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Be be bane tae ee « ~e va Reve be oo hat Bar pao ee erdinior a temo ta hatnb-o- tot ine o-arAwivbn reso Gotr ehan G-Aat Sled WS Go Se ¥ SS > — te ~ oe Aman hrs Be EN an ie eee aaa a ne parte Penn Gn Sie epcears Stee Te eee gar ibe ety tan d- Olaln G-Star Poet bre ale ete ® me eg: INP em de eee & eal pn > —* a _ a VA er ae eV Oe ee 4 Fee A etn te Oe nw Re A nde lp tee AM A ety One atin tinh Candie ioe inet a a CTE aa ta eatene Ar ae fate Oo ee het @rtns fat tot ae a eee ee ey oe a ee ered 2: Bete beth gM rarer Sarr ia natletn tate on eet myn toate a ticthe Rept eatin Rat Be v= ee IEE alte pte We Rerte ll Mee te et feb~tebemathrrfael = t-fafiet mo Me paige won uremia Reale np Ane Ine Se le -_ an a Sef oe toto ¥ amar re a ees Pa ptr er weir reese ee ee ee ee ee ee et ee ee Ty te ane tinn ple Bile See = te eee mim hie tag we ane te Fale Pte enn a NM ethenon We Om oa ees ee oe eto a ree Si ee ee ee ee Sr eee ee . ee en een ee ee et bee ee ee One ee ee eT er ee ere es Athi ie PB A Nhe Mt ahmpete sy Sede ean dh > oe Nab Pe Rte ee rn ai teri anhaand~ a eae eer oe ~ ee ee foPen ie Pat Qt ma ~ — ba re eet ie ee re 1 Ae ee tee ~ i Me Tip a hee coe hy to alt ne Nadl Rt EDM ly e , + OB moe - a i ee Sedat dnd 4-4- orto! = ode geet er Se eee ee 0h ate tt ne ate FN fm Daa Bet ethene iw toe Be Mehene FF Oe ee wee ee ee ee ee Bet - Ane he BE _" a ae eee et a ee eee ta - tL NL al ot aa Ds ein Menon pn gS. oP nd wee — Pow iets. 4 8 oe bLk © eal fi _ —— winotig telat nen > ne Res ape Raper em Spee «ete. oh alot Mal De Fate yh tele ile ali Rae Repeat th Am ae eee - “ om? ~ ames ee ee ee ee ee ee ~ Se eee ere ee eee ee — fe hat a AG Od . TS ee ee Pe tet Patel 4, a a tow Se ws Pine Beta ohn rte hehe ie ‘ . A - a - ae es) .. > “i = > ?. . * eo ~ > Ww - . ~ » - a aw 2 wt 4 “. J ee ee . - ‘s — 2 - “8 : " - s » . oe = = « “ > + . ee ~ oi: ~ a . be - . - +2. . ni _ -- . - - . . a — len 7 a P A a » > - . - i . an Pilly Nps 2 > = — v 4 . * + > ud Ke ui . —s . . Ps re sn 7 . ‘ y > . : : be ae - « = ‘ - ~ ¥ = - - a we a 7 ~ A - . m “ey ~ - : “ - “ “— > es —= 7 . - . — - x ard ws x - om ~— ~ . < - - vs . “ mite ° . : -* “ ~ rs = _ ~ us 7 ~ - - ' oa > , ° ~e . - — ~ - - . e - ) ‘ * ¥ ~ 7 m wd ~ = © 1-4-8 ~ ¥ ee or Are ws - ~ — - - ‘ ee ie a j oor . ‘ : é (a7 ‘ ‘ % joo . . . . ‘ ‘ ; ' she" a . - % *-.-~" ee” a eee ee. oe pemae (ee pte - a oe eo er a aad eee ee ne ee = AE SOE Oem te BH AMR AG cas ash OPM ee ee es aoe. — ni ee a 7 ‘ ip i >» \\ THE QUARTERLY JOURNAL OF THE GEOLOGICAL SOCIETY OF LONDON. EDITED BY THE ASSISTANT-SECRETARY OF THE GEOLOGICAL SOCIETY. (Juod si cui mortalium cordi et curz sit non tantum inventis hzrere, atque iis uti, sed ad ulteriora penetrare; atque non disputando adversarium, sed opere naturam vincere ; denique non belle et probabiliter opinari, sed certo et ostensive scire; tales, tanquam veri scientiarum filii, nobis (si videbitur) se adjungant. —Novum Organum, Prefatio. , VOLUME THE FIFTY-SEVENTH. 1901. LONDON: Z21943 LONGMANS, GREEN, AND CO. PARIS: CHARLES KLINCKSIECK, 11 RUE DE LiLLE. LEIPZIG: T.0. WEIGEL. SOLD ALSO AT THE APARTMENTS OF THE SOCIETY, MDCCCCI. List OF Tih OFFICERS OF THE GEOLOGICAL SOCIETY OF LONDON. RARAADARAR ALARA RADI VPI DI YY™ Present. J.J. H. Teall, Hsq., M.A., V.P.R.S. Oice-Presivents, J. E. Marr, Hsq., M.A., F.R.S. Prof. H. G. Seeley, F.R.S., F.L.S. H. W. Monckton, Esq., F.L.S W. Whitaker, Esq., B.A., F.R.S. Secretaries. R. 8. Herries, Esq., M.A. | Prof. W. W. Watts, M.A. Foreiqu Secretary. Sir John Evans, K.C.B., D.C.L., LL.D., F.R.S., F.L.S. Treasurer. W. T. Blanford, LL.D., F.R.S. COUNCIL. W. T. Blanford, LL.D., F.R.S. | Prof. H. A. Miers, M.A., F.R.S. Sir John*Evans, K.C.B., D.C.L., LL D., = Right Rev. John Mitchinson, D.D., D.C.L. B.RB,S., F.LS. H. W. Monckton, Esq., F.L.S. Prot. E. J. Garwood, M.A. EK. T. Newton, Esq., F.R.S. Prof. T. T. Groom, M.A., D.Sc. G. T. Prior, Esq., M.A. Alfred Harker, Hsg., M.A. _ F. W. Budler, Esq. R. S. Herries, Esq., M.A. | Prof. H. G. Seeley, F.R.S., F.L.S. William Hill, Esq. | Prof. W. J. .Sollas, M.A., D.Se., LL.D., W. H. Hudleston, Esq., M.A., F.R.S., | FE.R.S. ie Sen el Breer | J.d.H. Teall, Esq.,.McA.. ViP ais: Prot a2 We Judd, CB. LL.D. BRS: Prof. W. W. Watts, M.A. Lieut.-Gen. C. A. McMahon, F.R.S. W. Whitaker, Esq., B.A., F.RS. J. H. Marr, Esq., M.A., F.R.S. H. B. Woodward, Esq., F.R.S. Assistant-Hecretary, Clerk, Librartan, anv Curator. L. L. Belinfante, M.Sc. Assistants tn @Dklice, Library, anv Museum W. Rupert Jones, ; Clyde H. Black. TABLE OF CONTENTS. Barrow, GrorcE, Esq. On the Occurrence of Silurian [?] Rocks in Forfarshire and Kincardineshire along the Eastern Border of PDE TEI SO) Sin Ie ae ai ae Rea eee peerage Oe Pee a Bonnety, Prof. THomas Grorer, & the Rev. Epwin Hutt. Additional Notes on the Drifts of the Baltic Coast of Germany. BuckMAN, 8. 8., Esq. Bajocian and Contiguous Deposits in the North Cotteswolds: The Main Hill-Mass. (Plate VI.) ...... BULLEN, the Rev. Roperr AsuHineron. Note on a Well-Section eee anehoo GSutolle\a int sais cee ee cs se eek a5 sche wheel at Cuarke, WILLIAM JAMES, Esq. The Unconformity in the Coal- Measures of the Shropshire Coalfields . 3. ...2.0.0..0.6.005-s Cooméra-Swdmy, Ananpa K., Esq. Note on the Occurrence of Corundum as a Contact-Mineral at Pont Paul, near Morlaix CUTEST TREE) 9, Soa et an a a eR Evans, Dr. Jonn Witttam. A Monchiquite from Mount Girnar, Sunegach (Mathiawar), (Plate IT). sl ovo ies ea eae. Gispson, WaLcot, Esq. On the Character of the Upper Coal- Measures of North Staffordshire, Denbighshire, South Stafford- shire, and Nottinghamshire; and their Relation to the Pro- ODE RY TY, STEELER an 0S a AE a Groom, Prof. THEODORE Tuomas. On the Igneous Rocks associated with the Cambrian Beds of the Malvern Hills. (Plate VIL.) .. Gunn, WitiiaM, Esq., & Messrs. B. N. Peacu & EK. T. NEwron. On a Remarkable Volcanic Vent of Tertiary Age in the Island of Arran, enclosing Mesozoic Fossiliferous Rocks ............ Harmer, Freperic Wiiir1aM, Esq. The Influence of the Winds upon Climate during the Pleistocene Epoch: a Paleeometeoro- logical Explanation of some Geological Problems............ Hix, the Rev. Epwin, & Prof. T.G. Bonnry. Additional Notes on the Drifts of the Baltic Coast of Germany................ Hu, James Basrian, Esq. On the Orush-Conglomerates of ANE apy UMP Ha NOt 9. 55. ey etioclipi nie ala «of oUa wabels, vs ts a2 = Page 328 126 285 86 185 38 313 1V TABLE OF CONTENTS. Hinp, Dr. WHEELTON, & JoHN ALLEN Howe, Esq. The Geological Succession and Paleontology of the Beds between the Millstone Grit and the Limestone-Massif at Pendle Hill and their Equivalents in certain other Parts of Britain. (Plate XIV.) .. JUKES-BrowNneE, ALFRED Joun, & J. Scanes, Esq. On the Upper Greensand and Chloritic Marl of Mere md Maiden 1 oe in Wiltshire. (Plates III-V.) eee eee eee et tee eee ee, es ets eewvese KiLRo£, JAMES Rosrnson, Esq., & A. McHenry, Esq. On Intrusive, Tuff-like, Igneous Rocks and Breccias in Jreland ............ LYDEKKER, RicHarp, sq. On the Skull of a Chiru-like Antelope from the Ossiferous Deposits of Hundes (Tibet) Mariey, Caartes A., Esq. The Geology of Mynydd-y-Garn (Awelesey) ie be OO eee rr McHenry, ALEXANDER, Esq., & J. R. KitRok, Esq. On Intros Tuff-like, Igneous Rocks and Breccias in Ireland © 8 © (9 0) e e-teiie) ome MoncxtTon, Horacr Woo.u.aston, Esq. On some Landslips in Boulder-Clay near Scarborough .................0.0 ee Mor@an, Prof. Conwy Lioyp, & Prof. 8S. H. Reynoups. The Igneous Rocks and Associated Sedimentary Beds of the Tort- worth Inher. (Plates X & XI.) ......4...45% .. ohio NEwTon, Epwin Tutey, Esq., & Messrs. W. Gunn & B. N. Peacu. On a Remarkable Volcanic Vent of Tertiary Age in the Island of Arran, enclosing Mesozoic Fossiliferous Rocks. (Plate IX.). OrpHaM, RrcHarD Drxon, Esq. On the Origin of the Dunmail Raise (Lake District) 0.660.002 ls on ee a ee PARKINSON, JOHN, Esq. Notes on the Geology of South-Central Ceylon Se oe Wh ie 8 6 tte Oe ©. 9 e600 e © 0 6 6 8,0 ses ws 8 8 6 a 8 SS elim) Meer meer we es The Hollow Spherulites of the Yellowstone and Great Britain, (Plate VOIL.) 222.) 80... i. Pracu, BrnyamMin NEEVE, Esq.,& Messrs. W.GunNN & E.T. NeEwrTon. On a Remarkable Volcanic Vent of Tertiary Age in the Island of Arran, enclosing Mesozoic Fossiliferous Rocks ............ Ratsin, Miss CATHERINE A. On certain Altered Rocks from near Bastogne and their Relations to others in the District ........ REYNOLDS, Prof. Sipnry Hueu, & Prof. C. Luoyp Morean. The Igneous Rocks and Associated Sedimentary Beds of the Tort- worth Inlier. (Plates X & XD) olen. . abies tac RutLey, Franx, Esq. On some Tufaceous Rhyolitic Rocks from Dufton Pike, Westmorland, (Plate) ©... 1.20)... 1. ee Scangs, JoHN, Esq., & A. J. Jukes-Browne, Esq. On the Upper Greensand and Chloritie Marl of Mere and Maiden Bradley in Wiltshire. (Plates III-V.) oie g © 8 8 Reg ee’ Lig fo ease oe ig) igh eae alls mone Page 267 226 189 198 211 267 TABLE OF CONTENTS. Vv Page Sorxtas, Miss Iczrna B. J. Fossils in the Oxford University Museum, V: On the Structure and Affinities of the Rhetic Berememnmim. CP lsie XIE) ii. ok oa een ce Sa ee he 507 SpENCER, Prof. JosepH WiLi1aM WintTHROP. On the Geological and Physical Development of Antigua. (Plate XV.) ........ 490 On the Geological and Physical Development of Guadeloupe. 506 . On the Geological and Physical Development of Anguilla, St. Martin, St. Bartholomew, and Sombrero ................ 520 . On the Geological and Physical Development of the St. Christopher Chain and Saba Banks 5 CAS thee ARE rae 534 STRAHAN, AUBREY, Esq. On the Passage of a Seam of Coal into mocamo Dolomite: (elate XIE) ooo. eed cece es 297 THOMPSON, BEEBY, Esq. On the Use of a Geological Datum. MN ee oe a oh 6 ahs cae op chale J vhkea Gin! aya! op nce aw ds 346 Wepp, CHARLES Bertix, Esq. On the Corallian Rocks of St. Ives (iiaanedoushire) and Blsworth-. 0.2.2.0... ee ee te 73 Wricut, Prof. GEoRGE FREDERICK. Recent Geological Changes Mmononimere and Central Asia «40155 verde o i eee ee ke 244 PROCEEDINGS. Pecceamos or the Meetings). se ces. ca wok ce edhe ee 1, Ixxxvii Pm PeODOTE 05005 be sige oy oe SE AA A es. aS, A RN vill PasomUnnors tothe Mibrary 6... ce a be ee ew ee ce ne xiii Mice orerem Menmbets) Coe... . rei he we Babee ease XXlil List of Foreign WirereMennenbs 2.55 bss pekeien Re 6 eb XX1V asin Vy ollashonm Medallists... c..je ev ca lcna ct vee ee ele XXY ae minrenmon eed alists: 2.5. es oe ars ws Boe ewe ce ea XXVil eye pee AN ISES a ee ws ayes clot te ve ee eee XX1X Mamas Dy a CA AMISES peel cle ss ee nee wae eee XXxi Applications of the Barlow-Jameson Fund................4. XXX Financial Report .......... RE) I ee on ec XXXIi Award of the Medals and Proceeds of Funds........... } MEE ee Me: 6.2. 0B. Pewee tee ites As. hes ankle bse ee ee deaess | Kivi OAS ERS DS EWS 2 Re Ixxxvll, XCiv Special General Meeting .................055 Ct AP AMARA Ber yaa X¢ii al TABLE OF CONTENTS. ABBOTT, GEORGE, Esq. On Cellular Permian Limestone from Hulwell) Sunderland 3). 3.5)... an wees ae ae eee Batuer, Dr. Francis ARTHUR. On Ioneous and Metamorphic Rocksttrom the. Mayenne |.) cae Wor dom ete ate seus CoomMAra-SwAmy, ANANDA K., Esq. On Spherulitic Structure ny sulpham. lic Acid) ,.)). 2 ils. alae sek Fone a ane oho ee Harrison, Prof. Joun BurcHMoRE. On the Geology of British CTIA oa ci 3 Sank sw thd RPE iis, Wis en rec ee eee Hott, Prof. Epwarp. On the Submerged Valley ys the Mouth of the River Congo yo. .20 (25. ieee eee PEE belive) aeefesteckie dc fy selec nen Rte ea tee aye Uae Oe ee Woopwarp, Horace BoxrncBroxr, Esq. On Landscape Marble or Cotham Stone... sa sos «0 2 2s ee ERRATA. Page Xevl - vl vii Ixxxvii Ixxx1x vli x¢Cl P 4i—uaines 26-29 from the top should be read after line 15, the name Whitman Cross’ being substituted Sor ‘ Washington. P. 160—Line 33 from the top, for ‘nearly’ read ‘never. LIST OF THE FOSSILS DESCRIBED AND FIGURED IN THIS VOLUME. Name of Species. | Formation. Locality. Page PLANTA. Natadta taneeolata. Figs. ok Bhatie Ae sae. ' Pylle Hill, Bristol) 307-312 2)c'5 6-21 eo | CRINOIDEA. ey |} Lower Uing.....| Arcan......... A 237 ANNELIDA. ; es g moe ee 1%, {\ Lower Rane ty wera Sh no 230 LAMELLIBRANCHIATA Avicula lanceolata. PI. ix,| \ ( SE eRe cece ranicctecstae 5221 | | 232 Cardinia Listeri. PI. ix, figs. | | “fog L853 0 ne ee ge ce see | 235 Cardita Heberti. P\. ix, fig. isi 235 Goniomya sp. Pl. ix, fig. 17.. | 236 Gryphea arcuata. PA. ix, (At has eee cen eee | 2353 Lima pectinoides (1). PA. ix, | LRAT ee eRe | 233 - succineta. PI. ix, fig. 8., 233 Myoconcha, psilonoti (2). Pl | BNO Hee ae. ace 234 anes nih Oi. 8 Sea | | & Lower Lias ne RPEAM toed eau ‘ 234 Nuculana (Leda) Tatei. Pl. Cl oe a ere ae | | 234 Spe EL ix, figs 13. 2). if | 235 Ostrea irregularis CO | | | 233 Peeten(Chlamys) subulatus( oe . ois SRG Te 5 ae | 232 Pholadomya (2). PI. ix, fig. 19 236 Protocardium truncatum (2). Tancredia (?) Peachi, sp.nov. | lin, pe else Unicardium cardioides. PE} ix, fig. 18 ] Vili FOSSILS DESCRIBED AND FIGURED. Name of Species. | Formation. Locality. | Page GASTEROPODA. Amberleya acuminata. Pl. ix, , | | ( . I | | oe 5S ai AO teen, RR ets | | 281 Cerithiuin Semele (2). PI. is, Howe ilgis ae |" Anan Saree 4 : PAO aah eRe Ns we ee ee cae mek {| 231 3) CRABB eR Res: des) J | (281 CrPnALOopopA. Ammonites ( Aigoceras) angu-| | : Pe 3 lapis ee | j Lower ILias...... | SATAN 2. deere | 231 | Mammatta. ee i Ree ae a | ; Upper Pliocene | Hundes (Tibet)... 289-92 i el il a el gel) ae EXPLANATION OF THE PLATES AND FOLDING-TABLES. Puatse i Pact MICROSCOPE-SECTIONS OF TUFACEOUS RHYOLITEs FRoM DuFrron EL Pike (WEstTMoRLAND), to illustrate Mr. Frank Rutley’s | feaerrOn bi One TOCKs gs Cheeses Ae, 8s ool seca edie asic gun eae JuNAGARH (KaturAwar), to illustrate Dr. J: W. Evans’s Microscorz-sections or Moncuiquite From Mount Girnar, i Peale Ott blll MOC ete aes bite ah eauacicnd ven ea cues’ dl enancs (GroLocicaL Map or Tux District or Mere anp MAIpEN | Brapiey; View or Marpen Brapdiey Quarry; and View TII-V.{ or Deav-Maip Quarry, Merz; to illustrate Messrs. A. J. | Jukes-Browne & J. Scanes’s paper on the Upper Greensand { and Chloritic Marl of the above-mentioned district......... (a Mar oF THE BasoctAn DENUDATION, CORRECTED TO ApRin, VI., 1900, to illustrate Mr. 8. 8. Buckman’s paper on Bajocian | and contiguous Deposits in the North Cotteswolds ......... MIcRosCcoPE-SECTIONS OF LGnrous Rocks rrom THR CAMBRIAN or THE Matvern HI.zs, to illustrate Prof. T. T. Groom’s pice te Otte pee ROCKS eo con awed dy cinch tu ceGeican covadedestsraad VII. VEL. Mr. John Parkinson’s paper on the Hollow Spberulites of the wellewstome anc: Greab Brita eles sicsicccococcoescodec Lower Liassic Fossi_s FroM ARRAN, to illustrate Mr. E. T. Newton's Palxontological Notes on the Mesozoic Fossili- ferous Rocks found in a Tertiary Volcanic Vent in that i LitHoPHys& FrRoM Boutay Bay AnD WrockwakDIngZ, to illus- | asl ELON Ae ete oes hes Satie Mane Tatiek saws d Deas Wel odswad ences ( GEOLoGIcAL SkETCH-MAP OF THE Ia@nEOUS Rocks AND ASso- | CIATED SEDIMENTARIES OF THE TortTwortH INLIER; and ! Microscorge-Sections or Pyroxenn-ANDESITES AND CAL- { carEous Turr rrom Tor Tortworti INrter, to illustrate | Prof. C. Lloyd Morgan & Prof. S. H. Reynolds's paper on ETAL OMNI OT ogee ot cee rgd van sys 2s sone wave dgemoneansvnay oxiveunes dl 38 96 126 156 211 226 EXPLANATION OF THE PLATES AND FOLDING-TABLFES. PLATE PAGE { Microscorz-sxcrions ILLUSTRATING THE PassAGu or COAL XII. InTO DoLomirE, to accompany Mr. A. Strahan’s paper on | that subject | 2s. { 00. assert head) nae aa 297 XIII f Figures or Narapira LANCEOLATA, to illustrate Miss I. B. J. oot, Sollas’s paper on the Structure and Affinities of that: plant. 307 ( CoMmPARATIVE VERTICAL SECTIONS OF THE PENDLESIDE GRovr, XIV. to illustrate Dr. Wheelton Hind and Mr. J. A. Howe’s | paper on that growp (7.535 2.0. sci oe eee eee et GEOLOGICAL SKETCH-MAP OF THE ISLAND oF ANTIGUA, to illus- XV. trate Prof. J. W. Spencer’s paper on the Geological and Physical Development of that island ..................4. ceeee, 490 Apprenpix A.—TueE Fauna or THE CarBonirerous Limestone ) SeRIES OF WENSLEYDALE, THE HpEn VALLEY, AND THE | Norruern Mipuanps; and | facing Apprnpix B.-—Tue Fossirs or tur Penpiestpr Grovp, to illus- r p- 402 trate Dr. Wheelton Hind and Mr. J. A. Howe's paper on | Hab OTOUP oc. -2% os aiemcieteotinntewdestigas emwaeeOakee he een ) PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES, BESIDES THOSE IN THE PLATES. Fig. PAGE nn beara and micropegmatitie structures in obsidian and Siteenie a Wo gall acasccssedanmans cov aracebs connotes jasblersta clasts vase lxxv Hast side of one of the troughs (Drift near Warnemiinde) West side of the same trough Pew sees sete sea et esse reese srestsesest tenses Cece metre ree ee ers ee soaserteisessseres 1 2 3. Generalized section of a trough 4 Chalk and Drift below the Lighthouse station, Arkona 5. Gakower Ufer (as exposed in 1899); northern end of the section. 6 Section between the Wissower Bach and the Wissower Klinken : (southern end) See eter ee Feet ees eeeees eet oeFeesesesetseneess ess eeseneeeses 7. The same (northern end) oe ee ee od 8-9. Diagrammatic sections, to illustrate the ‘ folding hypothesis’ . 10. Diagrammatic section, to illustrate the ‘ faulting hypothesis’ . 11. Section in Von Hausemann’s Quarry [Crampas-Sassnitz] 1 Section across Mynydd-y-Garn, west of (and subparallel to) the 5 Garn-Castell Fault Ce CO Sk i i i ee rr) 2. Geological Map of Mynydd-y-Garn and the surrounding area. Sketch-map of the central ridge of Mount Girnar er 1. Craglet north-east of Bastogne, by the road to Longwilly Banded rock including a garnetiferous nodule: same locality . ies) Microscope-section taken from the above-mentioned nodule ... 4 Band containing garnets, etc., north-east of Bastogne, in quarries along the railway to Gouvy ee ee ee Sketch-imap of the outcrops of Elsworth and St. Ives Rock . i i ee ee i 1. Section in Madeley Court Colliery 9 { Diagrammatic section across the Madeley District, Coalbrook- we dale Coalfield ee ee i i ie a 4 4 4 8 ll Xi PROCESS-BLOCKS AND OTHER ILLUSTRATIVE FIGURES. Fig. PAGE 3 { Section taken from Mareus Scott’s paper, but redrawn with the : basement-beds of the Upper Coal-Measures as a datum-line. 89 4&5. { Sections showing the present position of the strata [Shropshire Bh ee ee i 91 1. Section in Maiden Bradley Quarty...........:..........) 101 2. Section at Rye Hill Rarm) 22... cbe. cites scsss 108 3. Section at Dead-Maid Quarry, Mere ...... ate aad «tule ee 11] 1. [Diagrammatic section from the North Cotteswolds toCrickley] 128 2. Diagrammatic section across the Vale of Moreton... 140 3. { Diagrammatic section across the North Cotteswolds, from west to east) sc... (Uh cea asides snenGldrtalesievelece c secon nidcvantensceecesensas 316 Isodietic line for Nuculana attenuata, Nucula gibbosa, and & { DORI UCU OSIIS. ne ee He sic ssa die aa guia d aoe ae'sdvie ables acavies sda. 380 3. Isodietic line for Carbonicola, Anthracomya, and Naiadites ... 382 1. [Map of Gieus MPO MEISEL pete aco Meieiecraietig peste se See also ‘Forschungen zur Deutschen Landes- u. Volkskunde’ vol. vii, pt. v, . OTe sa He states that the total thickness of this Drift varies considerably: in the cliffs of Granitz it is from 30 to 40 metres (98:4 to 131-2 feet), on Hiddensde 70 metres (229°6 feet), in well-sinkings it ranges from 20 to 60 metres (65°6 to 196°8 feet), and at Quoltitz reaches 96 metres (314-9 feet). 3 «Beitrag zur Geologie Mecklenburgs’ pts. vi & vii (1884-85). [This work was not in the Society’s Library when we wrote, but a copy has now been procured. Pt. vi contains a map of the distribution of the Drifts; pt. vii a panorama of the cliffs, in which, however, the sea appears to have made changes since 1885. ate oe te Fihrer durch Mecklenburg’ Berlin, 1899. = — OS ee ee Vol. 57. ] DRIFTS OF THE BALTIC COAST OF GERMANY. 3 illustrations of its most remarkable sections ; but, as the work is not likely to be generally known, and the only reference to the Warne- munde Drift which we have come across in our own language is liable to be misunderstood, we offer to the Society the results of our examination. In so doing we shall endeavour to avoid theories and describe facts, referring only to the former so far as to point out what is demanded by the latter; for we think that if this plan were more generally followed, better progress would be made in solving the problems presented by the Drifts of Northern Europe. Warnemiinde, the port of Rostock and a watering-place on the Baltic, is on the western bank of the mouth of the Warnow. The river on the other side expands into a broad sheet of water, separated from the sea by a peninsular lowland. Beyond it the ground rises a little, but as careful searching with good field-glasses was un- promising, and it is mapped as dunes, we left this without further examination, and confined our attention to the other bank of the Warnow, where we studied the coast between Warnemiinde and Heiligendamm, a distance of about 10 miles as the crow flies. This, however, for a considerable extent at each end, is without interest, as a line of very low flattened dunes separates the Baltic from an almost equally level alluvial plain. But in the middle is a gently undulating tract rising from this plain to a maximum elevation of slightly over 60 feet, which is scarped by the waves into cliffs. These extend along the shore for nearly 2 leagues, and usually afford very fair sections of the glacial deposits, which, however, are generally uniform in character: all the more interesting occurring along about 14 miles of the coast, and commencing rather more than that distance from Warnemunde. The results of our examination, we think, will be more readily understood if we begin our description at Heiligendamm, so as to work from west to east. For some 2 miles east of this place the coast, as intimated, is low, but there is higher ground to the west, which, however, we did not visit as it gave no promise of clear sections. Beyond the dunes the ground gradually rises, forming a cliff which, for a considerable distance, ranges from 2 to 3 yards in height, and consists of a strong, stony, brownish-grey clay. The cliff dies away towards an opening, on the other side of which it again rises, attains a greater elevation, often 4 or 5 yards, and occasionally about twice as much. Here the lower part consists of a clay, not quite identical with that already mentioned. Over it comes a rather sandy band, often only A or 5 inches thick, and then a clay, such as we have already seen, which passes up into a sandy soil from 18 inches to 2 feet thick. We will call these clays, for the purpose of reference, the lower and the upper. The former is grey, and contains the following materials :— _(a) Chalk: much of it being in small grains,. from the size of a mustard-seed downward ; these often are about as common in the matrix as carraway-seedsinacake. The rock also occurs in pebbles, B2 Fig. 1.—East side of one of the troughs. (See p. 5.) a NY ~—= <4 = ~ oR ES Ga OL See ty - TH SS [The notice-board is at the western end of the wood mentioned in the text. ] 1 = Lower boulder-clay. 2 = False-bedded sand. 4 = Sand banded with clay ; much bent, as indicated. 3 = Upper boulder-clay: behind !this: at x are traces of a beach-like layer. Fig. 2.— West side of the same trough. —- ~~) -Q > as = [For the explanation of 1, 2, & 3 see fig. 1. Beach-like layer below 2.] 4&5 = Sand banded with clay, lying as indicated: 5 continues visible, with some contortion, for about 12 feet. 6 = Boulder, measuring about 24 x 14 feet in a beach-like layer. Fig. 3.—-Generalized section of a trough (about 100 yards wide). 3 [For the explanation of 1, 2, & 3 see fig. 1.] 4 = Sand banded with clay, more or less contorted, and especially so at 4’. | | = a Se ee eee eee ee ee a a Vol. 57.| THE DRIFTS OF THE BALTIC COAST OF GERMANY. 5 generally well rounded, which are seldom larger, and usually smaller, than a pigeon’s egg: these seemed to us more local in distribu- tion, and to be a little less common in the higher part of the clay. (6) Flint: this is less abundant, the fragments varying from fairly rounded to practically unworn; usually they are small, but now and then a block a few inches across may occur. (c) ‘Scandinavian’ rocks, chiefly crystalline and rather dominating in bulk over the flint: these vary in size from a coarse grit to stones, generally well-rounded, of considerable size, specimens some inches in diameter not being rare. We saw two or three boulders of large size actually embedded in the clay, and blocks ranging from 2 to 4 feet across are numerous on the beach. Some of these are smoothed on one side and retain well-marked striations, while a few are facetted. We observed also in the clay two or three boulder-like masses of a rather fine, stratified, clayey gravel, containing numerous small pebbles of chalk with some flint and ‘Scandinavian’ rocks; possibly also one or two similar masses of sand. This lower clay often reminded us of the Cromer Till and the lowest of the clay-beds in Holderness ; occasionally also of parts of the Chalky Boulder-clay in East Anglia, | The upper clay does not differ materially from the lower, so far as the stones are concerned, but its matrix is browner and is more apt to become locally sandy. The lower clay’ and the sandy band rise gently eastward, and the latter after a time can be no longer distinguished ; but even then the clay in the upper part of the cliffs appears to be more sandy than that in the lower, which maintains a generally uniform character. This description holds good till we have passed another opening, and are rather more than a league from Warnemiinde. Here the cliffs reach their greatest elevation, and the somewhat monotonous uniformity of the sections is locally interrupted by the presence of sandy material, forming slight recesses and occasionally little valleys. The first of these occurs some 150 yards west of the end of the low wood, perhaps 3 league long, which covers this part of the upland—called Stolteraa; another is just under the end; and they are found at intervals—being about ten in all—over a distance of rather more than 14 miles. (See figs. 1-3, p. 4.) In the intervals the cliff generally is formed of boulder-clay, its lower and larger part being of that described above as the lower one ; but the upper 10 feet or so show a more sandy variety, corresponding better with the upper clay farther west. The top of this clay (1) on each side of arecess descends at an angle of some 25°. Above it, with apparent conformity, comes a false-bedded yellowish sand, 4 or 5 feet thick (2); and above this again is another clay (3), also stony, but a little yellower and more sandy than that below. This is overlain by a mass (4) of stratified sand with more clayey layers, which fills the greater part of the trough, and is usually much contorted. 1 We occasionally saw the lower clay exposed on the beach in shallow water ; and it was disclosed less than a mile from Warnemiinde, in a cutting made for the foundation of a groyne. : 6 FROF. T. G, BONNEY AND REV. E. HILL ON THE [Feb. 1901, Beneath it, on the top of the second clay, we occasionally find a layer of grit and stones, sometimes subangular, once or twice asso- ciated with a boulder a couple of feet in diameter. This layer generally is only a very few inches thick, and closely resembles the material of the present beach. In one or two of the recesses we found traces of a similar layer between the bedded sand and the clay beneath it. Small stones sometimes occur in the sands which occupy the trough, but chiefly if not wholly in the more clayey layers; and in one section a band of very dark laminated clay is present, with numerous small pebbles of chalk, flint, ete. This band is rather jagged in outline, generally about 3 or 4 inches thick, but occasionally more than a foot: these irregularities being probably due to fracture and packing during subsidence. But the deposits in the ‘ Contorted Drift’ seem to show greater variability than the more uniform masses beneath them. In one place two of these recesses are near together, parted only by a ‘gable’ of the lower clay ; and in another, a low mound of this material apparently rises up for some 3 yards above the shore, interrupting the ‘Contorted Drifts’ near the western end of a trough. But this possibly may not be a situ. The larger number of these recesses are to the west of the track leading down from the Wilhelmshéhe restaurant, but three or four lie on the other side of it. More details could be added, but enough, we think, has been said to bring out the principal features of these interesting sections. The sand (2) clearly overlies the main mass of clay, and the clay (3) comes above it. But whether these correspond with the sandy band and the upper clay in the extensive sections to the west is not easily determined: on the whole we are inclined to suppose them represented by the more sandy part of the main mass (1) in these eastern sections, and regard (2) & (8) as more recent, though underlying the ‘Contorted Drift.’ This probably once extended over the whole area, whence it has been generally removed by denudation. But how were these troughs formed? It seemed to us impossible that they could be ordinary valleys excavated in the lower boulder- clay in which the beds 2, 3, etc. had been afterwards deposited. The synclinal slope of beds 2 & 3 and the contortions of the overlying bedded sands, in which, however, traces of a similar structure are perceptible, indicate that the mass as a whole has been let down and probably puckered by unequal movements or by packing during that process. Of faulting in the ordinary sense of the term we found no trace, and dismissed that hypothesis as improbable. Still more- impossible did it seem to attribute the relations of the Drifts to the action—thrusting, ploughing, or dragging—of an ice-sheet. The structure would more naturally be produced by the gradual removal of material which had once supported these beds nearly in an hori- zontal position. The Drift, if we rightly understand Prof. Geinitz, is probably very thick, and it rests upon Chalk.’ We can hardly suppose * The maximum thickness in the district (E. Geinitz, ‘ Uebersicht iiber die Geologie Mecklenburgs’ § vy, 1885, p. 29) is 133 metres. Chalk is shown as cropping out inland near the western end of the Stolteraa. i LIL LET DA ag At Cll Riel Bp = i ae = ee tataniginanl © Vol 67.| DRIFIS OF THE BALTIC COAST OF GERMANY. 7 that subterranean denudation of the latter rock would be locally so intensified as to produce these down-drops in the Drifts ; but if pre-existent valleys in the Chalk had been filled up with frozen snow, prior to the deposit of these alternating strata, or if the lower part of the Drift had enclosed tabular berglike masses of ice, which afterwards melted away, such a structure might be produced.’ Of the two hypotheses, we view the latter with the less favour, but the former also has its own difficulties. We do not, however, see our way to suggesting anything better. Itt, Arkona. The headland of Arkona, above the northern end of Rigen, may be described in general terms as an insular mass of Chalk rising about 200 feet above sea-level, and situated at one corner of a slightly lower plateau of Drifts.? But on closer examination we find that it also is capped by Drift, though of a different colour and composition. Thisisoften from 3 to 5 yards thick ; but at one place, where the coast is projecting towards the east, it apparently reaches a much greater thickness, for the Chalk-cliff below seems to be only 30 or 40 feet high.* It is a light-coloured clayey material, containing numerous flints with some Scandinavian pebbles or boulders, not without a resemblance to the ‘ whitish boulder-clay ’ which occurs, among other places, near the Waldhalle.* In the cliffs facing east- ward, the Chalk can be seen for a space overlain by the ordinary Drift. Its surface at first seems to sink irregularly, though somewhat rapidly southward, perhaps, even to below the sea-level; but the slipped Drift and grassgrown slopes make any precise statement impossible. In about 150 yards, however, the Chalk certainly rises into a kind of ridge, the top of which is not much below the edge of the cliff. After this, so far as we could see, it finally dis- appears, and the cliffs or slopes are formed of Drift. This bears a general resemblance to the boulder-clays of Jasmund, and reminded us in its general aspect of the masses seen last year néar Gobren. In one or two places it was sandy, but whether a tripartite division exists here seemed to us more than doubtful. We were unable to examine the corresponding section on the northern face of the headland, but carefully studied the singular ‘inlier’ of Drift in the Chalk (seen in the crag near the buildings of the lighthouse) which has been described by Prof. F.Johnstrup.* His diagram had suggested 1 To this view, we infer that Prof. Geinitz, on the whole, inclines. * It was once a stronghold of the Rugii; their earthwork, sometimes over 30 feet high, still remains crossing the headland. 3 Possibly the other Drift may come in below, but we had not time to attempt a minute examination of this part, if indeed it is accessible, and had to content ourselves with what we could see from the deck of the steamer. 4 Dr. Credner appears to place both in the ‘Ober Diluvium,’ Forsch. z. Deutsch. Landes- u. Volkskunde, vol. vii (1893) p. 448. Certainly they appear to be unconformable with the Drifts below, assigned to tie ‘Unter Diluviam.’ 5 Zeitschr. d. Deutsch. Geol. Gesellsch. vol. xxvi (1874) p.572. More briefly also by Dr. R. Credner, Forsch. z. Deutsch. Landes- u. Volkskunde, vol. vii (1893) p. 448. 8 PROF. T..G. BONNEY AND REY, E. HILL ON THE [Feb. 1901, to us the possibility that a great erratic of Chalk rested on clay, like those in the Contorted Drift of Cromer. That, however, is not the which runs for a considerable distance to the north-west, forming cliffs overlooking the sea. As shown in the appended diagram (fig. 4), the Fig. 4.—Chalk and Drift below the Lighthouse station, Arkona. fine 1 . ZAl SO po | I = Clay, containing on the right a little seam of Chalk about 3 inches thick, and becoming more distinctly laminated and crumpled towards 2, where is a boulder some 15 inches long ; about 6 or 7 feet at most exposed in a vertical section, 3 = Slipped clay; a little bedded sand disclosed near the numeral. 4 = Chalk-with-flints, Chalk seems to overlie the Drift; but, on closer eXamination, the latter appears more probably to have filled a cavity cut in the former, The upper margin of this cavity, it will be observed, is not quite parallel with the bands of flint. The Drift is mainly a somewhat laminated and banded clay, containing but few stones, though we Saw one about 15 inches in diameter. Near the top surface one or two thin films of chalk were interbanded with it. This Drift is much contorted. . Rots! ~ \ = ~ got Saale) 1 = Whitish boulder-clay, or rearranged material from it. 2 = Vertical wall of Chalk ; flint-bands locally curved, cut obliquely. 3 = About 1 foot of banded clay and sand, apparently in a vertical position. 4 = Nearly vertical face of a grey stony clay. 4a, 4b = Bedded sands in the same—possibly only parted by a ‘wash-over’ of clay ; but if so, the latter band is much thinner than the former. 5 = Variable stratified, sometimes false-bedded, sand, about 10 feet thick. 6 = Grey boulder-clay (the lower mass), very characteristic, with fairly large boulders (Scandinavian) at the base. Nearly 9 feet thick. 7 = Chalk with flint-bands (not clearly displayed). As the sections are not in parallel planes and the curvature in 2 is very local, the discordance in bedding is more apparent than real. 8 = Pebbly beach and sea. x = Soil and vegetation, about 15 to 18 inches thick, and rather overhanging near the position of the letter. y = Sand rather obscured by slips. z = Slope of chalk-rubble, the southern side the Drift rests against an old cliff of Chalk, while on the northern it overlies a sloping surface of the same rock.’ A short distance south of the Kieler Bach, Drift is seen high up on the cliff apparently filling a shallow valley or basin, but as this spot is 1 This, on approaching the bottom of a glen, rises in a slight ridge. 14 PROF, T. G@. BONNEY AND REV. E. HILL ON THE ([Feb. 1901, inaccessible we merely note the fact as significant. The second descent of Drift to the beach, at a rough estimate, is 400 yards south of the Kieler Bach; a third comes, perhaps, in another 300 yards, followed after an interval by a fourth. The Drifts descend the cliffs obliquely ; in the second and third sections they seem to be interstratified with the Chalk, but in the fourth some reddish sand appears (it is rather masked by slip) over part of that rock and the upper clay, while at the top of the cliff the whitish boulder-clay extends over the whole. In all these sections, the lower boulder- clay is fairly constant in thickness, some 18 or 20 feet; so also is the sand (perhaps 15 feet), which exhibits progressive changes upward, showing in two instances at least a seam of gravel at the bottom only ; but the upper clay in two sections is much thinner (not much over a third), and in one considerably thicker than the lower clay. Itis therefore impossible to consider that these deposits are doubled up. But another grave difficulty exists, which appa- rently has not struck those who support this hypothesis. The folding, as we can see, must have occurred immediately after the deposit of the older Drifts, which then must have consisted, not of clay, sand, and clay, but of one clay followed by sand. Even if we suppose these to have been frozen, they must have adhered with singular persistency to the Chalk to permit of the beds, shown in the first diagram (fig. 8), being doubled up so neatly (like a closed book) as in the second (fig. 9). Certain of these sections, Figs. 8 & 9. —Diagrammatic sections at first sight, seem favour- to alustrate the ‘ folding hypothesis,’ able to the hypothesis of showing the relations of the Chalk faulting. But it also pre- (a) and the Drift (b, ¢) before and sents serious difficulties, after the doubling-up. some of which we men- tioned in our former paper, while others came out more strongly during our revision. The gravest of these is of a general character. As stated Beeb above, we are justified in WPL i assuming the Drift to have formerly rested upon the Chalk in a nearly horizontal position. Why, then, do the members of this Drift plunge, as a rule, so sharply and suddenly towands the fault-plane on its downthrow side? The appended diagram (fig. 10, p. 15) will suffice to show the abnormality of the arrangement.’ 1 Of course, the difficulty may be got over by making the faults reversed (as is done by Dr. R. Credner at the Kieler Bach), but for this we can find no evidence. [We may refer here to a difficulty raised by a friend after this paper had been read: namely, that as the flint-bands exposed in the cliff appeared generally to have a southerly dip, the Chalk must be extraordinarily thick. But we pointed out in our former paper (p. 306) that the folds in that rock Vol. 57. ] DRIFTS OF THE BALTIC COAST OF GERMANY. 15 We again failed to discover any signs of conspicuous faulting in this district. Slight dislocations do occur where the Chalk shows most indications of folding, as in the part nearer Sassnitz, though certainly not in the region of which we have just spoken. But we did find additional evidence of the letting-down of these Drifts into valleys. One we have already mentioned. The Lenzerbach section is another; for in this, when regarded from the sea, the junction- surface of the Chalk and the overlying Drift takes the form of a reversed flattened arch. wostniagign elt ae. : Ca i SAILlS YIE/F Katb-an, WHA, yyy) WW YO Wypyyp oP? «la/42ub, 40 pazsoqlion Mpauialye MSY RD ye LE MIL, Lis pe ‘SUM Ua24E Ayyib waryso ‘sopyphifd EE? OREELZ TED EERO Wo ie ARGS SES YY Yj Dy 7 : oy D27IOAUU ! Nggold spay *IAOL Late Sgenep panaiion | 'd'0'33002 : Ci, Pag AMusOyOun 7 <-----S9/A9G UIIDAL) ---> Sr rrr nn enn meen nnn -- Of//2aPUe/7 ope S oie a wee ee <—e be EZ Yue Yo, Myeysyoars IIS Snomdly yoeg ple Vii Ye = lS YD ttjj VEYA. SOU [Yo KI9149 said pie ; Y 4 J ti Seats 2 yy Tae ZY ,p}.14 ppt” y ‘O'u ef ey>} Wty yjjp LE is YZ 7 Yj Zl i es ; > MIN'N i ULE UIeD Z oy uoeur-A-us], a el sesu % JTe9u "a'0 "4 00F penuyuog HNOT [1098D) -Utng) ayn (02 Jayvendqns pun) fo rsan ‘wing-h-pphuhyy ssouov uoroogy—"T “OLA Vol. 57. | THE GEOLOGY OF MYNYDD-Y-GARN. 23, and against green breccias on the south. This fault is readily traceable on the ground ; and though its plane cannot actually be seen, it is most probably a thrust-fault, on account of the intense contortions of the green phyllites, and because the green breccias. appear to be inverted and to pass below the phyllites. Garn Conglomerate, Grit, and Breccia. This formation is perhaps 400 feet thick: its base rests upon the phyllites, and it passes upward into Black Slates. Its main outcrop crosses the summit of the hill, and forms a band divided into two portions by a transverse fault (the Garn-Castell Fault). In addition, on the north-west, near Pen-mynydd, its upper portion is seen, caught in between faults; and at the opposite extremity of the hill, near Cefn-du-mawr, its upper zones are once more exposed, represented by green breccias. The formation is sometimes a coarse angular breccia, sometimes a conglomerate with pebbles fairly well rounded, often a grit with or without pebbles. In its north-western part the fragments are commonly of quartz and grit, and of quartzose, schistose, gneissose, and granitic rocks. To the south-east, towards Cae-engan, pieces of green phyllite are very abundant. Rocks corresponding to the former are found zm situ near Mynachdy, 14 miles to the north, and at Pen Bryn-yr-Eglwys, 2 miles to the north-west; while the pebbles of green phyllite agree precisely with the rocks of the inlier, and show conclusively that the latter were in their present condition of alteration before the deposition of the conglomerate. The Garn Conglomerate has approximately the same strike and dip as the underlying phyllites, and it therefore presents in the field a false appearance of conformity with them; an illusion which is only dispelled by the evidence of the contained pebbles mentioned above. The conglomerate is often crushed and coarsely cleaved, and its bedding is sometimes obscure. Its dip is northerly and north-easterly, at angles varying from 20° to 75° or 80°. Its highest beds contain some layers of black shale, and a transition- zone of black shales with courses of grit and breccia intervenes between it and the Black Slates. The green breccias at the southern end of the hill which are faulted against or overthrust by the green phyllites, represent the uppermost part of the conglomerate. They dip towards the phyllites, and contain bands of black shale. They are made up almost wholly of angular pieces of green phyllite," and in places are almost indistinguishable from brecciated portions of the phyllites themselves. These breccias are thought to be inverted because they apparently pass down into black shale, whereas the sequence on the east side of the hill shows that the black shales lie above the breccias. 1 See Quart. Journ. Geol. Soc. vol. lv (1899) p. 676: note on microscope- slide N.A. 53. Fig. 2.—Geological map of Mynydd-y-Garn and the surrounding area. an SCALE: © Jinches=imile SS x a, Z Ys \Hendre-f Dsl yyy Yl: MP 7, Llanfaix-y’nghorn MUMS "-y-maen ity = 1A:Mynydd-y-Garn o,° 2 6 0 Sass a Lixpanation:- Ss I S (Llanfair Uf 2 Blac S Yntfornwy Beas LL RO Jad Shales... N =S) onélomerate, N ES. SS | Lslomente een — “ Post Ordpician y ret se, x ROCKS. Vol. 57.] THE GEOLOGY OF MYNYDD-Y-GARN. 25 There is sufficient evidence to show that the rock-sheet of which the Garn Conglomerate forms part was once of fairly wide extent; and its frequent absence from the edges of the Black-Slate areas is the result of faulting and not due to lack of deposition. Portions of it are met with on the eastern slope of Pen Bryn-yr-Eglwys,* 2 miles to the north-west; at Porth Padrig near Mynachdy in the same neighbourhood, where it contains fossiliferous limestone- nodules?; and at Clymwr,’ 4 miles to the south-east, whence it has been traced for some miles southward. ‘The conglomerates and grits of Northern Anglesey are, in all likelihood, parts of this same rock-sheet.* The Garn Conglomerate is inferred to be of Llandeilo age, partly because it lies immediately below Black Slates containing Upper Llandeilo fossils, and also because it can be correlated with neighbouring conglomerates of Llandeilo age. Several microscopic sections have been examined, and they bear out the descriptions just given. Crushing and shearing are observable in most of them. A small well-rounded pebble obtained from the Conglomerate near Cae-engan was sliced [N.A. 141] and -was found to consist of rock-fragments of schistose grits, etc. embedded in a slaty matrix. The schistose area from which this pebble obtained its fragments must have been of considerable antiquity, because it is clearly separated in age by two strong unconformities from the Llandeilo conglomerate.’ Black Slates and Shales. On the north-eastern slopes of the Garn these contain at their base bands of grit and breccia, which connect them with the underlying Conglomerate. The beds above this transition-zone are black laminated shales with courses of hard black unlaminated mudstone. About 600 feet in all of these rocks is here seen; they dip steadily north-eastward at angles of 35° to 45°, and are suddenly terminated on the lower slopes of the hill by an overthrust of the Llanfair-ynghornwy Beds, near which they are usually quartz- veined and very pyritous. South of the Garn inlier they are black or dark-blue slates of a rather uniform and monotonous character, and their strike follows the general curvature of the boundary-thrust. The dips, often wavy, are high, averaging about 70°, and usually are northerly, though southerly dips occur. These dips may sometimes be merely 1 Quart. Journ. Geol. Soc. vol. xliv (1888) p. 474. 2 Ibid. vol. lv (1899) p. 647. * Ibid. vol. xl (1884) p. 571. 4 Ibid. vol. lvi (1900) pp. 234 et segg. > Compare also the occurrence of schistose and gneissose fragments in the Green Series grit of Llanfechell (Bonney, Quart. Journ. Geol. Soc. vol. xxxvii, 1881, pp. 234-35, and Watts, 24d. vol. lv, 1899, p. 676). The evidence derived _ from this pebble supports Mr. Greenly’s interpretation of the coast-section at (Careg-Onen in the eastern corner of Anglesey, that below the Ordovician rocks of the island there are two older groups of rocks unconformable one to the other and to the Ordovician (Quart. Journ. Geol. Soe. vol. lii, 1896, p. 620). 26 MR. C. A. MATLEY ON THE [Feb. 1901, cleavage, but im many cases they certainly correspond with the bedding. The slates appear to be thrown into a number of steep folds. On the south and south-west they are faulted against older rocks. At Craig-y-gwynt (the ‘Telegraph Station ’ of the old Ordnance Survey map) a compound anticline of hard bluish-grey quartzose grit, whose base is not exposed, appears below the slates and passes up into them. “The conclusion seems to be a safe one that this grit represents the top of the Garn Conglomerate and _ the passage-beds to the Black Slates; but it must be admitted that, although it resembles lithologically the top zone of the Conglomerate near Pen-mynydqd, it differs strikingly in general character and in the © nature of its inclusions from the green breccias of Cefn-du-mawr, now less than } mile distant. It would seem that the angular green phyllite-fragments were distributed over a very limited area of deposition. Oolitic Ironstone. A fault runs along the western side of Mynydd-y-Garn in a south-easterly direction across the Black Slates. On the western side of this fault, in a field between Nant-bwbach and Rhald, are two exposures of a rock crowded with oolitic and a few pisolitic grains, which closely resembles the Penterfyn oolitic iron- stone of Northern Anglesey.” In the more southerly exposure it is a black oolitic ironstone or ferruginous mudstone, which passes upward into soft blue-black shale and downward into fine grit. About 8 or 9 feet of it contains oolitic grains, and there may be more oolitic rock con- cealed below the grit. The beds dip steadily north-westward at an angle of 58°. In the second exposure, 100 yards away to the north, the beds dip in the opposite direction, namely, south-eastward, at 20° to 30°. The oolitic rock is flaggy, and passes upward into grey grits that resemble the bottom beds of the exposure just described. It thus appears that the grit lies between two bands of ironstone.’ The zone appears to be not less than 20 feet thick. Un- fortunately its base is not exposed. Black shales dip towards it as if to pass below it, but they may be cut off from it by faulting. The presence of grit suggests that its horizon is at or near the base of the Black Slates, which is also the horizon of the oolitic ironstone of the northern coast of Anglesey; but if this be so, the rock should also occur on the slopes of Mynydd-y-Garn in the zone above the Conglomerate, where I have not found it. It is to be hoped that more outcrops of this interesting rock will be discovered, and that. its horizon will be definitely settled. 1 Quart. Journ. Geol. Soe. vol. lvi (1900) p. 236. * Mr. J. H. Stansbie, B.Sc., of the Birmingham Municipal Technical School, was good enough to make a rough assay of one of my specimens. He found in it about 28 per cent. of iron. Vol. 57.] GEOLOGY OF MYNYDD-Y-GARN. 27 Llanfair-y’nghornwy Beds. Between the Green Series of the Northern District and the Black Slates of the northern and eastern slopes of Mynydd-y- Garn intervenes a group of rocks consisting of green, blue, and brown gritty slates and phyllites, with layers and nodules of grit, and beds of grit, quartzite, and limestone. For convenience of description I style them the Llanfair-y’nghornwy Beds, as the village of that name is built upon them. In a quarry near the church they are exposed as grecn slaty rocks (phyllites), and they there lie upon the Black Slates and appear to dip conformably with the latter, but there is no passage between the two kinds of rock, which are crushed at the junction. The junction, in fact, forms part of the great thrust-fault which sweeps in a curve through Llanfflewin in one direction to the sea at Porth y Corwgl, and in the opposite direction in a sinuous line to the sea at Porth yr Ebol.’ Near the thrust the rocks are often broken, crushed, and sheared ; the structure is usually phacoidal, and coarser and harder portions of rock are broken up and involved in the finer and more slaty—the structure, in short, is frequently that of a crush-conglomerate. Good examples of these effects of pressure-action are to be found on and around the farm of Tyn-y-maen, where the weathered surfaces of the beds have a conglomeratic aspect. In these broken beds occurs a thick band of limestone, which has no visible out- crop but was met with, close to the thrust-plane, in a ‘level’ driven through these rocks; and irregular masses of quartzite of the ‘ quartz-knob’ type also lie in them. A thick bed of the same kind of quartzite can be traced at intervals from Llanfair- ynghornwy Church in a north-westerly direction to Hendre-fawr; and similar quartzites are again exposed near Mynachdy, where there is also an intrusion of granite. The Llanfair-y’nghornwy Beds are cut off on the west by the Porth yr Ebol thrust, and on the east by the fault which brings the rocks of the Green Series against them. For some distance these dislocations have a parallel course, but they converge southward and meet south-east of Llanfair-ynghornwy Church. From the beds of quartzite and limestone that they contain, the Llanfair-y’nghornwy Beds may be correlated with the rocks of the _ Llanbadrig Series of the northern coast; and they probably lie at-or near the base of that Series, for as a whole they resemble more particularly the rocks along the southern border of the ‘ Northern Complex, where the present writer has sometimes felt that the boundary between the Green and Llanbadrig Series has been rather arbitrarily drawn. Some of the Llanfair-y’nghornwy Beds also resemble the rocks under the Conglomerate very closely, both in the field and under the microscope. 1 See description in Quart. Journ. Geol. Soc. vol. lv, (1899) p. 645. The a a map shows that the fault does not fork at Caerau, as I there stated, ut ata point south-east of Llanfair-ynghornwy Church. 28 MR. C. A. MATLEY ON THE [Feb. 1901, III. Fossrts. The few fossils that have been discovered have all been collected from the Black-Slate zones. The zone of interbedded grits and slates above the Garn Conglomerate has yielded none near the Garn itself; but similar rocks are exposed a few miles away to the south- east, in a quarry near Llanbabo Church referred to by Dr. Callaway,’ and I there collected Lingula sp. (common), and the following -graptolites :—Duplograptus teretiusculus (common), Leptograptus ef. validus, and possibly, though doubtfully, Climacograptus sp. These have been identified by Miss E. M. R. Wood, who remarks that ‘the age of the beds as determined by the graptolites is Upper Llandeilo, about the age of the Cenograptus-beds. Prof. Lapworth has also examined these specimens.’ At Bwlch, south of Mynydd-y-Garn, in the Black Slates without grits, I obtained a single. graptolite—Leptograptus, probably the same species as above. Distant 7 mile from Bwlch is the oolitic rock already described, which contains an occasional horny brachiopod :—Lingula or Sipho- notreta (?), Acrotreta sp. (brachial valve only). TY. Earta-MovemMeEnts IN THE Districr akounD Mynypp-y-Garn. The region around Mynydd-y-Garn has been affected since Llan- deilo times by earth-movements acting from two directions. This is easily inferred by studying the strike of the rocks and the trend of the faults ; for both faults and strikes fall readily into two groups, according as they run more or less (1) eastward or (2) south-- eastward. About 5 miles south-east of the Garn a third movement has produced a third system of faults and bedding-strikes, which run north-eastward. ‘This last-mentioned movement, which has affected the largest part of Anglesey, has not been studied by me, as it has produced but slight effects in the area under notice. The easterly strike is the result of a powerful movement acting from the north. All the country west of the Garn and away to Carmel Head has felt its effects markedly. At Carmel Head green phyllites with broken beds of quartzite and limestone have been driven over Llandeilo Slates*; wihile, farther south, Llandeilo Slates and older rocks alternate with and are dovetailed into each other in augen-like outcrops, the Llandeilo Beds tailing out to the west, the older rocks to the east. The rocks are faulted, overthrust, cleaved, crushed, and shattered, and, with the exception of the Llandeilo Slates, are largely in the condition of crush-conglomerates. The boundaries between. the rock-groups are sometimes fault- dykes. The south-easterly strikes have been produced by movement acting from the north-east, and its effects are best seen at Llanfair- ynghornwy and in the country lying north-west and south-east of 1 Quart. Journ. Geol. Soc. vol. xl (1884) p. 580. 2 Tbid. vol. lv (1899) p. 646. Vol. 57.| GEOLOGY OF MYNYDD-Y-GARN. 29 that village. The crushing and thrusting that have resulted in this area have been already described in the foregoing pages. In the tract south-west of the Garn the principal faults still have this south- easterly course; but at and near the southern end of the hill the bending of the faults and the curvature of the strike suggest that the movement from the north-east has been combined with a movement from some other direction, perhaps from the north. V. Summary. The stratigraphical study of Mynydd-y-Garn and its neighbourhood yields the following results :— (1) There are three groups of rocks, whose descending order is as follows : C. Llandeilo, comprising the Garn Conglomerate, Grit, and Breccia, which passes up gradually into Black Slates. (Unconformity.) B. Lianfair-ynghornwy Beds, correlated with part (probably the lowest part) of the Llanbadrig Series of Northern Anglesey. A, Garn Phyllites, correlated with part of the Green Series of Northerm Anglesey. (2) The rocks are much compressed, crushed, and faulted, and the apparent order suggested by the dips is quite different from the true sequence. The Garn Phyllites have apparently been pushed over the Llandeilo rocks; the latter are also overthrust by the Llanfair-y’nghornwy Beds, and these in their turn by the Green Series of Northern Anglesey. (3) An oolitic rock is found in the Black Slates in the neighbour- hood of the hill, but the evidence is at present insufficient to correlate its horizon with that of the similar oolitic ironstone of the northern coast of Anglesey. | (4) In the country to the west and north-west of the hill the rocks have been extensively crushed by earth-movement acting from the north, and the pre-Llandeilo rocks are largely in the condition of crush-conglomerates. (5) Around the Garn itself and east of it the principal direction of movement has been from the north-east; south of the hill the structure is perhaps the result of the interference of these two movements. In conclusion, I wish to express my indebtedness to Prof. Watts, M.A., Sec.G.S., for having again examined my rock-sections and for permitting me to incorporate the results of his examination in my paper; also to Miss E. M. R. Wood and Prof. Lapworth, F.R.S., for kindly identifying the graptolites. Discussion. The Rev. J. F. Buaxe said that he was familiar with the ground described by the Author, and had no criticism to offer on his con- clusions. The most interesting feature appeared to be the existence 30 THE GEOLOGY OF MYNYDD-Y-GARN. [Feb. 1901, of an isolated mass almost everywhere bounded by faults. The difference also of the breccia-conglomerate here from the pebbly conglomerate a little farther north is very remarkable. Much of the older rocks hereabouts and to the south are breccias ; some of them are crush-breccias, which are local; but most are originally eruptive, though squeezed later. The speaker thought that the pisolites here would be found to represent a definite horizon, like those in the Lleyn and near Bettws Garmon. Prof. Warts also spoke. The Avruor thought that very little reply was needed. The pisolitic iron-ore of the mainland of Wales, according to the text- books, is of Arenig age, while the oolitic ironstone of the northern part of Anglesey is assignable to the Llandeilo. Vol. 57.] | TUFACEOUS RHYOLITIC ROCKS FROM DUFTON PIKE. 31 3. On some TuFacreous Ruyoxiric Rocks from Durron Pixs (West- MORLAND). By Frank Rurtey, Esq., F.G.S. With Anarrsus by _ Purp Horranp, Esq., F.1.C., F.C.S. (Read November 21st, 1900. ) [Puate I.] THE specimens which form the subject of this paper were selected for examination on account of their peculiar appearance, and because it was thought probable that they might afford some evi- dence of solfataric action on British rhyolites of considerable geological age. ‘Through the kindness of my friend Mr. H. B. Woodward, F.R.S., I have been able to learn a few particulars concerning the geology of Dufton Pike. From these it appears that the central portion of the Pike consists of volcanic rocks of the Borrowdale Series, bounded by four faults, those on the east and west being approximately parallel and running in a north- north-westerly direction. The rocks faulted against this central mass of volcanic rocks are of Lower Silurian age on the north, south, and east; while those on the west are Upper Silurian, consisting of Stockdale Shales and Coniston Flags. The specimens about to be described were collected by the late Prof. A. H. Green, F.R.S., and Mr. J. G. Goodchild, F.G.S8., and were evidently procured from the Borrowdale Volcanic Series which con- stitutes the central mass of Dufton Pike. The specimens were given to me many years ago, so that, never having visited that part of - Westmorland, I am ignorant of the precise spots from which they were derived. The chief interest which attaches to them lies in the peculiar character of the alteration that they have undergone: an alteration which appears to me to have been probably due to solfataric action. For the careful analyses which accompany this paper I am indebted to the kindness of my friend Mr. Philip Holland, F.1.C., F.C.S., and for some admirable photographs to Mr. F. Chapman, A.L.S., F.R.M.S. The rock from the northern end of Dufton Pike appeared at first sight to be very like one previously described by Mr. Harker, but further examination leads to the belief that it differs therefrom considerably in some respects. The following is a description of these rocks :-— No. 1. Northern end of Dufton Pike.—A pale brownish rock, with some darker brown specks and diminutive colourless crystals which have a vitreous lustre. The cut surface shows minute greyish-white specks and a few small irregular veinings. A section of this rock, when examined in ordinary transmitted light under the microscope, shows a nearly colourless to brownish- yellow groundmass, containing numerous porphyritic crystals and fragments of felspar, most of them in a more or less altered condition, and crystals which for the most part give square or approximately square sections. The latter are generally opaque and of quite microscopic dimensions, so that when examined in 32 MR, F. RUTLEY ON TUFACEOUS RHYOLITIC [Feb. 1901, reflected light under low powers it is difficult to say more than that some of them are dark or even black, while others are opaque and white. Since, by this means of illumination, none of the former display any brassy colour or lustre, they may probably be regarded as. magnetite, while the latter are evidently pseudomorphs of a white substance, possibly replacing crystals of spinel or garnet. Throughout the groundmass occur a great number of apparently circular, dusty-looking, brownish to brownish-green spots, averaging about =}, inch in diameter (Pl. I, fig. 1); but occasionally they are elliptical, or appear to have been drawn out in the direction of the rather obscure fluxion-banding. In polarized light these spots undergo extinction between crossed nicols, and are seen to be small fragments of crystals surrounded by a narrow isotropic border of the groundmass (PI. I, fig. 6). The fragments scarcely ever exhibit any definite crystal-form; but some of them may here and there be found which show what is apparently the edge of a crystal, and sometimes obscure traces of cleavage parallel to that edge. Selecting such examples, it is found that the extinction-angle made to this edge is sometimes 0°, but very frequently about 37° or more: the mean of half a dozen measure- ments gave an angle of 37°to40°. The mineral may be regarded as augite. Itshows no appreciable pleochroism, and in some instances the fragments exhibit indications that the obscure traces of cleavage intersect nearly at a right angle. The nuclei of some of the small spots apparently consist of fragments of felspar, and in some cases. chlorite may possibly be present. It does not seem that the spots are in any way due to the infilling of very small vesicles, but rather that the diminutive fragments represent a shower of volcanic dust incorporated with the lava. The porphyritic crystals and fragments of felspar are some- times comparatively little changed, but the majority are partly or wholly represented by alteration-products. The larger porphyritic crystals are in some cases orthoclase; in others, judging from their extinction-angles, they are oligoclase and andesine. In some instances they have been partly or wholly replaced by muscovite (Pl. I, fig. 1). This figure also shows the spotted character of the groundmass or devitrified glass. In other cases the crystals have been so greatly corroded that they no longer exhibit any definite crystal-boundaries, but merely form irregularly-shaped, spongy-looking patches which may be regarded as greatly altered and highly corroded vestiges of felspar- crystals. See Pl. I, fig. 2, where a patch in the upper right quadrant. is ina position of extinction, while other similar patches are brightly illuminated. Occasionally these irregular patches are connected by strings of the same substance or lie in close proximity (as in Pl. I, fig. 3), when it is possible, from their simultaneous extine- tion, to see that they form portions of the same original crystal, of which they are now mere vestiges. From this it would appear that these crystals were derived from an earlier source than the less corroded felspars in the rock. Whether their corrosion is due to fusion in the rock in which they Vol. 57. | ROCKS FROM DUFION PIKE. 33 now lie, or to solution by hydrothermal causes, seems to be an open question ; but it appears more probable that it may be attributed to a slowly dissolving solfataric action. This view is favoured by the presence of a small amount of opal-silica, which has been demonstrated by the staining of certain spots in an uncovered section of the same rock by treatment with malachite-green, and the permanence of the stains after the section had been washed in hot alcohol. The spongy-locking fragments, above mentioned, have a very fine granular structure which renders them readily distin- guishable from the other porphyritic crystals in this rock. Car- bonates are present to a trifling extent: an uncovered section, when treated with dilute hydrochloric acid, effervescing chiefly around the margins of included crystals and fragments. Here and there clear, colourless streaks, which are rarely persistent for more than short distances, may be seen to lie in the groundmass. In some cases they apparently constitute bands following the general direction of the fluxion-banding. They consist for the most part of quartz, with slightly translucent brownish or reddish-brown crystals; also opaque white pseudomorphs with approximately square sections, which may possibly have been spinel or garnet, but it is difficult to form any decided opinion upon this point. There are also small opaque black octahedra, which are no doubt minute crystals of magnetite. Possibly a small amount of ilmenite may have been present; but, if so, it is now altered to leucoxene, and evidence upon this subject is unsatisfactory: the analysis of the rock shows, however, a small amount of titanic acid, only 0°45 per cent. The rock occasionally contains a few crystals, which in ordinary light are clear, colourless, and in some sections appear as elongated prisms with sharply-defined transverse cleavages ; while in what appear to be basal sections of the same mineral the cleavages intersect at right-angles. I think that this mineral is possibly scapolite. It is, however, only an exceptional accessory. Taking the whole of the evidence afforded by the microscopic examination of this rock, it may be regarded as a tufaceous rhyolite. Its very exceptional spotted groundmass is due to the inclusion of volcanic ejectamenta, mainly as a rather coarse dust, con- sisting chiefly of augitic, mingled with felspathic material, which has, to a considerable extent, undergone alteration. Small fragments of other rock, possibly of an andesitic character, but too much altered to permit of precise determination, may also be detected. ‘These lapilli constitute a very small proportion of the rock. . The great alteration of many of the porphyritic felspars; the corrosion of what appear to be felspars derived from an earlier source; the pseudomorphic nature of many of the smaller crystals in the rock; the presence of a small amount of opal-silica, indi- cated by the staining produced by malachite-green ; and the general appearance of a disintegration of crystals by solution, rather than by fusion; all seem to point to solfataric action as the chiet cause of the changes which this rock has undergone. Q.J.G.8. No. 225. D 34 MR. F, RUTLEY ON TUFACEOUS RHYOLITIC [Feb. 1901, According to the analysis made by Mr. Philip Holland (see p. 36), the rock may be regarded as having the composition of a soda- rhyolite. Its tufaceous character, although scareely pereeptible in the hand-specimen, is sufficiently demonstrated under the microscope. The specimen was given to me many years ago by my former colleague, Mr. J. G. Goodchild, who (I believe), from field-evidence, considered that it was probably a tufaceous rock. That he was right in this surmise is sufficiently clear. Whatever construction be put upon it, it is certainly a very peculiar rock, and one upon which a variety of discrepant opinions might be given. No. 2. Dufton Pike.—A very compact, pale bluish-grey to brownish-grey rock, with a few darker grey and blackish-green specks. The specimen has a somewhat uneven platy structure, which on transverse fracture gives an irregularly ‘ stepped’ aspect to the broken surface. Under the microscope the section appears, in ordinary transmitted light, to consist of a pale yellowish to colourless substance: this might be mistaken for a groundmass filled with small colourless rods, which on further examination can be proved not to be microlites. Numerous less translucent, granular-looking patches occur throughout the nearly colourless matter. These are most irregular in form, and their outlines are suggestive of little shreds cut from an ordinary bath-sponge. This brown substance con- stitutes apparently less than one-half of the rock. The nearly — colourless substance really consists of small fragments:of altered felspar, while the smaller proportion of brown matter les between the often closely-packed fragments, and is the groundmass in which they are embedded. Apart from the fragments, of which the rock is mainly composed, a few crystals and fragments of felspars, apparently oligoclase and andesine, are seen in this section, but they are usually too much altered to admit of precise determination. There are also some irregularly-shaped, opaque spots, visible here and there, which in reflected light are seen to be snow-white. They are doubtless leucoxene in most cases, since the analysis of the rock shows the presence of 0:47 per cent. of titanicacid. If the leucoxene be the result of an alteration of ilmenite, that alteration must have been complete, since no trace of unaltered ilmenite is to be seen in the section, nor do these white opaque bodies exhibit any definite crystal-boundaries. The entire section is seen, both in transmitted and in reflected light, to be traversed by an excessively delicate streaking, the lines being tuo fine to be described as banding. They pass quite indis- criminately through matrix and fragments, a circumstance which | shows that, if due to fluxion, that fluxion must have resulted from reheating of the rock after its consolidation. It seems more — probable, however, that this streakiness has been superinduced by solfataric action. Igneous fusion and the accompanying motion of a fused mass would scarcely have permitted the delicate structure of the altered felspar-fragments (later to be described) to have escaped injury, if not disintegration, through any such movement, and it seems more reasonable to attribute the delicate streaking to hydrothermal agency. Vol. 57.] ROCKS FROM DUFTON PIKE, 35 In polarized light, the few clearly recognizable crystals and portions of crystals of felspar are, as already stated, apparently to be referred to oligoclase and andesine; but, with regard to the more highly altered fragments which chiefly constitute the rock, still less can be _ affirmed with any confidence, since a definite boundary indicative of an idiomorphic crystal, other than a ragged and approximately straight line, can rarely be discovered to form part of the boundary oi one of these fragments or lapilli. When, however, such a boundary does occur, it is often found to he at 0° to approximately pie with the direction of maximum extinction, so that it seems probable that these fragments may in many cases be referred to orthoclase. Some of them, moreover, show indications of twinning on what looks like the Carlsbad type. The most remarkable feature about these fragments is that they appear to consist of a meshwork of small, colourless rods, lying apparently in any direction and intersecting at any angle. That these rods are not individual crystals is proved by the fact that, in each separate fragment, all the rods undergo simultaneous extinction between crossed nicols. It is evident, then, that they all belong to one and the same crystal. ach of these fragments, therefore, represents not only the breaking-up of a crystal into fragments, but the partial erosion of that fragment both superficially and internally (PI. I, figs. 4 & 9). There is one, and, so far as I can ascertain, only one, fragment in this section that affords clear proof of the foregoing statement. It isa rudely triangular fragment of unaltered felspar, which is seen to pass into a mesh of reticulating rods (Pl. I, fig. 7). Both the fresh felspar and portions of its adherent mesh extinguish simultaneously, thus proving that the meshwork of rods and the unaltered fragment of felspar are parts of the same fragment, the whole having originally formed part of one crystal. The little rodlike bodies which constitute the mesh, partly fringing and continuous with the fragment of felspar, have apparently the same refraction and other characters as the felspar-fragment from which they proceed. Why the felspar has been removed from the spaces lying between these small intersecting rods ig a matter which I leave others to decide. The removal of the felspar could scarcely have taken place along planes of more ready solubility, because the interbacular spaces are for the most part small triangular or polygona! areas ; yet that some kind of selective solution has caused this peculiar honeycombing of the felspar- fragments seems an unavoidable conclusion. The matrix or ground- mass in which these fragments are embedded appears dark during all stages of rotation between crossed nicols ; and, when tested with a Klein’s plate, scarcely any perceptible difference in the uniformity of the tint is to be observed, except that here and there a few minute birefringent specks may be discerned. When, however, this prac- tically isotropic matter is examined in ordinary transmitted light, it is seen to be crowded with globulites and little rods like those ‘which constitute the altered telspar-fragments, except that, as a rule, they show no double refraction. Without the aid of polarized light it is, therefore, difficult to distinguish the altered fragments from the matrix in which they lie; but in those parts of the D2 36 MR. F, RUTLEY ON TUFACEOUS RHYOLITIC [Feb. 1go1, section which exhibit a brown colour in ordinary transmitted hight the globulites are more densely packed, and where these cumulitic aggregates occur we may easily recognize them as portions of'the nearly isotropic matrix, As already mentioned, the fine streaky markings cut through both the matrix and the meshes of the altered felspar-fragments, the latter causing no deflection of the streaks. It is, therefore, clear that the streaks cannot be indicative of the fluxion of a lava. The rock may possibly have been a vitreous lava, freighted with a preponderance of felspathic lapilli and dust. This seems indeed to be the case, since the ‘rock partakes more of the character of a tuff than of a lava. It appears that solfataric action is mainly accountable for its present condition. No. 3. Dufton Pike.—This specimen was given to me by the late Prof. A. H. Green, F.R.S., and in general appearance so closely resembles the rock last described that it seemed quite likely that it would present the same microscopic characters, This supposition is fully borne out by an examination of the section ; therefore the foregoing description of No. 2 applies equally well to No. 3, except that in the latter the fragments are somewhat less densely packed, save along a few irregular lines. The following are Mr. Philip Holland’s analyses :— ANALYSES oF Rocks rrom Durroy PIKE. IE, EY: Per cent. Per cent. SIAC AA, Ae Pepe ett i OE 69-00 71:05 1°150 1°184 OO | actions Ath este: "45 47 MILs @ SARS Hepen op AY Cee 16°88 15°36 165 150 211) OAS, ale Si delete ele ep "88 “70 P “005 004 BOTY aie 8 SEMI i urs — "66 “009 Min® = 225: Joao eee not sought trace GEN Cece Fat eee eieoaee 1-04 29 015 “005 PAO a ee sie Bd pont not sought ‘ll JE O eS e a ke em ‘02 25 “006 OS Oa ee eet 3°88 6°18 “041 065 UN AND) Se cee ROY, OE, eo Si 4°64 324 CO,*. Combined water,; 4 - and matter not deter- 321 1°69 MEM Care dent epee eee 100-00 100-00 * Carbon-dioxide was detected in both rocks, and, for equal weights of the powdered rock, the effervescence noticeable on m oistening with hydrochloric acid was much more marked in No. I than in No. IT. The small figures represent the molecular ratios for the percentages beneath which they are placed, a a ed a ee ine ie Quart.Journ.Geol.Soc Vol. LVI. PLL. Frank Rutley del. M.P Parker lith. Mintern Bros imp. TUFACEOUS RHYOLITES FROM DUFTON PIKE, WESTMOREASi=s Vol. 57.] ROCKS FROM DUFTON PIKE, 37 The Brogger diagrams constructed from the molecular ratios of these rocks correspond so closely with -those of rhyolite (=Dufton Pike No. 2) and soda-rhyolite (= Dufton Pike No.1) that it is need- less to reproduce them, since such diagrams accompany the paper by Prof. W. H. Hobbs, entitled ‘ Suggestions regarding the Classification of the Igneous Rocks,’ published in the Chicago ‘ Journal of Geology,’ vol. viii (1900) p. 1. It is singular that so tufaceous arock as Dufton Pike No. 2 should be practically identical in chemical composition with a rhyolite ; but this coincidence may no doubt be, in a large measure, accounted for by the almost exclusively felspathic nature of the lapilli and dust which constitute so large a proportion of the rock. I have been unable, so far, to locate the small amount of baryta (=0-11 per cent.) shown by analysis to be present in this rock. It may be present among the felspathic constituents in the form of hyalophane, or it may exist as witherite, barytocalcite, or barytes; but the last surmise appears improbable, since the presence of sulphur is not indicated in the analysis. EXPLANATION OF PLATE I. Fig. 1. Dufton Pike No. 1.—Altered tufaceous rhyolite of Lower Silurian age showing very numerous spots in the partly devitrified groundmass. The spots are in most cases augitic, in others apparently felspathic fragments of extremely small dimensions. The partly corroded crystals and fragments of much larger size are felspar, sometimes orthoclase, at others oligoclase or andesine. In the centre of the figure is a crystal of orthoclase mainly altered into muscovite. x30. Nicols crossed. (See p. 32.) . Dufton Pike No. 1.—Fragments of corroded felspar, that im: the right upper quadrant being in a position of extinction. x 380. Nicols crossed. (See p. 32.) 3. Dufton Pike No. 1.—Vestiges of much corroded and altered felspars. All of these patches, with the exception of that just appearing on the right edge of the figure, undergo simultaneous extinction, so that they are parts of one crystal. x 140. Nicols crossed. (See p. 32.) 4. Dufton Pike No. 2.—Altered and highly tufaceous rhyolite. Smalb fragments of felspar in a partly vitreous groundmass: that on the right being represented by small rods of unaltered felspar which extinguish simultaneously ; that on the left shows very slight traces- of such erosion. x 140. WNicols crossed. (See p. 35.) 5. Dufton Pike No. 2.— Similar but larger fragments of felspar in the same section as that represented in fig. 4. x 140. Nicols crossed, Such fragments constitute fully ome half of the rock. (See p. 35.) bo The following figures are drawn from microphotographs made by Mr. F. Chapman, A.LS., F.R.MS. :— Fig. 6. Dufton Pike No. 1.—Showing a spotted part of the same section as that: represented in fig.1. Here some of the diminutive fragments, mostly pyroxenic or felspathic, are seen to constitute the nuclei of the spots. x 20U. Ordinary transmitted light. (See p. 32.) 7. Dufton Pike No. 2.—Showing portion of a small fragment of unattacked felspar, whence proceed small rods of precisely the same character as the mesh-like fragments (fig. 5) which constitute a very large pro- portion of this rock. The photograph was taken in the position of maximum illumination between crossed nicols. On rotation, the fragment of felspar and the mesh of rods proceeding from it undergo simultaneous extinction. x 200. (See p. 35.) 38 DR. J. W. EVANS ON A MONCHIQUITE FROM [FF eb. 1901, 4, A Moncureurtze from Mount Girnar, JunacarH (KatTHiawaR). By Jonw Wittiam Evans, D.Sc., LL.B., F.G.S. (Read Novem- ber 21st, 1900.) [Puatz IT.] ConTEN's. Page I. Monchiquites and their Isotropic Groundmass...............:..sseseee0 38 IE. Analeime.asya Rock-torming Mineral «......2..22.0.<:s.-. seen eeeeeeaane 40 11. A Rock with a Monchiquite-Matrix, from Mount Girnar ............ 4] TV Chemical Analyses eo - 0100). ccietiens caus 0 ts. «co sine onicle« eee 46 WV,’ The Nature-of the Isotropie Groundmass) ......0....c.-semseeeneeeeetee 48 Vi. The Historyrof the Rock cacseccaes cacbavces adda. is icons o-oo eee ee 49 NALD. S Bilbo sma ply gy. iyeisigc oe cel -cesiveesciins'v ach Se qui celeinceoibja aie eee 52 Sketch-map of the Central Ridge of Mount Girnar..................... 42 I. MoncuHiQuitTEs AND THEIR IsorRoprc GROUNDMASS. Tor term monchiquite is now recognized as the designation of a rock, consisting mainly of ferromagnesian silicates in an isotropic groundmass, which has approximately the chemical composition and specific gravity of analcime. The name was given in 1890 by Hunter & Rosenbusch [10]* to a rock occurring in narrow dykes, near Cabo Frio in the Serra de Tingua and elsewhere in Brazil, and containing pyroxene, soda- hornblende, mica, and olivine-phenocrysts in a colourless—or, rarely, transparent brown—matrix. This material, which they assumed to be a glass, contains numerous microlites of the porphyritic minerals and, when in a fresh condition, is completely isotropic. It has a specific gravity of 2°31. Ina few cases nepheline and, rather more frequently, a felspar with twin lamellation occur. The groundmass is very subject to alteration, natrolite and analcime being formed [20] p. 539 & [24] p. 283. In one instance fluidal structure was noticed to be present. The rock was distinguished from camptonite on account of its glassy base, and received the name of monchi- quite, as L. van Werveke had described a similar rock from the Serra de Monchique in Southern Portugal [7]. Rocks with a groundmass of the same character, but without olivine, have been reported from Bohemia by Boticky[ 4,5 ]and Hibsch [15]. Nepheline [5] p. 176, and leucite [15] p. 99, are sometimes present. J.R. Williams [11] described similar rocks from Arkansas, in which he believed a glassy base had once existed but had since become devitrified.? J. F. Kemp found rocks of this class in the 1 The numbers in square brackets throughout this paper refer to the Bibliography, § VII, p. 52. 2 In this case the glasslike groundmass showed greyish-blue interference- colours under crossed nicols, and was described as nepheline. * He proposed to separate the varieties without olivine, under the names of fourchite for those containing amphibole and pyroxene, and ouachitite for those containing biotite. But Rosenbusch does not consider olivine an essential constituent [20] p. 545 & [24] p. 233, and in any case the new names appear to be unnecessary. oe ee = Vol. 57.] MOUNT GIRNAR, JUNAGARH. 39 same district, in which an undecomposed isotropic matrix still exists fll] p. 395; and Kemp & Marsters have described similar rocks from the Lake Champlain region [13]. In 1896 Mr. L. V. Pirsson, of the United States Geological Survey, advanced the contention that the supposed glassy matrix of the monchiquites consisted in fact of analcime. He had been investi- gating rocks of this class in Montana, and at first accepted the view that they consisted of ferromagnesian silicates in a glassy base [19]; but ‘when the rocks were studied in connection with their geological mode of occurrence, it became a source of perplexity as to why such basic magmas... should have formed so much glass,’ while the more acid types which accompany them do not, under similar conditions, present glassy forms. Optical methods failed to yield any decisive results as to the real nature of the supposed glass, and reference was made to the chemical composition of the rock as shown by the analyses. After allowing for the chemical constituents of the minerals known to be present, the remaining silica and the alkalies, alumina, and water were found to correspond with the formula of analcime as nearly as could be expected, taking into account the fact that the com- position of the ferromagnesian silicates was not exactly known. The analysis of the isotropic matrix in the monchiquites described by Hunter & Rosenbusch was dealt with in a similar manner. The iron, lime, and magnesia, as well as the silica needed to form bisilicates with them, were removed; and the proportions of the remainder of the silica and of the alumina, alkali, and water were found to be those of analcime :— ‘It has the exact chemical composition, the exact specific gravity,! the property of gelatinizing with acids, and the optical properties of analcite; and must therefore be that mineral, and not a pitchstone-glass, as had formerly been supposed ’ [19] pp. 682-83. Pirsson further states that in the original Brazilian monchiquite ‘the analcite often shows a tendency to crystal-form by the production of areas which are free from the larger prisms of the ferromagnesian minerals, the latter being arranged around them in wreaths. The areas thus resemble phenocrysts of leucite, and they are in reality phenocrysts of analcite. They are sprinkled full of the microlites of hornblende described by Rosenbusch, which do not, however, show any tendency to the zonal arrangement shown by such inclusions in leucite.’ He considers the analcime to be primary, because of the fresh unaltered character of the minerals (op. cit. p. 686), and has difficulty in understanding how the base could have undergone a thorcugh chemical change and decomposition without the minerals being affected in the slightest degree, especially the olivine. 1 The specific gravity of analcime varies between 2°15 and 2°28, which is less than that (2°31) of the base of the type-monchiquite; but the latter contains microlites of heavier minerals. It is, however, not necessary that a glass of the same composition as analcime should have a different specific gravity. 40 DR. J. W. EVANS ON A MONCHIQUITE FROM ~~ [ Feb. 1901, More recently, Mr. G. T. Prior [21] has noted the occurrence of rocks of the monchiquite-type on Fernando Noronha, associated with the well-known alkali-magma rocks of that island. They are very similar to the Bohemian roeks. The colourless groundmass is isotropic, except in one case when it feebly depolarizes. He defers his decision as to its real nature. In an interesting paper published in the present year, Mr. John S. Flett has described dykes from the Orkneys, which are very similar to the Brazilian monchiquites [27]. He believes that the colourless matrix, which in this case has a slight action upon polarized light, is a glass which readily passes into analcime and other zeolites (op. cit. p. 890). The question of the true nature of the morthiquilesarc amen has also been discussed by Prof. Leewinson-Lessing [26] pp. 291-94, who suggests that, if it be analcime, it may be the result of the hydration of an original glass. II. Anatcrme as A Rocx-rormine MiInERAt. Attention was first drawn to the importance of analcime as @ rock-constituent by T'schermak, in his paper on the teschenites of Moravia, where he describes it as intergrown with felspar in a granular mixture, and sometimes amounting to as much as 27 per cent. of the rock [2 & 3]. Rohrbach described it in the same rock as without definite outlines, and filling the interspaces between other minerals [8]. Opinions have differed as to the origin of the analcime of the teschenites. HH. Mchl believed that analcime and natrolite were formed by the decomposition of a glassy matrix [6]. Rohrbach and Zirkel consider that analcime is an alteration-product of plagioclase [8, 14], while Rosenbusch would derive it from nepheline [12} p. 882 & [20] p.279.° I cannot find a suggestion that it was in any case an original constituent. In some instances it is undoubtedly secondary, but it seems quite possible that when it is intergrown with felspar or forms the groundmass it may be original. If this. be so, the rock may be regarded as an altered variety of the monchiquites, with which it agrees in chemical composition, except that it contains a little more water. In 1890 Lindgren [9] described an ‘analcite-basalt’ from the Highwood Mountains (Montana), containing augite, analeime, © olivine, and magnetite-phenocrysts in a fine-grained matrix of augite, analcime, and magnetite. ‘The analcime has definite erystalline boundaries, and occasionally shows double refraction. He believed it to be original, because the other minerals (including olivine) are in so fresh a condition. In 1897 Mr. Whitman Cross reported 1 It was first reported from these rocks by Glocker [1] in 1852. 2 A similar rock with interstitial analcime has also been described from California [16] p. 284 & [17] p. 27. See also [31] p. 191. 3 See also [11] pp. 66, 78-79, [16] pp. 284-89, & [17] pp. 27-29. Vol. 57.] MOUNT GIRNAR, JTUNAGARH. 41 another ‘ analcite-basalt’ from Colorado [22]. The rock contains, besides augite, olivine, and magnetite, a ‘considerable amount of a colourless and isotropic substance both in large and small grains’ without crystalline form. The groundmass consists of small grains of the material in question and of augite, magnetite, and felspar. Further, we are told that: ‘The larger grains are almost wholly free from inclusions. While probably the last substance to crystallize, the isotropic mineral has pushed back the smaller grains of augite and magnetite, so that they often form a distinct zone about it,’ ? The fracture is irregular. Becke’s method showed its index of refraction to be less than that of Canada- balsam. It was sepa- rated and analysed (see p. 47), and has approximately the compo- sition of analcime. The low proportion of silica in this analysis is attributed to the probable presence of nepheline among the felspar. An ‘ analcite-tinguaite’ from Essex County (Massachusetts) has been described as follows by Mr. H. 8. Washington [23]: ‘The clear colourless micro-groundmass ... . is holocrystalline, and com- posed of nepheline and analcite . . . . The patches of analcite are readily dis- tinguished by their cubic cleavage, exhibited by well-defined straight cracks erossing at right angles, by their generally isotropic character, and by the fact that their refractive index is notably lower than that of the felspars. In places they sbow a very faint double-refraction analogous to that of leucite, but not so well marked. ... The analcite areas are rather poorer [in inclusions] than those of nepheline.’ This rock is said not to be associated with nepheline-rocks, and Mr. Washington does not believe that it differs appreciably in chemical composition from an ordinary basalt, except by the presence of water. The three rocks last referred to ought not, I think, to be included among the monchiquites, as in them the isotropic material does not form the groundmass of the rock. It seems clear that it is in each case a primary constituent. III. A Rock wirh a MoncurevitF-Marrix, rrom Mount GirnaR. (See Pl. II.) I now proceed to give a brief description of a rock which presents many points of resemblance to the monchiquite-type. In the year 1893 and the earlier months of 1894, I was engaged in a geological survey of the State of Junagarh in Kathiawar, and soon recognized the occurrence of nepheline-syenite in the small isolated mountain- 1 While no crystalline form was observed, rings or wreaths of small inclu- sions were noticed in a.few grains, and these so strongly suggested leucite that, until the chemical analysis had been completed, he thought that the rock was a leucite-basalt. Occasionally the grains have a smoky tinge, and in a few cases the colouring-matter is arranged in zones clearly suggesting a crystalline form. Leucite also has been found (in missourite) in ‘formless masses filling the interspaces between other minerals.’ It is ‘perfectly clear and free from all inclusions, except now and then a grain of the ferromagnesian minerals.’ {30} 42 DR. J. W. EVANS ON A MONCHIQUITE FROM [ Feb. 1901, group of Girnar.* I took specimens, but have only recently had leisure to study them in the laboratory. The rock, which is the subject of the present paper, is closely associated with the nepheline-syenite, and is met with on the north- western shoulder of the central ridge of Girnar (which runs east and west). It is easily accessible from the small steps on the compara- tively little-used route up the mountain which, starting like the main ascent, at the end of the carriage-road from the city of Junagarh, turns off at once to the left, and passes round to the north of the rock known as the Bhairadva Jap. Sketch-map of the central ridge of Mount Girnar. y Scale:- 1 Inch =? Mile JOH ANMANDHARA UNDE PLE o~ Aa c - xSESAWAN T EMPLE Laem gBHAIRAVA JAP Be (GAOMUKI ‘ IK HUND z HATH! PAGLA KHUNDx ie AREA DEVE EMPLE “ BHAVESHWAR TEMPLE % A ae J y as —>,. : KHUND-AND Nes » Fort SSIKADIKA ween? 3295 Te, ~ Sa xX DHARMSALA KHUND we ie KXASHAPIR WELL M = Monchiquite. -===<={= = Footpaths. N = Nepheline-syenite, containing isotropic material in the interstices of the other minerals. Note.—‘ Khund’ means a spring or pool; ‘nes,’ a forest-hamlet. The central mountain consists of a mica-augite-diorite, passing peripherally into an olivine-gabbro which occupies the lower ground. These rocks are at many points penetrated, and some- times broken up, by dykes rich in alkalies, apparently of nearly the ' This lies immediately east of the city of Junagarh, and must not be confounded with the hills of the Gir Forest, which extend over a wide area in the east of the State. * I have to acknowledge the facilities afforded to me by Prof. Judd at the Royal College of Science, and the kindness of Prof. Bonney in arranging for the chemical analysis of rock-specimens. Vol. 57. ] MOUNT GIRNAR, JUNAGARH, 43 same age as the diorite; among these is the rock described in the following pages. It occurs on the margin of a nepheline-syenite containing very little ferromagnesian material." In hand-specimens it is fine-grained, and deep black except for numerous white specks. On examination under the microscope, the small white spots are seen to be colourless spaces, which are as a rule accurately circular and evidently sections of spheres. In most cases they are free from any of the darker constituents of the rock, though now and then a small crystal of hornblende is visible, or a long prism of the same mineral projects into the colourless area.” The mineral composition of these spaces differs from point to point, and will be dealt with later. Outside these colourless areas are abundant crystals of a slightly greenish-brown hornblende; some of the darker crystals, that have a slightly reddish tint, resemble the soda-hornblende barke- vikite. They are of all dimensions, from minute microlites up to 1 millimetre or more in length. Common green hornblende is occasionally found. A pale-green non-pleochroic augite occurs in much less quantity than the hornblende, and is the only important constituent that shows a likeness to any of the minerals of the diorite. It is sometimes found in comparatively large crystals, approaching 1 millimetre in length. These show occasionally terminal patches of dark-green pleochroic egirine-augite in crystalline continuity.” In other cases it forms the nucleus of a brown hornblende, likewise in crystalline continuity. The augite also occurs in small grains either disseminated through the rock or, more frequently, collected in glomeroporphyritic masses, usually irregular in outline, but in some cases showing definite rectilinear contours with angles that suggest pseudomorphs after hornblende. , Biotite is very rare, only one or two occurrences being noted in a large number of microsections. Sphene is fairly common. A few small granular crystals of an apparently uniaxial mineral with a high refractive index, but very low double-refraction, were seen in one of the irregularly-shaped colourless areas. It may possibly belong to the eudialyte-eucolite group. Itis of a pale yellow colour, like some of the eudialytes from Kangerdluardsuk (Western Greenland) ; but, so far as could be ascertained by the examination of these small grains in convergent light, the sign was negative, as in eucolite, not positive as in eudialyte. The interspaces between the coloured constituents are filled with colourless material, which will now be described in conjunction with that filling the circular areas. 2 Other portions of this rock are composed almost entirely of small grains of nepheline, which occasionally show the parallelism of flow-structure. 2 Occasionally similar spaces with irregular boundaries are seen. These are sometimes due to the coalescence of two spheres: not infrequently they contain .coloured minerals. ° The angle ¢:c¢ appears to measure about 60°. 4 Jn one case a twinned augite was seen to be surrounded by a twinned horn- blende having the same plane of composition. ; 44 DR. J. W. EVANS ON A MONCHIQUITE FROM __—[ Feb. 3901, In portions of the rock (including in some cases the greater part of a microscope-section) both the circular areas and the interspaces consist of a colourless isotropic substance of low refractive imdex. It has no definite boundaries, and is quite continuous, without any indication of break to mark the circumference of the circles. ‘These are defined only by the brown hornblende and the augite that surround them, and occasional grains of nepheline which play the same part as the coloured minerals. Between these the clear isotropic material passes out, and fills the interstices of the coloured minerals. The whole has a curious resemblance to a lake nearly covered with floating vegetation, between which and in occasional open spaces the clear water is visible. (See Pl. I, fig. 1.) In other places both interspaces and circular areas are made up of anisotropic crystals. Nepheline—sometimes dark in all positions between crossed nicols—is the chief constituent, but a variable amount of orthoclase is also present. A felspar with very fine twin- lamellation is occasionally seen, but not in sufficient numbers for determination: it is not improbably anorthoclase (soda- microcline). Microperthite can sometimes be recognized. The telspar occurs most frequently in the interspaces, while in the open circular areas there is nearly always an excess of nepheline. Elsewhere, while the interstices between the coloured minerals contain orthoclase and nepheline, the larger circular spaces are either entirely isotropic or partly so, and in part filled with nepheline or orthoclase’; but even in the former case the isotropic material does not show definite crystal-outlines. In the case of one area only where the anisotropic crystals were collected round the margin, their inner (apparently idiomorphic) borders seemed to give a regular polygonal shape to the isotropic space in the centre. This isotropic substance is in some places decomposed into small colourless rod-like crystals, with parallel extinction and interference- colours ranging from white to red and even blue of the first order. The cleavage is parallel to the length.’ The vibrations in this direction have the greatest velocity of transmission ; and if the crystal were uniaxial, and this were the direction of the axis, the sign would be negative. This appeared to be confirmed by exami- nation in convergent light, so far as the minute size of the crystals would permit. The mineral is probably cancrinite,’ and in this case it has every appearance of being an alteration-product. The presence of cancrinite would explain the evolution of gas, pre- sumably carbon-dioxide, when the powdered rock is treated with acid. The nephkeline, too, occasionally contains specks showing higher interference-colours, which probably indicate incipient alteration to cancrinite. | ! 1 In some cases idiomorphic nepheline is surrounded by the isotropic base. ? The terminations are not well-defined, and an indistinct transverse jointing, which is not always exactly at right angles to the length, may sometimes be observed. 3 See [11] pp. 79, 80. The comparatively low interference-colours are explained by the fact that the crystals are usually too small to occupy the whole thickness of the section. ~ <1 SEUERKR. SSS = 2 ea ae = = es naa BIR [Scales: vertical, 600 feet-=1 inch; horizontal, 40 chains=1 inch.] plotted to the new datum-line, with the exception of Halesfield, which i is in the Madeley district. ' This syncline is both wider and deeper than the Madeley syncline, 90 MR. W. J. CLARKE ON THE UNCONFORMITY IN THE [ Feb. 1901, and if the section be extended so as to include the Hadley and Wombridge district, which is the deepest portion and consequently forms the axis of the syncline, three more seams of coal and two more beds of ironstone (namely the Fungus Coal Group, belonging to the Middle Coal-Measures) are found, over and above those met with in the axis of the Madeley syncline. The extension of this section beyond Hadley, so as to include the other and steeper horn - of the curve, is prevented by the interposition of the north-western boundary-fault of the Coalbrookdale Coalfield, cutting off the coal- seams and bringing in the Bunter Sandstone in their place. This fault, with a downthrow of great extent, is a continuation of the Church Stretton Fault. Fortunately, however, the direction of this fault, and the anticlinal axis of which we are in search, do not run quite parallel, but intersect at a very acute angle in the neighbourhood of Donnington Wood. Thence past Muxton Bridge to the trial-pit at Lilleshall, the Middle Coal-Measures are found to rise sharply north-north-westward, as in the Madeley district. At Donnington and Muxton Bridge, however, the Upper Coal- Measures are wanting, having been denuded away, but at Lilleshall Trial Pit, Granville, Woodhouse, and Stafford Pits they are in their usual position. Therefore, a section drawn through the Coalfield, from Lilleshall across these pits to the Stafford, again shows the same unsymmetrical syncline as that exhibited in our former sections, but on a larger scale. In passing, I wish to make the suggestion that the Granville section, the best developed in the Coalbrookdale Coalfield, does not (in my opinion) represent the fullest development of the Middle Coal- Measures originally attained in Shropshire. I surmise that originally this coalfield approximated very nearly to the extraordinary thickness of the North Staffordshire Coalfield from the Bassey Mine downward. ‘The evidence for this view is not, I confess, conclusive, resting chiefly on these two facts: firstly, the gradual increase in number ofthe beds of coal and ironstone coming in under the Upper (red) Measures as we proceed from south to north; and secondly, the existence of a Spzrorbis-limestone above the Bassey Mine at Fenton. Retracing our steps to the Coalbrookdale field we find another little coal-basin, namely, the Inett-Caughley basin, again forming an unsymmetrical syncline on a small scale, of exactly the same type as that at Madeley. The Upper (red) Measures cut out all the productive Middle Coal-Measures on the ridges of the containing anticlines. The bounding anticlines were all mentioned by Prestwich in his famous memoir on the Coalbrookdale Coalfield, and it appears to me singular that their full significance has not been realized; to my mind they constitute the key to the whole problem. Passing over the intermediate ground between here and the Forest-of-Wyre Coalfield, two facts are worthy of notice: firstly, that at Eardington Deep Pit the Upper Measures repose directly on Devonian strata, and if my theory is correct we must regard this Vol. 57.] | COAL-MEASURES OF THE SHROPSHIRE COALFIELDS. a pit as being sunk on the top of a broad anticline. On the other hand, the outlier of older Coal-Measures on the Brown Clees would point to the surmise that there we are in the axis of a syncline; but denudation haying in this district operated in comparatively recent times, the data are not very plentiful, and I do not insist. Coming, however, to the Forest-of-Wyre Coalfield and its outlier of older Coal-Measures on the Titterstone Clee Hills, we undoubtedly again meet with the same phenomenon as that noticed in the Figs. 4 & 5.—Sections showing the present position of the strata, the post- seein Faults beng re-inseried. N.N.W Pudley Hi lp S,S.E | TE Pile nae 222 RES SE eal ea) _ N ~~ = SSC 2 2 ei Sales ta + YU Go 5N\ =i 1 as = Pe ao Upper Coal Measures \ a Middle Coal Measures M [Scales: vertical, 600 feet=1 inch; horizontal, 2 miles=1 inch.] N.W Sy TC 7 fe P3in ett EZ LL LL Wy —= a a te Ee — a = anticlines. | Pie ame Group. f= Faults. B=Best Coal Group. F = Fungus Coal Group. T = Top Coal Group. [The horizontal scale has been enlarged to 2 inches to the mile in fig. 5, in order to show the Madeley and Coeney Banltsi(f wif 2)? is Node in Prestwich’s Map and Memoir. | Coalbrookdale field, as shown by the dips on the Geological Survey Maps. This syncline in my opinion (an opinion which I deduced from its general direction, the similarity of the coals at Highley to those at Cannock, and the subjacent formation in both cases being red Devonian strata) continues to Huntington in Staffordshire, This syncline is bounded on its north-western side by an anti- cline ranging from Titterstone Clee Hill through Billingsley, and, J ee eee or ie 92 MR. W. J. CLARKE ON THE UNCONFORMITY IN THE [Feb. 1901, assume, continued underground, until a similar ridge is met with at Huntington Colliery. On the south-eastern side it is bounded by the Trimpley anticline through Shatterford and Compton, as shown by Mr. T.C. Cantrill." There, however, we meet with certain pheno- mena not found in the Coalbrookdale field. Firstly, there is, as pointed out by Mr. Daniel Jones, a series of unproductive measures, intermediate between the Middle productive grey Measures and the Upper non-productive red Measures (whose basement-beds are here represented by the rocks and marls under- lying the Main Sulphur Coal). As these measures are very thick in the Highley and Shatterford Pits, and on the other hand very thin or non-existent in the Harcott and Billingsley pit-sections, between which two groups a fault exists, it would seem as though this fracture had commenced before the Upper (red) Measures were deposited, whereas in the whole of the Coalbrookdale field I know of no fault that has occurred before the Upper Coal-Measures were first deposited, excepting of course minor slips. They all seem to be post-Carboniferous in date, affecting Upper and Middle Coal-Measures equally. Secondly, on the north-western flank of the Trimpley-Shatterford anticline the Upper Coal-Measures have been tilted to a greater extent than the Middle Series, owing, as I suggest, to voleanic action continued in Permian or post-Permian times. Summarizing the foregoing observations, we find in the Middle (productive) Coal-Measures of Shropshire a series of undulations diminishing in amplitude and length as we proceed from the north- west towards the south-east. The axes of these undulations have a general east-north-easterly direction, the synclines being unsym- metrical in form, having steep slopes on the north-north-west and rising at a very small angle to the south-south-east, as though the force of the undulatory movement originated in the north-west and was directed towards the south-east, the apparently rising ground of the Shatterford district forming a point of resistance. Between these synclines are a series of anticlines, from the tops of which all the productive Coal-Measures were removed, and the subjacent formations laid bare before the Upper (red) Measures were deposited. Such, I submit, is the nature of the unconformity which exists between the Upper and Middle Series, and constitutes the so-called Symon ‘ Fault.’ But the existence of undulations of this nature in the Middle Coal-Measures is not confined to Shropshire. Commencing with the Pendle line of upheaval, which runs past the mouth of the Dee through Ormskirk to Pendle Hill, and forms the northern boundary of the Lancashire Coalfield, we pass firstly the Rossendale anti- cline; then one in connection with the Great Bala Fault, dividing the Flintshire from the Denbighshire Coalfield, and visible at the surface at Caergwrle Castle and Caer Estyn, the coals on the south-eastern flank of which it has been the writer’s privilege to 1 *A Contribution to the Geology of the Forest-of-Wyre Coalfield’ Kidderminster, 1895. Vol. 57.] COAL-MEASURES OF THE SHROPSHIRE COALFIELDS. 93 work, the coal-seams lying both as to inclination and strike exactly the same as the coals at Madeley (Shropshire). Then there is the well-known Staffordshire anticline, running from Mow Cop past Madeley ; and others are more obscurely evidenced in the district about Shrewsbury, Haughmond Hill, and Childs Ereal. All these have the same general east-north-easterly direction as those in Shropshire. From this I infer that they were formed at the same time, under the same conditions, by the same causes, and that we must there- fore regard the region comprised between the Pendle range on the north, the Shatterford anticline on the south, the Welsh Hills on the west, and the Pennine Chain and its prolongations on the east, as one and the same coalfield, with the same geological history. Prof. Hull, in his ‘ Coalfields of Great Britain,’ has gone fully into this matter, and there claims to have been the first to show, in his paper read before the British Association at Liverpool in 1870, the pre-Permian age of these flexures, but dates them as post-Carboniferous. It is a difficult task to enunciate a view contrary to so eminent an authority, but I respectfully submit that the evidence which I have adduced goes to establish that the stratigraphical break (in Shropshire at any rate) was during Carbouiferous times, after the deposition of the Middle Coal- Measures, and prior to the deposition of the U pper (red) Measures. Should this contention prove to be correct, it will then follow that in searching for coal below the Triassic rocks, the presence of the Upper series of Coal-Measures forms no guarantee that the Middle and Lower productive series will be present underneath. The source from which guidance is to be obtained is the presence of synclines in the Middle and Lower Coal-Measures in the collieries in operation marginal to the Triassic area. For this purpose all sections of borings and sinkings should be carefully recorded, and in plotting out these sections all faults of later date than the Upper Coal-Measures must be carefully eliminated. On both the eastern and western sides of the above-mentioned region the exposed coalfields now in operation are believed, on fairly good grounds, to be separated from their underground con- tinuations under the Triassic area by downthrow faults of considerable displacement. The coal under these Red Beds will be struck only at a very great depth, and every unsuccessful attempt will entail an enormous loss. In order to avoid such a loss, too much pains cannot be taken to arrive at the exact configuration of the seams in the marginal workings. Discussion. Prof. Lapworra congratulated the Society upon the clear and business-like manner in which the Author had laid his facts and conclusions before the meeting. The general structure of the Coalbrookdale Coalfield had been more or less familiar to geologists since the publication of Frestwich’s fine memoir upon it in 1840, 94 THE UNCONFORMITY IN THE [Feb. 1901, The remarkable phenomenon of the Symon ‘ Fault,’ as originally described by Marcus Scott, had keenly interested geologists from the first; and his suggestion that it was due to a mere local denudation-valley had since been largely corrected and amplified by Mr. Daniel Jones. But the Author of the present paper was the first to demonstrate, by actual plotted sections, that in the Coalbrookdale Coalfield the Symon ‘Fault’ is a phenomenon of folding as well as of broad denudation. The transitional period of time between the deposition of the typical Middle and Upper Coal-Measures had long been recognized by Midland geologists as one of more or less regional upheaval and denudation ; and abroad this special inter-Coal-Measure period of crust-movement was described by Prof. Suess and others as one of the grandest in geological history—namely, that of the great Hercynian movement: the mountain-making period of the Harz, the Alleghanies, and the Armorican chains. It was of extreme interest to note from the Author’s sections that the Coalbrookdale crust-creep, although Armorican in date, so to - speak, was Caledonian in direction. There was much to be said also in favour of the Author’s opinion that other parallel and similarly denuded folds of Caledonian trend affect the Middle Coal-Measures under the Red Rocks of the Midlands, and that consequently the presence of Upper Coal-Measures affords no certain guarantee that Middle Coal-Measures actually occur below. Unfortunately, this was only one danger among many. The Coal-Measure Period as a whole was one of crust-movement, and there is evidence of this in the four usual directions. Though the predominant movement in the Coalbrookdale Coalfield was from the north-west, in the Bristol-Channel region the Armorican creep made itself most felt; whereas in other parts of England, as locally in the Midlands, sometimes the Charnian, and sometimes the Pennine creep has the greatest effect. Careful observations and conclusions, such as those of the Author, made by mining-engineers and bringing out the dominant local directions of movement, are certain to prove of ereat assistance in opening out the hidden coalfields of our country. Prof. Groom expressed his gratification that the Author’s results were in harmony with the views which he (the speaker) had pre- viously expressed. He congratulated the Author on obtaining a much-needed clue to the age of the north-easterly and south-westerly folds of the Welsh Border. It was necessary, however, to recognize that all the British folds parallel to this direction were not of the same age. A considerable part of the British Isles appeared to have been built up at different periods by successive addition of zones of plication, each lying south-east of its immediate predecessor. The Rev. J. F. Brake enquired whether there was any Spirorbis- limestone, or underclay beneath the coal in the Upper Measures here, since otherwise Prof. Hull’s suggestion of their possible classification with the Permian might be correct. But, assuming them to be true Upper Coal-Measures, the Author had drawn them horizontal and spoken of a plane of denudation of the Lower Measures; while gy A gg eign ms ——eEeEeEeEEEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeEeOoO Vol. 57.] COAL-MEASURES OF THE SHROPSHIRE COALFIELDS, 95 Marcus Scott had represented the line of junction of the two series as met with at various depths along a valley-like line. This locality had been already quoted as affording evidence of a period of mountain-upheaval in the middle of Coal-Measure times, and the Author’s account was more favourable to this than Scott’s; but in any case the bendings were comparatively feeble. The other localities quoted afforded very little satisfactory evidence of any great upheaval at this period, as was shown by the speaker seriatim ; and there was no proof that the patches in relation with the Haffield Breccia belonged to the Upper Coal-Measures—or had been originally deposited where now found. On the other hand, the neighbouring Upper Coals at Abberley are themselves inverted, as pointed out by Murchison. The authority of Prof. Suess had been invoked for the existence of an upheaval at that time throughout Kurope; but the upheaval to which Suess referred, as was evident from the context, was one at the end of the Carboniferous Limestone Period—his ‘ Upper Car- boniferous’ embracing the whole of our Coal-Measures. If, therefore, there were three great upheavals—at the beginning, middle, and end of the Coal-Measure Period—that period must have been one of oreat disturbance, alternating with the most tranquil conditions necessary for the formation of coal, a supposition which was scarcely credible. Prof. Watts pointed out that Scott’s paper was founded on the interpretation of afaulted and disturbed district. He interpreted it on the assumption that the Middle Coal-Measures were horizontal ; the present Author supposed that the Upper Coal-Measures were horizontal. It was significant that in these two cases theoretical results of far-reaching importance were brought out from the careful consideration and plotting of the sections obtained during colliery- operations. Prof. Hutt also spoke. The Avrnor said that these Upper (red) Measures extended from at least the Wrexham district on the north, to the Forest of Wyre on the south, as well as to North and South Staffordshire. The Main Sulphur Coal, the only workable seam in them in the Shropshire district, is found in the Shrewsbury, Coalbrookdale, and Forest-of- Wyre fields. As the Author believed, it had its representative in South Staffordshire ; it was a true coal-seam, with its own proper underclay, and must have been deposited horizontally. The inter- Carboniferous folds, though very important practically and econo- mically, could not be called ‘ mountains,’ as their greatest amplitude was about 160 yards, the thickness of the productive series. Whether these Upper (red) Measures ought to be classified as Permian, the Author was not competent to decide on palxontological. grounds, but they undoubtedly contain numerous thin coal-beds. The Lower or Gannister Series was not represented in Coalbrook- dale, unless the Little Flint Coal and the immediately contiguous beds could be regarded as such. The Carboniferous Limestone and Millstone Grit also thinned out and died away here. 96 MESSRS. JUKES-BROWNE AND SCANES ON THE [Feb. 1901, 8. On the Upper Gresnsanp and Cutoritic Mart of MzrEe and Marpen Brapizy in Wittsuire. By A. J.JuKes-Brownn, Esq., B.A., F.G.8., and Joun Scanus, Esq. (Read December 19th, 1900.) [Puates ITI-V.] ConTENTs. Page Lv ainibrod aehrony) ooo. .-cence sess 0 eins dens ccdes cles deuce eee 96 II. General Succession in the District .............c..ececceccees 97 TUG Mixposuresyor Gault; oo... csc ec ecenceeeecan sees eee eee 98 IV. Exposures of Malmstone and Micaceous Sands............ 98 VY. Exposures of Chert-Beds and Chloritic Marl ............ 100 VI. List of Fossils from the Chert-Beds and Junction-Beds. 114 Wels Conclusions 9} ..5 GN | im] ee S38 o~ s = 3 Se SAW wore GN a oo oe. ao > ee nO iS | L sp. nov. (sixteen Tibs) © ........6+eees esses sp. nov. (many TIbs) ...-.....++.seeee see tte es odiola Cotte (see Septifer lineatus). \ | Se | es | | Vol. 57.] UPPER GREENSAND AND CHLORITIC MARL OF WILTSHIRE. List oF Fossius (continued). 117 Ostrea canaliculata, Sow. Jeon coke, Meneame ne O. frons, Park... O. ‘Normanniana, @Orb. | O. vesicularis, Sow. O. vesiculosa, Sow. . Nucula cf. impressa (cast). Nuculana sp. (cast) Pecten asper, Lam. P. Beaveri, Sow. . elongatus, d’Orb. Galliennei, d’Orb. . hispidus, Goldf. . orbicularis, Sow. Passyi, @ Arch. Puzosianus (?) @Orb. subacutus, Lam. . sp. (close-set rounded ribs). sp. (with straight ribs) .. (N.) cometa, d’Orb. (N.) quadricostatus, Sow. (N.) quinquecostatus, Sow. . Pectunculus sublevis (2) . Perna sp. Pholadomya decussata, Phil. Pleuromya plicata (d’Orb.) .. ea Se a P. elongatus, Lam. Ee enispus, ‘Goldf. i subinterstriatus, a aera odeceiaiset . (Neithea) equicostatus, Tee wae Plicatula pectinoides, Sow. ............ss0see0 Pl. pectinoides var. inflata, Sow. Pl. sigillina, Woodw. Radiolites Mortoni, Mant. Ne ok We Septifer lineatus (Sow.) ... Spondylus striatus, Sow. Sp. sp. T. sp. Thetis Sowerbyi, Rem. . Thracia carinifera, Sow. 0... Teredo amphisbena, | (Cres WO Ss 2 I Trigonia crenulifera (?) Lyc. (cast) « Pre Tr. scabricola (?) Liye. (cast) . Tr. Vicaryana, Lyc. (cast) Unicardium ringmeriense, Mant. Venus rothomagensis, d’Orb. (cast) pela: BRACHIOPODA. Lingula subovalis, Dav. Kingena lima, Deft. Rhynchonella dimidiata, eng ite ae Rh. dimidiata var. convexa, Sow. Bee senses eose x e | Chert-Beds. OO: : PANN oH ow aam: : Sand above Cherts. Do FF ah NS eee aeons a ro cs mo & oM | £55 s.¢ | 3H aa! ae BS) oe Spy Vea iS) mH i IV b br b b m br b,m | br b Be 5 br | br br aa b oe b db br b b o b b br arate dps b b b 5 ae b auf b at r Bee |g $8. b A b : b ae r ante br ne b Bes 7) 7) b 6,7 : b ie b b b oe b b b b, m b m b Ee 6: , b br Chloritic Marl. 118 MESSRS. JUKES-BROWNE AND SCANES ON THE List oF Fosstts (continued). [Feb. 1901, Phosphate-Bed and Rye Hill Sand. Chloritic Marl. ee | ee | ee | ee o is | Siee 6 | 20s 3) () a jae) 2 oo a asi +e ae) nD Oy a ao) sa A) aes © M © I II III Rhynchonella dimidiata var. Schlenbachi, ... des b Dav. Ri RUT ASCU IO LOL ON Peed he... Wecnestucdcevsceecs|. 1 act b br Re UGRTCUIANGs SOW: iokcts eine sosmceace cee cak| Sex ef br Se PEDIT ET ROOW 2 x eee! ole Pan aee ieee cee aay ee ae fh Terebratella pectita, SoW. .....0.s.cccecececeees| oes b br Terebratula arcuata, Roem. ..........6..eccceces| one 6b 6b TESOL ULICMUG IOW «ac cas oan neuentedsecchweeeawdetwel | bas b b, m T. biplicata (flat variety) .. A Sern ace bs m T. squamosa, Mant. .... aS eee See eA IA sis br Terebratulina ig a Wahl. 2.000 3 T. triangularis, Eth. . be T. sp. (broad) . ; Terebrirostra lyra, ‘Sow. Bryozoa. Diastopora escharoides, Mich.................+. Heteropora ........ Membranipora (two. species) _ kc kate Meliceritites semiclausa Maer aks Micropora sp. Radiopora tuberculata .. eee Reptomultisparsa megalopora (Vine)... drsees . a Stomatopora granulata, HW. ..........60.ce| oe ase | Oba Spiropora micropora, Vine ..... ~~] CRUSTACEA. Necrocarcinus Bechei, Deslong. ............... NN. glaber, H. Woodw. . NV. tricarinatus, Bell .. Paleocorystes (?) Fe Phlyctisoma ? (claw of) | seh Yew me Ras leita ae se Potlacipes Bronwi, Roem. .....0.0.c..cclcccsceenel oa he b Ei ) ANNELIDA. i] aS Serpula annulata (?) Sow. S. plexus, Sow. Ge ARNE ERA EO Aa Bene of 6 iN oe Bc Se MUU B IEC SOW ea eis sundiosc.cis + «eens. Geskssresceseccaliy kee ie b EcHINODERMATA, Cardiaster fossarius, Benett C. suborbicularis (2) .. -_ oO BC) Catopygus columbarius, Lam. ....ecceccc| |B |by 7,20 Cottaldia Benettieg, Koenig .................... Discoidea subucula, Klein xo a: ~ s NO: br a i) oN n S al Ss | 2 | gi | se] 2 See Geol. Mag. 1894, p. 495. Vol. 57.] UPPER GREENSAND AND CHLORITIC MARL OF WILTSHIRE. 123: the former contains a fauna comparable with that of the Cornstones and the Rye Hill Sand*; while the base of the latter is a glauconitic chalk which has a Chalk-Marl fauna, but does not contain Stauro- nema. Here, therefore, the sub-zone of Stawronema appears to be absent; and a fauna resembling that of Rye Hill and Maiden Bradley occurs in a bed which is inseparable from the Greensand, and strongly marked off from the Chalk. The same is the case both in Western and in Southern Dorset, many exposures occurring in both districts and displaying the same general features. In the Isle of Wight the circumstances are different: the Stauronema-beds are well developed, and in most places have a nodule-bed at their base, which rests on a piped surface of laminated sand. This sand, however, does not contain many fossils, and, if comparable with anything at Maiden Bradley, it may be paralleled with the sand below the Cornstone-Bed. Here, therefore, on the contrary, we have no satisfactory base to the Lower Chalk, without including something that may correspond to the Rye Hill Sand. In Northern Wiltshire, near Urchfont and Devizes, there is again a well-marked base to the Stawronema-zone, and an absence of any beds exactly comparable to the upper part of the Rye Hill Sand. The evidence of these other localities is therefore conflicting, and it cannot be denied that the systematic geologist is here confronted with the horns of a dilemma: he must either exclude the Rye Hill fauna from the zone of Ammonites varians, although the cephalopoda of the Chalk-Marl are prominent members of it; or else he must include in that zone beds which are in some places separated by a strong physical and ontological break. If the succession in Dorset and Northern Wiltshire were like that in Southern Wiltshire, we should have no hesitation in so dividing the __ two formations as to place the Rye Hill fauna in the Cenomanian or _ Lower Chalk stage, because that would seem a natural inference from the evidence which we have recorded in this paper. We feel, a moreover, that such an arrangement would bring the Cenomanian _. of England more into line with the Cenomanian of French geologists, ** who insist upon including within it every bed that contains Ammonites varians. It is consequently with some reluctance that we retain the arrangement that is at present accepted, and we wish it to be clearly understood that we do so only for the sake of convenience, and in spite of the evidence adduced.in the foregoing pages. It is, in fact, one of those cases in which the palxontological is in conflict with the stratigraphical evidence. If the break in Dorset were not where we believe it to be, we could follow the lead of paleontology ; but, in the present state of our knowledge, we prefer to take the stratigraphical line in Dorset as the least awkward of the two alternatives, * See Proc. Dorset Nat. Hist. & Ant. Soc. vol. xvii (1896) p. 99, & Mem. Geol. Surv. ‘ Cretaceous Rocks of Britain’ vol. i (1900) pp. 248 et seqgq. 124 MESSRS. JUKES-BROWNE AND SCANES ON THE ([Feb. 1901, There is, however, a possible way out of the difficulty. The contemporaneous fauna of the top bed of the Upper Greensand in Dorset is certainly similar to that of the Rye Hill Sand and the phosphate-bed at Maiden Bradley ; but though fossils are abundant therein, Ammonites varians is not common. Hence it is possible that this bed is really the equivalent of the sand below the Cornstones only, and that the gap in Dorset is represented in Wiltshire not only by the Stauronema-bed, but also by the Cornstones and the sand between them. If this be the case, the objection to the inclusion of the Cornstones and the fossiliferous part of the Rye Hill Sand in the zone of Ammonites varians would cease to exist. We propose to make further examination of the Dorset sections in order to satisfy ourselves on this point. Meantime, both in order to emphasize the importance of the Rye Hill fauna, and to distinguish these beds from the rest of the Selbornian Sands, we propose to group these debatable beds as a distinct zone or sub-zone. For this the Echinid Catopygus columbarius will serve as an appropriate index, since it is especially abundant both at Rye Hill and Maiden Bradley as well asin Dorset, while it is rarely found in the Chloritic Marl above. Where most complete, as at Rye Hill, this sub-zone consists of three distinct beds, which, in descending order, are :— (8) Brownish sand, with many fossils, passing up into greenish-grey sand. (2). A layer of calcareous concretions (the Cornstones),. (1) A greenish sand-rock, with calcareous concretions. The recognition of such a zone or sub-zone of Catopygus colum- barius will be of service, because it will not only indicate the existence of certain passage-beds in Southern Wiltshire, which form an important factor in the complete sequence, but it will also enable us to refer with greater precision to their correct horizon in the series such portions of a less complete succession as occur in other places. Thus we can say that, in Dorset, a part at least of the sub-zone of Catopygus columbarius is present, and it will be in- teresting to ascertain whether there are any traces of the former existence of this zone in the Isle of Wight. The following is the sequence of beds which can be recognized at the junction of the Selbornian and Cenomanian, where the succession is complete :— 4. Chalk-Marl. 3. Sub-zone of Stauronema Carteri. 2. Sub-zone of Catopygus columbarius. 1, Chert-Beds. ; ) 3 ¥ — : ; : 5 : c - _ ¢ . =< - red : 3 : aii en — - ——— - > ; ' A ' ‘ e =| Ne - . re = See | £ .- f Deets : : ae . f : : ; \ _ : Fic ; - oar 1 ae. «a “a * 4 = re Fe : | ; «4 » | _ 7 * *. 5 eet ip . >See) Pe aes. ee ated et ee BPA COO | CSA) ALL ary eee le GEOLOGICAL MAP OF THE district of MERE anp MAIDEN BRADLEY in WILTSHIRE. Scale: 1 inch = 1 mile. EXPLANATION VA Ea Upper & Middle Chalk a4 Lower Chalk Upper Greensand A Gault Kimeridge Clay Coral Rag \ Kate's Benches Jump nea mana AUS oer Or ant ren aT Quart. Journ, Geol. Soc. Vol, LVII, Pl. IIT. *S9U04SU0G) = Gree escns ‘spog W0qD = C “9sUq olf} 4B ‘gaUOJSUIOH OY} MOTEG pueg = O pues UMOAG YIM “PAV OLIOTTD = VW (SAMIHSLIIM) AYYVNO AaTAvVaa NACIVW = ae eS c = —--— — a ——-- =~ -— - ———————— ee ee in - —~ ~—. = Be ES SIAM ILO LAS AIRE AAS DIE ie lial 8 PA i al an Sil ee = i ee ee ee — — F) —— — — - is - = GQ Quart. Journ. Geol. Soc. Vol. LVII, Pl. V. SBS ries a porn li ole aes DEAD-MAID QUARRY, MERE (WILTSHIRE). Hard Chalk Marl; C = Chloritic Marl; D = Popple Bed ; Bed C of Maiden Bradley (see Pl. IV). A = Chalky Clay; B E [The vertical line A’ B' indicates where the section was taken. | II Vol. 57.] UPPER GREENSAND AND CHLORITIC MARL OF WILTSHIRE. 125 EXPLANATION OF PLATES III-V. Prats III, Geological Map of the District of Mere and Maiden Bradley, on the scale of 1 inch to the mile. Puate LY. View of Maiden Bradley Quarry, showing the following succession :— A = The Chloritic Marl, with the position of the nodule-bed represented - by the uppermost stippled line. B = The Cornstone-Bed. C = The sand below the Cornstones. D = The Chert-Beds, obscured at the base by fallen débris, Prats V. View of part of Dead-Maid Quarry near the eastern end, where the fossil _ tree-trunk was found, a portion of which is embedded in the Popple- Bed, a little to the right of the vertical white line. This line indicates the point where the section given on p. 111 was measured. The lowest stippled line marks the uneven base of the Popple-Bed. The line denoting its summit rather exaggerates the actual unevenness, which may be partly due to lateral pressure affecting beds of different degrees of hardness. : Discussion. Mr. Lampiuen remarked that one of the Authors had shown inconsistency in taking a lithological in preference to a paleonto- logical division in this case, whereas in the parallel case of the zone of Ammonites mammillaris at the base of the Selbornian he had recently taken the opposite course. These constant difficulties in regard to the boundaries of formations showed how local most of such boundaries were, and how arbitrary and conventional they must necessarily be when applied over extended areas. The Rev. H. H. Winwoop and Mr. Wurraxer also spoke. 126 MR. S. 8. BUCKMAN ON THE BAJOCIAN [Feb. rgor, 9. Basoctan and Contievous Deposits in the Norra Correswonps: The Main Hitr-Mass. By 8.8. Buckman, Esq., F.G.S. (Read December 5th, 1900.) [Prats VI—Map. ] ConrTENTs. Page Ee Tintrod ne tron aco. cet sostiocca eacsansacsdoontense ieee 126 IT. Cause of the Bajocian Denudation ............s.secsccecassecees 128 III. Generalized Section of the North Cotteswolds ............... 129 IV. Detailed Sections in the North Cotteswolds .........cscseeces 130 ¥. Supplementary Notes ....0:....:.00ieessssoscassonce5 eee 138 (a) The Snowshill Clay. (6) The Harford Sands. (c) A Review of Work accomplished. (d) Section through the North Cotteswolds, from west to east. (€) Comparison with Prof. Hull’s Section. (f) Bajocian Denudation and the Vale of Moreton. (g) Bajocian Denudation and the Vale of Bourton. () Penecontemporaneous Erosions and the Position of Coal. Vi. Appondix Dy iiss sane sedhessiagactaci oie stsnnuneeeee eee eee 149 (a) The Position of the Upper Trigonia-grit. . (0) Note on the Upper Freestone Series. (c) Note on the Sandy Ferruginous Beds. (dZ) The Various ‘ Sands.’ VII. Appendix IT (Dates of some Erosions in ‘Jurassic’ Time)... 152 WELT. Suimantiary 3,5. h sae ste wnsadeeesees dasiewea sents schSeee- eee eee 154 I. IntRopvction, THis paper is a continuation of two former communications published by the Society, namely, ‘The Bajocian of the Mid- Cotteswolds,’ Quart. Journ. Geol. Soc. vol. li (1895) p. 388, and ‘Deposits of the Bajocian Age in the Northern Cotteswolds: The Cleeve Hill Plateau,’ vol. liii (1897) p.607. So far as the sequence of the strata themselves was concerned, the results arrived at in these two papers may be best expressed in Table I (p. 127). What the Table indicates is this :—In a north-easterly traverse from Birdlip to Cleeve there are found, at Leckhampton Hill five distinct beds separating two strata which at Birdlip were in juxtaposition; and at Cleeve Hill, three more distinct beds separating two beds which at Leckhampton Hill were in juxta- position, namely, the Upper Trigonia-grit and the Notgrove Freestone, and another distinct bed separating two other beds similarly placed at Leckhampton—the Snowshill Clay and the Upper Freestone. Consequently where nothing is intervening at Birdlip there are five beds inserted at Leckhampton Hill, and nine beds inserted at Cleeve Hill: that is, with regard to the five at Leck- hampton, three additional at the top, and one more at the bottom. Vel. 57. | OF THE NORTH COTTESWOLDS, 127 TABLE I.»—-SEQUENCE OF STRATA. Birdlip. Leckhampton Hill. Cleeve Hill. Upper Trigonia-grit. Upper rgmivgit Phillipsiana-beds. Bourguetia-beds. Witchellia-beds. Notgrove Freestone No tgrove Freestone. (a remnant). Upper Gryphite-grit. ———————_ Gry phite-grit. _ Trigonia-grit. Ye an Upper . T. Buckmani-grit———___ TI. Buckmani-gvit. oo Lower Trigonia-grit tH Lower Trigonia-grit. Snowshill Clay! Snowshill Clay. (a trace). Harford Sands. Upper Freestone. —————__ Upper Freestone. The ‘interest which attaches to the exploration of the North Cotteswolds is to ascertain how and in what manner this inter- vention of strata continues in a farther north-easterly traverse. The results are these :—That the three upper intervening beds at Cleeve Hill—the Phillipsiana-Witchellia-beds—have been planed away, so that Upper Trigonza-grit rests upon Notgrove Freestone ; but in the lower part of the intervening series there has been a considerable development of strata, so that an important series of deposits separates the Lower Trigonia-grit from the Upper Freestone. Other results are that the Lower Trigonia-grit is very considerably altered in lithic character, and that in the south-eastern part of the district there has been removal of beds below the Witchellia-grit, with the consequence that the Upper TZrigona-grit rests upon Snowshill Clay. What these results indicate are as follows:—After the deposition of the Upper Freestone there was denudation of the deposited strata, with greater erosion south-westward. Then there was gradual depression producing overlap of deposits,—the Harford Sands being deposited over the North Cotteswolds as far as Cleeve Hill, but not beyond ; the Snowshill Clay being deposited over a wider area, ? Entered in the paper on ‘The Mid-Cotteswolds’ as Harford Sands equivalent ; afterwards distinguished and corrected, see paper on ‘ The Cleeve Hill Plateau’ Quart. Journ. Geol. Soe. vol. liii (1897) p. 611. 128 MR. S. S. BUCKMAN ON THE BAJOCIAN [Feb. 1901, for it stretches to Leckhampton Hill; the Lower Trigonia-grit reaching farther—its lower part, however, not extending to Crickley, near Birdlip, though the rest of it does. The position of affairs may be roughly indicated in the appended diagram (fig. 1) :— Fig. 1. 5 D 3 é Z 2 = = g ae z ?) Cs] © ~ er a> > sas rs) a ro) RE, OS = ® BS ° 5 = 3 A Lower Trigonia-grit. Snowshill Clay. Harford Sands. Upper Freestone. After the Lower T7’rigonia-grit had been laid down, there was continuous deposition of other strata, until the Phzllipsiana-beds of Cleeve Hill had been laid down. Then there occurred another— the Bajocian—denudation, which again was most effectual in the Birdlip district, where it removed a whole series of beds down to, and perhaps lower than, the originally denuded Upper-Freestone surface. When deposition again set in, and the Upper Trigonia- grit was laid down, this deposit necessarily rested upon a denuded surface of the outcrops of diverse rocks. Il. Causz or tHE Basocran DENUDATION. In my paper on ‘ The Mid-Cotteswolds ’ (p. 481), I spoke of the Bajocian denudation as having -cut out a wide, shallow trough through the intervening beds of the Birdlip district. I was inclined to think that the strata had not properly consolidated, and that current-action might have swept away accumulations in certain places. But I have found evidence that the strata just deposited had consolidated. I obtained from the Cleeve-Hill plateau a bored — piece of Phillipsiana-beds, where the borings pass through shell and stone equally: that implies that the stone was as hard as the shell, otherwise the shell would have been avoided. The beds, therefore, were thoroughly consolidated before the denudation. Then Prof. T. T. Groom, writing to me about my Mid-Cotteswold paper, suggested that the previously-deposited strata had been thrown into folds whereof the anticlines had suffered denudation, SS Nol, s57.| ' OF THE NORTH COTTESWOLDs. 129 otherwise the Upper Trigonia-grit would have been deposited in the hollows. I was indisposed, however, to accept this argument, because the hollows found were so slight (they have only a fall of 7 feet per mile) that the surface would have been sufficiently horizontal to allow of the Upper 7’rzgonza-grit resting there. But there are other points to be considered besides the matter of consolidation. I have now found, by researches over a larger area, that the denudation of Jurassic rocks affected both England and Normandy, and that so far as the South-west of England is concerned, the lines of denudation fall into a fairly definite series of curves. ‘Therefore I am inclined to accept, and very gratefully to acknowledge, Prof. Groom’s suggestion. And I would put the matter in this way. During the deposition of the Bajocian, and at other times, small earth-movements occurred which threw the _ Jurassic rocks into folds of extremely slight elevation, in, probably, a very shallow sea. The anticlinal folds were denuded, and thus the edges of various deposits were cut across, exposed, and bored, and upon the surface so formed a deposit such as the Upper T’rigonia- grit was laid down. There were evidently two such periods of earth-movement and denudation during the deposition of the Inferior Oolite of the Cotteswolds,'—one after the deposition of the Upper Freestone ; another after the deposition of the Phillipsiana-beds. The latter was the most important: it extended into Normandy. At Sully, near Bayeux, are pebbles containing ammonites of the Sauzei- Witchellie hemeree—date of the Phallipsiana-to- Witchellia-beds of Cleeve Hill. Then at the base of the ‘ Oolithe ferrugineuse’ is a kind of remanié deposit with Stepheocerata; and then deposition proper commences with the ‘Oolithe ferrugineuse’ of the niortensis hemera—that is, it commences at an earlier date than in the Cotteswolds, for the Upper Trigonia-grit is one hemera later, namely Garantiane. Still the recommencement is only local in Normandy. About 7 miles away from Sully, between Port-en- Bessin and Ste. Honorine des Perthes, there is no ‘ Oolithe fer- rugineuse, —the recommencement of deposition started with strata of Truellii hemera. The advance of deposition was slowly towards the north-west, indicating where the anticline might be expected. Ill. Genera.izeD Section oF THE NortH CorreswoLps. A generalized section of the deposits found in the main mass of the North Cotteswolds may now be given, and then the details of the different sections which afforded the evidence whereon it is constructed. 1 Similarly in Somerset and Dorset ; see Appendix II, p. 153. Q.J.G.8. No. 225. x a ee ay a on 130 MR. §. S. BUCKMAN ON THE BAJOCIAN [Feb. 1901, Generalized Section of the North Cotteswolds. Formation. I. Upper Trigonia- grit. V. Notgrove Free- stone. VI. Gryphite-grit ... VIL. 7. Buckmani-grit. VIII. Lower Trigonia- grit. IX. Upper Snowshill Clay. IX a. Tilestone Sereeccen Xb. Lower Snows- hill Clay. X. Harford Sands. XI. Upper Freestone. Thickness in Feet. 6. bo Ou 32 10 7 to 10 15 to 20 About 15 5 10, or perhaps: more. Localities. Above Snowshill; Farmeott Wood; near Campden Hill Farm; Bourton Clump. Above Snowshill ; Farmcott Wood; near Campden Hill Farm ; Snowshill— road to Broadway Tower. Sudeley Hill. Sudeley Hill. Sudeley Hill ; Hill. Stanway Hill; Seven Wells. Generally in neighbour- hood of Broadway Tower. Bourton Clump; near Hyates Pits; Guiting Hill. Bourton Clump; Guiting Hill. Near Snowshill ; Bourton Clump; Upton Wold ; Sudeley Hill. Stanway TV. Derartep Sections 1n THE NortH CoTreswoLps. The following sections give the evidence upon which the gene- ralized section has been founded. The first section is nearest to Cleeve Hill, and has necessarily most affinity therewith. It is as follows :— Section I.—Farmcott Wood and Sudeley Hill. (From Winchcombe 13 miles east, by the side of the main road to Stow.) A. Farmecott Wood. Upper Trigonia- grit. I. 1. Shelly limestones with earthy partings : numerous Trigome (moulds) and the characteristic brachiopoda VY. 1. Whitish, very oolitic stone, with a planed and bored surface. Level-bedded Notgrove Free- stone. eeeeccece oe 63 2. The same, but very noticeably false-bedded aati. shown 8 Add about i0 feet for the difference in ground-level between this ex- posure and the next. Probably some feet more should be added for the dip sere etoosecseas Lower Tri- VIII. Hard, brown-speckled, somewhat Vol. 57.] OF THE NORTH COTTESWOLDS. ISL B. Sudeley Hill. Bint” Bits Notgrove Free- V. Fragments in soil. stone. Gryphite-grit, VI. 1. Yellowish marl and stone; broken fragments of Gryphea ............ 1 2. Shelly ragstone, with numerous Gryphee; and with Belemnites gingensis near the top ........... - 2 ks T. Buckmani- VII. 1. Yellowish, sandy stone with T7ri- grit. gome ; Terebratula Uptoni, 3 feet down; TZ. Buckmani, single, 43 feet down. The top of this series is a somewhat hard, projecting bed. Visible Add perhaps ho @ Cer cesses eesosersesssseseocess gonia-grit. sandy stone. Ostrea ; smooth Pecten ; very large Cucullea. Lower 24 feet visible in the quarry at a waggon-loading ledge. Possible. Chickmessh qi. qsane:-> 2-2 +0—-- 7 [Tbe part above the 23 feet is hidden by rubble over the face of the quarry. | Norrs.—Some 20 feet lower down the hill is an exposure of what look like ‘Harford Sands, near the bench-mark 920, on the right-hand side of the road to Winchcombe. ‘There is an undoubted exposure of these sands in a rabbit- burrow, in the copse under the steep brow of the hill tothe left. This is at about the same level. The sandstone is crowded with lamellibranchs. iis: T. Buckmani-grit. VII. 1. Stone with marl; Gryphea Re od and Ostrea. Lower Tri- VIII. 1. Stone with Hyperlioceras(: ?) gomia-grit. MIVPREEWNON | eos yaok es on cntne 8 2. Marl with Hyperlioceras (B). PG GMENUDDLY (SUONG)..1..-.:500-s0csieenee 9 4 Marland SONG . 2.4, «.< os - J . ne fe rege ea re ee eee eee oe Zee gies es Wigan. —— oO = OC f 0 Me L i Baa 1 <—— SONIM LN3IVAaYd 4O NOILOSYIG H 7, { = zy Oe HSIH pz ° Loy x 3 ky is) 0 2 uy) fea Eee ) ae? esis ze aC AErEatSO; Li : 05 =o {o} SLO, ESS wt ~ NS ‘ “ ‘4 ie) WN x SS NX A RN x WN ‘ Sz 4 ~ SN ~ ~ \ xn SS > > “eS \ S \ WS \ > SSS VEN N 2g N] x As S a ==) = \ ZOU ANS 6 — PSN Taree = N en S : = = SS ——puesza = N SS WENSSRIANS SIC = FOYK, i — ———— E . S g SS SSeS ZS KA ——— Sa A ° NM ‘ a1 | . S KX \ \ SH = —K si x WS Se aS Ea ee = sis = 70GI7 70 Wi: Zi LR LE S = RATT SSS oe 15 : South-easterly winds could only have prevailed in the Liakof Islands during winter, while the isobars ran in a south-easterly and north-westerly direction; and this could hardly have occurred, unless the centre of the North American anticyclone occupied some such position as that shown in fig. 18 (p. 452). Vol. 57.] CLIMATE OF THE PLEISTOCENE EPOCH. 429 boreal character.’ This does not: seem, however, to have been due to the existence at that period of cold currents from the Polar seas. Although, according to American geologists, the Behring Strait region stood at a lower level in pre-Miocene times, causing then considerable interchange of water between the Arctic Ocean and the Pacific, this state of things appears to have ceased before the com- mencement of the Miocene Epoch. The existence at that time of an area of low pressure in the North Pacific would, however, have caused southerly winds in winter, as it now does, with a warm climate on the western coasts of America, and northerly winds and colder conditions in Kamtchatka and Japan. TV. Tue Former Existence oF Great LAKES IN THE BASIN OF NEVADA AND IN CENTRAL ASIA. Turning now to the New World, we may remember that American geologists have shown how enormous lakes existed during the Glacial Period in the great basin lying between the Rocky Mountains and the Sierra Nevada, a region at present without outfall, and of extreme aridity. These, to the largest of which the names of Bonneville and Lahontan have been given, have been described by Prof. G. K. Gilbert* and Mr. I. C. Russell,’ of the United States Geological Survey. Such facts, together with the evidence of more humid conditions in Asia and elsewhere in later Pleistocene times, have given rise to. the hypothesis that generally the climate of that epoch was of a pluvial character.* While believing that such was the case, I think that pluvial conditions may have been to some extent local. Exces- sive rainfall occurs at present in many parts of the world, but always locally, and it arises from one cause only, the prevalence of moist and warm winds from the ocean.° The summer rains in India, for example, do not now reach Persia, the climate of which is consequently very dry. The pluvial condi- tions of the former country at that season, and the arid conditions of the iatter, are equally due to the relative position of the areas of high and low pressure of the Asiatic continent and the adjoining 1 See also E. Kayser’s ‘Text-book of Comparative Geology’ transl. Lake (1898) p. 354. 2 ‘Lake Bonneville’ 2nd Ann. Rep. U.S. Geol. Surv. (1881) p. 169. 8 ‘Lake Lahontan’ 3rd Ann. Rep. U.S. Geol. Surv. (1882) p. 195. 4 It may have been during such a pluvial period that the excavation of gorges like the chines of the South of England took place. These, with similar valleys elsewhere, which are out of all proportion to the streams which now flow, or ever could have flowed in them, seem to me to have been caused by sudden and repeated floods of great violence, rather than by the steady and continuous erosion of a time when the rainfall was excessive. Rainfall was no doubt greater, however, in the South of Europe during the Pleistocene Epoch than in the British Isles, as the diluvial deposits of the former region are on a grander scale. 5 The term ‘ oceanic climate’ is frequently used, but this can only mean a climate influenced by winds blowing from the ocean. The winds could not all have been oceanic at one time, however, during the Pleistocene Epoch. 262 430 MR. F. W. HARMER ON THE [Aug. 1901, oceans. It would not be difficult to suggest such an alteration in the alignment of the isobars as would bring oceanic winds over the deserts: of Persia, like those which now deluge Burmah and Bengal with rain during the monsoon.’ It is to such changes (acting locally, I suggest) that the former extension and the subsequent drying-up: of the Pleistocene lakes of Utah and Nevada were due. The succession of events in the region in question, according to Prof. Gilbert? and Mr. Russell,’ was as follows :—a period, previous to the flooding of the plains, with a climate as rainless as that of the present day; afterwards a moist period, during which Lake Lahontan attained a depth of 500 feet, and Lake Bonneville a level 1000 feet higher than that of the Great Salt Lake at present ; then a time of desiccation; followed by a return to humid conditions, and finally, by the evaporation of the water to its present level. During the pre-Lahontan and inter-Lahontan periods, with their arid climate, the distribution of pressure may have been, more or less, similar to that of the present day (figs. 17 & 19, pp. 450 & 454). If, however, the anticylones of the North Pacific and of the North American continent had been shifted from their present positions to those shown in fig. 20 (p. 456), a low-pressure system obtaining statistically at the same time off the western coast of Mexico, similar to that which I suppose may have existed in the Mediterranean area. during the pluvial period of the Sahara, more humid conditions would have been caused over the southern and western portions of the United States by warm and moist southerly or south-easterly winds: trom the Gulf of California, or the Gulf of Mexico. At the present day, a comparatively moist climate in Florida and the regions ad- joining it is caused by such winds, but their influence does not extend far north-westward. These changes in the basin of Nevada, assuming their origin to: have been meteorological, may have been due to the presence, at the pluvial stages of the period in question, of an ice-sheet in North America, the pressure of the anticyclone of which disturbed the atmospheric conditions which had existed in the pre-Lahontan period, altering the prevalent direction of the winds, those con-: ditions being re-established when, owing to the disappearance or retreat of the ice, that pressure ceased.* 1 The failure of the monsoon rains to which the last Indian famine was due: coincided with an increased rainfall in Mauritius, the Seychelles, Zanzibar, and part of South Africa. An alteration in the relative positions of the centres. of high and low pressure diverted at that time the oceanic winds from their usual course, causing them to enrich some regions with moisture,at the expense of others. 2 «Take Bonneville’ 2nd Ann. Rep. U.S. Geol. Surv. (1881) pp. 172-76.3 3 *Lake Lahontan’ 3rd Ann. Rep. U.S. Geol. Surv. (1882) p. 230. 4 Mr. Russell not only expresses the opinion generally held by American geologists, that the existence of these lakes was contemporaneous with the Glacial Period, but also that the fluctuations in their water-level indicate changes of climate, the humid periods having coincided with increased cold, and the dry. pericds with comparative warmth, op. cit. p. 231. oa a j Vol, 57.] CLIMATE OF THE PLEISTOCENE EPOCH. 431 The more humid conditions formerly existing in Central Asia (indicated by the greater extension of Lake Baikal), in Tibet, Turkestan, the Han-Hai Basin, and elsewhere, may belong to some stage or stages of the Glacial Period when the relative position of the high- and low-pressure systems, different from that of the present day, favoured the prevalence of moist winds over those regions. These may conceivably have come from the Mediterranean, the Black Sea, or the Caspian, the latter at one period covering a much larger area than it now does. Moreover, the prevalent storm-tracks must have been different during the Pleistocene Epoch from those of our ownera. As before stated, a considerable portion of the cyclonic dis- turbances which approach the continent of Europe from the Atlantic pass to the north or north-west of the British Isles, towards Scandinavia.” During the existence of an ice-sheet in those regions, this course would not have been open to them; so far as they continued to travel eastward, they must have done so to the south of the ice-clad region (figs. 21 & 22, pp. 458 & 460). Some of the Atlantis storms do move that way now, but none of them penetrate into Central Asia. In dealing with the post-Glacial Period, in his valuable work on Prehistoric Europe, Prof. James Geikie calls attention to the alternations of dry or humid, and of cold or mild climates, by which it was characterized. That climatic changes occurred also after the climax of the Great Ice Age need not surprise us. The meteorological disturbances set up during that abnormal and remarkable chapter in geological history may well have continued to exert their influence during the post-Glacial Period. It would not be possible, within the limits of such a paper as this, to attempt to discuss these matters in detail, nor is the necessary information available. It will be sufficient to call attention to the general principle that anomalous weather in the past, even if more or less permanent, may have been due to that which causes temporary changes of a similar character at present, namely, to a change of wind. Even if the cold of the Great Ice Age was due to some extra-telluric cause, it seems hardly necessary to invoke such an origin for the various changes of climate, some of them evidently local, which charac- terize it, if some simpler explanation can be found. VY. Tur Mereorotocicat ConpiITIoONns oF THE PLEeIsrocENE EPocH. Ido not venture to express any opinion as to the cause of the Glacial cold. There was a Glacial Period, and the refrigeration of climate by which it was distinguished had been long coming on, gradually, and apparently without intermission. There is no _ 1 See further as to this, § VIII, p. 461. . '2 The low-pressure areas on statistical maps represent, to a considerable - extent, the prevalent track of cyclonic storms. 432 MR. F. W. HARMER ON THE [Aug. IgOT,; evidence to show that any other part of the Tertiary Era was cha- racterized by marked fluctuations of climate, still less that any Great Ice Age occurred, even during Pliocene times. With the advent of the Pleistocene Epoch, however, an era of climatic dis- turbance commenced.* | It seems to me that it is @ prior? less probable that important alterations of climate, more than once occurring at intervals of a few thousand years only, were due to astronomical or physical causes affecting the whole of the Northern Hemisphere, than that the Glacial and Interglacial deposits of different regions may represent one era only of greater cold, with local changes in the distribution of climatic zones. It will be urged perhaps that the value of some of the conclusions here arrived at is seriously affected by the fact that geologists are by nO means unanimous in their interpretation of the geological record. It is widely believed, to take one example only, by such authorities as Warren Upham,’ Le Conte,*® Chamberlin,’ and others that at a period immediately preceding the Glacial Period, for which the name Ozarkian has been proposed,’ the North American continent stood at a level greatly higher than that of our own era: the supposed eleva- tion being regarded by the first-named of those writers as the direct, and by Prof. Chamberlin as the indirect, cause of the Glacial cold. Prof. J. W. Spencer believes, moreover, that an elevation of the Antillean region took place in Pleistocene times, which may have reacted upon climate.° Prof. Hull argues in a similar way, con- tending that the Pleistocene elevation which affected America was continuous round the northern and eastern shores of the North Atlantic.” Prof. James Geikie, on the other hand, adversely criticizes these views.° Some persons may, therefore, feel that until a more approximate consensus of opinion has been attained on these and other points which it is not necessary to mention, it is premature to discuss the meteorology of the Glacial Period at all. There seems, however, sufficient general agreement as to certain facts to justify a preliminary enquiry, it being understood that any conclusions arrived at must be subject to such modifications as may hereafter be necessary. We may, I think, accept, as a working hypothesis, the view that in the New World there were certain definite centres of ice- accumulation, one in Labrador, another west of Hudson Bay, and 1 The earliest evidence of this kind in Great Britain is that of the Cromer (so-called) Forest Bed, containing Elephas meridionalis, and other mammalian remains preponderatingly southern, together with a temperate flora, which is intercalated between the Weybourn Crag (with the Arctic mollusea, Astarte borealis and Tellina lata) on the one hand, and the Arctic freshwater-bed (with Salix polaris and Betula nana) on the other. 2 Journ. Vict. Inst. vol. xxix (1897) p. 201. - > Journ. Geol. Chicago, vol. vii (1899) p.525. * Ibid. p. 667. > Hershey, ‘ Science’ vol. iii (1896) p. 620. © Geol. Mag. 1898, p. 38. 7 Journ. Vict. Inst. vol. xxxi (1899) p. 141. ° did. vol. xxvi (1893) p. 221. tT tint Vol. 57. | CLIMATE OF THE PLEISTOCENE EPOCH. 433 a third in British Columbia ; that in Europe the ice lay thickest in the Baltic area, crossing the Scandinavian watershed towards Norway, with independent centres of dispersal in the British Isles, in Switzerland, and in other mountain-regions ; and further, that the ice travelled outward from these centres to a considerable distance in both hemispheres.* The direction in which the ice-streams travelled may have varied from time to time, but the centres of dispersion were possibly always more or less the same; and this, from a meteorological point of view, is important, since it is upon the position of the centres of the anti- cyclonic or cyclonic systems that the direction of the winds largely depends. It seems satisfactorily proved, moreover, that the ice-sheets were for a time melted back more than once, if they did not altogether dis- appear,” and that climatic conditions comparatively genial prevailed during the ice-age, locally at least, both in North America and in Kurope. As the form and extension of the ice-sheets varied from time to time, the position of the continental anticyclones would vary also; but so far as the centres of the latter remained the same, their general relation to the low-pressure systems of the Atlantic and the Pacific during the cold periods would be unaltered. For the purpose of my argument, I propose to take those stages at which, in the eastern and western continents, the ice-sheets are supposed to have attained their greatest development, adopting the views expressed by Prof. James Geikie*; and I shall endeavour to trace out what may possibly have been, under such circumstances, the meteorological conditions of the period or periods in question. It has often been urged that the existence of great ice-sheets must have been accompanied by excessive precipitation, Itis clear, of course, that no ice could accumulate, except in regions visited from time to time by oceanic winds. The amount of precipitated moisture necessary to produce permanent glaciation may not, how- ever, have been so great as has been sometimes supposed. When in summer, heavy and sudden downfall takes place, or when in Winter, rain is continuous for many days, the streams are flooded, and the greater part of the water which falls is quickly carried out to sea.’ On the other hand, when the temperature drops below the ' The outward travel of the ice-sheets may have been partly due, as Mr. G. W. Lamplugh points out, to the accumulation of snow falling on them, other- wise than at the great ice-centres, Geol. Mag. 1901, p. 142. ? Prof. Chamberlin considers (Geikie’s ‘Great Ice Age’ 3rd ed. 1894, p. 769) that the character of the fauna and flora of the Interglacial deposits of Toronto, first described by my friend, Dr. G. J. Hinde, F.R.S., in Canad. Journ. vol. xy (1877) p. 388, points to the existence of milder climatic conditions than those of the present day in the same region. > ‘Great Ice Age’ 3rd ed. (1894) pl. ix facing p. 437, & pl. xiv facing p. 724. * The loss of water, in this way, from the great ice-sheets would have been, on the contrary, comparatively small. : 434 MR, F. W. HARMER ON THE [Aug. 1901 freezing-point, a comparatively small amount of precipitation, none of which is for the time being lost to the land, may cover the latter with a thick mantle of snow. It is not necessary that snow should fall constantly, or perhaps even very frequently, in order that per- manent ice-fields should establish themselves. The prevalent winds blow, for the most part, outward from Greenland, and the yearly precipitation in the centre of that country is probably but small. Asa matter of fact, however, sufficient snow does fallthere to have produced a great thickness of ice, and the latter can only have been derived from moist oceanic winds occasionally caused by some such an alignment of the isobars as thatshown, for example, in fig. 13(p.442). ‘We need not suppose, therefore, that westerly winds were prevalent in Scandinavia during the maximum glaciation of Europe, or easterly winds in Labrador during that of North America; but such winds may have—indeed must have—occurred there from time to time. The northern part of the Atlantic area would probably have been at all seasons, during the Pleistocene Epoch, one of atmospheric disturbance, as it is at present in winter: the storms being then, for reasons before given, more violent, and the rainfall more copious. It will not therefore be difficult to understand that, although the prevalent direction of the winds must always have been more or less outward from the ice-sheets, a considerable amount of moisture may have reached these from the ocean. If snow falls faster than it melts or evaporates, it may accumulate, time being given, to 9 almost any extent. The absence of warm winds in summer may | be perhaps more necessary for the growth of an ice-sheet than great precipitation.” It will perhaps be pointed out that in Dr. Buchan’s maps (figs. 17 & 19, pp. 450 & 454) the alignment of the statistical areas of high and low pressure, and of the isobars, in the Northern Hemisphere, is shown to be generally from south-west to north-east, whereas in my hypothetical restoration of the meteorological conditions of the Glacial Period (figs. 18 & 20, pp. 452 & 456, and 21 & 22, pp. 458 » & 460) some of them are represented as pointing from south-east to north-west. Seeing that currents, either oceanic or atmospheric, passing in the Northern Hemisphere from south to north must tend to be deflected eastward, and those flowing from north to south westward, it may be asked whether a prevalent south-east to north- west arrangement of the isobaric lines in former ages is physically probable, or even possible. A reference to the Daily Weather Charts will show, however, that such conditions occur even now not infre- quently. When the centre of the Icelandic cyclone lies to the east of 1 My old friend and master, Searles V. Wood, Jr., in his paper on ‘ The Cause of the Glacial Period’ (Geol. Mag. 1883, p. 296), stated his reasons for believing that the stupendous mass of land-ice under which the glaciated area of North-eastern America was buried may have accumulated under a precipitation less than that which now takes place in the same region. ? There must have been more precipitation, however, over the southern parts of the ice-sheets than there is now in Greenland, as the sun’s heat in summer, and its melting-power, would have been greater in the former case than in the latter. a * Pol, 57. | CLIMATE OF THE PLEISTOCENE EPOCH. 