnc;tyl)c scclion: (v. ) donovani c y) Kimmeridge Clay, reportedly of the Wheatleyensis Watcrrncad, Aylcsbrrr q) q26 c' P. (V.) el.egans -l lolntirn's Ilr itlgc Sh;rlc Murrlrcr ( ncw n;rntc; tyl)c ol G. gigas Zone, was exposed(Arkell, 1947). (The Elegansarrd o & c. irius Scituluszones were not establishedat this time.) A section:Walcrnrcirrl. Ayk'slrrrry) about here ( l".l -Gi- revisedaccount of the stratigraphy of Rid's Hill has The [,owcr Kirrrrrrcrirlgc lirv rr rrol sulxlrvidcd ltcrc. subdichotomoceras No Kinrnrcrirlgc ('liry lrr llrc :rrc;r is pcnrrirrrcrrtly been publishedrecently (Cox & Sumbter, l9tl9). Beds !, LOWERKIMMERIDGE CLAY " . grgas apparentlyspanning the interval recorded at Water- exposcd, but tlrc n('w rrrcnrlrcrsslroulrl be availrrlrlc in .2 a-" tcmlx)rary sccliorrr lrorrr t[[c to tinre. mefres o , autissiodotensis mead were formerly exposedat Wheatley, and also at f 'l'hc ( Chawley,north of Abingdonand Radley(e.g. Arkell, lull tl1tlx'r Krrnrrrcrrtlgc l;ry srrcccssiorr, c contllilcd frorrr lhc Wirtcrnrc;rtl cxc:rv;rliolts, tlrc I q, 6 auti ssi odorens is ßaT Gig. 4). A late 19th century plrotograph of b 6l British transient) Chawley Brickpit by a Mr. C. J. Bayzand is Walton Strcct holer irrrrl thc prcviorrsly dcscribcd Ilartwcll ( liry rcttrons. rs illrrrtr:rtctlirr l;ig. 2, irnd the o reproducedby Bond, Gosling & Rhodes (l9tt0, p. 23) 'I'he 6v\ utneria rebhoTzi and a sketchof the sameincluded by Pringle (1926,p. Watcrtncrrrl sc(lron r\ rlt.pretctl ilr lrig. 3. E 98). Motorway excavationsin 1989/1990at Waterst- successiortis tlcstrrlrt'rl lrt'low irr ;rsccrrtlingonlcr. 6\spidoceras sp. (V. ) woodward,i 'utneria ock, eastof Oxford, allowed some further detail to bc 6 Ce .: 6 I rebhoLzi (s) ( o -t added to the general description of the Kimmeridgc l,owor Kinrnrcrklgr. ley (It.7 rlrrr, hirsc not seen) o ( r')\ er'l Clay successionaround Oxford. A section from thc 'l'hc ( hasc ol thc Krtnrrrt'rrrlgc l:ry Iirrnrirtion wirs not .: old recordsof Wheatleyamended by recent lickj work cxposcrl :rt Wrrlcrrtrr':rtl llt.rtt.irtlttllc l()wcst otrscrvctl o 6\ by the authorand Il. P. Powcll(University Muscurn, llctls, crtitr':rlot ()l)(t;rlots rr'lxrrtcrl I hrown cl;ry Oxford) is includedin Fig. 4. c, WheofleyNodule Bed Cru u Am. (Nannocardioceras ) sI 'I' member is evidently absent, having been cut out 4m and 5 m above the baseof the unit. phosphatised Pleuromya, Hiatella and Pectinatites along outcrop to Thame and Brill, beyond which it beneathor laterally replacedby silts of the succeeding Comparison with the standard Upper Kimmeridge pectinatus was obtained. These are also known to may be cut out by pre-Portlandian erosion for a short unit, which overlicsdircctly on to presumedHolman's Clay beds of Cox & Gallois (1979) suggeststhat the occur at outcrop locally, where they have been distance, or may pass into the Wheatley Sand. To the Bridge Shale (seeFig. 