435 Greenland, it may stretch towards the north-east, as shown in the January chart (fig. 17, p.450). When, on the contrary, it shifts to the west, it often points north-westward. This happened constantly, for example, during the months of September and October, 1881, so that the statistical diagrams for those months show a low-pressure system with a distinct south-easterly and north-westerly alignment, accompanied by the advance of the Asiatic anticyclone towards Scandinavia and the North Sea (see fig. 10, p. 436). If such a state of things may prevail for a space of two months at present, when generally the conditions are favourable to a contrary arrangement, there does not seem any insuperable difficulty in supposing that, under the altogether different and more permanent circumstances set up by the existence of the great ice-sheets, it might have persisted during a lengthened period. In attempting to restore the probable distribution of areas of high and low barometric pressure during the Pleistocene Epoch, I found it nearly impossible to do so in such a way as to fulfil what seemed to me to be the necessary meteorological conditions, on the hypothesis that the maximum glaciation of North America and Europe took place at the same time. No such difficulty arose, how- ever, when I adopted the view that the most important glacial and interglacial periods may have been more or less alternate in the eastern and western continents. On my mentioning the matter to Mr. W.N. Shaw, he was kind enough to call my attention to an instructive case of anomalous climate which occurred during the winter of 1898-99. From December to February in those years the weather on the western side of the Atlarftic was persistently and abnormally severe, temperatures of from —40° to —60° Fahr. having then been com- monly registered in different parts of North America. ‘The excessive cold extended in February as far south as the mouth of the Missis- sippi: the thermometer falling there to 10° Fahr., the swiftly-flowing rivers of the Southern States were frozen over, and ice was carried out into the Gulf of Mexico. On February 11th, the barometer fell to nearly 28-5 inches in the Atlantic, rising .at the same time in Canada to 31°42 inches. For some weeks gales of great violence occurred almost daily in the Atlantic, and in different parts of the North American continent, a wind-velocity of 72 miles an hour being noted in Massachusetts; while in New York Harbour, during a blizzard, one of the great ocean liners, the Germanic, sank at her moorings under the weight of the snow and ice which covered _ her deck and sides. Exceptionally mild weather prevailed at the same period in Western Europe as far east as the Ural Mountains, there having been an entire absence of cold weather in January over Great Britain. Maximum temperatures of 70°'5 Fahr. were recorded in February at Liége (131°-5 above the American minimum of the preceding night), 69° in Paris, and 66° in London. The wave of warm air affected in a similar way the Alpine regions: at Davos Platz, in the South-east of Switzerland, 5000 feet, above sea- ‘level, a maximum of 63° Fahr. was reached, the highest previously ae ——— —————_ af Y — D Wp 2 /, 4// y MU) Hp < Uap C7 ) aN py, LTT Ty WTO, “iy Wy Wf Yn .° Tp i Uf y 4] bp // y 4 / 7 Wi jj jj > YY XS ui Yf YY | / , ‘6681 HL Axeniqo 4 TOF Y YI] ¢ \ yj / 1] )) XY , ‘| LYVHO OINVEOSI | | NAN YI a Ll) x 43 ) My) ‘IL Bld /\ \ — : = 438 THE CLIMATE OF THE PLEISTOCENE EPocH. [Auwg. 1901. known temperature at the latter place during February being 52"; and the average maximum 38°. The explanation of these facts is not far toseek. In fig. 11 (p. 437), the isobaric chart for February 7th, 1899, is seen an example of the meteorological conditions of the period in question, which shows that the severity of the winter in North America and its excessive mildness in Kurope were alike due to the existence of strongly-marked cyclonic conditions in the North Atlantic. Cold winds were constantly pouring over the western continent from the frozen regions of the north, while southerly winds, strictly comple- mentary to them, were flooding Europe with heated air from the subtropical zone.’ Under the meteorological conditions now prevalent (fig. 4, p. 414), the average winter climate of the north-eastern part of the American continent must generally be colder than that of North-western Europe at the same latitude; but the facts just stated seem to indicate that weather unusually mild in the latter may be the necessary accompaniment, and possibly the measure, of extreme cold in the former. On the other hand, it is not difficult to understand that the existence of an ice-sheet on the eastern side of the Atlantic may not only have been coincident with, but possibly even the cause of, an amelioration of the winter climate of Labrador and New England. When, in winter, Greenland and Scandinavia are anticyclonic at the same time, and the high-pressure system of North America shifts westward, the North Atlantic depression moves westward with it towards the American coast, and when the latter lies sufficiently far south as in fig. 12 (p. 439), the isobaric chart for February 28th, 1886, south-easterly winds are experienced in Labrador. The temperature of the latter region during winter varies greatly from day to day. If the winds blow from Greenland or the Polar regions the weather is very cold, but when they veer to the south or south- east the thermometer rises rapidly. On the day just named, the British Isles, Greenland, and Scandinavia being anticyclonic, a low-pressure area lay in the North Atlantic, near Newfoundland, having a south-easterly and north-westerly alignment. ‘The mild winds arising therefrom caused the temperature of the north-western — coast of Labrador to rise to 32° Fahr., 63° higher than that registered at the same spot three days previously, and 42° above the average for the month of February.2. In Norway and the Gulf of Bothnia at the same time the thermometer stood 36° Fahr. lower than in Labrador, - although statistically it should have been 30° higher. Such sudden 1 A number of charts, illustrative of the facts here stated, were exhibited by the Meteorological Council at the Royal Society’s soirée in May, 1900, and the subject was further dealt with by Capt. Campbell-Hepworth, of the Meteoro- logical Office, at the Bradford meeting of the British Association in the same year ; see Brit, Assoc. Rep. p. 651. 2 In the ‘ Wetterkarten’ we find the following morning temperatures on the coast of Labrador :—Feb. 25th, 1886, —34° C.= —29° Fahr. ; Feb. 28th. 1886, 0° C.=+32° Fahr. oq} >, y) ] / / YY Uy Ma | , y | ij, / ¢ Sp | | y Tes y YY Uff GL. LHD ai 2 DLL ] i ‘Oe Z one ‘9,0 (suru.tout) ‘OS8T ‘Sz ArenAqey 10F 440 MR, F. W. HARMER ON THE [ Aug. IQOl, changes, moreover, are not uncommon; between Feb. 27th and March 7th 1892, for example, the temperature of the coast of Labrador, in lat. 56° north, rose 61° Fahr., owing to the shifting of the wind from north-west to south-east. The climate of the Northern Hemisphere could not have been wholly cold during any part of the Pleistocene Epoch. Even when the Glacial conditions reached their maximum, regions of com- parative warmth must always have been the necessary complement of those lying in the grasp of a perennial winter. On the other hand, it need not have been everywhere warm during the Inter- glacial episodes; if mild seasons or mild periods were caused by southerly winds in one region, colder conditions would have been produced in others at the same time by winds from the north. The existence of extensive areas of high pressure, upon which air from the higher regions of the atmosphere is constantly descending, flowing outward from them at a lower level, involves also the existence, in regions more or less contiguous, of areas of low pressure of corresponding importance’; reservoirs, in fact, into which the air from the anticyclones may be poured, and from which it may ascend, as by an aerial chimney-shaft, in order to complete the vertical atmospheric circulation. If therefore high-pressure centres existed over the ice-sheets, they would have been necessarily accompanied by low pressure over the adjoining oceans, areas at all seasons, during the Pleistocene Epoch, of comparative warmth and atmospheric bumidity. . Statistical maps, such as figs. 4 & 5 (pp. 414 & 415), give an im- perfect idea of the meteorological changes going on from day to day. When in winter, for example, the Eurasiatic anticyclone advances westward, and that of North America retreats also to the west, a low- pressure system often exists in Davis Strait, as in fig. 13 (p. 442); when the first-named anticyclone is situated farther north-west, extending from Scandinavia to Greenland, the cyclone lies more to the south? (figs. 12 & 14, pp. 4389 & 443). Sometimes an anticyclone stretches from Greenland southward ; at others that of the Azores sends out a tongue towards the north (figs. 15 & 16, pp. 446 & 447). In that case, two cyclonic centres are formed, one resting against the American, the other against the European shores. The anticyclone of the Azores seems to be an important factor: generally its centre lies to the east, as in fig. 5 (p. 415), but at times it moves towards the American coast. When the Atlantic is strongly cyclonic, as in fig. 11 (p. 437), the anti- cyclone seems to be driven southward, but it never disappears entirely ; and it must always have been in existence during the 1 These may be either large and shallow, or smaller with steep gradients, the air ascending more rapidly through the latter. 2 The statistical chart for January (fig. 4, p. 414) shows the North Atlantic cyclone lying well to the north. As a fact, however, high-pressure conditions frequently exist during winter to the north of it: one or other of the conti- nental anticyclones, and sometimes both of them at once, overspreading Green- land (figs. 14, 15, & 16, pp. 448, 446, & 447). . Wol.57.| CLIMATE OF THE PLEISTOCENE EPOCH. 44] Glacial Period, forming then, as now, part of the northern sub- tropical belt of high pressure, the necessary complement of the Equatorial low-pressure trough. In any case, the general result is that so long as the north- eastern part of the North Atlantic is prevalently cyclonic,’ so long must southerly and south-westerly winds often occur there, with mild or warm weather over the British Isles. It is only when the influence of such winds is diverted from our shores, and the alignment of the isobars produces northerly or easterly winds, or when Great Britain is anticyclonic, that our winters can be severe. Equally, it seems to me, no great ice-sheet could have originated in Great Britain, and especially in the western part of these islands, while they were under meteorological conditions similar to those now prevalent during winter. The effect of winds upon the accumulation or melting of snow is well known. In Siberia, for example, the heat of the sun in spring exerts little or no effect upon it, but when, early in June, warm breezes from the south begin to blow, the ground is cleared of its wintry covering, as if by magic, and heated winds ‘eat up’ the snow everywhere.? Prof. James Geikie says, as showing the influence of winds upon climate, that where the flat lands of the Arctic regions are exposed to the northern blasts, the tundras invade the forest-zone, but where they are sheltered from them, the woods encroach on the tundras, so as nearly to reach the shores of the Polar Sea.° The meteorological conditions which may have been prevalent in summer in the North Atlantic during the maximum glaciation of America, resembling to some extent those now prevalent there in winter, would also have been adverse to the accumulation of an ice-sheet in Great Britain. At present the south-westerly winds caused by the Icelandic cyclone may start in winter from a region as far south as the latitude of the Azores, bringing, even in December and January, air sufficiently warm to produce in this country a maximum temperature of from 55° to 60° Fahr. ; in summer, similar winds are, of course, considerably warmer. Even in Labrador, and the Hudson Bay region, where the rainfall is as great, and the average winter-temperature as low (from 0° to — 20° Fahr.) as in Greenland, the heat in summer is sufficient to prevent the accumulation of a permanent ice-sheet, and such must equally have been the case in Great Britain, I think, under the conditions just stated. ; The view that the maximum extension of the ice may have taken place at the same time on both sides of the Atlantic, involves the 1 This must often have been the case during the maximum glaciation of North America. _ ? See Sir Henry Howorth, ‘Glacial Nightmare’ vol: ii (1893) p. 389; also A. Russel Wallace, ‘Island Life’ 2nd ed. (1892) p. 140. 3 Scot. Geogr. Mag. vol. xiv (1898) p. 282. * The warmth of such cyclonessis partly due to the latent heat set free by condensation, but this also is distributed by the action of the winds. 0687 ‘aquraceq 10F LYVHO OluvdoOsl TVOILSILVLS~'8t #14 Y Uy, BS | y Coy [ ;uoqaeyroq90\\ oysiqdouds oyorpsey, , ay} wory | ag aia 'O68T ‘mOZ Tidy 403 LYUVHO OlYVEOS! TIVOILSILLVLS ‘PT Bld. Vii) Wy oe ‘N/ / / Ny Yo) 7 Q. J. G. S. No. 227. : > i , di ~ x “4 D. ~~ VU : 0 S \ ‘ Q ¢ ’ . 7 i % ‘ 4 ‘ % a Y, Y i ; ° “ . 7, 2\ 2 hy 2 NS ’ ‘tif A) y g Sa ij ‘| aie ae FU Ly . Y LDS pei’ . : een OY YU fv D>, Wt : nae rie : j . Ue a SK COMMING rm ON NIM EU TTLLEIKELEE LL ON, ~ ~ ~~ r= . A a ttf ae =) ‘ = C485 Mf es ae - vs — = = — ee --~ Rese — = : > ee © . . . : in I - _~ = = - - a eS — ——SSEE—EE =~ ‘ SOI a kn ie il a A ice 444 MR. F, W. HARMER ON THE [ Aug. gor, admission that the isotherm of 50° Fahr. or thereabouts? reached at that period in summer coincidently to lat. 37° 35' N. in North America, the supposed southern limit of the American ice-sheet, that is, to within 14° of the Tropic of Cancer, where the sun’s rays are then vertical, and to about lat. 50° N. in Europe. The meteorological equilibrium of such astate of things, if even it could have been for a time established, would have been, I think, of a most unstable character. Such a theory requires, however, not that these conditions might have occurred occasionally, but that they should have been persistent for periods extending over thousands of years, which seems to me to be highly improbable.* At present it is in winter, when the isotherms are crowded together in North America, that cyclonic storms arise there most frequently. In summer, when the difference in temperature between adjoining regions is not so ereat, they are less numerous. The marked contrast between the summer climate of the southern part of the American ice-sheet during its greatest extension, and that of the region immediately to the south of it, might have caused (to an even greater extent than now) atmospheric disturbance at that season, and cyclonic storms, with southerly winds to the east of their centres, would have then occurred more frequently in the eastern part of the North Atlantic.’ It may, perhaps, be suggested that by the pressure of an anti- cyclone, extending from the Polar regions over North America, Greenland, and Northern Europe at the same time, the Atlantic cyclone might have been driven so far to the south, that the influence of the south-westerly winds thereby caused, even in summer, although affecting Spain and France, may not have extended to the British Isles. We have seen, however (fig. 11, p. 437), that when the North Atlantic cyclone reaches as far south as lat. 35° N., no such effect is produced, the contrary being rather the case.* The necessary existence in the southern part of the North Atlantic at that time of a high-pressure system, complementary to the Equa- torial trough of low pressure, raises the question whether the Icelandic cyclone could have been forced indefinitely southward. The farther it was driven in that direction, moreover, the warmer would have been the winds on the eastern side of its centre. The 1 The southern coast-line of Greenland now coincides with the isotherm of 45° Bahr. An average summer-temperature in Labrador of 50° Fahr., on the coutrary, seems sufficiently high to prevent the permanent accumulation of snow. 2 The farther southward the isotherms of low temperature reached, the greater, I think, would have been the instability of the atmospheric equilibrium. 3 Mr. Borchgrevink states that sudden storms of great violence are prevalent near the edge of the Antarctic ice-sheet ; see ‘ First on the Antarctic Continent ’ 1901, passion. 4 It is the existence of an ice-sheet under such conditions, and especially during the summer, in Great Britain (leaving Scandinavia out of the question), — that is the difficulty. No great ice-sheet could have accumulated in a region under the prevalent influence of warm winds. Vol. 57. ] CLIMATE OF THE PLEISTOCENE EPOCH. 445 greater extension of the glaciers of the Alps and of the Pyrenees shows that the climate of those regions also, during the maximum glaciation of Europe, must have been considerably colder than it is at present. Unless the southerly winds of the North Atlantic had been diverted from the coasts of Europe, I do not see how the British Isles could have been glaciated. On the other hand, if they had been turned prevalently towards Labrador and New England, the climate of that region, in summer at least, could not have been severe. The view that there may have been such a reduction of the heat of tropical regions in Glacial times as to cause the southerly winds of the North Atlantic to lose their warmth makes, I think, a greater demand upon our imagination than does the hypothesis that I have suggested. The facts that the Swiss glaciers did not invade, to any extent, the great plain of Lombardy, and that there is no evidence of extensive glaciation in the regions bordering the Mediterranean show, however, that the climate of Northern Italy, and generally of the South of Kurope, during the Pleistocene Epoch, was not abnormally cold. VI. Tue MeEreorotocicaL ConDITIONS DURING THE Maximum Gruactation oF Norta AMERICA, Accepting, therefore, as a working hypothesis, the theory that glacial conditions may have been to some extent alternate in the. Western Hemisphere with those of comparative warmth in the Eastern, and conversely, we may now endeavour to ascertain the meteorological conditions which in such a case may have obtained in the former region during the above-named stage of the Pleis- tocene Epoch. . As before stated, the present winter-climate of Labrador and of the region north-west of Hudson Bay (the North American centres of ice-dispersal, according to Prof. Chamberlin)’ is as severe as that of Greenland. These formerly ice-clad areas lie entirely to the north of the January isotherm of 10° Fahr., while the isotherm of 30° Fahr. for the same month includes nearly all the country supposed to have been covered by the American ice-sheet at the period of its maximum extension (fig. 6, p. 418).* Such an ice- sheet might therefore exist at the present day, so far as the winter- conditions of North America are concerned. ‘The summers, however, are hot, almost all the regions supposed to have been ice-clad on the American Continent enjoying in July an average temperature ranging from 50° to 70° Fahr. (fig. 7, p. 419). ‘The temperature varies widely from day to day in Labrador during summer and 1 See map in Prof. James Geikie’s ‘Great Ice Age’ 3rd ed. (1894) pl. xiv, . facing p. 724. : 2 Taking the average for the whole year, we find that the North American ‘ice-centres of the Pleistocene Epoch lie well to the north of the present isotherm of 80° Fahr. 2H 2 A} Otf} UI A|Aoq}NOS Suleq SPUIM Ov a ; ’ | peureu-jsRy o4 UT ATLOISvVE PUB ‘SBVEIG JOULAO] OA a ee i NG aa Bi i ces eee nl estat ane nl pag nig psi Re, Re ; «SB Otu'S OTT} ATAVOU o7Vp SI} JB SBM 4SBOO UVIGIMION OT} PUB LopvaquT Jo ornqzvroduio, ayy —~/ue we 7 Pp /, Yi Yd yy i Wi 4 YY Yf Y, Wy / : Bo, J y fj ifs i; Yi f by) . : 1] Math C9LN0,24= GGL\ 094 ——bi (Surus0u1) ‘2681 iL WOT! 1OF LYVHO OlNV EOS! 74 Yan x Z (Surujou) * yj Ni 8) ‘oss ‘gr Arenuel 20x | | TSU Le &S a Phe ///// MA aS ae W19m So 950 Wi a7 vallas eal 448 MR. F. W. HARMER ON THE [Aug. 1901, autumn, as we have seen it does during winter and spring, the variations being coincident with changes of wind.! It seems therefore to be the influence of the warm winds prevailing intermittently during the summer that now prevents the permanent accumulation of ice in this region: their character being due, so far as they blow from the land and from the south, to the heated state of North America at that season. When once, however, in consequence of the increasing cold, an — ice-sheet had begun to establish itself in North America, the region covered by it would have been protected from such winds. Being anticyclonic, the air would have tended to move outward from it in all directions, as Nansen says is now the case in Greenland.* Cold northerly winds would have been prevalent over Labrador and Hudson Bay at all seasons, and the summer-climate of those regions being changed, the causes which now prevent the formation there of a permanent ice-sheet would have been removed. Under such circumstances, I think, the ice might have gradually crept southward. Moreover, as it did so, the storm-tracks would also have shifted in the same direction. At present, the region between the Great Lakes and Newfoundland is one of much atmo- spheric disturbance, and it is to the cyclonic storms that are there frequent that the variable climate of Labrador is largely due. As anticyclonic conditions established themselves, more uniform climatic conditions would have prevailed. Jn this way, the accumulation of the ice might have been self-accelerating.® In figs. 18 & 20 (pp. 452 & 456) I have endeavoured to reproduce the arrangement of areas of high and low pressure which may have been prevalent in winter and summer during the maximum ~ glaciation of North America. For the purposes of comparison I have given also (figs. 17 & 19, pp. 450 & 454) statistical isobaric charts of the Northern Hemisphere for January and July, constructed from those in Bartholomew’s ‘ Atlas of Meteorology’.* I have not, however, adopted Mercator’s projection (as in figs. 4 & 5, pp. 414 & 1 The following changes in temperature and in the direction of the wind (2 p.m. local time) took place, for example, in the summer of 1882, at a station in Hudson Strait, on the northern coast of Labrador :— Temp. . Wind. Temp. Wind. June 4th............ 59° Fahr. S.W. June 23rd ......... 68° Fahr. S.W. Other secse 37 N.E. Zoth\ hecaeace 72 W. Wath estes By) S.W. Dithy Gores GOS N.E. T2 thi vee eaeee 37 N.E. 28thyie sce 15 S.W. 14th ........- 50 W. July 3rd ............ 53 N.W. SGD: Uiriceseoees 08 8. Stlineeo vaeeees 47 N.W 20th. so.sesees 34 N.E [From the synchronous weather-charts of the North Atlantic, published under the authority of the Meteorological Council. ] 2 «The First Crossing of Greenland’ vol. ii (1890) p. 496. * That the growth of an ice-sheet, when once established, would be self- accelerating, was shown by James Croll in ‘ Climate & Time’ 1875, p. 74; and also by Dr. A. R. Wallace in ‘Island Life’ 2nd ed. (1892) p. 15], by Prof. Chamberlin in Journ. Geol. Chicago, vol. vii (1899) p. 675, and others. * In summer the isobars of 29-90 inches seem rather to group themselves with the high-pressure centres, that of the Polar regions forming a distinct anti- cyclone, and I have so shown it in figs. 19, 20, & 22 (pp. 454, 456, & 460). rol. 57.1 CLIMATE OF THE PLEISTOCENE EPOCH. 449 415), assuch maps are out of scale for the Polar regions, and do not represent so clearly what I consider may have been the movements of the Arctic high-pressure system during the different phases of the Glacial Period. Itis the oscillation of the centre of this high-pressure system from one side of the Polar Circle to the other during the Glacial Period, changing, as I think it would have done, the statistical alignment of the low-pressure system of the North Atlantic and the direction of the prevalent storm-tracks, which may have to some extent caused, or have been at least coincident with the climatal changes, both of Europe and America. In constructing these hypothetical diagrams I have repro- duced as far as possible the present meteorological conditions, with such alterations only as the former existence of the ice-sheets may obviously have required. I have given the different isobars in full, as in the statistical charts (figs. 17 & 19, pp. 450 & 454), for purposes of comparison only, and because the task of doing so proved a useful check on the work. I do not suppose for a moment that it can be possible to restore in such detail the meteorology of the Glacial Period. Dealing first with the baric conditions of winter, during the maximum glaciation of North America, and comparing figs. 17 & 18 (pp. 450 & 452), we may assume that the greater part of the Kurasiatic continent was then, as now at that season, an area of high pressure, Central Asia having been probably at least as cold during the Pleistocene Epoch as it is at present. As to America, I have drawn the central part of the anticyclone of that continent (fig. 18) to coincide roughly with what is supposed to have been the greatest southward extension of the ice,‘ and to include Greenland” and a part of the Polar Ocean, then perhaps permanently frozen over.° Not only would the actual position and form of this high-pressure system have varied from day to day, however, but it might have been subject also to secular oscillations, and have sometimes extended as far as the northern coasts of Scandinavia. Moreover, every change 1 See T. C. Chamberlin’s map in Geikie’s ‘Great Ice Age’ 3rd ed. (1894) pl. xiv, facing p.724. It is probable, however, that the anticyclones may not have corresponded so symmetrically with the limits of the great ice-sheets as shown on my charts ; but Ido not know how otherwise to represent the general relation of the former to the latter. _ ® Greenland may have been during the Glacial Period the pivot, so to speak, * upon which the climatal conditions of the Atlantic basin moved, as is the © case at present. While the land-tracts, both east and west of it, are now subject to coustant. changes, the condition of Greenland remains the same, not only at all seasons, but from year to year. It will be seen from my hypothetical charts that on the view taken by me, the winds blowing towards Greenland would . have come from a cold quarter during the maximum glaciation both of North America and Europe. 3 It seems doubtful whether the ice-sheet of Greenland was ever confluent with that of North America; Davis Strait, however, may have been at this period more or less permanently blocked with ice. Fig. 17.—Isobaric chart (statistical) for January. KYU DUT nd Zane t ry; WAT ae i 8) GaN ai La ill; Ve cs, 2 iy d V7), Vol.'57-] THE CLIMATE OF THE PLEISLOCENE EPOCH. 451 in the physical conditions of the Glacial Period must have been accompanied by disturbances of the meteorological equilibrium. As before stated, low-pressure systems would have been prevalent during the winter over the North Pacific and the North Atlantic, but probably with a somewhat different statistical alignment from that of the present day. The form of cyclones corresponds more or less closely with that of the anticyclones adjoining them. Isobaric lines arrange themselves around centres of high pressure on the one hand and of low pressure on the other, but they represent portions of one system of atmo- spheric circulation, and must, to a great extent, be roughly parallel one to the other. Hence, if we can ascertain the position and form of the anticyclones at any period, we may form a general idea as to the position and alignment of the cyclones complementary to them, the alignment of the latter being for our present purpose specially important. The statistica] alignment of the North Atlantic cyclone in winter during the maximum glaciation of America (fig. 18, p. 452) may therefore have been of a character similar to that of our own era at; the same season, its north-western margin being more or less parallel to that of the American ice-sheet. It may have been situated, however, farther south, because the North American anticyclone would then have been north and north-west of it. South-easterly winds would have been prevalent on the western side of the latter, preventing, together with the cyclonic winds already referred to, the permanent accumulation of ice to the west of the Mississippi and in Alaska. The North Pacific cyclone, with its longest axis parallel to the western edge of the American ice, may have then pointed statisti- cally south-east and north-west, instead of east and west as at present, carrying warm south-easterly winds into that part of the Polar basin which lies west of Behring Strait, and over the northern coasts of Siberia; and such a state of things may have continued until a late stage of the Pleistocene Epoch. This view offers an explanation, as we have seen ($ III, p. 422), of the former abundance of mammalian life in that region. While, therefore, it is not difficult to understand that the winter-distribution of pressure in the Atlantic during the maximum glaciation of North America may have been of a similar character generally to that of the present day, causing severe seasons in that continent to coincide with milder weather in Europe," it is not so easy to ascertain the baric conditions which may have existed during the summer at the same period. The daily synoptic charts afford us rio assistance, since the arrangement of the isobars, which must have then prevailed at that season, is never met with 1 My hypothetical chart (fig. 18, p. 452), showing the possible distribution of pressure in winter during the maximum glaciation of North America, cor- responds closely, as to its general principles, with the isobaric chart for January of the present era (fig. 17, p. 450). a 4 Fig. 18.—Hypothetical restoration of the relutive positions of areas of high and low) barometric pressure, and of the prevalent direction of the winds, nm the} Northern Hemisphere, during the maximum glaciation of North America, } WINTER. er pi Mj] iy So Wi ae OM Wel 57.] THE CLIMATE OF THE PLEISTOCENE EPOCH. 453 at present. A study of Dr. Buchan’s monthly charts shows, how- ever, that as spring advances and the land-tracts of the temperate regions of the Northern Hemisphere are heated by the sun, the continental anticyclones shrink in extent and move north- ward, finally coalescing over the North Pole as represented in the statistical chart for July (fig. 19, p. 454), and forming there a small anticyclone with a maximum pressure of 29-90 inches only, that of the circumpolar regions as far south as lat. 50° N. being but little lower. At that season, moreover, the isotherms of the northern regions coincide more nearly with the parallels of latitude than they do in winter. No permanently ice-clad area now exists (except in the southern part of Greenland) south of the present July isotherm of 40° Fahr.! The American ice-sheet is believed to have extended, however. considerably beyond the present isotherm of 70° Fahr., and in one direction to have approached that of 80°. (See fig. 5, p. 415.) The existence in North America during summer at that stage of the Glacial Period of a cold area of such magnitude so far south must have been accompanied, as already urged, by a distribution of pressure different from that which now prevails. Under such circumstances the Polar anticyclone may have been stronger, and may have reached farther south at that season than it now does. At the same time, pressure over the ice-sheet must have been prevalently higher than that over the adjoining oceans, though the baric gradient may not have been so steep as during the winter. The barometer is not statistically high in Greenland in summer at present, but there is a distinct though gentle gradient of lower pressure from that country towards the south (fig. 19, p. 454), the winds blowing in the same direction as they would do if the pressure were greater all round. While, therefore, during the maximum glaciation of North America there might have been in winter a frequent recurrence of conditions like those described on p. 437 (fig. 11), south-westerly winds may also have been then frequent during the summer on the eastern side of the North Atlantic. If so, the climate of the British Isles would have been warm at that season, and no permanent accumu- lation of ice could have taken place there. On the other hand, north- easterly winds would have been prevalent during the summer in North America, instead of mild or warm winds as at present.” We have little knowledge as to the conditions obtaining in Central Asia at the different stages of the Glacial Period. There is evidence, however, that at some period the glaciers of the Himalayas and of other mountain-regions on that continent attained a greater exten- } The July isotherm of 45° Fahr. includes the whole of Greenland. * In connection with the suggested anticyclonic condition of the ice-sheet during the summer, it is necessary to remember, as Mr. H. N. Dickson has kindly reminded me, that the air descending upon the anticyclone would have been warmed by compression, and it would therefore have tended to melt the ice. On the other hand, the melting of the ice would have lowered the temperature, as would radiation during the night. Moreover, some of the warmed descend- ing air might have flowed outward at a higher level, without reachinz the earth. See Ekholm, Quart. Journ. Roy. Met. Soc. vol. xxvii (1901) p. 23. Fig. 19.—Isobaric chart (statistical) for July. ‘ Y My 0, YU yp gM ee 1F = - Gee G Ny ym i De) , 2 Wy y} Wy EC Regions nowpermanently giaciated. 1 ih aaxmse Prevalent storm-tracks. ae Prevalent? ng} | Vol. 57. | THE CLIMATE OF THE PLEISTOCENE EPOCH. 455 sion than that of the present day. Prince Kropotkin, quoted by Prof. James Geikie,’ believes that ‘the whole of the upper plateau of Asia and its border-ridges were under a mighty ice-cap.’ * Even if such a view may be regarded as extreme, it seems probable that the summer climate of Central Asia may have been sufficiently cold to permit of the existence of permanent snowfields on a more extensive scale than those of the present day. VIL. Tae Merrorotocicat Conpirioys purine THE Maximum Giactarion or Koropr aNd oF THE Bririsu IsxEs. While, however, the meteorological conditions of Northern Europe in winter during the maximum glaciation of America may have more or less closely corresponded with those of the present era, the state of things in the North Atlantic basin must have been widely different when the Scandinavian ice invaded the North Sea, leaving its traces far to the south in Holland’ and elsewhere in Central Europe; when the glaciers of Switzerland and the Pyrenees extended greatly beyond their present limits; and especially when independent centres of ice-dispersion existed in the British Isles. It is difficult to understand why, when such conditions as those described as possibly obtaining during the glaciation of North America: had once eshiblished: themselves, they did not become permanent, so long as the wave of cold air (to which the glaciation of the Northern Hemisphere was due) continued. If, however, we accept the view that Kurope and the British Isles were probably not glaciated contemporaneously with the maximum extension of the ice in North America, we are justified in endeavouring to trace out the meteorological conditions under which ice-sheets . could reasonably have existed in the former, even if it is difficult to explain how it came to pass that they extended southward from the Arctic Circle, at one time over the New, and at another over the Old World. It was shown by James Croll that the direction of oceanic currents corresponds generally with the direction of the prevalent winds,* and that the former are largely due to the latter. He further pointed out that an alteration in the direction of the marine currents would affect climate.’ His view was that, during the Glacial Period, 1 «The Great Ice Age’ 3rd ed. (1894) p. 697. * [The recent observations of Prof. G. F. Wright, Quart. Journ. Geol. Soc. | vol. lvii (1901) pp. 244-50, do not support this view. I have consequently | omitted from two of my diagrams a small anticyclone which I had shown as | formerly existing during the summer in Central Asia. ] 3 Scandinavian boulders are exceedingly common in some morainic deposits near Utrecht; see Quart. Journ. Geol. Soc. vol. lii (195) p. 774. 4 “Climate & Time’ 1875, pl. 1, facing p. 212. In the Bay of Bengal, the _ Arabian Gulf, and the Chinese Sea, moreover, the local surface-currents vary at different seasons with the changes of the wiud, 5 Op. cit. p. 26. Fig. 20.—Hypothetical restoration of the relative positions of areas of high and low) barometric pressure, and of the prevalent direction of the winds, mm the} Northern Hemisphere, during the maximum glaciation of North America.) Wi) YY /; Wi y YU, / U/ Wy V4 ys ONE y Up yes KZ / ’ Up —~ SRBAX —- ——@ =— Vol. 57.] THE CLIMATE OF THE PLEISTOCENE EPOCH. 457 a portion of the Gulf Stream now flowing northward from the Equator may have been deflected southward by the agency of winds. Even under such circumstances, I think, an interchange between the Equatorial and Arctic waters must have taken place so long as the channel, 500 miles wide, between Iceland and Great Britain, remained open. Warm currents flowing northward would probably have still hugged the coasts of Europe and have been accompanied, as now, by the frequent recurrence of cyclonic conditions and mild winds in winter over the British Isles, the currents and the winds acting and re-acting on each other.” It appears necessary, therefore, to suppose that the Icelando-British Channel must have been closed,” either by some elevation of the submarine ridge which stretches, although not continuously, from Iceland to Great Britain, or by ice, or possibly by both causes combined, before a permanent ice-sheet could have accumulated in Great Britain.’ There does not seem anything intrinsically improbable in this view; indeed, there is evidence to show that such may formerly have been the case. Danish naturalists believe that at some stage during the Glacial Period the depth of the sea between Norway and Iceland was much less than it is at present, the dead shells of shallow-water forms of Arctic mollusca having been dredged there in great abundance from a considerable depth. An elevation of 2000 feet would have created a land-communication between Greenland and Great Britain, while one of half that amount would have restricted the communi- cation between the two seas to a few comparatively narrow channels of moderate depth*; these, under such circumstances, might have become wholly or partly blocked by the grounding of icebergs, which can only float in deep water, nine-tenths of their volume being necessarily submerged.’ If, however, the Greenlando-British Channel had been closed at that period, a condition of things would have arisen similar to that now existing in the Polar Sea north of Behring Strait.° The influx of warm water from the Atlantic having been cut off, the region to the north of the Greenlando-British ridge would have become anticyclonic. The south-westerly winds (the influence of 1 It seems impossible in these matters to distinguish between cause and effect. Temperature, pressure, winds, and oceanic currents act and re-act on each other as links in an endless chain. 2 Warm currents from the Atlantic enter the Polar basin to the east only of Iceland. 3 An additional argument in favour of this view wil] be found on p: 464. * These channels may have been deepened by the scour of currents since the commencement of the Glacial Period. If communication between the Polar Sea and the Atlantic has been cut off and again gradually reopened, this seems more than probable. ° Croll estimated that the submerged portion of an iceberg to that above water is as 8'7:1; see ‘Climate & Time’ 1875, p. 384. ® Behring Strait is about 36 miles wide at one point, but for-the most part con- siderably more ; the amount of water entering the Polar Sea through the strait, is not sufficient to influence, either directly or indirectly, the winter-climate of the adjoining regions, Fig. 21.—Hypothetical restoration of the relative positions of areas of high and low : . : : .- barometric pressure, and of the prevalent direction of the winds, in the | Northern Hemisphere, during the maximum glaciation of Huropé, WINTER. i am _ = 5 Regions supposed to have, been glaciated. SSSS Supposed Anfiffiean” continent, ; manne> Prevalent storm-tracks, -— > Prevalent winds. ol. 57. | THE CLIMATE OF THE PLEISTOCENE EPOCH. 459 which now extends as far north as Nova Zembla) being diverted from the shores of North-western Europe, the Arctic Sea, under the colder conditions of the Glacial Period, would have become per- manently frozen over, as the Paleocrystic Sea is now’; ice-sheets might have formed over the Scandinavian highlands and the British Isles, and high-pressure conditions might have extended thence to Greenland and northward towards the Pole, as shown in figs. 2I & 22 (pp. 458 & 460). Assuming that the maximum glaciation of the two continents did not take place at the same time, it is necessary to suppose that the ice, and with it the anticyclone of North America, retreated northward (Greenland prebably remaining ice-clad), and that coincidently an anticyclone began to spread itself over Kurope with the commence- ment of glacial conditions there. When the ice-sheet had once established itself in Europe, it would have tended, as in the case of America before discussed, to become permanent. Not only would it have been protected at all seasons against warm breezes from the south by its prevalently anticyclonic condition, but such winds: would have been diverted from Kurope and towards the American coast, because the Atlantic cyclone, no longer able to intrude itself into the Polar basin, would have lain to the south of the Greenlando- Scandinavian anticyclone, its longest axis, parallel to the edge of the Greenlando-European ice-sheet, probably pointing. west-north- westward as shown in fig. 21. The diversion of the prevalent winds of the northern part of the North Atlantic from a south-westerly to a south-easterly direc- tion would have tended, moreover, to divert the Gulf Stream, or what might have remained of it, towards the American coast. Some part of the warm water might possibly under such circum- stances have penetrated into Hudson Bay and Baffin Bay, and have ameliorated, concurrently with the south-easterly winds, the climate of the adjoining regions*; while another part, having lost a portion of its heat, might have bent round eastward, returning to the south in the form of an eddy along the shores of Western Europe. This would have reduced the temperature of Great Britain, while the possible closing of the channel between Greenland and Iceland might have arrested the Polar current which now affects in a similar way the climate of New England and Labrador. If the anticyclonic conditions existing statistically over Western Europe in October 1881 (fig. 10, p. 436) had been continued north- westward so as to include Greenland, the cyclone shown as lying at that time over Davis Strait would have been driven south- 1 A similar view has been expressed by Prof. James Geikie and Dr. Buchan; see ‘Great Ice Age’ 3rd ed. (1894) p. 805. 2 Croll mentions (‘Climate & Time’ 1875, p. 261) several cases pointing to the former existence of a mild winter-climate in the extreme north of America at a comparatively recent period (as, for example, in Prince Patrick Island, Banks Land, Wellington Channel, and Melville Island), which may have been due to the existence, at some stage or other of the Pleistocene Epoch, of such a state of things as that here suggested. Q. J. G.S. No. 227, 21 } on of the relative positions of areas of high and low d of the prevalent direction of the winds, m th} 4 jie, 2 ypothetical restoratt barometric pressure, an Northern Hemisphere, during t | SUMMER. he maximum glaciation of Europe. (i; J Bp | i YW yy, , HW gle. (Oh Nase ory = (Vers NS : NM) : AS pig au: wk - AGS Nie SOE Eni Mp one Fe M lk Vy YU 2 os W LY jj Ti oat UK NEM \\ YUM i 0. = Regions supposed to have been glaciated. ass=2- > Prevalent storm - tracks. MMM Supposed Antillean continent. ae ——> Preyalent winds. — Vol..57.] THE CLIMATE OF THE PLEISTOCENE EPOCH. 461 westward, and a state of things would have arisen closely corre- sponding with that which I suggest (fig. 21, p. 458) may have obtained in winter during the maximum glaciation of Europe. In fig. 22, which may be compared with fig. 19 (p. 454), the statistical isobaric chart for July, and with fig. 20 (p. 456), that of summer during the maximum glaciation of North America, I have shown the meteorological conditions of the Northern Hemisphere which may have been prevalent in summer during the greatest extension of the ice-sheet in Europe. If, as seems possible, the Antillean region was then cyclonic’ at that season, warm oceanic winds would have been prevalent in North America over the southern part of the region covered by ice during the colder epochs of that continent. Interglacial conditions may thus have existed in the Western, coincidently with the maximum glaciation of the Eastern, Hemisphere. It forms no part of my theory to suppose that minor fluctuations of climate in one hemisphere (like those, for example, referred to in the first footnote on p. 432) were necessarily accompanied by con- ditions of an opposite character in the other. Cold weather often exists now on both sides of the Atlantic at the same time. It seems to be under circumstances of exceptional intensity that the state of things arises illustrated on p. 437 (fig. 11), when excessive cold in North America coincided with abnormal warmth in Western Europe. Similarly it may have been during the climax of the Glacial Period only that alternate glaciation of the Eastern and Western Continents took place. VIII. Tae Prevatent Storm-Tracks or THE Pieistocens Epocu. In figs. 17 & 19 (pp. 450 & 454) I have drawn the prevalent storm-tracks of the present era during winter and summer, according to Dr. Buchan.” Originating at the former season in the China Sea, cyclonic storms travel in a north-easterly direction by Japan to Kamtchatka, their course continuing eastward through Behring Sea towards the American coast. Crossing the American continent between 45° and 50° lat. N., the region of prevalent storms passes by the Great Lakes to Newfoundland.’ Avoiding the Arctic current flowing southward between Greenland and Iceland, and reaching the 40th meridian or thereabouts, some storms move northward, along the western edge of the Gulf Stream, towards Iceland and the North Cape; others take a more southerly course across the British Isles to the Baltic, while some traverse France and Southern Europe to the Black Sea. Storms occasionally pass 1 As to this, see p. 467. 2 Bartholomew’s ‘ Atlas of Meteorology ’ pl. xxix. ; 3 An examination of the American synoptic charts shows that sume of the eyclonic disturbances of the North Pacific do not cross the Rocky Mountains. Others frequently arise, however, at the same time in similar latitudes, to the east of that range. 212 462 MR. F. W. HARMER ON THE [Aug. 1901, eastward in winter into Siberia, penetrating at times even to long. 90° E., but as a rule they die out when they reach the Ural or the Caucasus Mountains, and the anticyclonic regions of Asia. The course of cyclonic storms seems to depend upon the daily or seasonal variations in the position of anticyelonic systems. In April, for example, when the winter-anticyclone of North America moves northward, and extends to the north of the Icelandic cyclone, pressing the latter southward, the prevalent storm-tracks no longer approach Iceland, but are situated farther south than in winter. In July, moreover (fig. 19, p. 454), although storms originate in the China Sea, as indeed they do all the year round, they do not cross the,North Pacific, that region being then anticyclonic. Other storms, however, arise in North America and in the North Atlantic, and some of them invade Europe. A few penetrate into Asia at that season, but as a rule they die out, as in winter, when reaching the Urals, or the Caucasus. For a great part of the year the prevalent storm-tracks of the North Atlantic nearly coincide with the statistical isobars of 29°90 and 29-95 inches, as shown in the chart for July (fig. 19, p. 454), that is, with the division between the high and low-pressure systems. Although cyclonic storms, when once started, traverse high latitudes, sometimes even crossing to the north of the 70th parallel, they originate for the most part in regions farther south. Occasionally, however, they arise as far north as lat. 60° N., as, for example, in Behring Strait.’ Applying these considerations to the meteorolegy of the Pleistocene Epoch, it wil] not be impossible, I think, so far as my hypothetical charts may represent correctly the general isobaric conditions which then obtained, to arrive at a reasonable idea as to the regions in which storms may have been prevalent at the different stages of that epoch. Referring first to fig. 18 (p. 452), the isobaric chart for winter - during the maximum glaciation of North America, storms may have arisen then in the China Sea, as they do now, and have crossed the Pacific towards America, but so long as they continued to travel eastward, they must have passed to the south of the anti- cyclone of the American ice-sheet, the stronger contrast between the climatic zones of that period coinciding with atmospheric disturbances of a strongly-pronounced character. Storms crossing — the Atlantic might then have often hurled themselves with much violence against the western shores of Europe and the British Isles, and preceded always, as they must have been, by southerly and south-westerly winds, would have tended to ameliorate the climate of those regions.” Possibly their eastward progress may have been arrested then, as at present, by mountain-ranges. + See Maps of storm-tracks, Bull. Int. Met. Washington. ? Cyclonic storms would, I think, have continued their prevalent north- easterly track from the Atlantic towards Laplaud, as at present, so long as the Icelando-British Channel remained open, and warm currents flowed northward along the shores of Scandinavia and the British Isles. Wol.-57:1 CLIMATE OF THE PLEISTOCENE EPOCH. 463 During the maximum glaciation of Europe, storms may have passed in winter from Japan to Kamtchatka, across Behring Sea, while others traversed North America; but those which crossed the Atlantic towards Europe must have more often than at present taken a south-easterly course (fig. 21, p. 458). In this way, as we have seen, a humid climate may have been caused in the Sahara. The great extension of the Swiss glaciers during the Pleistocene Epoch shows that a considerable amount of moisture must have reached them from the ocean, some doubtless from the west. Cyclonic storms, possibly of small diameter, travelling eastward from the Atlantic, as suggested in fig. 22 (p. 460), may have then occurred in South-western Hurope from time to time. The climate of the region north of the Swiss massif was colder at this period than that to the south of it, the former having been more or less under the influence of the anticyclonic winds pro- ceeding from the ice-sheet of Northern Europe. While ice was accumulating from age to age in the north, and the great glacier of the Rhone Valley was piling up its moraine against the flanks of the Jura, the sun’s heat on the southern slopes of the ice-clad mountains during summer, and the rains which may have there fallen, pro- duced floods of incredible violence, which have covered the low- lands of Piedmont and Lombardy, from the foot of the Alps to the Adriatic, with a thick and continuous sheet of diluvial gravel and mud.’ It is only when standing on the tower of the Cathedral at Milan, or on the summit of the Superga, near Turin, looking across the great plain towards the distant mountains rising abruptly from it, that one can realize the strength and volume of the torrents which must have issued from the Alpine valleys at this epoch. The Pleistocene deposits of Northern Italy here mentioned are believed by Italian geologists” to belong to the Saharien zone of Meyer, that is, to a period contemporaneous with the humid condition of the desert region of Northern Africa, and of the great extension of the Swiss glaciers. This view harmonizes with the meteorological conditions suggested in figs. 21 & 22 (pp. 458 & 460). To the same period has been referred part of the vast sheet of coarse detritus, often containing blocks of large size, which extends northward from the foot of the Pyrenees to the Garonne, and thence to Bordeaux, and also the gravels of the Rhone delta and of the valley of the Var,* as well as the enormous sheet of gravel which covers the plains of Hungary. The inundations by which these deposits were caused can only have occurred during the prevalence of atmospheric disturbances of far greater intensity than those of our own era. 1 On the contrary, the snow-line descends much lower on the southern than on the northern slopes of the Himalayas, moist winds reaching that region from the former quarter only. ' 2 For much interesting information as to the Pleistoeene deposits of Southern Europe I am indebted to my good friends, M. G. F. Dollfus, of Paris, and Prof. Sacco, of Turin. 3 As to the latter, see Chambrun de Rosemont’s ‘ Etudes Géol. sur le Var & le Rhone’ Nice, 1873. The former have been described by many observers. 464 MR. F. W. HARMER ON THE [Aug. Igor, Floods of great violence must also have been prevalent in Northern Italy and elsewhere in Southern Europe during the Miocene Epoch. I noticed, during a recent visit, in the coarse Miocene conglomerates (Aquitano) of the Superga, an enormous waterworn block, measuring at least 12x 6 feet. In Prof. Sacco’s opinion, the Miocene Epoch was characterized by alternations of periods of tranquillity and of great floods. Some meteorological explanation of these recurring atmospheric disturbances may hereafter be found. Referring now to the prevalent storm-tracks of North-western Europe during its period of maximum glaciation, the fact that the accumulation of ice was greater in the Baltic region than in Norway indicates that the cyclonic disturbances from the Atlantic, by which the necessary humidity was supplied, did not cross the latter country, else precipitation would have been greater on the Nor- wegian highlands than in Sweden, as it is at present.’ Moisture must therefore have reached Scandinavia from the south-west, possibly as shown in figs. 21 & 22 (pp. 458 & 460), the cyclones moving towards the Baltic along the region lying between the mer de glace of Great Britain and that of Switzerland. This view supports, I think, that suggested on p. 457, that during the maximum glaciation of Europe the Icelando-Scandinavian channel was closed, an anticyclone then existing prevalently in that region, by which the passage of cyclones from the North Atlantic to the North Cape was more or less barred. 1X. A Possrpte EXPLANATION oF THE SEcuLAR MovEMENTS OF THE . Icz-SHEETS, AND OF THE PoLAR ANTICYCLONE, DURING THE PLEISTOCENE EPocuH. It will be less difficult, I fear, to show that glacial periods in one hemisphere may have coincided with milder conditions in the other, than to offer a satisfactory explanation of the way in which such changes of climate may have been brought about. As Huxley once observed, however, there are two kinds of difficulty: that | of which we cannot at once find the solution, and that which knocks us down altogether; and our present difficulty is of the first class. Moreover, if the theory now proposed is rejected, we are confronted by what seems to me the still greater difficulty of accepting the opposite view. The present meteorological condition of the temperate regions of the Northern Hemisphere is that of unstable equilibrium, charac- terized by never-ceasing change. We observe and register the daily and seasonal movements of the isobaric curves to which the variations of the weather are due, but we cannot trace the ultimate + The average annual rainfall on the western coast of Norway is very heavy, amounting at Bergen to 73 inches. In Sweden it is low: 21 inches, for example, at Upsala. See Bartholomew’s ‘Atlas of Meteorology’ p. 20. -~_ Vol. 57. ] CLIMATE OF THE PLEISTOCENE EPOCH. 465 causes of those movements. Nevertheless, we know that any im- portant meteorological disturbance at one point, however produced, may affect, in a greater or less degree, the atmospheric conditions in regions far removed from it, so that the initiation of secular movements of the Polar anticyclone during the Glacial Period may have arisen at some distant point, or in some unsuspected manner.' It seems, however, that any permanent shifting of the Polar anticyclone which may have taken place during the period in question (possibly not of a more serious character than that which occurs from time to time at present) must have followed rather than have preceded the suggested transference of the ice from one side of the Atlantic to the other. The existence of an ice-sheet in either hemisphere must have produced more or less permanence in the climatic conditions of the regions under its influence, so that changes in the relative position of areas of high and low pressure would have been of a temporary character, tending always to revert to the normal. It seems neces- sary, therefore, to suppose that it was by the means of some outside disturbing force that alterations in the position of the ice-sheet were initiated. Unless that force were extra-telluric, or some such as that suggested by Prof. Chamberlin (mentioned below), the hypothesis which attributes climatic changes to tectonic movements of subsidence and elevation seems to offer the best explanation of the difficulty. The view that the Pleistocene Epoch was one of epeirogenic dis- turbance is held on both sides of the Atlantic. ‘The late Prof. Le Conte believed that the eastern part of the North American Continent stood during the Ozarkian Period (already referred to) from 3,000 to 5,000 feet at least above its present level, and it is to this he attributed the glaciation of that region.” Prot. Chamberlin adopts Le Conte’s view, although he considers that the glacial refrigeration was not so much due to this cause directly, as indirectly, through its effect on the amount of carbon-dioxide in the atmosphere. American geologists trace, moreover, at a later stage in the Glacial history, that of the Champlain deposits, a great subsidence, affecting principally the eastern and northern portions of the continent. The apparent connection between glaciation and subsidence has also been pointed out by Prof. James Geikie,’ who has adduced many cases of alterations in level during the Pleistocene Epoch. In both the New and the Old World, therefore, we have evidence of upheaval on the one hand and subsidence on the other, during various stages of the Glacial Period. We can in some measure establish, locally, the sequence of these tectonic changes; but there may have been other oscillations of level, especially such as may 1 Prof. Fairchild remarks: ‘The various elements affecting climate, geographic, atmospheric, and astronomic, are thought to be so nicely balanced, that a comparatively slight change or maladjustment may produce serious climatic effects.’ Proce. Amer. Assoc. Adv. Sci. vol.-xlvii (1898) p. 271. 2 Journ. Geol. Chicago, vol. vii (1899) pp. 527 e¢ segq. 3 «Great Ice Age’ 3rd ed. (1894) pp. 66, 794, ete. 466. - MP. F. W. HARMER ON THE [Aug. 1901, have given the land-tracts an elevation greater than that of the present day, of which we have no evidence. In the earth-movements of the Glacial Period, we may poste have a causa vera, or possibly one of the cause, ‘which (admitting the view here taken to be correct) induced the shifting of climatic zones. Hpeirogenic ehanges, whether of upheaval or depression, must have altered the distribution of pressure, and the consequent direction of the prevalent winds, thus varying or limiting the areas. within whieh the great ice-sheets could have existed. It has been sometimes assumed that movements, etther of up- heaval or subsidence, would have similarly affected different parts of the Northern Hemisphere at the same time: that, for example, elevation and extension of the land occurred simultaneously in North Ameriea and in Central America on the one hand, and in Greenland, Scandinavia, and the British Isles on the other.’ It seems at least possible, however, that the rising of one area may have coeineided with the sinking of another, and such earth-move- ments were probably of an irregular or complicated nature. Changes of level in adjoining regions, during past epochs, have not always been of an uniform character.» The researches of American geologists, especially, show that unequal movements of the earth’s crust were characteristic, im the Western Continent, of the Glacial Period. The case mentioned in one of my former papers, where the elevation of the southern portion of the Anglo-Belgian Basin, in Pliocene and Pleistocene times, coincided with a great subsidence to the north, may also be mentioned.* Moreover, the iee seems to have moved, as to its general eourse, both in Europe and America, in different directions at different periods, and this may not improbably have been due to differential earth-movements.* Such an elevation of the North American continent as that postulated by Le Conte would have lowered its temperature, and ~ so have favoured the accumulation of ice upon it; but alterations of level in outside areas might also have affected the climate of the regions in which glaciation took place. Accepting, for the purpose of argument, Prof. J. W. Spencer’s © view as to the Pleistocene elevation of the Antillean region, a 1 See, for example, Hull, Journ. Vict. Inst. vol. xxx (1898) p. 305. 2 Prof. James Geikie says that, at one stage of the Glacial Period, a depres- sion which reached only 130 feet in Scotland attained 880 feet in Scandonceae Deposits containing northern shells are found at levels in North America successively higher as we trace them northward, namely at 200 feet in New England, 560 feet at Montreal, 1000 to 1500 feet in Labrador, and 1000 to: 2000 feet in the Arctie Regions; see ‘Great Ice Age’ Srd_ ed. (1894) Pp. 780-81. 3 Quart. Journ. Geol. Soe. vol. lii (1896) p. 7 + It may perhaps be worthy of notice that, a in Scandinavia and North America, basin-shaped depressions now exist near regions where, during the. Glacial Period, the ice lay thickest. Local changes in the movement of = ice may, however, have been sometimes due to other causes. ey ~ ta Wal.57.| CLIMATE OF THE PLEISTOCENE EPOCH. 467 continental land-tract, the eastern margin of which is supposed to have lain to the north-east of the West Indies, as shown by a dotted line in fig. 21 (p. 458), would seem to have existed at some stage of the Glacial Period over what is now the Gulf of Mexico. ‘This region, under the influence of the vertical rays of the sun in summer, must have been then very hot (with an average temperature of possibly 80° Fahr.), and would therefore have been cyclonic, instead of anticyclonic at that season as at present. But such conditions would have caused a prevalence of heated south-easterly winds, over the southern part of the United States, as shown in fig. 22 (p. 460), which would have rendered the existence of an ice-sheet in North America as far south as lat. 37° 35’ N. (its supposed maximum extension) impossible. . Let it be assumed that a gradual elevation of the Antillean region coincided with subsidence in Labrador, the North American continent having moyed from south to north as on a pivot, as did the Anglo-Belgian Basin in Pliocene and Pleistocene times: ice would then have accumulated more slowly in the north, while, at the same time, it would have been melted back in the south. If, further, the depression of Labrador had been contemporaneous with an elevation of Scandinavia and the british Isles,‘ and especially of the Icelando-British ridge, an ice-sheet might have begun to form on the Scandinavian highlands, coincidently with the shrinking of thes ice in North America. In the struggle between the anticyclones of the Old and New Worlds, similar to that which goes on during the winter at the present day, but attended with more permanent results, the anticyclone of the Hastern Continent might thus have gained the ascendency, and the statistical align- ment of the low-pressure system of the Atlantic.might have been altered from south-west and north-east to north-west and south- east, changing the prevalent direction of the warmer winds, and diverting them, together with the oceanic surface-currents, from the coasts of Europe to those of America. Under such circumstances, the ice-sheets of Eastern North America might have gradually diminished, and have finally disappeared, while at the same time glacial conditions established themselves in _ Europe. The fact that the cyclonic system of the North Atlantic, just referred to, now maintains statistically a south-westerly and north- easterly alignment, causing the prevalence of winters comparatively mild in Great Britain, and severe in Labrador, seems to indicate that the influenee of the North American anticyclone, other things being equal, may always have been stronger than that of Kurope. This being so, the former might have been able after a time, assisted .1 Prof. Bonney believes that an uplift of Great Britain and Scandinavia would have been necessary, in order to make the existence of an ice-sheet possible in those countries ; see ‘Ice-Work’ 1896, p. 277. Dr. A. R. Wallace argues also, that high land is necessary fur the initiation of a glacial periud, ‘Island Life’ 2nd ed. (1892) p. 184. 468 MR. F. W. HARMER ON THE [Aug. F90T, perhaps by meteorological changes arising, directly or indirectly, from tectonic disturbances in Europe or America,’ or possibly in Asia, to have regained its ascendancy, restoring the earlier state of things, though not perhaps to so great an extent as at first. Secular changes in climate arising from causes like these may thus have taken place during the Glacial and |post-Glacial Periods, gradually diminishing in intensity, until the exciting cause of the increased cold, whatever it may have been, had finally passed away. Glacial conditions seem to have existed during one stage or an- other of the Pleistocene Epoch in the Southern Hemisphere, as in Australia, New Zealand, and South America, due, it is supposed by some authorities, to changes in the relative levels of land and sea. Such changes must necessarily have been attended by disturbances of the baric equilibrium, and in the direction of the prevalent winds, and the influence of the former may have been felt even in the Northern Hemisphere.” When we consider the complicated character of the laws affecting the atmospheric circulation, it is not difficult to understand that in this way, or in others which it is not necessary to indicate, meteoro- logical disturbances may have been set up, the influence and extent of which it is impossible to determine. The hypothetical charts illustrating this paper are intended to — represent the conditions which may have obtained at two stages only of the Pleistocene Epoch—namely, those of the maximum ex- tension of the ice in North America, and in Europe, respectively. Almost any number of other meteorological combinations may, there- fore, have existed from time to time during that era. If all the facts were before us, the geology and the meteorology of the Glacial Period would necessarily prove to be in exact accordance. At present our information is but scanty, and the paleometeorologist must work with the best material that he can obtain, content with the enunciation of general principles, and with tbe solution of some of the more simple problems presented to him. In deprecation of the criticism that this paper is of a highly speculative character, I may perhaps urge that it is not the first of its kind on the climate-question. ‘The length which it has attained, much greater than I originally intended, must serve as my excuse that I have been able to treat this many-sided subject, which is clearly of great difficulty, from one standpoint merely, and, L fear, in a somewhat superficial manner. The views here stated are offered in a suggestive, and not in a dogmatic, spirit, and the 1 Prof. J. W. Spencer believes that movements of subsidence and elevation took place mere than once in the Antillean region during the post-Pliocene Epoch. 2 The opinion has been expressed that some of the climatic changes of the Glacial Period were more or less sudden; see, for example, Warren Upham, Journ. Vict. Inst. vol. xxix (1897) p. 201. Changes in the weather are pro- verbially so; the latter arise, as I suggest the former may have done, from variations in the direction of the winds. Vol. 57. | CLIMATE OF THE PLEISTOCENE EPOCH. 469 most that I can hope for is to have shown a prima-facie case for further investigation. My desire is to call the attention, especially of meteorological experts, among whom I have no pretension to rank, to a neglected, interesting, and possibly important branch of enquiry.’ i desire especially to acknowledge my great indebtedness to Mr. W. N. Shaw, F.R.S., who has not only permitted me to make constant use of the valuable library at the Meteorological Office, but has been kind enough to discuss the subject with me on more than one occasion, and to give me the benefit of his experience and of some important suggestions; and also to Dr. A. Buchan, F.R.8., and Mr. J. G. Bartholomew, F.R.S.E., for their courtesy in allowing me to copy maps from the ‘ Atlas of Meteorology.’ My best thanks are due, moreover, to Mr. H. N. Dickson, F.R.S.E., from whom I have received some friendly and valuable criticism, and to Prof. James Geikie, F.R.S., and others from whose writings I have largely borrowed. X. SUMMARY. The winds are an important factor in determining the distribution of climatic zones. Deviations of the monthly or yearly isotherms from the normal are coincident generally with the direction of the prevalent winds. The influence of marine currents upon climate is indirect rather than direct. Winds and currents, however, act and react on each other. Changes of wind cause marked and sudden changes in the weather: daily, as in Great Britain, or seasonally, as in India; though the general direction of oceanic currents remains more or less the same. Permanent alterations in climate would also have resulted during past epochs, had the course of the prevalent winds been permanently changed. The winds blow in a direction more or less parallel to the isobars ; the latter group themselves round centres of high and low pressure, the higher pressure being, in the Northern Hemisphere, to the right of a man standing with his back to the wind. Anomalous weather is due to some unusual arrangement of the areas of high and low barometric pressure. Similarly, former cases of anomalous climate can only have occurred when the meteoro- logical conditions were favourable. . At present, the continental areas are hotter than the ocean during summer, and are therefore cyclonic; they are colder in winter, and are then anticyclonic. Cyclones and anticyclones are necessarily mutually complementary, as are the troughs and crests of waves. ‘The baric conditions of the oceans at dilferent seasons 1 Among the services which paleeometeorology may hereafter render to the geologist, not the least perkaps may be that of assisting him to determine the chronological relations of geological zones in different regions where no direct evidence bearing on the subject may be attainable. 470 MR. F. W. HARMER ON THE [Aug. 1901,” are usually of a more or less opposite character to those of the neighbouring land-tracts. During the Glacial Period, the regions covered by ice might have been, to a greater or less extent, anticyclonic at all seasons, low- pressure systems prevailing at the same time over the warmer regions immediately to the south of them and over the adjoining oceans. ‘The relative positions of areas of high and low barometric pressure, the direction of the prevalent winds, and the consequent. distribution of climatic zones, would in such a case have differed from those of the present time: oceanic winds, with copious rain- fall, may have prevailed over regions now arid, and mild winters where they are now excessively severe. The teachings of geology will thus throw lhght on the meteoro- logy of the past, and meteorology may explain the causes of former cases of anomalous climate. At present, for example, dead shells are but seldom found on the eastern shores of Norfolk and Suffolk, though they are constantly driven on to the Dutch coast by westerly gales. The extraordinary profusion of such débris in the Upper Crag-beds of East Anglia, the littoral deposits of the North Sea in Phocene times, suggests that easterly gales were more common there at that period than they are now. The prevalence of strong westerly winds in that region at present is due to the fact that the centres of cyclonic storms approaching Great Britain from the Atlantic, pass to the north or north-west. When an anticyclone exists to the north, which is not often the case during the winter, cyclones take a more southerly course, and easterly gales are experienced in the Crag district. Such a state of things existed, not improbably, in the later Pliocene Epoch, as glacial conditions may have by that time established themselves, to a greater extent than at present, upon the Scandinavian highlands. During the existence of anticyclonic conditions over the European ice-sheet at the period of its maximum extension, when lower pres- sures prevailed in the warmer areas south of it, cyclonic storms may have passed farther south than they do at present, bringing oceanic winds over the Saharan desert, which, it is known, formerly enjoyed a more humid climate. The abundance of the mammoth in Pleistocene times along the shores of the Polar Sea (where no trees can grow at present, owing to the excessive severity of its winter- climate), may have occurred during the existence of an ice-sheet in North America, when a different statistical alignment of the Behring Strait cyclone, due to the more northerly position of the American anticyclone at that period, brought mild south-easterly winds from the Pacific over Northern Siberia, ameliorating its winter-climate, just as the prevalent alignment of the Icelandic cyclone now carries mild south-westerly winds over Great Britain and Scandinavia, and thence into the Polar regions at that season. The alternate humidity and desiccation, during the Pleistocene Epoch, of the now arid basin of Nevada, where great lakes formerly , Vol. 57.] CLIMATE OF THE PLEISTOCENE EPOCH. 71 existed, may have coincided with successive alternations in the alignment of the isobars, caused by the advance or retreat of the American ice-sheet, originating at one time moist oceanic, and at another dry winds from the land, over the region in question. It is difficult, however, to restore hypothetically the meteoro- logical conditions of the Pleistocene Epoch, on the theory that the maximum glaciation of the Eastern and Western Continents was ' contemporaneous. At present the influence of the Gulf Stream and the south-westerly winds indirectly caused by it carries a compara- tively warm climate northward during the winter over the British Isles and Scandinavia into the Polar Circle, but no permanent ice-sheet could have existed in those countries under such circum- stances. The view that the maximum glaciation of North America and Europe was contemporaneous, involves the admission that an enormous anticyclone extended more or less prevalently at that epoch from the Pole southward over a considerable portion of both continents at the same time, during the winter, and to some extent in summer. Such a state of things, however, if even it could have been for a time established, would have been meteorologically of a most unstable character, tending to produce at all seasons atmo- spheric disturbance in the Atlantic, with prevalent southerly and south-westerly winds to the east of the cyclonic centres, flooding North-western Europe with warmth. Conditions similar to those which may have prevailed during the maximum glaciation of North America occurred during the winter of 1898-99, when the weather was persistently and excessively cold in America, and abnormally warm in Europe; temperatures of —60° Fahr. were recorded on the same day in the one, and 70°5° Fahr. in the other ; the former being due to cold winds from the Polar regions, and the latter to warm winds from the subtropical zone, strictly comple- mentary to them, and due to the same cause. The northerly winds on the one side, either of a cyclonic or an anticyclonic centre, are the necessary equivalent of the southerly winds on the other. It is not possible, therefore, that the Northern Hemisphere could have been wholly cold at one stage of the Glacial Period, or wholly mild at another. The alignment of the isotherms and the distribution of climatic zones was probably at least as irregular then as at present, arctic and temperate conditions cc- existing in different areas at the same latitude. Indeed, if the disturbances of the atmospheric equilibrium in temperate regions were more marked at that period, as seems probable, the contrasts in climate may have then been even greater than they are now. No such meteorological difficulties arise if we adopt the hypo- thesis that the more important Glacial and Interglacial variations of climate may have alternated in the Western and Eastern Continents. Minor changes, however, may have been of more local distribution. The winter-temperature of Labrador (one of the North American centres of ice-accumulation during the Glacial Period) is as cold, and the annual rainfall as great, as in Greenland at the present day ; 472 MR. F. W. HARMER ON THE [Aug. 1901, the summers are, however, warm in the former, owing to the south- erly winds which there prevail intermittently at that season. Were it not for this, Labrador might even now resume its glaciated condition. The accumulation of an ice-sheet in North America would not necessarily have prevented Western Europe from enjoying a climate as temperate as that of the present time ; it might even have raised the winter-temperature of the latter region. On the other hand, it seems probable that the effect of the anticyclone of an ice-sheet, extending eastward from Greenland, over Great Britain, Scandinavia, and Northern Europe, would have been to change the prevalent alignment of the low-pressure system of the North Atlantic, producing warm south-easterly winds in Labrador and New England during the winter, instead of the northerly winds now prevalent there. The alteration in the direction of the winds would have tended, moreover, to divert the warm surface-currents of the North Atlantic from the European to the American coast. The maximum glaciation of Great Britain could only have taken place at a time when the Icelando-British channel was closed, either by an elevation of the submarine ridge connecting those countries, or by its being blocked with ice; or perhaps under the influence of both causes combined. There is evidence to shew that alterations in the level of this region did occur during the Glacial © Period. It is possibly to differential earth-movements of elevation and subsidence in different parts of the Northern Hemisphere that the suggested shifting of glacial conditions from one side of the Atlantic to the other may have been due. The views here taken afford a simpler explanation of the geolo- gical facts than those usually adopted. Instead of supposing that the climatic changes of the Great Ice Age, several times recurrent at intervals of a few thousand years only, were due to astronomical or extra-telluric causes, it is suggested that the average temperature of the Northern Hemisphere during the Pleistocene Epoch being, from some hitherto unexplained cause, lower than that of our own era, conditions of comparative warmth or cold may have been more or less local, as they now are, and that the more important variations of climate during that epoch may have affected the great continental areas at different periods. XI. APPENDIX. Two important communications, to which it is necessary briefly to refer, have recently appeared on the climate question: one from Prof. T. C. Chamberlin, of Chicago,! the other from Dr. Nils Ekholm, of Stockholm.? The first I had not seen when, in September 1900, I submitted to the Meeting of the British Association, at Bradford, 1 Journ. Geol. Chicago, vol. vii (1899) pp. 545, 667, & 751. 2 Quart. Journ. Roy. Met. Soe. vol. xxvii (1901) p. I. Vol. 57.] CLIMATE OF THE PLEISIOCENE EPOCH. 473 an abstract of the present paper; and the second had not then appeared. These writers adopt the view, not only that the more important changes of climate during past ages, such as that, for example, which is supposed to have occurred between the Carboniferous and the Permian, were due to variations in the amount of carbon- dioxide in the atmosphere, but also that to some extent the minor climatal oscillations of the Glacial Period may be traced to the same cause. Such an alteration in the atmospheric constitution must have been, however (as Prof. Chamberlin points out), of general and not of local operation, and the hypothesis that the latter group of events was so caused is inconsistent with that suggested by me that the maximum glaciation of one region may have been contempor- aneous with the existence of genial conditions in another, situated in a similar latitude. It does not follow, however, that because the carbon-dioxide theory may account for the climatal change at. the end of the Paleozoic Era just named, or for the long and gradual refrigeration which went on, apparently without intermission, during the Miocene,’ and until the end of the Pliocene, as well as for the general rise in temperature which has taken place since the end of the Glacial Period, that it must necessarily have been the cause of all, or even part of, the marked, repeated, and possibly sudden changes which, commencing at the close of the Pliocene, continued during the Glacial and apparently, though with less intensity, during the post-Glacial Period.” I cannot help doubting whether the suggested alterations in the constitution of the atmosphere could have been sufficiently rapid in operation to have originated the latter. Dr. Ekholm, indeed, remarks (op. cit. p. 26), dealing with the gradual reduction of temperature in Miocene times, that ‘the temperate Polar climate of that age, with its slowly-proceeding deterior- ation, may have occurred during a rate of carbonic acid not much greater perhaps than the present one, the cooling influence of a slow decrease of carbonic acid exhibiting its full strength only much later.’ Prof. Chamberlin points out that the reduction of the thermal absorption of the atmosphere during the Ice Age consequent on a deficiency of carbon-dioxide, would have intensified the difference in temperature between the Equatorial and Polar regions, and between that of the land and of the sea,’ and Dr. Ekholm expresses a some- what similar opinion.» This, however, would have tended to pro- duce, under the special circumstances of the Glacial Period, increased 1 The fossil moliusea of the various Miocene horizons of the Mediterranean region, for example, show, in Prof. Sacco’s opinion, no indication of alternations of climate. 2 Prof. Chamberlin indeed believes that some of the less important climatic changes of the Glacial Period may have been due to variations in the atmo- spheric circulation, Journ. Geol. Chicago, vol. vii (1899) p. 772. 3 Ibid. p. 558. 4 Quart. Journ. Roy. Met. Soc. vol. xxvii (1901) p. 24. ATA ‘MR. F, W. HARMER ON THE [Aug. tgor, atmospheric disturbance in the Atlantic, and a distribution of climatic zones even more irregular than that of the present day. Dr. Ekholm, however, while applying the carbon-dioxide theory to the climatal variations of the Glacial Period, believes that those of post-Glacial times (some instances of which he mentions) were due to secular changes in the obliquity of the ecliptic. He calculates that at the periods when, owing to this cause, the summers of the Northern Hemisphere were warmer, one series of which occurred about 9100 years ago, the amount of heat received directly from the sun at the North Pole during the months of May, June, and July, was from 4:1° to 44° Cent. (=7-4° to 7-9° Fahr.) greater than at. present, while about 28,300 years ago, when the summers were colder, it was from 6°3° to 7:1° Cent. (=11°3° to 13-1° Fahr.) less ; the difference in each case during the winter months, when the sun is there below the horizon, being of course zero. He further believes that it was during one of these warmer periods, occurring about 48,000 years ago, that the final melting of the great ice-sheets took place." The great centres of ice-accumulation do not seem to have been _atthe North Pole, however, but very much farther south : one of the most important of them, that of Labrador, being situated in about lat. 55° N., while the edge of the American ice-sheet, at the time of its maximum extension, is believed to have travelled 17 degrees farther southward. Generally the phenomena with which the glacialist has to deal did not take place in the extreme north. The excess of heat received from the sun in summer at lat. 55° N., during the warmer periods, was not nearly so great as at the Pole itself, and the winters having been colder, no material annual increase of temperature could then have taken place.* Both at the time when the obliquity was greatest and when it was least, the total difference in the amount of heat received from the sun in Labrador during the year was inappreciable, 0-54° Fahr. in the one case, and —0-54° in the other. When we remember that the summer-temperature of that region may be raised more than 30° Fahr., and its winter-temperature as much as 60° in the course of a few days, by a change of wind (see pp. 438 & 448), it will be seen how much more influence a permanent alteration in the prevalent character of the atmospheric circulation might have exerted on the melting of the American ice-sheet than the astronomical cause now suggested. 1 Tt seems to me improbable that the close of the Glacial Period took place at so remote a date. 2 Dr. Ekholm’s figures showing the increase or diminution of heat received from the sun at lat. 55° N., as. compared with that of the present era, are as follows :— 9100 years ago. 22,300 years ago. Cent. Fahr. Cent. Fahkr May | 2th. spite eee eee TS Eri ee ih Ms an —2'49= — 4°340 JUNE \Lissccsases veces abiosdanecoeeasenes +1:9°= +3°429 saaaeeues —3'0°= —5 40° Stl: sae ilacd gale toy aaa een +1°7°= +3°06° Rees —2'5°= —5-04° fummer months: Apl. to Sept. +1°=+2349 —2°0°= —3°60° Winter months: Oct.to March, —1:0°=-1°809° — a... Bae +1:7°=+3°06° Vol. 57.] CLIMATE OF THE PLEISTOCENE EPOCH. 475 Dr. Ekholm’s figures take no account, as he himself suggests, of the fact, that a part of the excess of heat received from the sun at the Pole would have been expended in the melting of snow and ice, and the evaporation of water. The cloudiness so produced, as at present in northern latitudes, must have tended to lower the temperature. The influence of the winds, moreover, would have dis- persed any excess of heat which may have there arisen. So long as an ice-sheet continued in Labrador, the winds would probably have blown prevalently from that country towards the Pole, and possibly thence, on the view taken by me (figs. 18 & 20, pp. 452 & 456), in the direction of Europe, and not from the Pole to Labrador. Evidence of a change of climate during the post-Glacial Period, similar to those mentioned by Dr. Ekholm, has been described by Mr. Clement Reid, F.R.S.,1 who in 1896 found, in a lacustrine deposit at Hoxne (Suffolk), a bed containing leaves of Arctic plants, including three species of dwarf willow (Salix myrsinites, S. herbacea, and. S. polaris) and the Arctic birch (Betula nana). In a bed con- formable to, and immediately underlying this, the character of the flora suddenly changes, no specimens being found in it except those of plants and trees now growing in the East of England. It seems to me improbable that these closely related strata can represent any such extended period as those referred to by Dr. Ekholm, and if so, the climatic changes that they indicate may have been due to meteorological rather than to astronomical causes. Dr. Ekholm gives many interesting particulars to shew that, during a period extending from the third to the end of the eighteenth century, the winters were occasionally more severe than they are now, in Scandinavia and North-western Europe on the one hand, and in Italy, the Adriatic, the Bosphorus, and Asia Minor on the other; but in no single case do the dates given for the abnormal seasons of the different regions coincide. Hestates, moreover, that Greenland and Iceland are believed to have formerly enjoyed a somewhat milder climate than that of the present day (op.cit. p.49). Extreme winter- temperatures have not been unknown in the British Isles during recent years: a minimum of —16° Fahr. was recorded at Kelso in December 1879,? and winter maxima of 60° Fahr. and upwards are not uncommon. At present, conditions of excessive cold do not last long in these islands, as the prevalent position of the winter- anticyclones is not favourable to such a state of things. The anti- cyclonic systems shift, however, not only from day to day, and from season to season, but possibly also from age to age.* Why this is so we have yet to learn, but it is not difficult to understand that a comparatively slight alteration in the prevalent alignment of the winter-isobars and in the direction of the winds so resulting, might 1 Rep. Brit. Assoc. 1896 (Liverpool) p. 400. 2 Quart. Journ. Roy. Met. Soc. vol. xxvii (1901) p. 62. - ‘3 Among other facts cited by Dr. Ekholm are some to show that 300 years. ago easterly and south-easterly winds were prevalent in Denmark, rather than those from the west and south-west as at present, op. ci¢. p. 52. Q.J.G. 8. No. 227. 2x 476 MR, F. W. HARMER ON THE [Aug. 1901, have caused, in former times, seasons milder in Greenland, and more severe in one part or another of Europe.’ While cordially acknowledging the great interest and value of the theories of Prof. Chamberlin and Dr. “Ekholm, especially as applied to the more important changes of climate during past epochs, I am still inclined to think that the minor variations of the Pleistocene, the prehistoric, and the historic periods may have belonged to one great series of events, and have been alike due to the cause which gives Great Britain its variable seasons at the present day, namely, to alterations in the direction of the prevalent winds. Discussion. Sir Henry Howorru commented on the difficulty of discussing a meteorological paper at the Geological Society. He found himself unable to agree either with the Author’s premisses or his conclusions. The Author, for instance, took the ice-sheet for granted. It was by no means clear whether he attributed his Pleistocene winds to the ice-sheet or his ice-sheet to the Pleistocene winds. He wished to know how the Author proposed to increase the evaporation of the temperate regions so as to secure a sufficient snowfall for his ice- sheet, and having got his requisite moisture, how was he going to increase the cold of summer sufficiently to prevent the winter’s snow — from being melted every year? ‘The speaker believed that at present a fortnight or three weeks was sufficient to denude all snow-covered surfaces of their winter snowfall, except mountain-tops and some parts of the Arctic lands. The theory that the periods of glaciation of North America and Europe alternated was contrary to the generally expressed opinions of glacialists. The arguments founded on the Sahara and North-eastern Asia seemed equally at fault; and the more he tested the paper, the less he could find in it to agree with. Prof. Sottas remarked that, if the conclusions to which the Author had been led might for the present be regarded as matters of con- troversy, there could at all events be no doubt as to the value of his methods. The Author had the honour of being the first to treat questions of ancient climate by the exact charting of Dr. Buchan, and this was likely to give greater definiteness to our discussions. One of the most important deductions to which the Author had been led, was that glacial conditions had alternated in the two hemi- spheres. It was to be hoped that it might be found possible to test this result by observation; but the extensive glaciation which had been found on high land within a few degrees both north and south of the Equator, and as well in the Old World asin the New, seemed to suggest some very general cause for the conditions of the Glacial Period; and if so, this might have operated in other ways than those considered by the Author. At present Greenland and Norway, 1 See also T. C. Chamberlin, Journ. Geol. Chicago, vol. vii (1899) p. 770. ¥ Vol. 57.] CLIMATE OF THE PLEISTOCENE EPOCH. A477 although under the influence of the North Atlantic depression, were both glaciated ; and a general lowering of the mean temperature might have led to an extension of glaciation from these centres simultaneously. There were other factors besides distribution of temperature to be considered, in tracing out the atmospheric circu- lation, and meteorology was scarcely at present sufficiently advanced to enable us to make certain deductions from its principles. Mr. A. E. Satter remarked that the theory advanced by the Author required the existence during the ‘period of maximum glaciation in Europe’ of a similar anticyclonic area in Central Asia. The diagrams and slides exhibited showed this very clearly. In the paper, however, on ‘ Recent Geological Changes in Northern & Central Asia’ by Prof. G. F. Wright (in the recently issued number of the Quarterly Journal), it was stated, as a remarkable fact, that in spite of careful research no signs of former extensive glaciation could be detected in those regions. Mr. P. F. Kenpatr said that he thought the Author had wisely made no attempt to explain the ultimate cause of the Glacial Period. He agreed with Prof. Sollas that that belonged to some extra- telluric agency, and was not the result of any modification in the attitude of the earth in relation to the sun. Mr. Culverwell had, he thought, shown very clearly that the eccentricity of the earth’s orbit in conjunction with precessional movements was quite inade- quate to producea Glacial Period. Moreover the very recent date and the long duration of the Ice Age were decisively against Croll’s hypo- thesis. At one time Interglacial periods were postulated upon very insufficient grounds, but he had been convinced by recent discoveries on both sides of the Atlantic that there had been mild intervals in the Glacial Period. The Author’s interesting and valuable speculations offered a reasonable explanation of them, without invoking the precession of the equinoxes. The speaker could not share Prof. Sollas’s optimism regarding the possibility of correlating the European and American Glacial and Interglacial deposits. Mr. J. Lomas said that, although many workers in the past had attacked the problems brought before the Society that evening, none had been armed with the weapons which modern meteorological research had placed in the Author’s hand. If it were acknowledged that glacial conditions ever existed over North America and North- western Europe, it followed that anticyclonic systems must have lain over the same areas, and these must have been fringed by com- plementary cyclonic systems. It seemed to him that the Author had worked on perfectly sound lines in reconstructing the areas of high and low pressure in the Pleistocene Epoch. It was quite obvious, too, that if the two hemispheres were anticyclonic at the same time, a condition of affairs would be set up which would be unstable; and it appeared almost essential that the fact should be recognized on meteorological grounds, that the Old and New Worlds were glaciated alternately. If these two important principles could be established, smaller points of detail might be left to adjust themselves. He did 2x2 ~_ ——————————— ee 478 THE CLIMATE OF THE PLEISTOCENE EPOCH. [Aug. roor,. not think it necessary to invoke epeirogenic changes to shift the centres of anticyclones. Such a system as that supposed to exist in the Western Hemisphere in Glacial times might move eastward by accretion on the east side, and an eating-away of the western side by the Northern Pacific cyclone. The Prestpent and Sir Joun Evans also spoke. The AurHor, in consequence of the lateness of the hour, replied very briefly to the various objections raised in the course of the discussion, expressing the hope that if the paper were published a number of these would prove to have been anticipated. Vol. 57.] INTRUSIVE TUFF-LIKE ROCKS IN IRELAND. 479 29. On Intrusive, Turr-1tixe, Ienzous Rocks and Breccras in _Inentanp, By James Rosinson Kirror, Esq., and ALEXANDER McHenry, Esq., M.R.I.A.* (Communicated by R. 8. Herrtss, Esq., M.A., Sec.G.S. Read June 19th, 1901.) For several years past it has been known to us that fragmental igneous rocks exist in different parts of Ireland, which, though they resemble tuffs, and in certain cases have been described as voleanic rocks, cannot be regarded as ejectamenta, on account of their character and mode of occurrence in the field. Of those which have come more especially under our notice, we may at the outset briefly mention a few particulars, to introduce our subject, before describing in detail the sections exposed in the South-east of Ireland which afford the chief evidence upon which our views of such rocks are based. In the Explanatory Memoir (1888) accompanying Sheet 24 of the ‘Geological Survey Map of Ireland, pp. 34 & 35, certain breccias occurring to the east of Lough Easke, in Donegal, are described as “ agolomerates,’ though not in the sense of their having been at any time considered volcanic rocks. In parts, these masses might better be described as crush-breccias, as they, in such cases, follow lines of dislocation. In parts, however, they consist of partly-fused, broken- up, felspathic mica-schist or ‘ gneiss,’ and they merge with felsite- dykes. Sometimes they occur dispersedly in sporadic masses in the mica-schist ; and north-east of Lough Easke the breccia forms a wide band adjoining the granite, suggesting the conclusion that its formation may be attributed to the earth-stresses which imme- diately preceded, or in a sense accompanied, the intrusion of the Barnesmore granitic mass. Rocks similar to these occur in the district of Forkhill, in Armagh, and are described as ‘ volcanic agglomerates’ in the Explanatory Memoir (1877) accompanying Sheet 70 of the Geological Survey Map of Ireland, pp. 13, 14, 30, etc. In parts they consist of brecciated slate or brecciated granite and felsite, the fragments being em- bedded in a scanty andesitic matrix. The matrix increases in proportionate quantity downward, and passes by insensible gra- dation into the adjoining felsite, so that no hard-and-fast line of separation can be drawn. between this rock and the so-called ‘ vol- canic agglomerate.’ Even where the mass is highly fragmental, the matrix is obviously crystalline, and therefore xenolithic andesite js the term which might more appropriately be applied to the breccia. This fact, considered in conjunction with the gradual passage above mentioned, points to the inference that, as all the fragmental so- called volcanic rocks of the region are of the same character, it is doubtful whether clastic rocks of volcanic origin exist there. It is 1 Communicated by permission of the Director of H.M. Geological Survey. Piga o Index-map of Bie Su) IRELAND A showing the areas occupied 4 § ONDONDERRY by the Lough Eask | Oxrex . BELFAST TURF-LIKE INTRUSIVES. Donegal Bay 4 Sapir ae Fork Hil Area Dundalk Bay Bellewstown Hill Area é : Caegieresan Y) iDUBLINa GALWAY “WATERFG @oush Guitane epee rea Waterford Area CORKe. English Miles © 10 20° 30 40) 350) R60 i [Figs. 2,8, 4, & 7 illustrate the occurrences in the Wexford area, and figs. 5, 6, & 8 those in the Waterford area. ] at ae % Vol. 57. | INTRUSIVE TUFF-LIKE ROCKS IN IRELAND. 481 _a case of petitio principit to assume, even if the masses occupy the throats of ancient volcanoes, that the contained fragments were ejected during eruption. Rocks of a similar character, apparently volcanic, though in reality hypogenic, occur at Balbriggan and Bellewstown Hill, north of Dublin, intrusive into Upper as well as Lower Silurian strata. Rocks at Blackball Head, in Kerry, have been ascribed by Jukes and others to a volcanic origin, because of their fragmental nature * ; but these rocks cross the bedding of the associated sedimentary strata of the region, are therefore intrusive and not contem- poraneous, and may be of much later date than that usually assigned to them. Similar remarks apply to the nature and origin of some of the supposed ‘ashes’ of the Lough Guitane district, near Killarney, and some of those occurring in the Limerick area. We do not intend now to refer particularly to these, but pass on to the igneous rocks of the South-east of Ireland, pausing only to mention the work of other inquirers in this line of study. It is with much gratification and encouragement that we have observed the remarks of Prof. Lapwerth in this Journal, vol. lvi (1900) p. 23, when commenting upon Mr. Lamplugh’s paper on ‘Some Effects of Earth-movement on the Carboniferous Volcanic Rocks of the Isle of Man.’ Considering the phenomena accompany- ing great movements of the crust, Prof. Lapworth conceives it possible that ‘igneous matter making its way between the moving masses may consolidate — as sills where the pressure is great. ... As movement progressed intermittently we should have the formation of subterranean agglomerates, tuffs, and breccias, which would be forced locally sometimes between bedding- planes, sometimes into dyke-like fissures.’ The manner in which Mrs. Ogilvie Gordon accounts for the ‘agglomerates’ of the Groden Pass and the Buchenstein Valley approaches somewhat closely the origin to which we attribute such masses. That authoress terms them ‘ shear-and-contact breccias’ associated with felsite-veins, as distinguished from Prof. Bonney’s ‘crush-breccias.’* If it had been further allowed that the insertion of igneous rocks from below, accompanied by partial fusion of fragments detached from the broken-up masses, played a large part in the phenomena of the region, Mrs. Gordon’s view of the origin of the agglomerates would nearly harmonize with that which we adopt to explain those that we have met with. We believe that in the South-east of Ireland are to be found abundant illustrations of the hypothesis suggested by Prof. Lapworth, namely, the sub- terranean formation of tuff-like masses. Their intrusion, however, does not always seem to have been accompanied by folding-move- ment of the adjacent sedimentary rocks, even if such were sometimes the case. 1 See pp. 91, 92 of McHenry & Watts’s ‘ Guide to the Collection of Rocks & Fossils Geol. Sury. Irel.’ 1895. 2 Quart. Journ. Geol. Soc. vol. lv (1899) pp. 567-69, 584, ete. 482 INTRUSIVE TUFF-LIKE ROCKS IN IRELAND. [ Aug. 1901. The accompanying map and sections (figs. 1-8) illustrate how tuff-like rocks invade black slate of Llandeilo age, generally adhering to the direction of bedding, but frequently cutting across it, and detaching Hh from the _ slate numerous pieces. These are more numerous near the margins of the in- trusion than at a distance, and re- tain so distinct a parallelism to the margins that we can only infer that in some instances there has _ been no great movement of the bounding walls. Sometimes the tuff-like rock con- tains large, irregu- lar masses, mostly lenticular, as in figs. 2&3. Some of these masses are themselves invaded and almost severed across by veins of tuff-like material projected from the enclosing magma. The section shown in fig. 5 (p. 484) is the bottom of a cliff-face about 60 feet in height ; the base is so exceedingly ash- like that speci- mens were col- lected as exhibit- ing the fragmental character of an ‘ash.’ Above the base the section is involved and not easily interpreted, and higher up are large included masses of black slate disposed generally parallel to the base, which, on the hypothesis of the mass being intrusive, represent the remnants of sedimentary pre-existing strata, TPT RAE ij Hide siye a aBCALI|D about 30 feet. | Lower Silurian (Llandeilo) shales and fine grits, showing the contortions of the strata. T'=Fragmental rocks (‘tuft’), with inclusions of black slate, grit, limestone, felsite, ete. {Length of section i : oStAvS ID” L Fig. 2.—COliff-section immediately under Ballymoney Coastguard Station, 34 males east of Gorey (County Weaford). LTT UH; Li, y; /. f /, /\ 4 , YY jj [Length of s2ction = 3 feet.] Fig. 4.—Section on the coast, a short distance south of Ballymoney Coastguard Station, 34 miles east of Gorey ( County Wexford). ———. [Length of section=2 feet. ] B=Bala Limestone. L= Llandeilo black slate. _ T=Fragmental intrusive rock (‘ tuff ’), with inclusions of slate, grit, limestone, basic and acid igneous rocks, ete. 484 INTRUSIVE TUFF-LIKE ROCKS IN IRELAND. _[ Aug. 1901. among which the tuff-like rock was intruded in the form of a suc- cession of thick sills. So distinctly is the mass as a whole not a rock of purely clastic, subaérial, or submarine origin that it contains masses of tuff-like rock as shown at A in the section; and follow- ing the direction of apparent dip westward along the cliff, the same mass is to be observed some 50 yards off, penetrating a remnant of the black slate of more important dimensions than any of the included pieces, and, as is believed, occupying its natural position in the stratigraphy of the sedimentary rocks. Passing the point at which this exposure of black slate is seen, the succession of massive layers of apparent ‘tuff’ continues westward for a considerable distance. . Fig. 5.—Cliff-section at St. Ronan’s Bay, south of Tramore (County Waterford). A atte tees ae aa a i Simian Wain? we ee . roe ae + . wat *. =e SEY Gsiss aia Aaa am = . ay alt a . ea at ee oa > . e a pane ¥) Sosa a Chee . we bn assdis Rat 71S * Sere es ‘Rees wa r Ved Fe , - os eater ee eae : : ee Lia SS : REEL cae ~ Th = Sy ee . ; = <= Le > = Aika eee a re —S—— = A ian = Pe, ee eee SS! SS SS SSS SSS or OE eS See eS aS Fa ETAT TS LT LN NT Ra ee LALA 2 a, TL IALTAY, ASL =i 4“. OST pe, ——— aren Prytragkiyr ple a Ge PT Tes ze ee Eo oy id fara perenne aay —— Se oy. 7 imal Waraaes — = [Length of section=30 yards. | L=Llandeilo black slate. A=Coarse fragmental rock (‘tuff’), with T= Fine fragmental rock (‘ tuff’) inclusions of slate, etc., and flow- F=Later felsite. structure at the base. ‘The rocks of this coast have lately been described by Mr. F. R. Cowper Reed, who regards some of the fragmental masses as xenolithic felsites, and some as ‘ agglomerates.’ The author refers to coarse igneous breccias at Annestown as xenolithic felsites (op. cit. p. 665). These were represented as volcanic ash on the Geological Survey Maps, and might be taken for such. They form, however, a succession of great sills such as that above described, and near Carrickadurrish rock, truneate a series of calcareous slate- beds, as may be well seen in the cliff, and is shown in fig. 6. This 1 Quart. Journ. Geol. Soe. vol. lvi (1900) pp. 657-92. Fig. 6.—Cliff-section at Annestown, south-west of Tramore | (County Waterford). SS a a SSS SSS ‘ SS Sosy 2S ee | | l Mi S (Length of section = 50 yards. ] L = Llandeilo black slate and calcareous grit. T' = Fragmental rock (‘tuff’), with inclusions of black slate and felsite. F= Felsite. . Fig. 7.—Section on the coast near Ballymoney Fishery, 34 miles east of Gorey (County. Weaford). me nen a ee So a Se —— 4 se ww = =e Z iS; Zi SSS ==, LY GLUE CALG a a [Length of section = 6 feet. ] L = Llandeilo black slate, showing contorted bedding in the inclusions. T = Fragmental intrusive rock (‘tuff’), sometimes rudely arranged in the mass to resemble bedding = ? flow-structure. A86 MESSRS, J. R. KILROE AND A. McHENRY ON’ [ Aug. Igol, mass, continued eastward across Annestown Bay, sends veins and sills into the sedimentary strata forming Green Island, and may be seen at low water surrounding a mass of black slate between the island and the mainland, A little farther east the coarse frag- mental rock, described as xenolithic felsite by Mr. Cowper Reed, contains and gradually merges into distinctly stratified rock which closely resembles tuff. ‘The origin of the whole mass is perplexing, for near to the spot where stratification is so distinctly seen a vein of black slate, only an inch or two in thickness, is traceable for a long distance in the face of the cliff. This we believe to be a rem- nant of the sedimentary rock which the tuff-like mass invaded, and not at all a deposit contemporaneous with the mass. The direc- tion of this vein, moreover, is not parallel to the structure of the stratified portion above mentioned, but is more nearly at right angles to the strike of the apparent stratification. A similar thin vein of black slate is to be observed near Ballymoney Fishery, in Wexford, as shown in fig. 7 (p. 485), At Arklow Rock and Duffcarrick, on the coast in the counties of ‘Wicklow and Wexford, the intrusive nature of those massive, apparently bedded, tuff-like rocks is most impressively exhibited. ‘This structure is well exhibited on the coast, 14 miles south of the town of Arklow, where tongues from the tuff-like rock penetrate black slate of Llandeilo age. A similar disposition of these igneous rocks is to be seen in the neighbourhood of Ballymoney Coastguard Station, and that they cannot be regarded as in any sense con- temporaneous with the slate is proved by their containing pieces of limestone of Bala age as well as pieces of the black slate (Llandeilo). Portions of the Arklow intrusive rock were examined micro- scopically, both by Mr. Teall and Mr. Seymour, and were found to yield the usual indications of rocks hitherto regarded as unques- tionable tuffs. Farther south, fine-grained felsitic rocks, arranged in layers, occur at Duffcarrick on the Wexford coast. These rocks, because of their stratified appearance, and because under the microscope they present a thoroughly clastic appearance, have been regarded as still more unquestionably tufaceous in origin. They nevertheless invade the adjoining sedimentary rocks, a peculiar banded slate— the prevailing rock of the country, known as ‘ribbon-slate.’ The * sections and plans selected for publication by no means exhaust the evidence bearing upon the important question at issue obtainable in the localities referred to; they are submitted to the Society as a selection, to illustrate the nature of the evidence for the intrusive character of these tuff-like igneous masses. The sections at Sheep Island, on the Waterford coast, 2 miles west of the entrance to Tramore Bay, are equally instructive, as showing that microscopic rock-structure cannot be relied upon, apart from field-evidence, to afford the ground of decision regarding the Vol. 57. | INTRUSIVE TUFF-LIKE ROCKS IN IRELAND. 487 origin of fragmental igneous masses. Fig. 8 shows a view of the mainland and the northern end of Sheep Island. Here are seen the light buff-coloured and green felsites, which in parts present a tuff- like aspect, and are described by Mr. Cowper Reed as tufts.’ The green rock has invaded the light-grey felsite and limestone, which it has in parts marmorized and in parts thoroughly impregnated with green (?chloritic) matter, as appears in the small islet in the figure. Though the green felsitic rock sends veins into the adjoining felsite, as seen in the accompanying figure and at the east side of the spur on the mainland near the islet (as shown in Sir Archibald Geikie’s sketch),’ the line of demarcation between the two- felsites on the western side of the spur is not so obvious; there seems, in fact, to be a gradation (though across a line of fracture) Fig. 8.— View of Sheep Island promontory, south-west of Tramore (County Waterford). [Length of section=50 yards. | L=Llandeilo black slate. T= Pinkish-grey felsite, | both in parts B=Bala limestone. F=Dark green felsite, tuff-like. from the green fragmental mass into broken-up, light-grey felsite, which contains a vanishing amount of green matter from the later rock as a cementing-matrix. Specimens from these two fragmental varieties have been microscopically examined and found to contain hourglass lapilli, indicative of tufaceous structure. Mr. H. J. Seymour has ingeniously suggested* a method of accounting for such lapilli in intrusive rocks, namely, that they represent the glassy interspaces between spherules in rapidly-cooled masses which were mechanically fractured by pressure after cooling. 1 Quart. Journ. Geol. Soc. vol. lvi (1900) p. 663. > ‘Summary of Progress of Geol. Surv. U. K.’ for 1899, p. 80. 3 Ibid. pp. 179, 180. 488 MESSRS. J. R. KILROE AND A. MCHENRY ON [Aug. IgoT, We suggested, and in this Mr. Seymour agrees with us, that the fracturing occurred in connection with continued intrusion after portions of the invading magma had solidified in smaller veins. The occurrence of lapilli cf pumice in these intrusive rocks we conceive may be accounted for in a somewhat similar manner, namely, the sudden opening out of fissures and subterranean chasms before the invading masses, which would admit of the development of a vesi- cular structure in the rapidly-cooling magma, and the subsequent fracturing and mincing-up of the newly-formed rock. The cleavage of these masses and of the felsites in certain places —subsequently to the folding of the strata which occurred prior to the invasion by the igneous masses—has led to the mistaken conception of the true origin of the intrusive rocks. Planes of cleavage which sometimes accord with the bedding-planes, though most frequently crossing the bedding, induced Jukes and Du Noyer, who examined the ground, to suppose that even the cleaved felsites ‘were volcanic ashes. Sir Archibald Geikie and Dr. Hatch, on visiting the ground some years ago, perceived that this was a superimposed structure.*. Mr. Kinahan seems to have observed the true disposition of the fragmental tuff-like rocks, as he mentions instances of their intrusive character in the Explanatory Memoir (1882) accom- panying Sheets 158 & 159 of the Geological Survey Map of Treland, p. 16, but did not follow up the inquiry. The importance of the subject in igneous geology will be readily admitted. That there are contemporaneous igneous rocks in the South of Ireland we are well aware, though the evidence for their local occurrence may need reinvestigation on the lines above indicated. Igneous action began in the district after the limestone of Bala age was formed, and was continued with intermissions up to the epoch at which Upper Old Red began to be formed, chiefly during Old Red Sandstone times, the period probably in which the Leinster granite and the associated felsites were intruded. To this period we venture to assign most of the tuff-like rocks. Indeed, we are strongly inclined to believe that these intrusive breccias in most cases represent the marginal phenomena of the granitic eruption, since we find outlying intrusions of the granite passing into the felsitic laccolites which are directly associated with the intrusive fragmental rocks. This passage is to be seen at many points in the South-east of Ireland. It is most apparent to the south of Vinegar Hill, near Enniscorthy (Sheet 158), where the fragmental felsite graduates into an elvan, and from that into a granite; also farther south-west, about 10 miles from Enniscorthy ; and again still farther south-west, in the laccolite-hill of Carrickburn (Sheet 169), where the granitic central core passes outward into a felsitic rock showing flow- and spherulitic structures, and which is, moreover, very considerably brecciated and fragmental on its outer margin, the rock-mass under these latter conditions being hitherto always regarded as ‘tuff.’ The passage from granite into felsite is also well shown near Mount Druid, in County Waterford. 1 «Summary of Progress of Geol. Surv. U. K.’ for 1898, p. 59. P etg Vol. 57.] INTRUSIVE TUFF-LIKE ROCKS IN IRELAND, 489 The present disposition, character, and behaviour of these rocks, and of their associated felsites, some of which are semivitreous and exhibit flow-structure, seem to us best to be explained by con- ceiving them to have been intruded among the strata as sills or successions of sills, and in certain cases as rudely-outlined laccolites. It is certain that, whatever the origin of the masses we describe, their true character and disposition have been overlooked in Ireland. Judging from what we know of so-called ‘ contemporaneous igneous rocks’ in the Lough Guitane district near Killarney, and their dis- position in the field, as well as of some of those in the Limerick basin, we believe that more rigid examination of these areas would reveal the existence of masses younger—possibly much younger— - than the surrounding sedimentary strata. The igneous rocks. of Wales have long been recognized to be the counterparts of those in County Wexford, and it may ultimately be found that among the great series of supposed volcanic rocks occurring in Wales are some tuff-like masses of even later date than the Silurian Epoch, as in Ireland. Discussion. The Presipent, Mr. Marr, Prof. Groom, and Prof. Warts spoke. : ADMISSION AND PRIVILEGES OF FELLOWS OF THE GEOLOGICAL SOCIETY OF LONDON. ey: Bren Candidate for admission as a Fellow must be proposed by three or more Fellows; who must sign a Certificate in his favour. The Proposer whose name stands first upon _ the Certificate must have a personal knowledge of the Candidate. Fellows on election pay an Admission Fee of Six Guineas. 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Fiscumr, — ee ee CONTENTS. Proceedings of the Geological Society, Session 1900-1901 PAPERS READ. .. . ; Page 18. Profs. C. Lloyd Morgan & S. H. Reynolds on the Igneous Rocks and Asso-— ciated Sedimentaries of the Tortworth Inlier. (Plates K & XI) ............ 267 © 19. The Rey. RB. A. Bullen on a Well-section at Dallinghoo (Suffolk) .......s-cse++- 285 20. Mr. R. Lydekker on Pantholops hundesiensis ....ccssccsscosconcentccanscnncens ivss0 DOG 21. Mr. H. W. Monckton on Landslips in Boulder-Clay near Scarborough ...... 293 : , 92. Mr. A. Strahan on the Passage of a Seam of Coal into a Seam of Dolomite. 4 CHALOM). “Psi Ue cu cites tcbays'c cawecanthy ae Sed twccides does ste en yer seaceetee (297 Ke 23. Miss I. B. J. Sollas on the Rhetic Plant Naiadita. (Plate XIII) .............. . 807 24. Mr. J. B. Hill on the Crush-Conglomerates of Argyllshire «.............+ cua 313 25. Mr. G. Barrow on Silurian[?] Rocks in Forfarshire and Kincardineshire 5 along the Highland Border .........ce0..-.005 iA ecg die steadier eee 328 26. Mr. Beeby Thomson on the Use of a Geological Datum. Abstract.]......... 846 — 27. Dr. Wheelton Hind & Mr. J. A. Howe on the Pendleside Group at Pendle Hill, ete: » (PIC IGDY) o.oo cadkavenies vane on ses pesnenssaness oases avaeis 347 28. Mr. F. W. Harmer on the Influence of the Winds upon Climate during the “ 4 Pleistocene Bpodh © vc. 626 vicecccke dase sechleedes cestode ances avede ecepadennih pean 405 29. Messrs. J. R. Kilroo & A. McHenry on 1 Intrusive, Tuff-like, Igneous Rocks ~ | and Breccias in Treland® \.i.cic5 cs scccgcthacdeshescedersucs:oienies sebneeauaieees eee 479 [No. 228 will be published next November. | [The Editor of the Quarterly Journal is directed to make it known to the Public that the Authors alone are responsible for the facts and opinions contained in their respective | Papers. } 3 : 5 *,* The Council request that all communications intended for publication by the Sones shall be clearly and legibly written on one side of the paper only, with proper P references, and in all respects in fit condition for being at once placed in the Printer’s” 5 hands. Unless this is done, it will be in the discretion of the Officers to return the communication to the Author for revision. se, : ae The Society’s Apartments are closed from August 5th to September _ 21st, 1901, both dates inclusive, for the purposes of Redecoration a4 and the Annual Cleaning. Communications by post will be £ attended to. . LL0 IOI $ Vol. LVII. NOVEMBER 2nd, 1901. No. 228. | Parr 4. THE QUARTERLY JOURNAL OF THE GEOLOGICAL SOCIETY. EDITED BY THE ASSISTANT-SECRETARY. LONDON : LONGMANS, GREEN, AND CO. PARIS:—CHARLES KLINCKSIECK, 11 RUB DE LILLE, LEIPZIG :—T. 0. WEIGEL. SOLD ALSO AT THE APARTMENTS OF THE SOOIETY, Price Five Shillings. ° . eA III OIL NN INL NNW OO eas Ss yas LIST OF THE OFFICERS OF THE wah Sc 8 abe SOCIETY OF LONDO! || Elected i February 15th, L90b i em é a ISS PrestVent. J.J. H. Teall, Hsq., M.A., V.P.R.S. Gice-Presivents. J. E. Marr, Esq., M.A., F.R.S. Prof. H. G. Seeley, F.B.S., F.L.8. H. W. Monckton, Esq., F.L.S. W. Whitaker, Hsq., B.A., F. B.S. Secretaries. R. S. Herries, Esq., M.A. | Prof. W. W. Watts, M.A. Foreign Secretary. Creasuver, Sir John Evans, K.O.B., D.C.L., LL.D., | W. T. Blanford, LL.D., F.R.S. E.R.S., F.L.S. COUNCIL. W. T. Blanford, LL.D., F.R.S. . Prof. H. A. Miers, M.A., F.R.S. Sir John Evans, K.C.B., D.O.L., LL.D., | Right Rev. John Mitchinson, D.D., D.O.L. 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S55 + cane detainees eseeewees 4-18 1902. 3s SV AMUATY a’ i dfea views do iaebaceds shoo aaaeke 8-22 x February (Anniversary, Feb. 21st) ... 5-26 “3 Waren: 54.0 7a hiwcs c cuveknaue dee aereennee 12-2 “4 DANG 5 Saal: sins intake tena one ee seo sae eee 16-30 ¥ INT siya ap poh bres ok oan have ameeeene cane eae 14-28 A DUMBO. shi 6bcs wae doe chs cueesaseeeeeted nee 11-25 [Business will commence at Hight o’ Clock precisely each Evening.] cing Vol. 57.| INTRUSIVE TUFF-LIKE ROCKS IN IRELAND. 489 The present disposition, character, and behaviour of these rocks, and of their associated felsites, some of which are semivitreous and exhibit flow-structure, seem to us best to be explained by con- ceiving them to have been intruded among the strata as sills or successions of sills, and in certain cases as rudely-outlined laccolites. It is certain that, whatever the origin of thc masses which we describe, their true character and disposition have been overlooked in Ireland. Judging from what we know of so-called ‘ contemporaneous igneous rocks’ in the Lough Guitane district near Killarney, and their disposition in the field, as well as of some of those in the Limerick basin, we believe that more rigid examination of these areas would reveal the existence of masses younger—possibly much younger— than the surrounding sedimentary strata. The igneous rocks of Wales have long been recognized to be the counterparts of those in County Wexford, and it may ultimately be found that among the great series of supposed volcanic rocks occurring in Wales are some tuff-like masses of even later date than the Silurian Period, as in Ireland.’ Discusston. The Presrpent, Mr. Marr, Prof. Groom, and Prof. Warts spoke. 1 (Mr. H. J. Seymour requests us to state that we have not quoted him correctly in the foregoing pages. For the correct reading of his views, see ‘Summary of Progress of Gecl. Surv. of U.K. for 1899’ pp. 179 & 180.— J, R. K. & A. McH., October 22nd, 1901.| 4d. G. 8S. No, 228. 21 490 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Nov. 1got, 30. On the Grotoctcan and Puysican DeveLopment of ANTIGUA. By Prof. Josepx Witriam Wintraror Spencer, M.A., Ph.D., F.G.8. (Read April 24th, 1901.) [Puatr XV—Map. | ContTENTSs, Page I. Introduction and Early Observations ...............sceseceecsecacs 490 IT. Situation and Physical Characteristics’ ............c.-sdeessemeen 491 III. The Igneous Basement of the Island ...............scssesesesssons 493 TY. The Seaforth Limestones ....... 0.00: se0sccost «sense eee 494 V. The Tuffs and included Marine and Freshwater Cherts ...... 494 VI. The White Limestones or Antigua Formation ..............000+ 496 VIL. The Hodge's Hill Sandstones ............ 1.3.00) sacs Ree 498 VILL. The Friar’s Hill Series... 24.02 .dsec~ eden baise deen s See eee 499 TX. ‘The Cassada-Garden Gravel, .. i. .0.0:cs0:+0ss000008 ee cee eee eee 500 XK. Recent Deposits: soi. i...c5 eachecesedsccestsrseashene cea 500 KI. -Coral-Reols eocic.c.ctespecncenesd sceee'essateacseeade nal 501 AIL. Notes on Barbuda. 0.02.60. ve.cccssceesesscaeosse ss = ene eEe ee 501 XIII. Erosion-Features of the Antigua-Barbuda Region ............... 502 XIV. Summary and Conclusions as to Changes of Level of Land ANG SCA sescyetacessncrees coessecacacietis secesevhteaneee tear 504 I. InrRopuction anp Karty OBSERVATIONS. Tar island of Antigua may be taken as a starting-point for the study of the Windward Islands, as within its area of 100 square miles almost all of the geological and geographical features of the region, except the later volcanic phenomena, are developed in such a way as to be easily understood. The only other island comparable for a base of study is Guadeloupe, which furthermore includes all the recent volcanic features on a grand scale, but some other features less easily distinguishable than in Antigua. On November 5th, 1819, Dr. Nicholas Nugent, a physician of Antigua, communicated to the Geological Society of London ‘ A Sketch of the Geology of the Island of Antigua’’; but a ‘ Memo- randum ’ of this had been sent to Benjamin Silliman on April 10th, 1818, and was published two years earlier in America? than the fuller London paper. Nugent also sent to the Geological Society large collections of the rocks and fossils, carefully labelled as to their horizons. These remained almost unstudied for over forty years, when P. Martin Duncan made an elaborate study of the corals contained in them,’ which appeared in 1863-64. Nugent had a companion in his studies of the island in the 1 Trans. Geol. Soc. ser. 1, vol. v (1821) pp. 459-75. . 4 Am. Journ. Sci. ser. 1, vol. i (1819) pp. 140-42. The petrified wood of Antigua had even before this attracted attention; and a notice of a collection made by Pelatiah Perit (of New York) is found a little earlier than Nugent’s ‘Memorandum,’ on p. 56 of the same volume of the Am. Journ. Sci. -3 *QOn the Fossil Corals of the West Indian Is.’ Quart. Journ. Geol. Soc. vol. xix (1863) pp. 406-58, & vol. xx (1864) pp. 20-44, 858-74. ~ Vol. 57.] PHYSICAL DEVELOPMENT OF ANTIGUA. 491 person of Dr. Thomas Nicholson, who wrote a short account of the geology of the island in the ‘Antigua Almanac & Register, ! a work forgotten or lost. Prof. 8. Hovey visited the island, with Nugent as his guide, and published a sketch of the ‘Geology of Antigua’ in 1839 (as he says) on account of the inaccessibility of Nugent’s paper in America. In this publication there was little marked advance. Nugent had described the igneous belt of the western portion of the island; the ‘clay ’ and ‘ conglomerate ’-zone in the centre, with the chert-deposits containing silicified wood, freshwater shells, etc.; and the fossiliferous white marl and lime- stones occupying the eastern or larger belt; as also the recent coral-fringes. Even in 1818, Nugent had recognized the Tertiary character of the marls, and said (Am. Journ. Sci. vol. i, p. 142) that in the West India Islands there was ‘proof of an extensive formation, more recent than those to which naturalists have heretofore principally confined their attention.’ Nugent’s paper showed a remarkable degree of perspicuity, and re- mained the only classic on the geology of the island for over sixty years, until the appearance of the studies of M. J. C. Purves, published at Brussels in 1885.? At the time of my visit, I had not seen the work of M. Purves (Curator of the Royal Natural History Museum in Brussels), which will be referred to in succeeding pages, and I am not aware that any geologist had visited the island for the purposes of investiga- tion subsequent to M. Purves, until my own visit in 1896-97. But I met there, interested in the geology of their island, two gentlemen, whose assistance and kindness I wish to acknowledge, Mr. Frank Watt, the. Island Chemist, and Mr. W. R. Forrest. The Rev. Mr. Branch is also keenly interested in the natural history of the island. None of the previous writers had made a study of the two formations more recent than the marls, or of the evolution of the physical features since the Oligocene Period (age of the limestones) ; all of which phenomena were the special objects of my visit, for the purpose of correlating them with the later life-history of the Greater Antilles and the adjacent continent, especially the evidence of great changes of level of land and sea. My theoretical expectations were realized. : IL. Srrvation anwp Puysitcan CHARACTERISTICS. Antigua and Barbuda rise from the same bank, which occupies the north-eastern portion of the chain of the Lesser Antilles.* 1 A copy was seen by Prof. Hovey in 1839. 2 At one time Professor in Yale and Amherst Colleges. See Am. Journ. Sci. ser. 1, vol. xxxv (1839) pp. 75-85. 3 « Hsquisse géologique de l’Ile d’Antigoa’ Bull. Mus. Roy. Hist. Nat. Belg. vol. iii (1884-85) pp. 273-318. * See U.S. Hydrographic Chart No. 40, or the corresponding British Admiralty Chart. 212 492 PROF, J. W. SPENCER ON THE GEOLOGICAL AND [ Nov. 1901, This bank is about 55 miles long and from 18 to 28 miles wide, with an area of 1400 miles. It is only slightly submerged, to a very uni- form depth of about 100 feet. But even from the nearest islands — Guadeloupe, Montserrat, and Nevis, which are situated on the same great submarine plateau or ridge — this island bank is separated by somewhat broad depressions reaching to a depth of 1800 feet, or in a few places the narrower channels have depths from 2000 to 2500 feet. Thus the bank presents a striking physical unit, as of an extensive plain interrupted by low hills, with the remains of mountains occurring on the southern side of what is now the island of Antigua. The margins of the bank are everywhere abrupt and precipi- tous, and they are somewhat in- dented by deep valleys extending to — the more profound depressions. The island of Antigua has a maximum length (east and west) of 16 miles and a breadth of 13, with rises out of tuffs south of the Hill, a later volcanic prominence line of section. Another voleaniec remnant rising through the White Limestones. SS fa == t Se LSS: LLLLSpspsSsSs=S== = Drew IN = S,UYOr'}S | SS SSSSS= t == Hodge’s Hill Series, on an isolated Cassada-Garden Gravels; Drew’s Friar’s Hill Marls. prominence near B. Section across Antiqua from Five Island Point to Hodge's Hill; distance about 9 miles. White Limestone Series. ‘Wleanr an area stated at 108 square miles. Hah oO But the coast-line, especially of the YSN eastern half, is very much broken up S yi o 4 into lobes by shallow bays. These are i ee occupied by numerous islands, keys, a and reefs, among which the extension | Sa of the land-valleys can be followed. o hoa ee The portion of the island south, or Fay eae ee south-west, of a line extending from ay Be #3 the hills 2 or 3 miles west of St. “| = 2 e 2 b John’s across the island to Falmouth WA, “yl 2B a 3 Harbour, forms a zone characterized a! Coa e by the remains of old mountain- if, Shee a8 ranges (the highest summit, Boggy Sas - Peak, reaching to 1330 feet above Ta | the sea), and relatively large deep A ater valleys. There are few precipitous XY cliffs, but the declivity of the mountain-sides is steep, and the streams in the deep valleys rapidly descend to the lower reaches, which are much broadened out, with flats so low that the deepening processes no longer obtain. The general erosion-features of this zone are those of a mountain-plateau, which has been dissected for Vol..57. | PHYSICAL DEVELOPMENT OF ANTIGUA. 493 so long a time by atmospheric agencies that only narrow ridges remain between the valleys and ravines. The central portion of the island, with the mountain-belt, as just described, on one side, and bounded on the other by a line of interrupted hills, extending from Dickenson’s Bay (near Wetherell Point) to Willoughby Bay, on the southern coast, is characterized by plains at only a slight elevation above the sea, out of which rise isolated hills, among which Drew’s has a height of 356 feet. The remaining, north-eastern portion of the island forms a third zoue, which is marked by undulating plains and hills rising to between 200 and 350 feet above the sea—in one case alone to 450 feet. In this portion of the island the drainage is largely absorbed into the porous strata, and is carried off below the surface, leaving it devoid of permanent streams. The diverse features of these three belts are dependent upon their geological structure, and their boundaries mark the confines of the principal formations. ILI. Tur Iannovus BAsement oF THE ISLAND. The foundation-rocks of the island appear at the surface, in the mountain-belt described above. Their general character, as then understood, was recognized by Nugent, and has recently been more fully described by M. Purves.‘ He shows that the rocks form a dolerite consisting of triclinic felspars, with little or no magnesian silicate. The phenocrysts are vitreous felspar; angular grains of magnetite are associated with them. This is an intermediate eruptive, and if included in Paleozoic rocks would be called a porphyrite, but if in Tertiary rocks an andesite. ‘There is nothing in the character of this rock to establish its age. All that can be said is that it is pre-Tertiary, on account of its underlying the older Tertiary deposits. In places the rock is strongly por- phyritic. Among the hard eruptives occur irregularly beds of fragmental materials or breccias and ashes, which have been more or less subjected to alteration, and these dip north-eastward, passing under the newer formations of the island. The compact trappean beds are often found decomposed, forming a residual soil many feet thick, The eruptive formations suffered great denudation, both before the succeeding deposition of the Tertiary formations and since the close of the early Miocene Period. ‘The long denudation, under varying conditions since that time, has largely given rise to the physical features of the island with which we are concerned. Such old igneous rocks occur in many of the Windward Islands, but in the ordinary accessible literature they are not generally distinguished from the much later volcanic eruptions which have broken through the older formation. ! Bull. Mus. Roy. Hist. Nat. Belg. vol. iii (1884-85) p. 279. 494 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Noy. 1901, IV. Tae Srarorta LIMEsToNEs. At a few points in the valleys of the mountain-zone, as at Seaforth and the adjacent estate of York (which I visited along with Mr. Forrest), there is a very compact dark-grey limestone, in appearance resembling old formations, even of Paleozoic age. The beds dip at considerable angles south-westward, Only fragments of these deposits remain, in protected places, on account of sub- sequent denudation. This appears to be the oldest formation succeeding the igneous rocks, although this limestone has not been found eastward of the mountain-zone, beneath the stratified rocks which overlie the old trappean deposits. Nothing can be said as to its age, for no fossils were found in it, but it resembles limestones of: other islands, and on this account, and because of its very different character from the Tertiary formations, it is possible that it may be as old as the remains of the Cretaceous Period, such as are seen in the island of St. Croix. V. Tuer Turrs AND INCLUDED MARINE AND FRESHWATER CHERTS. Extending diagonally across the island, in a belt from 23 to 43 miles wide, and occupying the central plains and the north- western flank of the mountain-zone (up to an altitude of 695 feet in the case of the isolated hill called Monk’s Hill), there is a very thick formation of stratified tuffs. These beds dip from 12° to 20° north-eastward. . The tuffs are made up of more or less decomposed angular and subangular fragments of trappean rocks, and contain minute erystals of felspar and magnetite. While the tuffs of fine texture predominate, near the mountains they become a conglomerate. In some cases the particles are waterworn. The colour is greenish to brown, and even whitish where kaolinization is more complete. These tuffs appear to have been derived from the denudation of the older volcanic formation, which extended to the nearest islands (30 miles distant). Drew’s Hill,’ situated in the middle of the zone, seems to have been produced by a renewal of volcanic activity, long after the commencement of the epoch of the tuffs, and may have contributed in a measure to the mass of that formation. Lying conformably within the tufaceous group are lenticular masses of cherty limestone, containing rounded or fragmentary remains of shells and corals. These rocks give rise to isolated prominences. Higher come strata of sands and grits with water- worn volcanic fragments; and still higher are irregular thin layers 1 The core of this hill is a compact crystalline eruptive, rising vertically through the tuffs to the summit, and is described by M. Purves as a trachy- dolerite, containing large crystals of triclinic felspar, with a pyroxenic mineral and grains of magnetite. It is the presence of the pyroxenic mineral which distinguishes this rock from the older igneous formation. Moles 7.) PHYSICAL DEVELOPMENT OF ANTIGUA. 495 of chert containing well-preserved fragments of silicified wood and freshwater shells. In the lower marine limestones the shells were too poorly preserved for identification, but M. Purves obtained five species of corals* suggesting Miocene age; and some of the corals described by Duncan” from the Nugent Collection showed that the age is not newer than the older Miocene. But Prof. Rupert Jones observed a fragment in the Nugent Collection containing Orbitoides Mantelli,? which would make the formation from which it came correspond to the Upper Kocene of the American continent. In the freshwater cherts M. Purves found eight genera* of gasteropods, all in an excellent state of preservation. Five of these genera are not found in more recent beds in the island; and the species of the other three genera cannot be identified with the more modern forms now living on the island. The evidence of the age, derived from these long-extinct forms, supports the antiquity indicated by the corals. Collections of fossils from the freshwater beds, which Mr. Forrest found intercalated in the tuffs, were kindly given to me by him. Suffice it here to say that the tufaceous deposits, while older than the succeeding marls resting conformably upon them, had a | fauna somewhat different from, though closely related to the latter. For other information concerning the beds of tuff and their enclosed cherts, M. Purves’s work should be consulted. 1 Prionastrea diversiformis, Mich. Upper Miocene, Bordeaux and Turin. Solenastrea turonensis, Mich. Miocene, Turin and Touraine. Stylocenia lubato-rotundata (Mich.). Miocene, near Turin, ete. Porites Collegnana, Mich., equivalent of incrustans, Ed. & H. Miocene, Turin. Alveopora Dedalea, Forskal. Recent, Red Sea, Indian and Pacific Oceans. 2 Astrea cellulosa, var. curvata, sp. nov. ; A. megalaxona, sp. noy.; Solenastrea turonensis, Mich. ; Isastrea conferta, sp. nov.; L. turbinata, sp. nov. ; Stephano- cenia tenuis, sp. nov.; Caloria dens-elephantis, sp. nov. ; Astroria polygonalis, sp. nov.; 4. affinis, sp. nov.; A. antiguensis, sp. nov.; Astrocenia ornata, Ed. & H.; Alveopora Dedalea, Blainv., var. regularis & minor; and later he added Stylocenia lobato-rotundata (Mich.), found also in the lower limestone of Malta. Thus, three species are like Huropean Miocene, nine peculiarly Antiguan species, and Alveopora Dedalea is recent. Dunean added three species as coming from the tuff, namely, Stephanocenia tenuis, Astrea cellulosa, and Meandrina, sp., but M. Purves points out that these come from a horizon in the tuff above the chert-beds. See Duncan, Quart. Journ. Geol. Soc. vol. xix (1863) p. 411 & Geol. Mag. 1864, p. 97. 3 Geol. Mag. 1864, p. 102. M. Purves thinks, however, that the specimen containing Orbitoides came from the higher limestone, which would suggest a somewhat earlier Tertiary date for all the deposits. 4 Bull. Mus. Roy. Hist. Nat. Belg. vol. iii (1884-85) p. 294. ‘The five genera confined to the island are Melania, Zonites, Nematura or Amnicola, Neritina, and Pomatias, and the three genera with species still living are Planorbis, Melampus, and Truncatella. M. Purves says that Me/enia proper does not live in the West Indies, but the subgenus Hemisinus occurs in Cuba. Zonites does not occur in the West Indies, though a species was found by M. Purves in Demerara. Neritina is scattered over the islands, but not, in Antigua. Nematura is found in the East Indies and in the Oligocene of the Isle of Wight. ES ee oie. —_—— a i ee Se elk, iidandiarmeeaasie ee a re - ehS SP PERSP SE ee PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Nov. 1go1, bo ie) (@P} VI. Tae Wuirt Livestones on AntTIGUA FORMATION. The north-eastern portion of the island is underlain by a white limestone or marl, which is the ‘ Marl’ formation of Nugent (or the ‘Upper Limestones and Marls’ of M. Purves). ‘This formation is composed of an earthy marl and beds of compact limestone, often hard and durable enough for building purposes. White is the prevailing colour, but it is sometimes greyish or yellowish in the lower beds. The limestones are distinctly bedded, and dip from 12° to 20° north-eastward; but the bedding in the earthy or marly beds is often obscure. These varieties of rock pass one into the other. This formation is apparently conform- able to the underlying tufaceous beds. The thickness of the limestone was not determined, but there still remain of it at least many hundred feet. The limestones are in part capped by a mechanical deposit, which has not been distinguished from the limestones by any previous observer. This series gives rise to the undulating hilly country occupying the north-eastern part of the island, the rolling features of which are the remains after the enormous degradation of the limestone at a comparatively slight altitude above the base-level of erosion. From the dip of the strata it naturally follows that the slopes towards the south- west are somewhat more abrupt than in the opposite direction. The importance of this formation arises from two facts :—first, that it was the last great accumulation before a very long period of denudation, which removed not only a large proportion of the limestones themselves, but also exposed the older features; and secondly, on account of its containing a fauna by which the age of the beds can be determined. The question is not one of local distribution on the island, but rather one concerning the whole North-eastern Antilles, as showing that the phenomena described did occur in that region, during the geological periods ascertained. These limestones generally form the summits of the higher hills, but at the lower altitudes they have their very much eroded surfaces covered by a thin mantle of mechanical deposits, which have sometimes been removed in artificial cuts and otherwise. At the north-western end of this belt, the sea has encroached upon the high lands, where at Wetherell Point it has formed a bluff about 100 feet high. Here both the hard and the marly beds occur, each being highly fossiliferous in places. Some of the harder beds appear to be made up of Ostrea. ‘There are also other species of molluscs, but they are mostly in a poor state of preservation, and seldom consist of more than casts. The most important fossils found here are the smaller corals which predominate in the softer beds and are often silicified, thus preserving the structure so as to be determinable. I observed fossils at other localities, but nowhere so abundant as at Wetherell Point. The only corals that have hitherto been collected were those sent by Nugent to London in 1819, and studied by Duncan, who enumerates eleven or Vol. 57. | PHYSICAL DEVELOPMENT OF ANTIGUA. 497 species (of three genera) and some additional varieties as here named ' :— Astrea crassolamellata, sp. nov., with varieties imagnetica, pulchella, nobilis, minor, Nugenti, and magnifica; A. antiguensis, sp. nov.; A. endothecata, sp. nov.; dA. tenuis, sp. nov.; A. barbadensis, sp. nov.; A. radiata, Lamarck, var. intermedia; A. costata, sp. nov.; Rhodarea irregularis, sp. noy.; Alveopora Dedalea, Blainv., var. regularis ; A. microscopica, sp. nov.; A. fenestrata, Dana. I have seen no determination of the shells collected by Nugent, but with regard to some of them, Duncan says that they were unfortunately determined by some good authorities to be specifically identical with forms now existing in the reefs round the island. I might suggest that these recent types of shells may have come from the lower altitudes above the sea, and belonged to a different horizon not distinguished by the collector from the White Lime- stone Series, for, as already stated, the earlier observers confounded an overlying accumulation with the great formation now being studied. My collection of corals has been kindly determined for me by Dr. T. Wayland Vaughan, who found the following species :-— Trochosmilia sp. nov. Orbicella endothecata, Duncan Stylophora sp. (=cavernosa, Linn.). Stephanocenia sp. Orbicella sp. Astrocenia ornata, Ed. & H. - Symphyllia sp. nov. Brachyphyllia sp. Astroria polygonalis, Duncan. Orbicella (Astrea) crassolamellata, Oroseris sp. nov. Duncan. Alveopora regularis, Duncan. Orbicella cellulosa, Duncan. Porites sp. nov. (?). Besides these corals a species of Orbitoides was also found. This list includes eight new or undetermined species of other genera, not found by Duncan, and six species common to the two collections. Two of these species are those which Duncan found in collections from the marl-beds; three from those belonging to the chert-beds (that is, midway within the great beds of tuff) or in the tuff itself; and one species common to the marl and the lower beds. Thus while Duncan recognized a difference in the fauna of the lower and upper beds, he found that they were closely allied, and the present collection still further emphasizes this point. Accordingly it would appear that the underlying beds of tuff with the overlying White Limestone form scarcely more than one geological unit, although characterized by great changes in the physical conditions during the accumulation of the system. This collection of mine contained old types only. Duncan iden- tified some of the species as belonging to the Miocene Period of the Old World. A few he found to be recent, but related to those of other West Indian islands, though the nearest analogies ure found in the Indian and Pacific Oceans. The majority of he species are peculiar to Antigua, but none’of them have any relationship with the living forms in the adjacent waters, showing a complete gap between them and the coral-fauna of the marls. 1 Quart. Journ. Geol. Soe. vol. xix (1863) p. 410. = teeta aie Keatcalti mi adi techie ath“? act oni ate Seeetaat pada a SA ae ” . K j 498 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Nov. 1901, From these considerations Duncan inferred that the formation belonged to the mid-Tertiary or Miocene Period. It has been stated before (p. 495) that Prof. Rupert Jones had found an Orbitoides Mantellc in the Nugent Collection. I also found a species of Orbitozdes in the marls of Wetherell Point. This fossil is one of the most important collected, as it affords a correlation with the Tertiary of the South-eastern States, and would suggest that the formation is somewhat older than the mid-Tertiary Period, in a word, that the rocks are older Miocene or Oligocene. Thus it would appear that the time of this formation was a con- tinuation of that of the fossiliferous beds of the tufaceous deposits (reaching probably to a thickness of several thousand feet)—the whole being one undivided geological unit, referable to the older Tertiary Period (including the Eocene and extending to the later Oligocene days).' The shells of the same formation, which, as before stated, are mostly in the form of casts, have not been determined, but Prof. W. H. Dall, having cursorily examined them, formed a general impression confirmatory of the evidence established by the corals. Prof. Gregory” mentions Echinanthus (or Dzuplothecanthus of Duncan) concavus, Cott. and H. Antillarum, Cott., sent by Mr. Forrest, as the first echinoids recorded as coming from Antigua, thus correlating the beds of this island with those of St. Bartholomew. The eroded surfaces of these limestones give form to the hills, rising to 200 or 350 feet (one point to 456 feet) above the sea, with the gently sloping depressions between them. The higher portions of the hills appear not to have been subsequently covered by the accumulations about to be described. But the question of the erosion-features produced during the different periods since the early Miocene emergence of the limestones will be considered as a separate topic. I have refrained from comparing the age of the rock-formations and other features with their equivalents in the other West Indian islands, as this subject should form a chapter bv itself. The series has become a type in the Antillean islands, and may thus appropriately be called the Antigua formation. VII. Tur Honvex’s Hirt Sanpstones. Hodge's Hill is situated at the north-eastern angle of Antigua, rising to a height of 154 feet above the sea. The exposed strata of this hill are composed of a creamy white calcareous sandstone. It is compact and suitable for building-material, hardening and darkening on exposure. The dip is in “the normal north- easterly direction, but less than that of the White Limestones—not ex- ceeding 10°. The rounded grains of calcareous sand give the 1 [Since I sent in the manuscript of this paper, Dr. Vaughan has shown that the Antiguan coral-fauna is identical with that of the lower beds of the Upper Oligocene formation in South-western Georgia. See ‘Science’ n.s. vol. xii (1900) pp. 873-75. | 2 Quart. Journ. Geol. Soe. vol. li (1895) p. 299. al Vol. 57.] PHYSICAL DEVELOPMENT OF ANTIGUA. 499 rock an entirely different appearance from that of the White Limestones upon which it rests unconformably, as shown along the sea-coast west of the hill. At one point near here, the White Limestones were seen to form a sharp anticline, the eastern arm being much steeper than the western, the axis running north and south. The age of these beds has not been determined; but as they have been involved in the dislocation of the White Lime- stones, one suspects that the Hodge’s Hill Sandstones belong to an epoch not long subsequent to that of the former rocks. VIII. Tue Feiar’s Hitt Sertss. Lying on the eroded surface of the White Limestones at Friar’s Hill is a thin layer of waterworn pebbles (formed out of the harder material of the underlying formation), succeeded by a bed of a homogeneous yellowish-white marl, 12 feet thick. In other artificial cuts in the hilly country, in the northern part of the island, as on the road to Millar’s Mill, etc., one may observe the eroded surfaces of the underlying series, covered by a mantle of fragmental deposits of pebbles and marls not exceeding a thickness of 20 feet, except in buried depressions. The marly beds of the series are most frequently seen underlying the pebbles. The marls are in places indistinctly laminated, in others the stratification is shown only by lines of pebbles within the finer material. The bedding appears to be everywhere horizontal, although there are slight undulations (but not tilting). This deposit, whether marly or pebbly, is evidently one of mechanical origin, where the lime- stone has been more or less pulverized and rounded by the action of the waves. Occasional fragments of the older rocks have been seen included with other pebbles. The White Limestone- pebbles form a very considerable portion of the whole mass. On the gently-sloping hillside, from which the accumulation has not been entirely denuded, the finer marl has been so washed out as to leave the fields covered with a very stony surface—the pebbles being those left from the denudation of the overlying mantle. As the substance of these pebbles is identical with that of the underlying rocks, it is not surprising that they should not have been distinguished from disintegrated fragments of the older surface-rocks, but the intervening unconformity should have been recorded if not explained. Although they are waterworn, the soft materials of which they are composed do not become so well rounded or preserve their forms as do those of harder rocks. Further- more, in places both the rounded pebbles of the upper series and the more angular surface-fragments of the limestones are inter- mingled; but where the waterworn pebbles are seen, they can usually be traced to lower altitudes, where their relationship to the typical deposits can be easily ascertained. The Friar’s Hill Series is widespread, covering most of the lower slopes of this part of the island, and occurs up to an altitude of 200 feet, above which the hills of the older formation rise from 100 to 250 feet higher. This superficial mantle has been greatly denuded, so as to reduce its SSE 500 PROF, J. W. SPENCER ON THE GEOLOGICAL AND [Nov. Igo1, thickness in places to only a few feet, or even to expose the underlying rocks, being, however, unmistakably preserved in the depressions of the older surface. The materials of the Friar’s Hill Series have not been trans- ported to any considerable distance. For this reason, and on account of the fragmental character of the tuffs, as well as perhaps on account of the subsequent denudation, the evidence of the submergence to 200 feet, during this short epoch of rapid deposi- tion, was not observed in the central portion of the island—unless it be in some of the cherty fragments (containing shells and petrified wood) scattered over the surface—where, however, the remains of a still newer deposit occur. No fossils belonging to this formation ' per se have been discovered as yet, but a few waterworn corals of the older beds occasionally are found among the pebbles. While the age cannot be determined from the included fossils, yet from physical considerations and from analogous accumulations with similar relationship—namely : the Matanzas formation of Cuba, the Layton of Jamaica, and the Lafayette of the American continent—the Friar’s Hill Series is thought to belong to the close of the Pliocene or the early part of the Pleistocene Period. LX. Tae Cassapa-GAarpgen GRAVELS. Cassada Garden Estate is situated about 2 miles east of St. John’s, on the eastern margin of the tuffs, and very near the south-western chain of hills of the White Limestone Series. Consequently, it is somewhat distantly removed from even the newer volcanic rocks of Drew’s Hill. At the mill on Cassada Garden Estate is a low eminence rising only about 20 fect above the plain. A chain of similar mounds extends south-eastward. These are composed of somewhat coarse, perfectly waterworn pebbles of igneous rocks, with fresh, compact, undecomposed surfaces. In section, at the pond of Cassada Garden, the gravels are seen to be interstratified horizontally with loam. Mr. Watt, who kindly took me to this locality, had examined the section shown in the well, sunk through the deposit, and found that it did not exceed 20 feet in thickness, or precisely the height of the knolls above the plain. The gravel-knolls do not attain an elevation of more than 60 to 75 feet above the sea. These deposits, trans- ported from considerable distances, and accumulated by currents, have also suffered denudation. The whole series resembles sections of the Columbia formation of America, the Zapata of Cuba, and the Liguanea of Jamaica, which belong to the early part of the Pleistocene Period. X. Recenr Deposits. Many portions of the island adjacent to the sea-shore, as at St. George’s Church, directly east of St. John’s, have their surface 1 [Some of the corals studied by Duncan may have come from these marls, or else from a still more recent formation not yet distinguished on this island, equivalent to the Usine Beds of Guadeloupe. | Wol.57.| PHYSICAL DEVELOPMENT OF ANTIGUA. 501 covered with a thin layer of marly earth, containing a considerable number of marine shells, such us are now living in the adjacent sea. I observed the deposit, which is horizontally stratified, only to an elevation of 10 feet above sea-level. This surface was defined by M. Purves as a terrace of ‘ Horizontal Marls,’ a feature of which, noticed by him, should not be passed over. In the upper portion of the accumulation he found a considerable number of land-shells, which had been washed down into the basins where the marls were formed. Among these shells he found Helix formosa, Férussac, to be the most abundant, but the shell no longer lives in this portion of the island, although it still survives in the mountain district of the south-western part of the island. He also found Helicina Crosbyi, Nob. now extinct, and known nowhere in the West Indies; and Succinea Boonii, Nob., a species no longer living. On account of these wholly or locally extinct species, although commingled with a number of living forms, he concluded that a considerable time has elapsed since the deposition of the beds containing them. XI. Corat-ReEers. Coral-reefs are extensively developed round both the islands of Antigua and Barbuda, rising to the surface of the sea, but they do not appear to form elevated reefs, characterizing the margin of the island. Even the low peninsulas and islands separating the bays on the north-eastern coast are composed of older forma- tions, but the reefs in part obstruct the entrances of the bays or - form ‘ keys’ in them. XII. Nores on Bappupa. Before considering the erosion-feat . s of Antigua, a word may be said with reference to Barbuda, which was involved in the denudation of the region. This island, nearly as large as Antigua, is a low undulating plain, passing into lagoons on its western side. The greatest elevation is only 115 feet. While I did not visit. the island, Mr. Watt informed me that it was everywhere com- posed of a limestone, poorly covered with soil, and he kindly gave me fragments of the rock containing casts of old fossil shells, the whole apparently identical with the White Limestones of Antigua. This resemblance was also noticed by M. Purves. The collection of Nugent contained specimens from Barbuda, among which was Cyphastrea costata, Duncan, a form of coral occurring in the older Tertiary beds of Santo Domingo and Jamaica. Although the evidence of the identity of the rocks in the two islands is incomplete, yet there can hardly be any doubt of it, especially as they are not distantly separated, and the beds of the one island lie almost along the continuation of the strike of the strata in the other, but they may represent higher beds of the same series preserved from erosion. The recent formations, at most forming thin mantles, have not been studied. M. Purves states that the land-shells are identical with those of Antigua, except one variety of /elicina, thus indicating a late connection of the two islands. 