4). basal Watermead (Dr. M. northeast, the member can only be traced until it 'l-hc Clay Member correlateswith base ascribedto the Lower Lydite Bed B. .Cox, following distinctivehorizons were recorded: Iled 43 in the lludlestoni Zone. This would be 1988, pers. comm.). A bed of silty clay some 0.5m disappears below unconformable Cretaceous strata in ---0.4m above the base of the member: conspicuous acceptableonly if it can be demonstrated that the thick, containing the same fauna in identical the neighbourhood of Stewkley and Wing, some layer of oblate sphaeroidal septarian doggers, range of P. (V.) woodwardi extends higher than the preservation, was well exposed at Waterstock, 12km distant. 'Shotover normally sorne0.4 m diametcr, with predominantly first appearance of P. (V.) reisifurmis (an ammonite immediatelyoverlying the Grit Sands'.The The ,Upper Lydite Bed (0.5 m) which was exposed honey-brown calcite infill. The doggers contained not recorded from Aylesbury) (Fig. a). absenceof an obvious Lydite Bed at this horizon in in the weathered zone at the top of the Hartwell Silt abundant, partially crushed P. (V.) woodwardi most Walton Street borehole recordssuggests that the sections described previously (Oates, 1974) is not Ncaverson (Fig. 7c). The same species, partially (iii) Elmhurst SiltMember (4.5 m) characteristicremani6 lithology is only developed in always seen. Although reportedly containing rolled, crushed and semi-pyritized with white powdery At Watermead,this Member was only seento 0.5m, pockets in what must otherwise be a significant phosphatized Paulouia rotunda (Casey, 1967) this bed aragoniticshells, occurred in clay at the same level, in the weathered zone. It was however. fullv omissionsurface, or more probably that it was simply probably belongq to the Albani Zone, forming the and also just above, and in a distinct brown- penetrated in Walton Street where the upwarä not noticed in the site survey. The base of the Lower base of the Portlandian strata in the area (Casey, weatheringhorizon 0.1m below. The horizon with passagefrom clay into a very silty clay which marks its Lydite Bed is taken as the base of the Swindon Clay 1967). The Rotunda Zone fauna was derived from 'Wheatley septariacorresponds to the Nodule Bed'; base, was well documented in site boreholes and Member. clays now unrepresented in the area apart from the ammonites compare closely with specimens auguredpiles. Fossils,though compressed,included many arago- remani6 nodulesand fragments. figuredfrom this horizon hy Neaverson(1925, Plate The unit comprises a dark grey, stiff argillaceous nitic examples with fiery iridescence when freshly IIl, figs. l, 3 and 4), and museum collectionsof silt. A I m thick more laminated and bituminous excavated. tsadly damaged perisphinctid ammonite materialfrom Wheatley. It hasalso been possibleto layer, some 3 m above its base, containeda restricted frilgments were'recovered from near the base of the 4. NOIES ON THE AMMOAIITE FAUNA correlate these septaria with an horizon of much bivalve fauna mainly of Isocyprina. member at the Walton Street site, and well preserved By analogy with Where possible, ammonite occurrencesare indicated reduced nodules at Waterstock. This nodule bed fossiliferoussandy Pectinatus examples of Paulouia pallasioides have been re- Zone to the southwest on the