502 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Nov. 1901, XIII. Eroston-Fraturss oF tue AntTicuA-Barsupa ReEGIon. As before stated, these two islands and connecting banks form a geographical unit, although the greater part is slightly submerged. Whatever erosion had affected the mountain-districts of Antigua, prior to the elevation of the White Limestones, it left but little effect upon the later topography. The physical features of the north-western part of the island are such as show the former uniform thickness of the White Limestones from one end of the belt to the other. The surface gently descends in the same direction as the beds are inclined. At an elevation of about 100 feet is a peneplain sloping towards the eastern coast, but out of it rise isolated ridges. Following the trend of the belt, the country is charac- terized by a succession of hills, from 200 to 350 feet above the sea (which in one case only rise to 450 feet), separated by broad undulating depressions reduced to 150 feet above the sea. Thus we find that the atmospheric agents had not merely removed a great thickness of the White Limestones, but dissected the whole region and transformed the incisions into gently-sloping depres- sions, leaving only the higher points as isolated hills, occupying a subordinate portion of the country. One cannot even guess to how enormous an extent these rocks have been removed by degradation. They must have also covered to a greater or less extent the tuffs to the south-west. Such topography indicates the denudation of a region rising only gently above the base- level of erosion (that is, the level of the sea, the margin of which was then located at least beyond the banks); for the peninsulas of the eastern coast are the remains, in part, of the White Lime- stones separated by the excavation of the intervening valleys now submerged. ~ The configuration of Barbuda conforms to that of the north- eastern portion of Antigua; and the banks between the islands represent a coastal plain now submerged to 100 or 120 feet, which does not appear to have been subsequently modified by the growth of corals, as in the shallower water immediately about the islands. The tufaceous deposits have evidently suffered a greater amount of erosion than the limestones, as the incoherent materials have been removed so as to form the low broad plains of the middle belt of the island, out of which some of the harder rocks, such as the remains of Drew’s Hill, rise to elevations similar to that of the limestone-hills to the eastward; and indeed one eminence at the southern end of the belt (Monk’s Hill) shows the remains of this deposit to an altitude of about 700 feet, indicating a differ- ential denudation of nearly this amount. — The broad valleys of the lower reaches of the streams, with their low gradients, deeply indenting the mountain-zone, appear to belong to the same long period of denudation, but the deeper valleys of the interior of the island have quite different features, suggesting that during the long Miocene-Pliocene Period it was a plateau or mountain-area only partly dissected by the rapidly- —<—- Vol. 57.| PHYSICAL DEVELOPMENT OF ANTIGUA. 303 descending waters. As a broad feature of this old erosion, it may be mentioned that the wide shallow harbours, such as Willoughby Bay, Falmouth Bay, and Five Island Harbour, are only sunken portions of the land-valleys. But between these, which were once surrounded by high hills in the form of amphitheatres, and the low interior country, the elevated lands at their heads have been so reduced in height as to form low passes, leaving the sides of the valleys characterized by prominent elevations. The broad undulating or rounded features were formed by atmo- spheric agents prior to the deposition of the Friar’s Hill Series, which at most covers the old surface by only a thin mantle. Consequently, the island was continuously a land-surface from the early Miocene to about the close of the Pliocene Period, when it was again partly submerged during the Friar’s Hill epoch. Throughout this long era, the topography of the region was a mountain-district, bordered by foot-hills of considerable elevation, among which was the adventitious volcano of Drew’s Hill, and perhaps later a volcanic outburst at Crosbie’s," beyond which the coastal plains extended to the edge of the banks north of Barbuda. After the Friar’s Hill epoch, subsequent erosion produced other characteristics throughout the region. The broad depressions indenting the margins of Antigua were greatly deepened and extended farther into the highlands. These valleys, on the coast, are now drowned to a depth of 40 or 50, and in one case to 80 feet. On the southern coast the channels of Willoughby Bay and English Harbour are distinctly traceable to a depth of 100 feet, and that of Falmouth to 140 feet, within the limits of the less submerged banks. Similar trenches can be traced upon the submarine plains between the two islands, having a depth of 25 or 40 feet, and in a locality west of Barbuda there is one of 100 feet below the surface of the banks, which are themselves submerged only 80 feet. Where the margins of the submarine plateau have dropped to 150 feet and more below the surface of the sea, they show valley- like indentations trending to those of the land. One of the most conspicuous occurs west of Five Island Harbour. It reaches a depth of 1290 feet within the line where the banks are covered by less than 150 feet of water. This deep amphitheatre opens out into the broad submarine valley, where the soundings reach over 1900 feet. Broad embayments encroach upon both sides of the plateau between Antigua and Barbuda, thus considerably reducing its breadth. I have just mentioned comparatively narrow channels upon the surface of the submarine plateau, and deep indentations into its margin. The former feature may be produced either where the land has no great altitude above the drainage-leve], or upon the surface of a high plateau, sufficiently far within its margin for the streams not to be affected by the deep declivity of its edge. 1 This is a dolerite containing far more pyroxenic elements than that of Drew’s Hill, one of the facts which led M. Purves to infer its more recent origin. 7 OPES, ee —— a NL TRE LA ITD LT ETE TEES ATIR 004 PROF, J. W. SPENCER ON THE GEOLOGICAL AND [ Noy. 1901, The second condition is the result of atmospheric denudation and rapidly-descending streams, producing deep valleys, headed by amphitheatres, which are constantly receding into the highlands, and cause the shallow channels upon the surface to become eventually transformed into cafions and valleys dissecting the plateau. The difference between the erosion-features of the Miocene- Pliocene and the early Pleistocene Periods (separated by the Friar’s Hill submergence) lies in the low undulating topographic forms of the first-mentioned, requiring a long period of development at a low elevation; and the deep valleys and sharp outlines of the latter, produced rapidly at considerable heights above the drainage-level of the region. But it should not be forgotten that the valleys on the high tablelands, well within their borders and not affected by the declivity of their margins, may still preserve the flattened features of a lower level of erosion. The erosion-features of the higher parts of the mountains of Antigua—highlands dissected into narrow ridges and deep valleys of great declivity—are the result of the older degradation continued to the present time without interruption by submergence. This complete dissection of the mountain-districts is an illustration of the effects which would have been produced upon the Antigua- Barbuda plateau had the secondary period of denudation under conditions of great elevation been continued sufficiently long. A considerable portion of the Friar’s Hill Series was removed during the early Pleistocene elevation. Again there has been a certain amount of denudation since the epoch of the Cassada-Garden Gravels, and also since the accumulation of the low marls on the eastern coast, this latter extending below sea-level. The relative amount of work during the last episode is not so well defined in Antigua as in other islands, and deserves further study in the field. XIV. Summary anD CoNCLUSIONS AS TO CHanGss oF LEVEL oF LAND AND SEA. As has already been shown, this region was an extensive land- surface during the Miocene-Pliocene Period, which was eventually reduced to a comparatively low elevation above sea-level before the close of that time. This is the conclusion arrived at from the evidence within the boundaries of the submerged plateau, sur- mounted by the islands of Antigua and Barbuda. But outside the limit of this paper there is evidence that leads me to think that during the earlier part of tue period the whole region was at least 2000 feet higher than now, when the broad valleys between the Antiguan mass and the neighbouring islands on the submarine Antillean plateau were being fashioned out of a higher tableland : of this a remnant remains in the Antigua-Barbuda plateau, the surface of which was reduced to its present form in the latter part of the period. J have not observed in Antigua the evidence of an insular elevation, as seen in the islands where late voleanic p nH | H) ti i 3 SOUND 61°50" Ed write LIMESTONES E221 _turrs ano CHERTS WITH SEAFORTH LIMESTONE AT THE BASE -.IGNEOUS ROOKS oS JOHN Quart. Journ. Geol. Soc. Vol. LVII, Pl. XV. GEOLOGICAL SKETCH-MAP of the ISLAND OF ANTIGUA. By JW, SPENCER PH.D MA. BGS. SCALE OF MILES act Bird 1. BELFAST BAY. 2 FIVE ISLAND HARBOUR MOSQUITO COVE 61950. Standfast Pt- HEIGHTS ARB INDICATED IN FEET, 75 Vol. 57.] PHYSICAL DEVELOPMENT OF ANTIGUA. 505 activity has prevailed, but this is a question for consideration when studying the general changes of level of the Antillean plateau. The Miocene-Pliocene elevation in Antigua was followed by a sub- mergence (the Friar’s Hill) to a depth of 200 feet below the present altitude. On this account it is possible that the mechanical accumulations of Antigua are represented in Barbuda by calcareous beds containing a recent type of organic remains. Following this submergence about the close of the Pliocene Period, the land rose to a great altitude. The evidence from the dissection of the banks shows the elevation to have reached 2000 feet. But the submarine plateau between Antigua and Guadeloupe is further incised by channels, indicating the elevation to have exceeded 3000 feet. This is not the extreme height to which the region rose, but the evidence lies beyond the province of this paper. These conditions did not continue sufficiently long to complete the dissection of the tablelands, and consequently the Antigua-Barbuda mass remains intact. This elevation (subsequent to the deposition of the Friar’s Hill Series) was in the early part of the Pleistocene Period, fuller evidence of which occurs elsewhere.’ Then followed a subsidence, which culminated in a submergence to a depth of 75 feet when the Cassada-Garden Gravels were deposited, to be succeeded by a re-elevation—not merely to this amount, but to 100 feet or more—when the shallow channels on the submarine bank were formed. ‘This feature would be in harmony with the later movements observed in other islands. Sufficient study has not been given to the subject to determine whether the recent marls on the eastern coast were laid down during the post-Cassada Garden emergence—in which case they were once considerably higher before sinking to the present level— or whether they belonged to a later episode indicating another subsidence and re-emergence to a height of 10 feet. However, a doubt is cast upon a very recent re-emergence, on account of the considerable age of the shells in the marls, and also because recent corals do not occur in the raised reefs. EXPLANATION OF PLATE XV. Geological sketch-map of the Island of Antigua, on the scale of about 23 miles to the inch. A south-western mountain-zone composed of old igneous formations; a central rolling valley-belt with undulating hills, formed of tufaceous’ deposits ; a north-eastern hilly or rolling country underlain by early Tertiary (Eocene-Oligocene) White Limestones, whose eroded surfaces are often succeeded by a denuded mantle of the Friar’s Hill Series of marls. There are also isolated patches of a later formation of gravel, as at Cassada Garden. 1 See ‘ Reconstruction of the Antillean Continent,’ Bull. Geol. Soc. Am. vol. vi (1895) pp. 103-40; ‘Geographical Evolution of Cuba,’ ibid. vol. vii (1896) pp. 67-94; and ‘Late Formations & Great Changes of Level in Jamaica,’ Trans. Canad. Inst. vol. v (1898) pp. 325-58. O).G.58. No. 228. 2M 506 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Noy. 1901, 31. On the Grotocicat and Puystcat DeveLopment of GUADELOUPE. By Prof. Joseph Witttam WintHrop Spruycer, M.A., Ph.D., F.G.S. (Read April 24th, 1901.) ConTENTS. Page Tantmaduenems hi... sees s eee eet vais 6820 sels ee 5U6 JI. Situation and Physical Characteristics..............+--0s+s:ssaceenen 507 Jil. Notes on Guadeloupe proper and the Basement of the Island. 508 IV. The Earler Tertiary Formations in Grande Terre ............ 509 V. The Lafonde Gravel and Marl 2.3.0.0... 4.2... 4.0.2: eee nll VI. The Limestones at the Usine of Pointe a Pitre .......0.......... 511 VII. Late Deposits and Coral-Reefs in Grande Terre................+. 512 VIET. The Petit-Boure Series... s.<..is .ssiens'si aon sepeee ete cee anins 513 IX. Other Calcareous Fragments in Guadeloupe pr OPeD veseeceeveee 515 X. Remaims' of Blephas 2... 06 2c cce con deen as on bane ‘vec OND AI. Hrosion-Heatures. .. 20.2050. 0lb. dec feed ode cette 515 XII. Marie Galante, Désirade, Petite Terre, and The Saints. .wccee 518 XIII. Summary and Conclusions as to Changes of Level of Land ANG Seaicccccevevectes vsrecsecererveren en ccacs sas oore tee 518 I. Intropvucrion. My visit to Guadeloupe in March, 1897, was for the purpose of extending my observations of the later geological features of the Antilles southward from Antigua ; especially those bearing upon the changes of level of land and sea since the early Miocene Period, and their necessary variation in adjacent localities. The features of the Guadeloupe archipelago present some striking contrasts to those of the Antigua-Barbuda plateau. The main island is divided into Guadeloupe and Grande Terre. The former is traversed by high mountains, surmounted hy recent volcanoes, which are unrepresented in Antigua; but all these features are reproduced in Dominica and other islands of the western belt. of the Lesser Antilles. Grande Terre is a limestone-country comparable with Antigua, and, therefore, forms the principal subject of this paper. The islands of Désirade, Petite Terre, Marie Galante, and The Saints, belong to the same physical unit as Guadeloupe—the three former having characteristics similar to those of Grande Terre, and the last, a group of seven islands, are remnants of the older volcanic rocks. This archipelago is dissected to much greater depths than the Antigua-Barbuda plateau, and shows modifications in the erosion- features, helping us to further understand the history of the Antillean plateau, most of which is now submerged. The earliest geological contributions appear to have been those of William Maclure,’ shortly afterwards followed by the writings of Alexandre Moreau de Jonnes.” Maclure’s paper, along with the 1 Journ. Acad. Nat. Sci. Philad. vol. i, pt. i (1817) p. 134. ay. 2 «Flistoire Physique des Antilles Frangaises’ Paris, 1822. eyo, 57. | PHYSICAL DEVELOPMENT OF GUADELOUPE. 507 studies of Pierre Duchassaing,’ constitutes our principal knowledge of the Tertiary formations of Guadeloupe, and will be referred to in the following pages. Il. Strvarion anp PuystcaL CHARACTERISTICS. The nearest point of Grande Terre is 36 miles from Antigua, from which it is separated by a broad depression in the Antillean plateau, submerged to a depth of about 20v0 feet, out of which rises an intermediate island now sunk to a depth of 300 feet.? This submarine ridge is dissected by channels and indegtations, reaching to depths between 2400 and 3000 feet below sea-level. The characteristics of the drowned valleys of the Guadeloupe archipelago will be considered under the heading of erosion-features. The southern part of the group is separated from Dominica by a submarine depression about 17 miles wide, having a depth of 2100 feet, but this is further dissected so that the indentation, south of The Saints, is found to reach a depth of 3294 feet. Grande Terre has a triangular form, composed of three lobes. It is about 18 miles from north to south, with a somewhat greater transverse diameter; but it is so deeply indented as to reduce the area to 217 square miles. It is an undulating limestone-country, the northern lobe being separated from the more southern portion of _ the island by a plain or valley, reaching to a width of 2 miles, and _of an elevation generally less than 50 feet above the sea. This extends north of west from Moule across the island. North of the depression, from near Port Louis extending eastward, is a limestone-escarpment, crossing the island, and rising 150 feet above the low country, or 200 feet above the sea. One point on this northern plateau rises to 279 feet. South of the great depression, the central portion of the island is broken into valleys and hills, one point rising to 354 feet. Thus there is a general resemblance in Guadeloupe, even as to height, with that district of Antigua which is underlain by the White Limestones. Natural rock-exposures are relatively few, as the surface is generally covered deeply with soil. Guadeloupe proper has the form of an ellipse, with a length of 28 miles, a breadth of 14 miles, and an area of 365 square miles. The high mountain-ridge traversing it is surmounted by four volcanic cones, the highest of which is 4868 feet. The descent of the mountains to the west is rapid, leaving little or no low land between their base and the coast. Even the delta-flats at the end ‘of the short steep valleys are insignificant. However, the high 1 Bull. Soc. Géol. France, ser. 2, vol. iv (1847) p. 1093, & zbid. vol. xii (1855) _p. 753. A note by Payen will be referred to later (p. 515). A contribution by A. Damour is found in Comptes Rendus Acad. Sci. Paris, vol. li (1860) p. 559 ; also Charles Ste.-Claire Deville published a ‘ Voyage Géologique aux Autilles ’ in 1848-59: but I have not seen the two last-mentioned works. 2 See U.S. Hydrographic Chart No. 40, or the corresponding British Admiralty Chart. 2M 2 ee Saee* + re is i 508 PROF, J. W. SPENCER ON THE GEOLOGIvAL AND ([Noy. 1go1, coast-line appears to be bordered by a narrow plain, now submerged, but deeply indented by ravines. The eastern side of the mountain- range descends less rapidly than the western side, having larger and more important valleys. \ Grande Terre and Guadeloupe proper are almost divided by the broad bays, called ‘Grand Cul-de-Sac Marin’ and ‘ Petit Cul- de-Sac Marin.’ They are separated by an isthmus about 3 miles across, which is traversed by a narrow strait (from 100 to 400 feet wide) called Salt River. These shallow bays are more or less obstructed with recent coral-growths. ‘The isthmus is only a few feet aboye sea-level, but it is bounded by low escarpments about 3 miles apart, that on the eastern side being of limestone. III. Norets on GUADELOUPE PROPER AND THE BASEMENT OF THE ISLAND. The oldest rocks in Guadeloupe may be seen along the flanks of the mountains. There are evidently several formations, varying in age from that of the old eruptive foundation to the recent volcanic accumulations, some of the intermediate deposits being of mechanical origin, derived from the older igneous rocks. There are also a few remnants of calcareous beds. Seen to an altitude of about 1200 feet, along the road east of Basse Terre, there is an old conglom- erate composed of angular and subangular fragments of volcanic rocks. Beyond this summit, and at various elevations down to near sea-level, there are recurring exposures of red residual soils, having a depth of more than 20 feet, which have been derived in situ from the old eruptive rocks. Near Trois Rivieéres is an underlying sandy tuff, in well-marked beds which are thrust up into an anticline. This tuff is probably the equivalent of the yellow tuff and volcanic sand underlying the limestones of Grande Terre, though the beds are not continuously traceable. Two miles north of Capisterre (which is on the south-eastern coast), and at various points to beyond the isthmus, one may see the interrupted exposures of loams and gravels which constitute a formation more recent than the limestones of Grande Terre. These accumulations, as well as the gravels about Basse Terre and some fragmental remains of limestones, will be referred to again (p. 513). The recurring exposures of residual soils, the loosely compacted tuffs laid down beneath the sea, and the loams and gravels, are due to the relative amount of erosion of the land-surface in late or recent geological times. At the northern end of the island, and thence westward to Port Deshayes, are thick beds of compact volcanic tuffs, con- taining numerous small fragments distributed irregularly through the fine materials of the beds, and large boulders; but the strata are often so distributed as to make their dip undeterminable. These same beds are seen, with some interruptions along the western coast to south of Bouillante, where they vary in position from horizontal to an angle of 20°. They rest upon a basement of eruptive rocks with denuded surfaces. The age of these tuffs, and that of the Vol. 57.] PHYSICAL DEVELOPMENT OF GUADELOUPE. 509 conglomerates above Basse Terre, is undetermined. They cannot be correlated with the submarine tuffs observed in the south- eastern part of the island, nor is it known whether they are older or newer. They may be contemporary with other kinds of Tertiary accumulations in Grande Terre. However, the observations show the great age of the underlying eruptive rocks, which are evidently as old as the igneous basement of Antigua, or of pre- Tertiary age. Such igneous and igneo-mechanical formations have been more fully studied in Dominica. As the old eruptives underlie the tuffs near Trois Riviéres, the apparent representatives of which were long ago described by Moreau de Jonnés and Duchassaing as underlying the limestones of Grande Terre, there is little reason to doubt their extension under the whole island, or even under the archipelago. The outwardly-sloping terraces, observed in places up to a considerable elevation, are simply the massive beds of tuff, giving rise to cliffs, 100 feet high, which have been deformed owing to the elevation of the mountain-mass due to volcanic forces. These have not affected the strata or configuration of Grande Terre. The late volcanic phenomena have not been studied by me, but eruptions were recorded at several dates in the eighteenth and nineteenth centuries.’ TV. Tue Eartrer TertrAry ForMATIONS IN GRANDE TERRE. The lowest beds in Grande Terre are seen in only a few localities at low elevations, beneath the overlying limestones east of Salt River. They are composed of yellow tuff, surmounted by 75 or 80 feet of voleanic sand redeposited by the sea, as described by Moreau de Jonnés and Duchassaing. In the lower beds those observers found only a few fossils, but in the upper layers Duchassaing obtained Arca umbonata, Pectunculus pulvinatus, Lam., Cyathina guadalupensis, and other organisms. The Pectunculus is an European Eocene type, and Cyathina may be placed along with the corals of Antigua, thus suggesting the carly Tertiary age of the strata. Conformably with these beds, and underlying most of the surface of Grande Terre, there is a calcareous formation consisting of beds of white or creamy limestone and marl, with the surface some- times weathered to drab. Some of the beds are fine-grained, compact, and hard, others are earthy and marly. In places they contain fossils, mostly in the form of casts. The rocks of more compact texture often abound in cavities. The strata are nearly horizontal, but dip north-eastward. These beds include the roches a ravets and part of the white marls or foraminiferal limestones of Duchassaing.° 1 In 1778, 1796, 1797, 1836, 1837, & 1846. 2 Duchassaing classified the formations of Grande Terre as follows :— Newer Pliocene: Alluvium and detrital formations, the Madreporic, and the Galibis or Anthropolite. Older Pliocene: Clays; and white marl or foraminiferal limestone. Miocene: Roches 4 rayets, voleanic sands, redeposited by the sea, and yellowish tuffs. See Bull. Soc. Géol. France, ser. 2, vol. iv (1847) pp. 1094-95, 510 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Noy. rgor, He includes in this last formation the ote bi 63 Seegas marls upon the hills, A nll Soames the limestones in ni Agac og the escarpments, and He | eS bf gs other calcareous ex- a fe 3.8 2 on posures at lower x hh = 85 gaa altitudes. This has Hil ee Sen, an Be given rise to diffi- Cll segs sss culty in determining A Ui no 2:5 zg 2 their age: for, upon ‘ih a3 Se é #4 some of the hills ih As Sy, San 8s there is an un- ti 35908 S Ss By SI Hi BABOSEPR conformable marl, yi) much newer than ti! I fl a the strata in the fi oR escarpments, a fact Hi dee BG apparently unno- iy on Bes ticed by him; and THT oP) rey fal = =) i BBhes) a again the beds at <<) ao ae ; ‘a ain 28 low altitudes, con- il S =e taining the modern i = types of organisms, i |: \ 3a are much more re- LP l 5a cent than the age JAY ues! | | eH which he assigns to this formation — the older Pliocene. (Moreau de Jonnés did not regard all of these deposits as so recent.) “From the fauna of the / voleanic sands, and from nearly the same which he found occurring in the lower lime- stones (roches & ravets), including a Terebratula, Duchas- saing concluded that all the lower beds mentioned belonged to the Miocene Period. The fossils in the limestones are poorly preserved, but among the few A<------- —== section, late Pliocene ?). Lafonde Mar the White Usine Limestones (south cene ?). White Limestone (Eocene- g= late gravel at Basse Terre. ¢¢=stratified tuff, LL U F ation pene- canice eruptions. educed in height). of central mass by pe proper; Ato A! , conglomerate, ete. owland and sea; A' to B is Section of Guadeloupe from Basse Terre north-eastward to near Port d'Enfer ; distance 38 miles. Sea |Level old igneous found trated by late vol dt summit of cones (r marginal coping tufts Grande Terre! ol Mass OI is ] Vv From C to A is Guadelou OT ol.'57.| PHYSICAL DEVELOPMENT OF GUADELOUPE. 511 which I collected near Les Abimes there is a species of coral of the genus Stylophora, which is an Oligocene or Miocene form (teste Dr. Vaughan). These limestones, with the underlying tuffs, appear to constitute one great geological system belonging to the older Tertiary Period, the same as the similar succession of like tuffs and limestones in Antigua. It may be noted that the systems of the two islands are located along the strike of the beds in both, separated by little more than 35 miles. There is no reason to doubt that the physical conditions of Antigua were reproduced in, or rather extended to, Guadeloupe, by way of the intermediate bank before mentioned. Accordingly we may designate this series as the Antigua Formation. V. Tue LaronpE GRAVEL AND Mart. On the plateau above the escarpment, which extends from Port Louis to the eastern coast, occurs a deposit of white marl with water- worn gravel, derived from the adjacent limestones mentioned in the cliffs of the escarpment. I have designated this superficial marl, resting on the older strata of similar composition (and often un- recognizable from them, where the gravels and the unconformity are both wanting or concealed), the Lafonde Series, after an estate at the foot of the escarpment. This deposit is only a few feet thick, and rests upon the eroded surface of the White Limestone Series, but in horizontal layers, the lamination being shown by the lines of pebbles. In places, the well waterworn gravels are mixed with the angular fragments of the disintegrated rocks of the under- lying beds, where the more marly earth has been washed away. These loams and gravels were observed at an elevation of 200 feet. I did not attempt to follow out the distribution of the Lafonde Series in Guadeloupe, but only sought to find the recurrence of the Friar’s Hill Series, of Antigua, with the results stated, showing that the thin mantles in both islands have precisely the same characteristics and elevation (200 feet), and rest unconformably upon the white limestones of the Upper Oligocene or Lower Miocene system." VI. Tue (Limestones at tHe Usrine or Pointe A PITRE. Adjacent to the sea-shore, at the Usine south-east of Pointe a Pitre, is a cliff rising to a height of 40 feet. It is composed of a creamy white, compact limestone in horizontal beds, containing numerous fossils, mostly in the form of casts, many of which are scarcely determinable. But on making a preliminary inspection of my collection, Prof. W. H. Dall considered that the fossil shells were mostly recent species. ‘Two corals, obtained in these beds, were kindly determined for me by Dr. T. Wayland Vaughan— 1 The character and position of these beds are the same as those of the Matanzas Series of Cuba, the Layton of Jamaica, and the Lafayette of the American coast ; the age of these is found to be older than the Glacial deposits, but there are no extinct forms among the few fossils contained in them, 512 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Noy. 1901, namely, Orbicella cavernosa, Linn. and O. acropora, Linn.—which are living species, indicating an entirely different coral-fauna from that of the typical Oligocene Period of the West Indies. Besides the shells collected by myself, others were kindly given to me by M. Louis Guesde, apparently from the same kind of rock, but from unknown localities. Here then, at Pointe a Pitre, is a formation, in appearance much like the older limestones (although more sandy and more uniformly hardened into a compact rock), but far richer in fossils, assignable to a different fauna. The contact of this outcrop with the lower beds was not observed. Duchassaing gave a list of twenty-six molluscs, thirteen echinoderms, and eight corals, as being derived from his upper calcareous marl. All the corals are living, so too probably most of the molluscs, but only seven of the echinoderms. And he notes an abundance of polyzoa and foraminifera (Lunulttes). This admixture of the foraminifer Lunulites (not differing from L. umbellata of the Paris Basin) and extinct echinoderms, and perhaps some molluscs, with forms now living, especially the corals, suggests that his collections were obtained from different horizons. This supposition seems probable, as his studies were centred in the low district of Moule, where later deposits than even those of Pointe a Pitre occur. From the general character of the beds at the Usine, such as the consolidation of the materials into hard rocks, the complete fossili- zation of the organic remains now preserved as casts, etc., and the very great erosion which they have undergone since their emergence, they must have a considerable antiquity. But on account of their containing modern fossils, I would provisionally place them at the close of the Pliocene or commencement of the Pleistocene Period, of nearly, if not quite, the same age as the Lafonde Series. ‘The different character of the Usine Limestones and the Lafonde Series may be explained by the fact that at Lafonde the country was submerged 200 feet, which still permitted of the small rocky islands supplying the materials for the loams and gravels round their shores; while in deeper water and at a distance seaward from the few remaining islets, the organic remains, and the sands derived from them, would be the only source of supply for the rock-making materials, and thus the exclusion of the fragmental remains. But the Usine strata represent a deeper and longer submergence than the Lafonde Marls, which have been greatly denuded.” ; VII. Lare Deposits snp Corat-REEFs 1n GRANDE TERRE. Raised coral-reefs occur on the eastern coast, as at Moule, up to a height of 6 or 8 feet above sea-level. They contain several 1 [From recent studies in Barbados it is now suggested that the Usine Lime- stones may be either a deposit representing the continuation of the Lafonde epoch, or even one subsequent to it and belonging to the earlier Pleistocene Period. The phenomena appear to be repeated in Anguilla, Sombrero, St, Kitts, Dominica, ete. | . : . mi titincn r ates Wol. 57.| PHYSICAL DEVELOPMENT OF GUADELOUPE. 513 species, which are all recent. It was in this district that the beds containing human remains were found. These are consolidated calcareous sands, to which Duchassaing gave the name of the Galibis or Anthropolite formation, and which he considered as contemporary with the coral-reefs now raised a few feet above the sea.’ The alluvium was described by Moreau de Jonnés. Duchassaing says that it contained Succinea cucullata, then very rare among the living forms. Neither these nor the thin layers of unfossiliferous clays beneath, mentioned by Duchassaing, were studied by me in Grande Terre. VIII. Tue Perit-Boure Serres. Along the eastern coast of Guadeloupe proper, from near Capis- terre to beyond the isthmus, I have seen recurring deposits of loams and gravels. One of the best exposed sections occurs at Petit Bourg, where the cliffs rise from the seashore to a height of 40 or 50 feet. At the bluff north of the village, sandy tuffs, like that near Trois Rivieres, form the base. Upon its eroded surface lies a deposit of coarse, well-rounded, waterworn gravel, which, where not denuded, has a thickness of 10 feet or a little more; but its surface is greatly eroded, so that at the southern end of the . section it is entirely wanting. Succeeding the underlying beds unconformably, whether gravel or tuff, is an upper loam, indis- tinctly laminated, except where it contains lines of pebbles. The more restricted exposure east of the village consists of about 10 feet of the upper loams, resting upon 10 feet of the coarse gravels (containing occasional volcanic bombs 12 inches in diameter), beneath which comes another unconformable bed of red loam, exposed to a depth of 20 feet. The country between Petit Bourg and the Salt River is character- ized by the remains of a base-level of erosion or peneplain, with the rounded hills rising from 50 to 100 feet above the sea. These consist of red loams and waterworn gravels, or where they have been washed away to a sufficient depth, the more ancient residual clays may form the surface. In some of the more massive hills and deeper cuts are large deposits of rounded gravel, resting upon the weatherworn surfaces of loams or in other places of tuff. These gravels contain volcanic bombs and angular fragments, evidently the product of some volcanic eruption, during which the ejectamenta were thrown into the sea in which the gravels were being deposited. These hills, composed of loams and gravels, are the continuation of the deposit at Petit Bourg, but the intervening ? Duchassaing thought that the human remains found (on the estate, at that time, of MM. Morrel), near Moule, belonged to a race antecedent to the Caribs. The word Galibis was taken from the old Carib name for the island, Bull. Soc. Géol. France, ser. 2, yol, iy (1847) p. 1096, ol4 PROF, J, W. SPENCER ON THE GEOLOGICAL AND [Noy. 1901, depressions show the surface of the country to have been greatly denuded. There are evidently two formations overlying the volcanic tuffs, each of loams and gravels with the pebbles of the upper series of smaller size, while the lower gravels are coarse and exposed only in sections along the coast or in the interior of the hills where access has been had to them. The upper deposits form a mantle over both the high and low ground, and have not been nearly so much denuded as the lower. Between Petit Bourg and Salt River, these mechanical formations rest upon white lime- stones, rising only in a few places above the sea. All the strata, whether limestones or loams and gravels, lie almost horizontally, dipping very slightly north-eastward. Accordingly, the outlying limestones west of the isthmus are the equivalent of those of Grande Terre, but separated by the broad shallow depression, occupied by the isthmus (2 or 3 miles across), excavated when the country was reduced to near the base-level of erosion, before the deposition of loams and gravels which lie on it. From all these facts it appears that both members of the Petit-Bourg Series are relatively of late origin. The occurrence of these two mechanical deposits, composed of the same materials, is only a rej:etition of the phenomena of the Lafayette and the Columbia formations of the coastal plains of North America, where the component materials can scarcely be distinguished, except by the unconformity, cte., which represents an enormous physical break in their succession. ‘The accumulation of the Lower Petit- Bourg Series in the same position as that of the Lafonde is what might be expected, owing to their both being the succeeding beds deposited upon the surface of the country, subsequent to the denudation of the Miocene-Pliocene Period. The Petit-Bourg gravels are situated at the foot of hills, supplying eruptive materials for the loams and pebbles, while the Lafonde gravels are derived from limestones of the small islands remaining above water during the submergence of this epoch. From the erosion-features it is mani- fest that the upper series of loams and gravels are very much newer than the lower, and occupy the same horizon as the Cassada- Garden Series of Antigua, or the Columbia Series of the American continent.’ The loams appear to be derived from the pre-existing residual — soils, such as those mentioned, and the upper loams and gravels seem to have been the material of the lower series worked over again. | In the weatherworn terraces above Basse Terre, upon the south-western side of Guadeloupe proper, thin beds of gravel occur up to an elevation of 250 feet. This superficial mantle has not been connected with the Petit-Bourg Series, but it has the general 1 These are also represented by the Zapata Series of Cuba, and the Liguanea of Jamaica. Furthermore, a corresponding formation is found in St. Martin, St. Kitts, ete. tis Vol. 57.] PHYSICAL DEVELOPMENT OF GUADELOUPE. 515 appearance of that of the Lower Petit-Bourg Series. The extreme elevation of the gravels on both sides of the island may be some- what greater than that of the exposures visited, and if there are higher sections observable, I should expect them to occur near the seacoast in the vicinity of Trois Rivicres. On the eastern flanks of the mountain-country they are apt to be concealed by the creep and washes of the soils. TX. Otser Catcargous FRAGMENTS IN GUADELOUPE PROPER. Payen’ mentioned the occurrence at Vieux Fort, near Basse Terre, of two beds of limestone: one at an altitude of 330 feet above the sea, resting horizontally on a volcanic foundation, the other at an elevation of 130 feet. Deshayes found that the fossils contained in them belonged to living species of shells and echino- derms, and concluded that the beds were Quaternary. Duchassaing also mentions the occurrence of limestones near Trois Riviéres.* I was in both of these neighbourhoods, but not having seen the original papers at that time, mentioning the localities, I could learn nothing of them from enquiries made of most likely persons, as but little interest or observation was manifested in the scientific features of the island. The calcareous beds described near Basse Terre seem to be reproduced in Dominica, and these I have studied. XX. Remains oF HLEPHAS. In the Library & Museum Building at Pointe a Pitre, M. Louis Guesde kindly showed me the tooth of a small species of Hlephas, which had been found in Grande Terre. It was 6 inches long, and upon the serrated crown it measured 5 by 2 inches. It appears to be something like the small Maltese type, and its occur- rence has an important bearing on the question of the elevation of the Windward Island chain. XI. Eroston-FEAtuREs. The evrosion-features of Grande Terre are characterized by undulations, where the rounded hills rise from 50 to 100 feet above the broad depressions separating them. As we have seen, the foundations of the country are carved out of the earlier Tertiary Limestones, except on the isthmus between the two parts of Guadeloupe and the adjacent district, where they have been washed away, so as to expose the underlying tuffs. The peneplain, to which the surface of Grande Terre and of a part of the main island was reduced, extended broadly beneath the now shallow bays north ' Bull. Soc. Géol. France, ser. 2, vol. xx (1863) p. 475. ? Ibid. vol. iv (1847) p. 1097. 516 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Noy. 1901, and south of the isthmus. This is also seen in the great banks reaching to Petite Terre and Désirade, and about The Saints and Marie Galante. The high bluffs of 100 or 150 feet along the eastern © coast and other points are the results of the recent encroachments of the sea; but the interior escarpment in the northern part of the island is a somewhat older feature. Undulating outlines are characteristic of the denudation of a country near the base-level of erosion, lasting throughout a long period. The duration of land- surfaces in Guadeloupe continued from the time of the early Miocene emergence until that of the introduction of recent types of life, or throughout the Miocene-Pliocene Period. The condition of low elevation of the country mentioned, which obtained during the latter part of the period, does not appear to have prevailed during the whole time; for we find the sunken plateau connecting the islands having the form of broad depressions or undulating plains like those of base-levels of erosion, though now 2000 feet below sea- level. The drowned plains and ridges are modified by the deep channels, some of which continue upward and extend to the deep indentations of the island-plateau formed by streams descending torrentially from tablelands. The recurrence of the Tertiary Limestones, etc., on several of the adjacent islands suggests their late continuity. That the archipelago of Guadeloupe was not bodily thrust up above the submerged ridge by volcanic forces is shown in the physical difference between the main island and Grande Terre, where the latter, as has been seen, was not. deformed, while the volcanic forces have only lifted the high mountain-ridges where there has been late activity, and have not differentially raised the islands in other districts which are characterized by old eruptive basements. Upon this hypothesis, the earlier Miocene-Pliocene elevation of Guadeloupe, during the formation of the broad depressions between the islands, reached an altitude of at least 2000 feet above that of the present day (except the volcanic mountains of more recent date). Then the Guadeloupe archipelago stood out as a plateau, like much of recent Jamaica, with its escarpments and surfaces broken by atmospheric denudation. The greatest of the broad valleys indenting the mass is that between Marie Galante and Grande Terre. With the gradual subsidence of the plateau, the encroachments of the sea modified the now submarine escarpments, and eventually brought the tableland so low that the recent features of Grande Terre could be produced ; but this comparatively low altitude must have been of long duration to have allowed of the moulding of the rounded topography. Then followed the submergence to a depth of 200 feet below the present height, with the accumulation of the Lafonde and Lower Petit-Bourg Series, which was a comparatively short interval. This episode was about the close of the Pliocene Period; after which there was another epoch of very great elevation and rapid denudation, since the introduction of the recent fauna of the Usine Limestones, Vol. 57.] PHYSICAL DEVELOPMENT OF GUADELOUPE. 517 when the Lower Petit-Bourg and Lafonde gravels were largely removed by denudation. The evidence of this great elevation is shown in the compara- tively narrow, but very deep valleys, dissecting the older rounded topographic forms. ‘Thus, between The Saints and Guadeloupe is a narrow valley less than 2 miles in width, reaching to a depth of 900 feet, or 700 feet deep in the submerged plain or bank. It deepens to 1200 feet a few miles westward, beyond which it attains a depth of 3000 feet. The data for determining the depth of the channel, through the embayment of earlier origin, between Marie Galante and Petite Terre, have not been obtained, though it is known to be greater than 2000 feet. Between the south-eastern extremity of Grande Terre and Désirade, where the plains are sunk to only 66 feet, there is an amphitheatre or cirque, with a depth of 990 feet, deepening to 1122 feet, and farther seaward to 1720 feet, beyond which no soundings have been taken. The valley between The Saints and Marie Galante is now drowned to 792 feet, and the descent to the broad depression beyond is very rapid. The deep indentations of the sunken border of the western side of Guadeloupe proper tell the same story of a former great elevation, when the gorges were being channelled out by rapidly-flowing streams. Thus, north of Basse Terre there is an indentation with a depth of 810 feet within the limit of the coastal plain. Opposite Ferry Point, a depth of 1740 feet is reached within the limits of the submarine bank, where it is covered by only 246 feet of water. ~ At the north-eastern angle, there is another valley seen at 1980 feet. South of The Saints, and between them and Dominica, the channel reaches to a depth of 3294 feet, indenting the submerged ridge between the two islands. This is the height to which the region was elevated so far as the evidence directly obtained from Guadeloupe bears testimony, but a much greater altitude is indicated beyond the immediate area. The epoch of great elevation and stupendous erosion, culminating in deep valleys, was in the early Pleistocene Period, after the introduction of recent types of life; but from the evidence of the deposits on the American continent, with similar geological associations, it was during, or prior to, the early Glacial time. It may be added, parenthetically, that to this epoch the abrupt features of the escarpment east of Port Louis owe their origin, when the streams on the tableland began to deepen their courses. Then followed a subsidence, during the accumulation of the Upper Petit-Bourg Series, to a depth of 100 feet or perhaps some- what more. The depressions now forming the isthmus became covered with the mantle of the loams and gravels of this series—a Mid-Pleistocene deposit. The succeeding rise of the land carried it above the present _ height, when the rapid streams made channels across the plains, now covered by the two very shallow bays north and south of the isthmus; containing many islets, some of which are the remains of 518 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [ Nov. 1901, the Petit-Bourg Series, etc. These drowned watercourses have a depth of 40 to 60 feet, but near the margin of the sunken terrace are gullies or canons, reaching a depth of 100 to 150 feet, where the neighbouring shoals are not covered by more than 1 to 6 feet of water, showing that the elevation reached this amount, while there was a considerable removal of surface-loams. Yet the epoch was not one of long duration, and in no way com- parable in denudation to the epoch preceding it. Another subsidence of the land brought it down to about the present level, although the reefs on the eastern coast are raised to a height of 6 or 8 feet, suggesting a subsidence to that amount below the present surface, and subsequent re-elevation; but the small oscillations of late date may be more or less local. The erosion-features of the mountain-mass are largely recent, without the mass being deeply dissected by the torrential streams. But the present volcanic activity dates back to the Lower Petit- Bourg stage—close of the Pliocene (?) Period—prior to which the mountains may have been no higher than those of Antigua. | XIL. Marie Garants, Diésrrape, Prrrre Terre, anp THE Saints. Long ago William Maclure reported the first three of these to be limestone-islands, and we may infer from their position that their history is doubtless that of Grande Terre. Désirade has a height reaching to 912 feet, and Marie Galante attains an elevation of 672 feet, while Petite Terre is scarcely more than a low bank. The Saints are old volcanic formations with the highest points reaching 1035 and 932 feet. All these outliers are much dissected by the atmospheric forces, still very active, owing to the great declivities of the land. XIII. Summary anp Conclusions AS TO CHANGES OF LEVEL oF LAND AND SBA. (1) A land-surface throughout the Miocene-Pliocene Period, with an elevation during the earlier days amounting to 2000 feet or more above the present height (except the later volcanic mountain- ranges), during the formation of the broad depressions between the islands ; tollowed by a sinking of the land to somewhat near the present altitude, and the formation of the undulating surface of Grande Terre. (2) A submergence to 200 feet at about the close of the Pliocene Period, with the accumulation of the Lafonde and Lower Petit- Bourg gravels and loams and the Usine Limestones (”). (3) A re-elevation to about 3000 feet, shown within the region of the archipelago—but this is only a small portion of the extreme height indicated outside of the group—in the early Pleistocene Period, with the formation of deep valleys and amphitheatres dissecting the old rounded topography. It was during this time Vol. 57.] PHYSICAL DEVELOPMENT OF GUADELOUPE. 519 that the EHlephas mentioned on p. 515 could have crossed from the American continent, since when there has been no connection. (4) A depression to 100 feet or more below the present height, in mid-Tertiary days, and the accumulation of the Upper Petit- Bourg gravels and loams. (5) A subsequent elevation to an altitude of 150 feet above the present, with the formation of short canons along the coast. (6) Again submergence to a little more than the present level with the growth of corals, as on the eastern coast. (7) These reefs have been raised to a height of 6 or 8 feet. These latter oscillations of small amount may differ in the several islands, owing to local variations. Remarkable as is the recurrence of so many changes in level, since the early Pliocene Period, yet the evidence is gathered from phenomena which also extend to the Greater Antilles and the American continent. 520 PROF. J. W. SPENCER ON THE GEOLOGICAL AND [Noy. 1901, 32. On the Gronoercat and Puysican Devetopment of ANe@UILLA, St. Marri, Sr. Barrnotomew, and Somsrero. By Prof. JosepH Wiit1am Winturorp Spencer, M.A., Ph.D., F.G.S. (Read April 24th, 1901.) ConTENTS. Page IL, PmGROGUCtoMmios, .cennenncincestetsvaiidck'sninma aden eae aoe er 520 TL. Physical Characteristics ....06 sec: .cscccunesce-nene see eee 520 III. The Older Geological Formations «........2..:..02254< eee 523 IV. The White or Antigua Limestones and their Fossils ......... 526 V. The Newer Formations: ‘s,s... Siekete edit nace 529 VI. Mammalian, Remains: 00. dace: Jecseevsesssscw cece ene 530 WIT. Brosion-Features ...2:...c.cccneccssenieccecsacesctec cee 5380 VIII. Summary and Conclusions as to Changes of Level of Land aT Wea ] Morlaix(Britanny), corundum occurrg. as contact-mineral near, 185-88 w. figs. Morton, G. H., obituary of, liv—lv. Mountain Limestone, see Carboni- ferous Limestone. Mud-fiows on Yorkshire coast, 295. Murr, H. B., 363. Morcutson Geological Fund, list of awards, XXvlil. Mourcaison medallists, list of, xxvii. Morcuison, Sir Ropericx, quoted, 268. Muscovite replacing felspar, 32. Museum of Geol. Soc., special general _ meeting, xcii-xciii. Myalina, Carbonif. spp. of, 384. Mynydd-y-Garn (Anglesey), geol. of, 20-30 w. map & sect. Myoconcha psilonoti (2), 234 & pl. ix. Naiadita lanceolata, 307-312 w. figs. & pl. xiii. Naiadites, ete., isodietic line for, 382. Natrolite (?) fr. Mt. Girnar, 45; in ophitic diabase of Malverns, 174. Neojurassic Series, 153. Nepheline in Mt. Girnar monchiquite, i. Nepheline -syenite of Mt. Girnar, 41, 42, 43. Nevada Basin (U.S.A.), former exist. of great lakes in, 429-31. Nevis (W. I.), see St. Christopher. Newara Eliya (Ceylon), granulites betw. Hakgala and, 207-208. Neweastle-under-Lyme Series, 255-56. Newton, E. T., 83, 285; on Grapto- lites fr. E. Peru, vii; on Mesozoic Fossils fr. Arran, 229-41 & pl. ix. Newton, R. B., xcii, 354. Newton Gill (Yorks), sect. descr. 359-60. Nidd Valley (Yorks), sect. deser., 363. North Esk River (Forfar), Silurian (?) & other rocks of, 328-36 w. figs. Northants stratigraphy interpreted by means of Marlstone Rock-bed, 346. Norwegian Geol. Surv. map presented, XcVil. Notgrove (Gloucest.), sect. descer., 139. 254, Notgrove Freestone, 126 e¢ segq. Nottingkamshire, Upper Coal-Mea- sures in, 262-64. Nucula gibbosa, ete., isodietic line for, 380. sp. [ Lr. Lias}, 234. GENERAL INDEX. 