graphic sectionof the Watermead site (Fig. 3). was not specifically noted in old records of the around Oxford the member is assigned to the coveredfrom the basal2 m at Waterstock. Wheatleyand Chawleysections (e.g. Arkell, PectinatusZone. The transition of this nrcrntrer up into the 1947), This is supported by the record of (a) Amoeb varying up to 0.5m diameter. They most closely by the record of Borehole CSU 71165(Gallois & Cox, resembfe specimcns of A. caletanwn figured by 1974,p.2tt). I-Iantzpergue(1987). The ammonite aptychi known as Laeuaptychusoriginated fr Fig.7. Ammonitcs from Walton Strcct (Fig.7a) and Watcrnrcad(l'igs. Ttrrg). All spccimcnsare in the collectionsI BuckinghamshireCounty Muscunr, Aylcsbury (llCM) $\ Peäinatites (Virgutosphinctoi.lcs)tlorroruni Copc; IICM 1991.1.9;about 3m above base of Watermead Clay [=l8r Fig.6. Amrnonitcs fronr Watcrnread. All spccimcns are in thc collcctions of the Buckinghamshire County Museum, below ground lcvcll; Hudlcstoni Zonc; x0.6. Aylesbury (BCM). (t:) Peitinatires(Pectiruttitcs) cornutilü (Bucknrrrn); llCM l99l.t.l0; 4.(rm above base Watermead Clay; Pectinatus Zon (a) Pectinatile.s(Virguo.rphinctoidcs) clauelli Copc trlns. smerlmorercß Copc; BCM 1991.t.5; ex llolmans Bridge Shale; x 1.0. WheatleyensisZone , xll.28. (c\ Pectinutites(Virgansphirctoidcs) wtxxlwurtli (Ncavcrson); IIC-M 1991.1.11; Wheatley Nodule Bed, near base , (b) Subdichotomocerw websteri Copc; BCM 1991.1.6; top surface of Lower Kimrncridge Clay; Autissiodorensis Zone; Watermcad Clay; Whcatlcycnsis Z)trc; x0.6. (-opc; xO.3' x0.28. (l) PectinatitcsiArketlitas) hudlestnni BCM 199| . L l2; 3.5 rn above bascof Watermead Clay; Hudlestoni Tnne; (c) Pectinatites(Virgatosphinctoides) elegans Copc; llCM 1991.1.7;cx basal2m of Holmans Bridge Shale Iin associationwith (c, Pccti4dtit(s(Virgakrsphinckridas) wheatleyensit dtlicatulus (Ncavcrson) with small trochid gastropods adhering lo she Grauesiairiw, Fig. 5bl; x0.38. Il('M 199| . | . l3; 5 tn rlrovc thc hilsc of I hlntans llridgc Shalc; WhcätlcycnsisZorrci x0.67 m. (rl) Aulacostephanus autlssiodorercir (Cotteau); IICM I99l.l.tl; 0.1-5nr bckrw top of Lowcr Kinrnrcridgc Clay; (t) I,cctinuritas(Virgottfphincnidcs) ltutnt,tus (irpc I ll(]M l99l . L l4; cx I lolmans Bridgc Shalc; Scitulus Zonc; x0.87. AutissiodorensisZore, xrJ.4. igl Ptcti,rutitcs(Virgonisphinctoit!$, whcutl(yusis Ncavcrson; IICM l99l.l.l5; doggcrs,2.lm abovc basc of tlolma Ilridgc Shalc;Whcatlcycnsis Znlc; x().(). uPl,trR KlMMlilalI)('IAN olr AYl-ttsuultY' llucKs 199 I(ll Mt(lt^l:I- J. ()AIIiS - & B. M. COX. 1974. Stratigraphy of the Upper l. r-52. 5. REGIONAL SETTING tered Kimrneridge Clay with septaria beneath Lower M. J. 1974. The stratigraphy and palaeoecology of Kimmcridge Clay of thc Wash arca. Bull. Geol' Suru' Gt' OATES, Greensand (Whitaker, 1982), which implics erosion Hartwell Clay (Upper Kimmeridgian) of Aylcsbury, Kimmeridge Clay thicknesses Br., $' l-28. thc Conrparisonof Uppcr down to at least the I'ludlestoni Zone,whereasin the Proc- Geol. /ss.' 85' 367-75. - & - 19?6. T'hc stratigraPhy o[ thc Lower Buckinghamshirc. bctwcen Chawlcy, Oxfordshire (Arkell, 1947), and (SP912f03), Lower Greensand of J. 1922-23. Manuscript notg in his copy of Tring-l Borehole KimmcritJge Clay of eastern England. Proc. Yorks' Ceol' PRINGLE, thc Wash area (Gallois & Cox, 1974),demonstrates a Woodward 1895. (Copies tn Coun,y Mßeum, Aylesbury Aptian age rests directly upon a fossiliferousUpper Soc.,41, 13-26. gradual thickening ENE along the strike of the LibrarY, KeYworth,) Oxfordian (Corallian) limestone. In the Little - & B. C. WORSSAM. l9li3. Stratigraphyof thc llarucll and B.G..S. Kimmcridge Clay outcrop (Fig. a). This is close to - Geology of the Country around Oxford, 2nd ed., Missenden Borehole (SP916007; Strahan, 1916) Borcholes. Inst. Geol. Sci. Rep , FLPU 83-14. 1926. parallel with the original shoreline of the Ment. Geol. Suru., Gt Br. being Sherlock (1922) reported Gault Clay (presumed HARKER, S. D., S. H. GUST'AV & L. A. RILEY. 1987. H. 1913. Certain Upper Jurassic Strata of northern flank of the London-Brabant Massif in Late Oxford Clay (Callovian- Triassic to Ccnomanian striltigraphy of thc Witch Cround SALFELD, Albian age) over tbe (J. Jl. geol. Soc. Lond.,69,42l-3O. Jurassictime (assumingthat the massif was still a Graben. /n (Brooks, J. & K. W. Glennie; cds) Petoleum Engfand. Oxfordiao). R. L. 1922. The Geology of the Country subaerial feature). The higher proportion of sand Geology of North Wes Europc. 809-114. SHERLOCK, Aylesbury and Hemel Hempstead. Mem. Geol. (particularly in the Pectinatus Zone) and non- HANTPERGUE, P. 19tt7.Lcs ammonites Kimmöridgiennes around du Häut Fond d'Europc occidcntale (Perisphinctidae, Suru., Gt. Br- sequencesin the thinner sections (on the palaeoge- On a Deep Boring at Little 'Oxford ACKNOWLEDGEMENTS Aulacostephanidae, Aspidoccratidac). Unpubl. Docteur STRAIIAN, A. 1916. ographical feature called the Shallows') also Sum. Prog- Geol. Sum', des SciencesNaturelles. Univcrsitd dc I'oiticrs. Missenden,in Buckinghamshite. suggestdeposition in nearshore shallow water, where Access to both development sites readily given by 1915. - & G. LAFAURIE. l9tt3.Lc Kinrrncridgicnqucrcynois: for proximity to a sandy clastic source of sediment and Royco (Watermead) and Equitable Life Assurance W. 1892. Some Hertfordshire Well-Sections un complcmcnlbiostratigraphiquc du Jurassiqucsupcricur WHITAKER, would have their Society (Walton Street). Personnel from contractors (second paper). Traß. Herts. Hßt. Soc. & Field Club,6' sensitivityto small sea-levelchanges d'Aouitaine. Ceobios, 16' 601-ll. T. Taylor Contracting Ltd., and Peter Felton of Ove 53-64. greatesteffect upon the stratigraphicsequence. LORIOL, P. DE, & G. CO'I-I'EAU. l9tl6. Monographic t{. B. 1895. The JurassicRocks of Brilain, Sand developmentin the Kimmeridge Clay at the Arup & Partners assisted by reporting and collecting Paleontologiquc et gcologiquc rJc I'Ctagc Portlandicn du WOODWARD, Vol. 5. The Middlc and Upper Oolitic Rocks of England PectinatusZone level also occurs in the North Sea in, material of interest, and providing site borehole logs. clepartement de I'Yonne. Bal/. Soc. .lci. /list. Nat Y Referencec 'l'hc ARKELL W. J. 1947. The geology of Oxfor