555 Nuculana attenuata, etc., isodietic line for, 380. (Leda) Tatei, sp. nov., 234 & pl. ix. sp. [ef. Leda Quenstedti], 235 & pl. ix. Nueent, N., 490 e¢ seqg. Nuneaton (Warwick), intrusive rocks contrasted w. those of Malvern Hills, 178-79. Obsequent valleys, 190. Obsidian Cliff (Yellowstone), hollow spherulites of, 212-15 w. figs. (Hatert, D. P., vi. Ohiya (Ceylon), garnetiferous rocks near, 208-209. Old Red Conglomerate along E. Bor- der of Highlands, 335, 339. Old Red Sandstone in Arran, 226; in Tortworth district, 267, 268; (?) age of porphyrite-dykes in Loch Awe district, 314. Oxpxan, R. D., on Origin of Dunmail Raise, 189-95. Oligocene (?) of Antigua, 498; of Guadeloupe, 511. Olivine-basalts in Malvern Hills, 168— 72 w. figs. & pl. vii (microse. sects.). Omai Creek (Brit. Guiana), rock- specims. from, ]xxxviii. Oolite (Inferior), see Bajocian. Oolitic ironstone in Anglesey, 26; do. in N. Cotteswolds, 132. Opal-silica in Dufton-Pike rhyolite, 33. Ophitic dolerite in Jasper & Green- Rock Series, 333; oph. olivine- diabases in Malvern Hills, 172-75 & pl. vii (inicrose. sect.). Orbitoides in Antiguan ‘ marls,’ 495, 497, 498. Ordovician roc.s of Mynydd-y-Garn, 20 et segg.; Ordovic. age of igneous intrusions among Cambrian beds of Malvern Hills, 181 ; Upper Ordovie. graptolites fr. E. Peru, vii. Orpington (Kent), drift-worn palo- lith from, xeviil. Osgodby Nab (Yorks), 293, 295. Ostrea arregularis (2), 233-34. Ottrelite in rocks of Bastogne dis- trict, 57, 60 et segq. Ouse River (Hunts), Corallian S. of, 75-79; do. N. of, 80-82. Oxford Clay in St. Ives district, 76 e seqq: Paleolithic implemt. fr. Minster, i; drift-worn do. fr. Orpington, xcviii. Palzometeorological explanation of some geol. problems, 405-78 w. maps. 506 Paleozoic folds in relat. to Jurassic folds, 147-49; see also Cambrian, Carboniferous, etc. Palakod (Madras) specim. fr. Char- nockite Series, v, 188. Pantholops hundesiensis, 289-92 w. s. ene Everard (Cambs), Elsworth Rock, ete., near, 77-78. Parkinson, Jonn, exhib. specims., v; on Geology of S. Central Ceylon, 198-209 w. figs. ; on Hollow Spher- ulites of Yellowstone and Great Britain, 211-25 w. figs. & pl. viii. Parsons, J., 279; quoted, 282. Paton, G., 183. Parterson, A., 409. Pracu, B. N., 332, 334, 385; (& W. Gunn), on Vole. Vent of Tertiary Age in Arran enclosg. Mesozoic Fossilif. Rocks, 226-29. Pecten (Chlamys) subulatus (2), 232-33 & pl. ix. Pecten valoniensis, 230. Pelican Point (St. Martin), 524, 526, 529, 030) Pendle Hill (Lanes), rock-succession at & near, 348-81. Pendleside Grit, 548 e¢ segq. Pendleside Group. 347-404 w. figs., lists of foss., & pl. xiv (vert. sects.). Pendleside Limestone, 347, 348 ez segg.; chem. char. of, 393-96 w. anal; petrology, etc. of, 396-401. Pendleton Hall (Lancs), seet. deser., 351 Penecontemporaneous erosion, 144 et segq., 152-54. Peneplain of subaerial denudation (Dunmail Raise), 195. Pentacrinus basaltiformis (2), 237 & eri. Puen Hie di, ixxxvit. Peru (E.), Upper Ordovie. grapto- lites from, vii. Petit-Bourg Series of Guadeloupe, 513-15. Petite Terre, see Guadeloupe. Petrographical provinces, ]xxxi. Petrological ideas, evolut. of, lxii- Ixxxvi w. figs. Phacops Weaveri, restricted occurr. of, ZT Philipsburg (St. Martin), 525, 524, Puruuips, J., quoted, 268-69. Phillipsia Van der Grachtii, horiz. of, B04. Phillipsiana-beds, 127 et seqq. Phoiadomya (2) [Lr. Lias], 236 & Pilscix, Phosphatic beds in Selbornian of Maiden Bradley, ete., 102 e¢ seqq. GENERAL INDEX. [Nov. 1901, Phosphatized limest. in St. Martin, 526. Pinnock Farm (Gloucest.), sect. deser., Pirsson, L. V., quoted, 39. Pisolitic, see Oolitic. ; Pitt-Rivers, Gen. A. H. Lane-Fox, obituary of, lv—lvii. Placer-deposits. so-called, of British Guiana. Ixxxvili-lxxxix. Plant-remains, fragmentary, abundant in Pendieside Group, 386-87. Puatr, J., 297. Pleistocene climate, influence of winds upon, 405-78 w. maps ; Pleistoe. (?) gravels in Antigua, 500; do. in Guadeloupe, 514-15; do. in St. Martin, ete., 529-80; do. in St. Kitts, 537-38 w. sect. ; vole. activity, ibid., 539. Pleurotomaria tectaria, 232 & pl. tx. Vliocene (Upper) age of Hundes ossiferous deposits, 292- Plioe. (¥) of Antigua, 500; of Guadeloupe, 511, 512; of St. Kitts, 587. Point Blanche (W.1I.), siliceous limest., ete. of, 524, 526, 529. Pointe-a-Pitre (Guadeloupe), stones at Usine of, 511-12. Polar anticyclone, explanat. of secular movemts. during Pleistoe. Epoch, 464-69. Polar Sea, former exist. of mammoth on shores of, 422-29 w. maps. Pouuarp, W., [chem. anal. of carbon- aceous dolomite, etc.], 303-304. Pont Paul (Britanny), corundum occurg. as contact-mineral near, 185-88 w. figs. Pontesford Hill (Shropshire), hollow spherulites of, 223. Popple or popplestone-bed at Mere, etc., 111, 112 e segg. Porphyritic basalt near Charfield Green, 280. Porth-yr-Ebol (Anglesey), 27. Posidonomya Becheri, distrib. of, 377, 379. Posidonomya - schists in posit. of, 375. Pottery Coalfield (N.~ Staffs), vert. © sects. in, 252, Potton (Beds), Elsworth Rock, etc. near, 77. — Pressure as a metamorphic agent, 56-57. Price, F. G. H., elected Auditor, v. Prior, G. T., 68, 183. Productus giganteus, zone-fossil, 403. Protocardium Philippianum, 2380. truncatum (2), 236. lime- Ireland, unreliable as Wold 57. | Pseudo-conglomerates, sce Conglomerates. Pseudoleucites, compared w. analcime- rotks,51.- Pseudomorphs (after spinel or garnet) in Dufton-Pike rhyolites, 32, 33. Pule Hill, see Marsden. Purves, J. C., 491 et scqq. Pylle Hill (Bristol), Naiadita fr. Rheetic of, 307-312 w. figs. & pl. xiii. Pyroclastic rocks absent fr. Cambrian of Malvern Hills, 179-80. Pyromerides, see Spherulites. Pyroxene-andesites of Daniel’s Wood, 281 & pl. xi.; of Middle Mill, 282- 83; pyr.-granulites of S. Central Ceylon, 204-209 ; see also Augite. Pythorns (Yorks), Carb. rocks at, 358. Crush- ‘Quartz vermiculé’ in rocks of S. Central Ceylon, 200, 202. Quartz-felsites succeedg. andesites in Cheviot district, Ixxxii-lxxxiii. Quartz-xenocrysts, inclusion of, in basic igneous rocks, 282. Quaternary limestones in Guadeloupe, 515. Qurrn Victoria, meetg. adjourned on decease of, vi. Rad Brook (Lanes), sect. deser., 350. Radiate symmetry of valleys in Lake District, 193, 195-96. Radiolaria (?) in jaspers of Highland Border, 332; in black Pendleside Timest., ete., 398, 400-401, 403. Rain-Hall Quarry (Lancs), sect. deser., 305. Rainfall in Lake District, 196, 197 ; in Sahara durg. Pleistoc. Period, 420 et seqqg.; in Nevada Basin & Central Asia at same period, 429 et seqg.; recent in St. Martin, etc. (W. I.), 522, 539. Rarsin, Miss C. A., on Altered Rocks fr. near Bastogne, 55-72 w. figs. Rambukkana (Ceylon), — gneissoid granulites, etc., near, 198—200. Recent deposits in Antigua, 500-501 ; in Grande Terre, 512-13. Red coloration of Upper Coal-Mea- sures in North Staffs, ete., 250. Redonda (W. I.), 539. Reep, F. R. C., 271 et seqg. ‘ Reef-knoll’ theory discussed, 362. Reefs, see Coral-reefs. Renaxrp, A., quoted, 60. Reynoups, 8. H. (&C. Lroyp-Morean), on Igneous Rocks & Assoc. Sedi- mentary Beds of Tortworth Inlier, 267-84 w. figs. & pls. x-xi (map & microse. sects. ). GENERAL INDEX. 557 Rhetic Beds nr. Bristol, Cotham Stone from, xci; Rh. foss. fr. Arran, 229-30; see also Natadita. Ihynchonella subdecorata as a zone- fossil, 150. Rhyolites of Yelluwstone Cafion, 216- we Rhyolitic rocks, tufaceous, fr. Dufton Pike, 381-37 w. chem. anal. & pl. i (microse. sects. ). Riddingwood (Lanes), 350. Rimmington (Lanes), 356. Roseers, T., quoted, 73 et segq. Rosinson, R. ¥. [chem. anal. of Pen- dleside Limest.], 394. Rock-classification, lxiv e¢ seqgq. Rock-species, origin of, lxxviii-lxxxvi. Rodlike bodies formed fr. altered felspar, 35 & pl. i, 219 w. figs. RosensBescu, H., quoted, Ilxx, lxxi, 162. Rottenstone fr. Pendle Hill, 395. Rowe, A. W., Wollaston Fund Award to, xli. ‘Ruckly flint ’=chert, 105. Riigen I. (Baltic), drifts of, 7-18. Rumanian Geol. Surv. maps presented, XCv. Russe, R., obituary of, lvii. Rorczy, F., on Tufac. Rhyolit. Rocks fr. Dufton Pike (Westmorland), 31-87 w. chem. anal. & pl.i (microse. sects. ). Rye Hill Farm (Maiden Bradley), Selbornian at, 108-110 w. sect., 121, 122 et seqq. Saba Banks, etc. (W. I.), geol. & phys. developmt. of, 534-43. Saddleworth & Marsden district, Carb. fauna of, 372-74. Sahara Desert (N. Africa), humid condits. durg. Pleistoc. Period, 420- 22. St. Bartholomew, etc. (W. I.), geol. & phys. developmt. of, 520-33. St. Christopher, St. Eustatius, ete. (W.1.), geol. & phys. developmt. of, 534-43 w. sect. St. Ives (Hunts), Corallian of, 73-85 w. map & lists of foss. St. Ives Rock, see St. Ives. St. Kitts Gravels, 537-38 w. fig. ; see also St. Christopher. St. Martin, etc. (W. I.), geol. & phys. developmt. of, 520-33. St. Ronan’s Bay (Waterford), cliff- sect. at, 484. Saints, The, see Guadeloupe. Salcombe (Devon) rock-specims. from, XCvlil. =. 208 Salm Chateau (Ardennes), crushed rocks near, 57. Salopian ‘Permian,’ see Keele Series. Sauter, A. H., exhib. specims., xciii. Scandinavian boulders in German Drift, 5, 7. Scangs, J. (& A. J. JuKkus-Browns), Upper Greensand & Chloritic Marl of Mere & Maiden Bradley, 96-125 w. sects., lists of foss., & pls. ii—v. Scapolite (?) in Dufton-Pike rhyolite, Scarborough (Yorks), landslips in Boulder-Clay near, 293-96 w. figs. Scarborough Barn (Gloucest.), sect. near, descr., 136. ScHEERER, —, quoted, Ixvii, lxix. Schists, crystalline, not prod. by mechan. deformat. alone, 342. Schizodus (Axinus) cloacinus, 230. Scuwarz, HE. H. L., exhib. photogr. illustr. 8. Afric. geology, ii, xcv. Scorr, Marcvs, quoted, 89. Scropg, P., quoted, 70. Seaforth Limestones of Antigua, 494. Sealands (Cheshire) boring, granitic material found in, 266. Seevey, H. G., exhib. specims., iv; on Crioceras occultum, xciv ; quoted, 73 et seqq. Selbornian, nr. Maiden Bradley, etc., 96-125 w. sects., lists of foss., & ls. ili-v. Sellet Hall (Yorks), Carboniferous fauna from, 365. Serpentine m Malvern camptonites, 160, 163, 165 w. figs. ; in olivine- basalts zhid., 169-70 et segg.; in igneous rocks of Tortworth inlier, 280, 282. Serpula sp. [Lr. Lias], 237. Seven Wells (Gloucest.), sect. descr. 134. Snymour, H. J., 487, 489. Sewarp, A. C., 112, 307. Suaw, W. N., 413, 485, 469. Sheep Island (Waterford), intrusive tuff-like igneous rocks of, 486-88 w. fi g. Shell-beaches, accumulat. of, 407-412 w. maps. SHergporn, C. D., x, 289. Shiskine (Arran), 226 et seqq. Shropshire coalfields, unconformity in, 86-95 w. sects. Silicification, secondary, exemplified in Tertiary formats. of St. Martin, etc. (W. I.), 524-25. Silurian of Tortworth district, 267 e¢ seqg.; (?) im Forfar & Kincardine along E. Border of Highlands, GENERAL INDEX. [Nov. 1gor, 328-45 w. figs. ; (Lr.), tufac. rhyolites fr. Dufton Pike, 31-87 w. chem. anal. & pl. i (microse. sects.). Skipton (Yorks), Carboniferous rocks betw. Bolton Abbey and, 357. Suaven, W. P., obituary of, lvii-lviii. Small Thorn (Gloucest.), Snowshill Clay at, 138. _ Sarvs, J. (of Kilwinning). 381. Snowshill Clay, 126 ez segq., 138. Snowshill (Gloucest.), sects. deser., 133-34. Solfataric action, evid. of, among Brit. rhyolites, 31, 33 et segg.; among Bastogne rocks, 71; effect of, in canon of Yellowstone, 216-17. Souuas, Miss I. B. J., on Struct. & Affinities of Rhetic Plant Naiadita, 307-312 w. figs. & pl. xiii. Souuas, W. J., 188. Solution-theory, in relat. to consolid. of igneous magmas, lxxii e¢ seqq. Sombrero, etc. (W. I.), geol. & phys. developmt. of, 520-33. Southern Uplands (Scotland), Arenig Beds compared w. those of High- land Border, 332, 834-35. Southwark (London), well-sections at, — 285, 287, 288. Special General Meeting [re Museum], xCli-xCiil. Spencer, J. W., on Geol. & Phys. Developmt. of Antigua, Guadeloupe, Anguilla, ete., 490-543 w. figs. & pl. xv (nap of Antigua). Spherosiderite, 303, 309. Spherulites, hollow, of Yellowstone & Great Britain, 211-25 w. figs. & pl. viii. Spherulitic structure in sulphanilic acid, vii; in obsidian & eutectic alloys, Ixxv-Ixxvii w. figs. ; spheru- lit. dolomite, sce Dolomite. Spirorbis-limestones, horizon of, 86 et seqg., 259, 261-62. Sponge - spicules in Selbornian of Maiden Bradley, ete., 104 e¢ segg. ; in Pendleside Beds, etc., 395, 397, 399. Stacheia in Group, 398. Staffordshire, Upper Coal-Measures of, 251-66 w. vert. sects.; (N.) & Derbyshire, Carb. succession in, 368-72. Stainforth Station (Yorks), sect. near, descr., 366. Stake Pass (Lake District), orig. of, 194. SraviyBrass, E., lxxxix. Sranspis. J. H., 26. Stanway Hill (Gloucest.), sects. deser., 132-83. cherts of Pendleside Nol; 57- Statia, see St. Christopher, St. Eusta- tius, ete. Stauronema Carteri, sub-zone of, 120 et seqg. Srespine, W. P. D., exhib. specims., XC, XCVill. Stepheoceratidan Epoch, dates of erosions in, 153. Stolteraa (Mecklenburg), 5, 6. Stonesfield Slate-pebbles, exhibited, iv. Storm-tracks, prevalent, of Pleistoc. Period, 461-64 w. maps. Srranan, A., on Passage of Coal-seam into Dolomite, 297-304 w. map, sect., chem. anal., & pl. xii (microsc. sects. ). Striation on slipped Boulder-Clay, 296. Stroud (Gloucest.), diagramm. sect. to Mendip Hills, 149. Submerged valleys, off coast of Africa & W. Europe, lxxxix; in West Indian region, 503, 507, 516-17, 520-21, 531-83, 540-41. Submergence, recent, of Turkestan, etc., 248, 249-30. Sudeley Hill (Gloucest.), sect. deser , 131, 137. Sulphaniliec acid, spherulit. struct. in, vii. Swavesey (Cambs), Elsworth Rock, ete. at & near, 79, 82. Symon Fault, see Shropshire coal- fields. Tancredia (2) Peachi, sp. nov., 236- 37 & pl. ix. Treat, J. J. H., re-elected President, xxii; addresses to Medallists & recipients of Funds, xxxix e¢ seqq.; obituaries of deceased Fellows, etc., xlviii-lxi; on Evolut. of Petro- logical Ideas, lxii-lxxxvi w. figs. ; quoted, 281. Terebratula-Buckmani Grit, 127 et seqq. Tertiary voleanic vent in Arran, enclosg. Mesozoic fossilif. rocks, 226-43 & pl. ix; earlier Tertiary of Antigua, 495 e¢ segg.; do. of Guadeloupe, 509-511. See also Hocene, ete. Texas(U.S.A.), specims. fr. Cretaceous of, xev. Thermal springs as agents, 70 ez seqg. Tuosmprson, B., on the Use of a Geol. Datum [abs.], 346. Tuomson, J., obituary of, lviii. Thorpe (Yorks), ‘ knoll ’-area of, 361 et seq. ‘ Through valleys,’ 196. metamorphic GENERAL INDEX. 509 Thrusts along E. Border of High- lands, 335 et seqg., 339 et segg. w. figs.; thrust-origin of knoll-lime- stones denied, 362. Thrust-conglomerate of Mynydd-y- Garn, 21. Thurgarton boring (Notts), 262-64. Tippemay, R. H., quoted, 351-52, 353, 361-62. Tilestone in N. Cotteswolds, 130 e¢ segq., 136 et segq. Tintamarre (W. I.), 522, 526, 528. ToreE.L, O. M., obituary of, xlix-li. Yortworth inlier (Gloucest.), igneous & other rocks of, 267-84 w. figs. & pls. x-xi (maps & microse. sects.). Trachydolerite of Drew's Hill (Antigua), 494. Tramore (Waterford), cliff-sects. near, deser & fig., 484, 485, 486-87. Trap-rocks, etc. of Tortworth inlier, 267-84 w. figs. & pls. x-xi (map & inicrose. sects. ). Traquair, R. H., Lyell Medal awarded to, xlili-xlv. Trebizond (Asia Minor), recent submergence, 249. Tremolite, asbestiform, in Malvern camptonites, 162. Trias in Arran, 226, 227, 228, 242. Tridymite, assoc. w. felspar in hollow spherulites, 214, 215, 222 w. figs. Trigonia-grits, 126 et segg.; posit. of Upper Trigonia-grit, 149. Tripartite Drift of Riigen, 9 ez segg. Trust Funds, statement of, xxxvi- XXXVil. Tufaceous rhyolitie rocks fr. Dufton Pike, 31-37 w. chem. anai. & pl. i (microsce. sects.). Tuffs of Tortworth inlier, 271 et segq. & pl. xi; of Antigua, 494-95; of Guadeloupe, 508-509, 513-14; of St. Martin, etc., 528-26. Tuft-like intrusive rocks & breccias in Ireland, 479-89 w. figs. Turkestan (Asia), recent submergence of, 248. TritpEn-Waiaest, C., obituary of, lviii. evid. of Ukuweia (Ceylon), limestone & granu- lite near, 204-206. Utricn, G. H. F., obituary of, lix. Unconformity in Shropshire Coal- fields, 86-95 w. sects., 266. Unicardium cardioides, 236 & pl. ix. United States Geol. Surv. maps pre- sented, i. Upton Wold Farm (Gloucest.), sect. descr., 135. Usine Limestones of Guadeloupe, 511-12, 560 Valleys in Lake District, radiate sym- metry of, 1938, 195-96; submerged, in W. Indian Region, 503, 507, 516- 17, 520-21, 531-38, 540-41 ; see also Misfits, Obsequent, ede. Vaueuan, T. W., 497, 512, 528, 537. Vermont (U.S.A.), so-called ‘ clay- concretions’ from, xcvii. Viel-Salm (Ardennes), crushed rocks near, 57. Viridite, 333. Volcanic vents in Carb. Limest. nr. Matlock Bath, iv; Tertiary, in Arran, enclosg. Mesozoic fossilif. rocks, 226-43 & pl. ix; vole. formats. of Guadeloupe, 508-509, 513-14 ; do. of St. Kitts, etc., 536, 5389. See also Tufts, etc. Waaaen, W., obituary of, Jix—lxi. Waddington fell (Lanes), Oarb. rocks of, 351. Waldhalle (Riigen), 9. Wales (N.), ee Levees of 223: WatrForp, EH. A., Warp, J., 253. Warnemiinde (Mecklenburg), drifts on coast near, 2-7. Warsaw End House (Lanes), Pendle- side Beds near, 349-50. Wasuineton, H. S., quoted, 41. See also Errata. Waterford County, tuff-like intrusive rocks of, 484 et seqg. w. figs. Waterhouses (Derby), Carb. near, 371-72. Wart, Fr., 491, 501. Warts, W. W., 29, 178, 182, 183. Waaver, T., quoted, 267. Wenpp, C. B., on Corallian Rocks of St. Ives & Elsworth, 73-83 w. map & lists of fossils. Well-section at Dallinghoo, 285-88. Wenlock Beds in Tortworth inlier, 267 et segg., w. lists of fossils. Wensleydale (Yorks), Yoredale Series disting. fr. Pendleside Group, 347, 376; Carb. Limest. fauna of, App. A, facg. 402. Wetherell Point (Antigua), 496. Wexford County. tuff-like intrusive rocks of, 482 et segq. w. figs. Wuitaker, W., elected V.-P., xxii ; receives Murchison Medal for A. J. Jukes-Browne, xli-xlii. White Limestones of Antigua, 496- 98; of St. Martin, etc., 526-29. rocks GENERAL INDEX. [Nov. rgor. Whitewell (Lanes), Carb. fauna from, Sia) Whittington (Yorks), Carb. rocks of, 364. Wicxss, W. H., 307. Winchcombe (Gloucest.), near, 130-33. Wind, not ae agent of de- position of loess, 245, 249 ; influence on Pleistoe. climate,405-478 w. maps. Wind-gaps, orig. of, 189 et segq. Windrush River (Gloucest.), 147. Wirral Colliery (Cheshire), passage of coal into dolomite at, 297-306 w. map, sect., chem. anal., & pl. xii (microse. sects. ). Wissower Bach (Riigen), sects. betw. Wissower Klinken and, descr. & fiz., 12-13. Witchellia-beds, 127 et seqq. Wouuaston Donati.n Fund, list of awards, xxv. Wotuaston medallists, list of, xxv. Wood, Mesozoic fossil, fr. Arran, 237. Bajocian Woop, Miss EH. M. R., quoted, 28. Woopwarp, Henry, presents ‘Table of British Strata,’ xclv; quoted, 354, 402. Woopwarp, Horacz B., quoted, 31, 75, xciv; on Landscape Marble, xci. Woolmer Green (Herts), Bunter pebble from Drift of, xeiii. Worm [?] -bored limest. fr. Hemp- stead Beach, xe. Worston Brook (Lanes), 350. Wricat, G. F., Recent Geological Changes in Northern & Central Asia, 244-50. Wrockwardine (Shropshire), hollow spherulites of, 221-22 w. figs. & pl. vill. Wyre Forest coalfield, unconformity in, 90 et segg. ; so- -called ‘ Permian ’ of, 266. Xenolithie andesite of Forkhill, 479. Yelling (Hunts), Elsworth Rock, etc. near, 76-77. Yellowstone (U.8.A.), hollow spheru- lites of the, 212-18 w. figs. Yons Nab (Filey), 295. Yoredale Grit (Lower), see Pendleside Group. Yoredale Series of Wensleydale, distinguished fr. Pendleside Group, 347, 376. Youna, J., obituary of, Ixi. END OF VOL. LVII. PRINTED BY TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET. PROCEEDINGS OF THE GEOLOGICAL SOCIETY OF LONDON. SESSION 1900-1901. November 7th, 1900. J.J. H. Teart, Esq., M.A., F.R.S., President, in the Chair. The List of Donations to the Library was read. The following communications were read :— 1. ‘Additional Notes on the Drifts of the Baltie Coast of Germany.’ By Prof. T. G. Bonney, D.Sc., LL.D., F.R.S., F.GS., and the Rev. Edwin Hill, M.A., F.G.S. | 2. ‘On certain Altered Rocks from near Bastogne, and their Relations to others in the District.’ By Catherine A. Raisin, D.Sc. (Communicated by Prof. T. G. Bonney, D.Sc., LL.D., F.R.S., F.G.S.) The following specimens and maps were exhibited :— Rock-specimens and Microscope-sections, exhibited in illustration of Miss C. A. Raisin’s paper by Prof. T. G. Bonney, D.Sc., LL.D., F.R.S., F.G.S. Paleolithic Implement found at Minster (Thanet), exhibited by George Clinch, Esq., F.G.S. Geological Survey of England & Wales: 1-inch Geological Map, n. s., Sheet 232 (Solid & Drift) and Sheet 316 (Drift). Geological Survey of Ireland: 1-inch Geological Map (new editions), Sheets 47, 80, & 88. Presented by the Director-General of H.M. Geological Survey. United States Geological Survey: Geologic Atlas, Folios 38-58. Presented by the Director of that Survey. VOL. LVII. li PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ Feb. 1901, November 21st, 1900. J.J. H. Teatt, Esq., M.A., F.R.S., President, in the Chair. _ John Norton Griffiths, Esq., Rhodesian Mining Co., 3 & 4 Great Winchester Street, E.C.; James Parsons, Esq., B.Sc., 6 Hillside, Cotham, Bristol; Frederick Ross Thomson, Esq., Hensill, Hawk- hurst (Kent); Hubert Tylden-Wright, Esq., Coalfields, Dundee (Natal), and Mapperley Hall, Nottingham ; and Arthur Vaughan, Esq., 9 Pembroke Vale, Clifton, Bristol, were elected Fellows of the Society. The List of Donations to the Library was read. The following communications were read :— 1. «A Monchiquite from Mount Girnar, Junagarh (Kathiawar).’ By John William Evans, D.Sc., LL.B., F.G.8. 2. ‘The Geology of Mynydd-y-Garn (Anglesey).’ By Charles A. Matley, Hsq., B.Sc., F.G.S. 3. ‘On some Altered Tufaceous Rhyolitic Rocks from Dufton Pike (Westmorland). By Frank Rutley, Esq., F.G.S. With Analyses by Philip Holland, Esq., F.I.C., F.C.S. The following specimens and photographs were exhibited :— Rock-specimens, Microscope-sections, and Lantern-slides, exhibited by Dr. J. W. Evans, LL.B., F.G.S., in illustration of his paper. Rock-specimens and Microscope- sections, exhibited by C..A. Matley, Esq., B.Sc., F.G.S., in illustration of his paper. Rock-specimens, Microscope-sections, and Lantern- slides, exhibited by F. Rutley, Esq., F.G.S., in illustration of his paper. Photographs of Buddhist Temples, excavated in AXolian Limestone, and showing False-Bedding in the Rocks, Junagarh (Kathiawar), exhibited by Dr. J. W. Evans, LL.B., F.G.S. Thirty-three Photographs illustrating South-African Geology, by KR. H. L. Schwarz, Esq. (of the Geological Survey of Cape ieee exhibited by Prof. J. W. Judd, C.B., LL.D., F.R.S., F.G.S. * December 5th, 1900. J.J. H. Teart, Esq., M.A., F.R.S., President, in the Chair. H. N. Bowden-Smith, Esq., B.A., Careys’, Brockenhurst (Hants), and Trinity College, Oxford ; the Rev. John Bufton, Bunbury (Western Australia); Hervic Nugent Grahame Cobbe, Esq., Burbank, Vol. 57.] | PROCEEDINGS OF THE GEOLOGICAL SOCIETY. lil Grand Junction Ltd., Coolgardie (Western Australia); John R. Don, Esq., Head Master of Waitaki High School, Oamaru, Dunedin (New Zealand); Robert Hugh Geoghegan, Esq., B.A., King’s College, Cambridge ; James Edward Gomersall, Esq., St. Andrew’s Terrace, Batley ; George E. Harris, Esq., Margherita, Upper Assam (India); Gordon William Harris, Esq., Assoc.M.Inst.C.E., 133 Lewisham Road, London, $.K.; Henry Hubert Hayden, Esq., B.A., B.E., care of Messrs. Grindlay & Co., 54 Parliament Street, S.W. : Primrose McConnell, Esq., B.Sc., Ongarpark Hall, Ongar (Essex) ; William McPherson, Esq., 2 Manilla Road, Clifton, Bristol ; Charles Stewart Middlemiss, Esq., Superintendent, Geological Survey of India, care of Messrs. Grindlay & Co., 54 Parliament Street, S.W. ; Fortescue William Millett, Esq., Marazion (Cornwall); Alexander Montgomery, Esq., M.A., Manukan Road, Parnell, Auckland (New Zealand); Herbert Brantwood Muff, Esq., Aston Mount, Heaton, Bradford ; Lieut. Francis Hungerford Pollen, Farley, Reigate (Surrey) ; William Poole, Esq., B.E., 87 Pitt Street, Redfern, Sydney (New South Wales); the Rev. Granville H. Ramage, 9 Comely Bank Road, Walthamstow, E.; Linsdall Richardson, Esq., 10 Oxford Parade, Cheltenham; Bernard William Ritso, Esq., Assoc.M.Inst.C.E., Public Works Department, Cape Town; William Young Veitch, Esq., L.R.C.P.Edin., The Crescent, Middlesbrough (Yorkshire) ; and Henry James Weaver, Hsq., Borough Engineer & Surveyor, Town Hall, King’s Lynn, were elected Fellows of the Society. The List of Donations to the Library was read. The Presipenrt announced that Mrs. Hicxs had presented to the Society a framed Photographic Portrait of the late Dr. Henry Hicks, F.R.S. (Secretary from 1890 to 1893, President from 1896 to 1898.) The following communications were read :— 1. ‘On the Corallian Rocks of St. Ives (Huntingdonshire) and Elsworth.’ By Charles B. Wedd, Esq., B.A., F.G.S. (Communicated by permission of the Director-General of H.M. Geological Survey.) 2. ‘The Unconformity in the Coal Measures of the Shropshire Coalfields.’ By William James Clarke, Esq. (Communicated by W. Shone, Esq., F.G.S.) 3. * Bajocian and Contiguous Deposits in the North Cotteswolds : the Main Hill-Mass.’ By 8S. 8. Buckman, Hsq., F'.G.S. The following specimens were exhibited :— Specimens exhibited by C. B. Wedd, Esq., B.A., F.G.S., in illus- tration of his paper. 1V PROCEEDINGS OF THE GEOLOGICAL socinTy. [Feb. 1gor. Specimens exhibited by 8.8. Buckman, Esq., F.G.S., in illustration of his paper. Pebbles from the Stonesfield Slate of Stonesfield, exhibited by oe H. G. Seeley, F.R.S., F.L.S., V.P.G.S. December 19th, 1900. J.J. H. Trapt, Esq., M.A., F.R.S., President, in the Chair. David Forbes, Esq., 3 Aytoun Road, Brixton, S.W., was elected a Fellow ; M. Gustave F. Dollfus, of Paris, was elected a Foreign Member; and Prof. Ernst Koken, of Tiibingen, a Foreign Corre- spondent of the Society. The List of Donations to the Library was read. The following communications were read :— ‘On the Igneous Rocks associated with the Cambrian Beds of the Malvern Hills.” By Prof. T. T. Groom, M.A., D.Sc., F.G.S. 2. *On the Upper Greensand and Chloritic Marl of Mere and Maiden Bradley in Wiltshire.’ By A. J. Jukes-Browne, Esq., B.A., F.G.S., and John Scanes, Esq. The following specimens and photographs were exhibited :— Rock-specimens and Microscope-sections, exhibited by Prof. T. T. Groom, M.A., D.Sc., F.G.S., in illustration cf his paper. Rock-specimens, Fossils, and Photographs, exhibited by A. J. Jukes-Browne, Esq., B.A., F.G.8., and John Scanes, Esq., in illus- tration of their paper. Boulder of Nepheline-Syenite-Pegmatite with Aégirine, found by Mr: Hinxman on the eastern slope of Coul More, probably derived from the plutonic mass of Cnoc na Sroine, 5 miles to the east, exhibited by the Director-General of H.M. Geological Survey. Columnar Structure produced in Clay-Shale exposed on the pit- bank (refuse) of the Shipley Colliery, Derby, and subjected to the heat arising from the spontaneous combustion of the waste-heap, exhibited by the Rev. J. Magens Mello, M.A., F.G.S. Photographs of Volcanic Vents in the Carboniferous Limestone Series at Grange Mill, 5 miles west of Matlock Bath (Derbyshire), photographed and exhibited by A. T. Metcalfe, Esq., F.GS. Vol. 57.] PROCEEDINGS OF THE GHOLOGICAL SOCIETY. Vv January 9th, 1901. J.J. H. Treat, Esq., M.A., V.P.R.S., President, in the Chair. Neil Dundonald Cochrane, Esq., Auckland (New Zealand); and Ebden Kemper-Voss, Esq., Assoc.R.S.M., 10 Rue de N amur, Brussels, were elected Fellows of the Society. } The following Fellows, nominated by the Council, were elected Auditors of the Society's accounts for the preceding year: Horacu W. Moncxton, Esq., F.L.S., and F. G. Hruron Price, Esq., F.S.A. The List of Donations to the Library was read. The following communications were read :— 1. ‘Notes on the Geology of South-Central Ceylon.’ By John Parkinson, Esq., F.G.S. 2. ‘Note on the Occurrence of Corundum as a Contact-Mineral at Pont-Paul, near Morlaix (Finistére).’ By A. K. Cooméra-Swamy, Heq.. Bise.,E-L:8., E.G. | The following specimens, photographs, and maps were ex- hibited :-— Rock-specimens and Microscope-sections, exhibited by John Par- kinson, Esq., F.G.S., in illustration of his paper. Ellipsoidal inclusion in the Charnockite Series near Palakod, Salem District (Madras), exhibited by John Parkinson, Esq., F.G.S. Rock-specimens, Microscope-sections, and Photographs of Sections, exhibited by A. K. Coomara-Swamy, Hsq., B.Sc., F.L.S., F.G.S., in illustration of his paper. Geological Survey l-inch Maps, presented by the Director- General of that Survey :—England & Wales: n. s. Sheet 187. Huntingdon (Drift), by A. C. G. Cameron & C. B. Wedd; Ireland: Sheets 50 & 57. Down & Fermanagh, by F. W. Egan, and Sheet 90. Meath, by A. McHenry. January 23rd, 1901. J.J. H. Tear, Esq., M.A., V.P.R.S., President, in the Chair. William Armstrong, Esq., Wingate Grange, Wingate, R.S.O. (Co. Durham); Alfred B. EK, Blackburn, Ksq., Old Bank House, Wednesbury ; andJ. Allen Howe, Esq., B.8c., Assistant Demonstrator VOL. LYII. b v1 PROCEEDINGS OF THE GEOLOGICAL socizty. [May r1gor, in Geology in the Royal College of Science, South Kensington, were elected Fellows of the Society. The List of Donations to the Library was read. The Presipent, having requested all those present to rise from their seats, said : ‘TI feel sure that the Fellows will desire to express their deep sense of the grievous loss which this nation has sustained in the death of our late beloved and most gracious Sovereign, by assenting to the immediate adjournment of the Meeting.’ The Meeting was accordingly adjourned. ~ February 6th, 1901. J. J. H. Tautz, Fsq., MA., V.P.RS., President, aioe Arthur Jodrell Bolton, Esq., 1 Armadale Road, Armadale (New South Wales); W. H. Cock, Esq., L.R.C.P., 40 Prospect Place, Swindon ; the Rev. Percy Herbert Collins, M.A., Edgeborough, Guildford; James Reeve, Esq., Curator of the Castle Museum, Norwich ; and Frederick Herbert Smith, Esq., Geological Survey of India, Calcutta, were elected Fellows of the Society. The List of Donations to the Library was read. Dr. F. A. Barner, in exhibiting Rock-specimens, Microscope- sections, and Photographs illustrating Blavierite, Ophitic Diabase, Felsitic Porphyry, Petrosiliceous Breccia, and other Igneous and Metamorphic Rocks of the Mayenne, said that the specimens had been collected by him in the course of an excursion of the VIIIth Inter- national Geological Congress, under the guidance of M. D. P. Oehlert. In the basins of Laval and Coévrons were many peculiar rocks due to the folding and crushing of stratified rocks penetrated by erup- tive dykes. ‘The tectonic features were illustrated by the maps of M. Oehlert and by the photographs. The slides were prepared in the Mineralogical Department of the Natural History Museum, where all the specimens would be preserved. Vol. 57.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. Vil Mr. E. T. Newron exhibited some Graptolites, which had been obtained by Mr. Herbert J. Jessop in the course of a prospecting expedition in Kastern Peru. The locality was in lat. 13° 40’ S. and long. 72° 20' W.; Limbani, near Crucero, in the neighbourhood of the Rio Inambari. The graptolites are closely related to Diplo- graptus foliaceus and indicate deposits of late Ordovician age. Mr. A. K. Coomdna-Swimy exhibited and commented on a lantern- slide showing Spherulitic Structure in Sulphanilic Acid. This had been described and figured by Mr. Henry Bassett, Jr., in the Geological Magazine for January, 1901, pp. 14-16. The following communications were read :— 1. ‘On the Structure and Affinities of the Rheetie Plant Naiadita,’ By Miss Igerna B. J. Sollas, B.Sc., Newnham College, Cambridge. (Communicated by Prof. W. J. Sollas, M.A., D.Sc., LL.D., F.R.S., Ne Pat.) 2. ‘On the Origin of the Dunmail Raise (Lake District).’ By Richard D. Oldham, Esq., F.G.8. In addition to the specimens, etc., mentioned above, the follow- ing were exhibited :— Specimens and Lantern-slides exhibited by Prof. W. J. Sollas, M.A., D.Se., LL.D., F.R.S., V.P.G.S., on behalf of Miss Igerna B. J. Sollas, B.Sc., and in illustration of her paper. Photographs and Lantern-slides, exhibited by R. D. Oldham, isq., F.G.S8., in illustration of his paper. Thirteen Platinotype Portraits of Fellows of the Society, presented by Messrs. Maull & Fox, Photographers. ANNUAL GENERAL MEETING, February 15th, 1901. J.J. Harris Tart, Esg., M.A., V.P.R.S., President,. in the Chair. ‘Report oF tHE Councrzt For 1900. Tur upward tendency of the number of Fellows, which has been a matter of congratulation in five successive Annual Reports, appears to have suffered a check during the past year, and a slight decrease has to be recorded. The undiminished financial prosperity of © the Society, however, justifies the inference that the sources from which the Society’s income is derived were in no way affected by the uncertain state of public affairs during 1900. During the past twelve months 59 Fellows were elected into the Society (7 more than in 1899), of whom 40 paid their Admission Fees before the end of the year. Moreover, 7 Fellows who had been elected in the previous year paid their Admission Fees in 1900, the total accession of new Fellows during the year under review amounting therefore to 47. On the other hand, there was a tota! loss of 57 Fellows during the past twelve months—40 by death, 11 by resignation, and 6 by removal from the List because of non-payment of their Annual Contributions. From the foregoing statistics it will be seen that the actual decrease in the number of Fellows is 10 (as compared with an increase of 5 recorded in 1899). Of the 40 Fellows deceased, 8 had compete a for their Annual Contributions, 26 were Contributing Fellows, and 6 were Non- contributing Fellows. On the other hand, 3 Fellows during the year under review became Compounders. The total accession of Contributing Fellows is thus seen to be 44 (47 —3), and the total loss being 43 (26+11-+6), the number of Contributing Fellows during 1900 was increased by 1, as com- pared with an increase of 12 in 1899 and 13 in 1898. With regard to the Lists of Foreign Members and Foreign Correspondents, it may be recollected that, at the end of 1899, there was no vacancy in the List of Foreign Members, and only Vol. 57. | ANNUAL REPORT. 1X one in that of Foreign Correspondents. During the past twelve months the Society has suffered the loss, by death, of 3 of its Foreign Members. The vacancies thus arising were in part filled by the election of 3 Foreign Members and 3 Foreign Correspondents, but at the close of 1900 there still remained a vacancy in the List of Foreign Correspondents. The total number of Fellows, Foreign Members, and Foreign Correspondents, which stood at 1344 on December 31st, 1899, had decreased to 1334 by the end of 1900. Proceeding now to consider the Income and Expenditure of the Society during the past year, the figures set forth in detail in the Balance-Sheet may be summarized as follows :— The total Receipts, including the Balance of £420 13s. 10d. brought forward from the previous year, amounted to £3450 13s. 1d., being £353 15s. 3d. more than the estimated. Income. But this surplus includes the sum of £200 repaid to the Society by H.M. Treasury. ‘This sum had been contributed by the Society in 1899 towards the cost of the improved lavatory accommodation at the Society’s Apartments, and the question of repayment was still under the consideration of H.M. Treasury when the Estimates for 1900 were framed and issued to the Fellows. The total Expenditure during 1900 amounted to £3061 18s. 3d., being £135 14s. 3d. more than the estimated Expenditure for the year. In the foregoing total is included a considerable item of non-recurring Expenditure, namely, the sum of £301 6s. 4d., _ expended on the completion of the Electric Lighting installation In the Society’s Apartments. Mr. Musgrave Heaphy, C.E., F.G.5., kindly consented to place his invaluable experience once more at the disposal of the Society, and the whole system of the Electric Lighting installation was carefully planned by him, and carried out under his supervision, with thoroughly satisfactory results. For his great services in this matter, the Society owes him a deep debt of gratitude. The Balance remaining available for the current year is £388 14s. 10d. This sum will go far towards meeting the expen- diture which it is proposed to incur during the present year in connexion with the long-postponed Redecoration of the Society’s Apartments, but it is estimated that between £100 and £200 more will be required to cover that item of Extraordinary Expenditure, to which the sanction of the Fellows is hereby requested. ° The Council have pleasure in announcing the completion of Vol. LVI of the Society’s Quarterly Journal, and the commence- ment of Vol. LVII. It will be observed that the cost of the Quarterly Journal for 1900, including the commission on sales, amounted to £989 18s, 4d., being £89 18s. td. more than the estimated Expenditure. As in the case, however, of the Volume ‘for 1899, the Council feel assured that the Fellows will agree that x PROCEEDINGS OF THE GEOLOGICAL SOCIETY, {| May igo!t, the great scientific value of the many important papers which Vol. LVI contains fully justifies the expenditure incurred in con- nexion with them. It will be remembered that the Council undertook, on behalf of the Geological Society, to supply to the Regional Bureau of the International Catalogue of Scientific Literature, which begins with the new century, the material referring to geology published in the British Islands. Mr. C. Davies Sherborn, F.G.S., has been appointed by the Council to prepare and edit the Catalogue-slips necessary for that purpose. As it appeared to be felt by many Fellows that some change in the details of procedure of the Annual General .Meeting was desirable, the Council appointed a Committee to enquire into the subject. After careful investigation the Committee made a report to the Council, the conclusions of which were adopted as follows :— 1. That the Report of the Council be printed in advance, and distributed to the Fellows with the Balance-Sheet. 2. That Recipients of Awards be not expected to reply. 3. That Visitors be allowed to be present at the Annual General Meeting, if introduced by Fellows or Foreign Members, but that no Visitors be permitted to be present before 3.30 P.m., or so soon thereafter as the Discussion on the Report of the Council has been concluded. 4. That the Names of the Visitors and of the Fellows or Foreign Members — introducing them be entered in a Book kept for the purpose. The following Awards of Medals and Funds have been made by the Council :— The Wollaston Medal is awarded to Prof. Charles Barrois, in recognition of the value of his researches concerning the Mineral Structure of the Earth, and, more particularly, of his masterly investigations among the Older Rocks of Britanny, by which he has so greatly added to the reputation already gained by his con- tributions to our knowledge of the Stratigraphy of the Cretaceous System of Britain. The Murchison Medal, together with a sum of Ten Guineas from the Murchison Geological Fund, is awarded to Mr. Alfred John Jukes-Browne, in recognition of the value of his excellent work in Stratigraphical Geology, especially in the Cretaceous Rocks. The Lyell Medal, with a sum of Twenty-five Pounds from the Lyell Geological Fund, is awarded to Dr. Ramsay Heatley Traquair, in recognition of the importance of his services to Paleontology, and particularly of his brilliant work among the Fossil Fishes. The Bigsby Medal is awarded to Mr. George William Lamplugh, as an acknowledgment of his eminent services in Stratigraphical Geology, and particularly of his work on the Speeton Clay and in the Isle of Man. The Balance of the Proceeds of the Wollaston Donation Fund is awarded to Mr. Arthur Walton Rowe, in recognition of his original and brilliant work on the Zones and Fossils of the British Chalk, and to encourage him in further research. oe! Vol. 57.] . ANNUAL REPORT. xi The Balance of the Proceeds of the Murchison Geological Fund is awarded to Mr. Thomas Sargeant Hall, in recognition of the value of his researches among the Graptolites and other Invertebrate Fossils of Australia, and to aid him in the further study of the Paleontology of the Southern Hemisphere. A moiety of the Balance of the Lyell Geological Fund is awarded to Dr. John William Evans, in recognition of the work done by him in elucidating the Geology and Mineralogy of Kathiawar and other parts of India, and to encourage him in further investigations. A moiety of the Balance of the Lyell Geological Fund is awarded to Mr. Alexander McHenry, in recognition of the value of his services in working out the Palzontology and Stratigraphy of Ireland, and to encourage him in further work. Report of THE LipraRy AND Museum CommMitresr For 1900. Although your Committee are unable to announce that the Additions made to the Library during the last year of the nineteenth century were greater than during any previous year of the Society’s existence, they have nevertheless pleasure in stating that the Additions maintained, both in number and interest, the high standard to which the Society is accustomed. The number of Donors is the largest yet recorded. During the past year the Library received by Donation 179 Volumes of separately published Works, 360 Pamphlets and detached Parts of Works, 182 Volumes and 142 detached Parts of Serial Publications (Transactions, Memoirs, Proceedings, etc.), and 17 Volumes of Newspapers. . The total number of accessions to the Library by Donation is thus seen to amount to 378 Volumes, 360 Pamphlets, and 142 detached Parts. The number of Maps presented by various Donors surpasses even the exceptional record of the previous year, no less than 665 Sheets of Maps having been given to the Society’s Library: about 397 of these are Ordnance Survey Maps. But the foregoing total is exclusive of the 21 folios of the Geologic Atlas of the United States which came in during 1900. Although it is hardly possible to make a selection from among the numerous Donations (of which the totals have been recited in the foregoing paragraphs) without omitting many important gifts, your Committee may perhaps be allowed to direct attention to the following: Dr. C. W. Andrews’s ‘Monograph of Christmas Island ’ and Prof. J. W. Gregory’s Catalogue of the Cretaceous Bryozoa, vol. i, both presented by the Trustees of the British Museum ; Prof. R. Zeiller’s ‘ Eléments de Paléobotanique’; Dr. D. H. Scott’s ‘Studies in Fossil Botany’; Prof. A. Rothpletz’s ‘Geologische Alpenforschungen’; the late Maurice Hovelacque’s ‘ Album de Microphotographies des Roches Sédimentaires,’ presented by his xil PROCEEDINGS OF THE GEOLOGICAL sociETy. [May igor, widow; Prof. V. Sabatini’s Memoir on the Volcanos of Central Italy; Messrs. Dupare, Pearce, & Ritter’s Monograph on the Eruptive Rocks of Ménerville (Algeria) ; M. Coste’s continuation of Gruner’s great memoir on the Loire Coal-basin ; and the following Memoirs of the Geological Survey: The Cretaceous Rocks of Britain, vol. i: Gault & Upper Greensand of England; Geology of the South Wales Coalfield, pt. i—Abergavenny ; and the Memoir on Atherstone & Charnwood. Moreover, numerous publications were received from the Geological Survey Departments of India, Denmark, and Sweden. Au extremely valuable and interesting donation was made to the Library by Mrs. Katherine Lyell, in the shape of the MS. Volume of Notes on the Huttonian Theory compiled by the late Leonard Horner. Turning again to the Maps, besides the Geologic Atlas of the United States, previously mentioned, the following Donations are noteworthy: Geological Survey Map of South Australia in 4 sheets ; 3 sheets of the Geological Survey Map of Western Aus- tralia ; 244 sheets (topographical and geological) of the Maps of the United States Geological Survey ; 8 sheets of Maps of the Geological Surveys of Canada, Denmark, Portugal, and Spain; and 9 sheets of Maps of the Geological Surveys of England & Wales and Ireland. The Books and Maps enumerated above were the gift of 186 Personal Donors; 101 Government Departments and other Public Bodies ; and 174 Societies and Editors of Periodicals. The Purchases made on the recommendation of the standing Library Committee comprised 54 Volumes and 11 Parts of separately published Works; 25 Volumes and 12 Parts of works published serially ; and 22 Sheets of Maps. A communication having been received in April lastfrom the Secretary of the Geological Photographs Committee of the British Association, it was resolved to subscribe to the annual series of Mounted Photographs. The total Expenditure incurred in connexion with the Library during 1900 was as follows :— Books, Periodicals, ete. purchased.......... 63 17 8 Binding of Books and Mounting of Maps.... 150 1 7 £213 19 3 The Society’s Collection of Portraits of eminent Geologists has been enriched by the following Donations: Framed Photograph of Messrs. Searles Wood, father and son, presented by Mr. F. W. Harmer; and a Framed Photograph of the late Dr. Henry Hicks, F.R.S., presented by Mrs. Hicks. Vol. 57.] ANNUAL REPORT. Xili Museum. No addition has been made to the Collections during the past year, and no Expenditure has been incurred in connexion with them. On February 10th, 1900, the Collections were thrown open to the inspection of the Geologists’ Association, and thanks were voted to this Society for the hospitality extended to the Association on that occasion. For the purpose of study and comparison the Collections were examined on nine different occasions during the year, about 80 drawers being had out for that purpose. The appended Lists contain the Names of Government. Depart- ments, Public Bodies, Societies, Editors, and Personal Donors, from whom Donations to the Library have been received during the year under review :— I. GovVERNMENT DEPARTMENTS AND OTHER Pustiie Bones. Alabama Geological Survey. University (Ala.). American Museum of Natural History. New York. Argentine Government. Athens.—Observatoire National d’Athénes. Augustana Library. Rock Island (1ll.). Australian Museum. Sydney. Austria.—Kaiserlich-konigliche Geologische Reichsanstalt. Vienna. Kaiserlich-kénigliches Naturhistorisches Hofmuseum. Vienna. Bavaria.—KO6niglich Bayerisches Oberbergamt. Munich. Belgium.—Académie Royale des Sciences, des Lettres & des Beaux-Arts de Belgique. Brussels. Berlin.—KO6nigliche Preussische Akademie der Wissenschaften. Konigliche Preussische Geologische Landesanstalt. Birmingham University. Bohemia.—Musée d’ Histoire Naturelle. Prague. British Guiana.—Department of Mines. British South Africa Company. London. Buenos Aires.—Museo Nacional. California.—State Mining Bureau. San Francisco. California University. Berkeley. Cambridge (Mass.).—Museum of Comparative Zoology, Harvard Colte ze, Canada. — Geological & Natural History Survey. Ottawa. Chicago. Field? Columbian Museum. Denmark.—Danish Ingolf Expedition. ——. Danmarks Geologiske Underségelse. Copenhagen. ——. Kongelige Danske Videnskabernes Selskab. Copenhagen. Dublin.—Royal Irish Academy. Egypt.—Geological Survey. Finland.—Finlands Geologiska Undersékning. Helsingfors. France.—Dépot de la Marine. Paris. Ministére des Travaux Publics. Paris. ——, Muséum d’Histoire Naturelle, Paris. PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May roo, Germany.—Kaiserliche Leopoldinisch-Carolinische Deutsche Akademie der Naturforscher. Halle. Great Britain.—Army Medical Department. London. ——. British Museum (Natural History). London. ——. Colonial Office. London. ——. Geological Survey. London. ——. Home Office. London. ——. Ordnance Survey. Southampton. Holland.—Departement van Kolonien. The Hague. Hungary.—Ko6nigliche Ungarische Geologische Anstalt (Magyar Féldtani Tarsulat). Budapest. India.—Geological Survey. Calcutta. Indian Museum. Calcutta. Indiana.—Department of Geology. Indianapolis. Italy— Reale Comitato Geologico. Rome. Jassy, University of. Kansas.— University Geological Survey. Topeka. Kingston (Canada).—Queen’s College. La Plata Museum. La Plata. London.—City of London College. ——. Royal College of Surgeons. —. University College. Louisiana.—Geological Survey. Baton Rouge (La). Madrid.—Real Academia de Ciencias Exactas, Fisicas & Naturales. Maryland Geological Survey. Baltimore. Mexico.—Instituto Geologico. Mexico City. Michigan College of Mines. Houghton. Michigan Geological Survey. Milwaukee.—Public Museum of the City of Milwaukee. Minnesota.—Geological & Natural History Survey. Minneapolis. Munich.—KoOnigliche Bayerische Akademie der Wissenschaften. New South Wales.—Agent-General for, London. ——. Department of Lands. Sydney. —. Department of Mines & Agriculture. Sydney. ——. Geological Survey. Sydney. New York Museum. Albany. New Zealand.—Department of Mines. Wellington. Norway.—Meteorological Department. Christiania. Paris.—Académie des Sciences. Perak Government. Taiping. Pisa.—Royal University. Portugal.—Commissao Geologica. Lisbon. Prussia.—Ministerium fiir Handel & Gewerbe. Berlin. Queensland.—Agent-General for, London. —. Department of Mines. Brisbane. —. Geological Survey. Brisbane. Rome.—Reale Accademia dei Lincei. Rumania.—Museum of Geology & Paleontology. Bucharest. Russia.—Comité Géologique. St. Petersburg. Section Géologique du Cabinet de S.M. ?Empereur. St. Petersburg. Sao Paulo.—Commissio Geographica & Geologica de S40 Paulo. South Australia.—Agent-General for, London. Government Geologist. Adelaide. Spain.—Comision del Mapa Geolégico. Madrid. St. Petersburg.—Académie Impériale des Sciences. Stockholm.—Kongliga Svenska Vetenskaps Akademi. Sweden.—Sveriges Geologiska Undersékning. Stockholm. Tokio.—Imperial University. . College of Science. Tufts College (Mass.). Tufts College. Turin.—Reale Accademia delle Scienze. United States.—Geological Survey. Washington. Department of Agriculture. Washington. —. National Museum. Washington. Upsala University. Mineralogical & Geological Institute. Vienna.—Kaiserliche Akademie der Wissenschaften. Vol. 57.] ANNUAL REPORT. Xv Washington (D.C.).—Smithsonian Institution. West Virginia.—Geological Survey. Morgantown. Western Australia.—Agent-General for, London. —. Department of Mines. Perth. ——. Geological Survey. Perth. II. Socretres anp Epirors. Acireale.—Accademia di Scienze, Lettere & Arti. Adelaide.—Royal Society of South Australia. Agram.—Societas Historico-Naturalis Croatica. Alnwick.—Berwickshire Naturalists’ Club. Auckland.—New Zealand Institute of Mining Engineers. Bahia.—Instituto Geographico & Historico. Barnsley.—Midland Institute of Mining, Civil, & Mechanical Engineers. Bath.—Natural History & Antiquarian Field Club. Belfast—Natural History & Philosophical Society. Berlin.— Deutsche Geologische Gesellschaft. Gesellschaft Naturforschender Freunde. —. Zeitschrift fir Praktische Geologie. Berne.—Schweizerische Naturforschende Gesellschaft. Bombay Branch of the Royal Asiatic Society. Bordeaux.—Société Linnéenne. Boston (Mass.).—American Academy of Arts & Sciences. Boston Society of Natural History. Brunswick.—Verein fiir Naturwissenschaft zu Braunschweig. Brussels.—Société Belge de Géologie, de Paléontologie & ad’ Hydrologie. —. Société Malacologique de Belgique. Budapest.—Foldtani Kézlony (Geological Magazine). Buenos Aires.—Instituto Geografico Argentino. —. Sociedad Cientifica Argentina. Calcutta.—Indian Engineering. —. Asiatic Society of Bengal. Cambridge.—Philosophical Society. Cape Town.—South African Philosophical Society. Cardiff.—South Wales Institute of Engineers. Chicago.—Academy of Sciences. Journal of Geology. Cincinnati Society of Natural History. Colombo.—Ceylon Branch of the Royal Asiatic Society. Colorado Springs.—Colorado College Studies. Copenhagen.—Dansk Geologisk Forening. Cérdoba (Argentine Republic)—Academia Nacional de Ciencias. Cracow.—Académie des Sciences (Akademja Umiejetosci). Croydon Microscopical & Natural History Club. Darmstadt.—Verein fir Erdkunde. Davenport (lowa).—Academy of Natural Sciences. Denver (Colo.).—Colorado Scientific Society. Dorpat.—Naturforschende Gesellschaft. Douglas.—Isle of Man Natural History & Antiquarian Society. Dresden.—Naturwissenschaftliche Gesellschaft ‘ Isis.’ Dublin.—Royal Dublin Society. Edinburgh.—Geological Society. Royal Physical Society. —. Royal Scottish Geographical Society. —. Royal Society. —. Scottish Natural History Society. Ekaterinburg.—Société Ouralienne d’Amateurs des Sciences Naturelles. Frankfurt am Main.—Senckenbergische Naturforschende Gesellschatt. Freiburg im Breisgau.—Naturforschende Gesellschaft. Geneva.—Société Physique & d’ Histoire Naturelle. Giessen.—Oberhessische Gesellschaft fiir Natur- & Heilkunde. Gratz.—Naturwissenschaftlicher Verein fiir Steiermark. Haarlem.—Société Hollandaise des Sciences. XY1 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. Halifax.—Yorkshire Geological & Polytechnic Society. (N. 8.).—Nova Scotian Institute of Science. Hamilton (Canada).—Hamilton Association. Hanau.— Wetterauische Gesellschaft fiir Gesammte Naturkunde. Helsingfors.—Geografiska Férening i Finland. [May rgot, Hermannstadt.—Siebenbiirgischer Verein fiir Naturwissenschaften. Hertford.—Hertfordshire Natural History Society. Hull.—Scientific & Naturalists’ Club. Kiev.—Société des Naturalistes. Lausanne.—Société Vaudoise des Sciences Naturelles. Lawrence.—Kansas University Quarterly. Leicester.—Literary & Philosophical Society. Leipzig.—Zeitschrift fir Krystallographie & Mineralogie. Liége.—Société Géologique de Belgique.. Lille—Société Géologique du Nord. Lima.—Revista de Ciencias. Lisbon.—Sociedade de Geographia.. Liverpool.—Geological Society. London.— Academy.’ ‘ Atheneum.’ British Association for the Advancement of Science. British Association of. Waterworks Engineers.. ‘Chemical News.’ Chemical Society. ‘Colliery Guardian.’ East India Association. ‘ Geological. Magazine.’ Geologists’ Association. Institution of Civil Engineers. Iron & Steel Institute. ‘Tron & Steel Trades’ Journal.’ * Knowledge.’ Linnean Society. Mineralogical Society. * Nature.’ Palzontographical Society.. * Quarry.’ Ray Society. Royal Agricultural Society. Royal Astronomical Society. Royal Geographical Society. Royal Institution. Royal Meteorological Soeiety.. Royal Microscopical Society. Royal Photographic Society of Great Britain. Royal Society. Society of Arts. Society of Biblical Archeology. Society of Public Analysts.. Victoria Institute. ‘ Water.’ Zoological Society. Madison.— Wisconsin Academy of Sciences.. Manchester.—Geological Society. Literary & Philosophical Society. Mexico.—Sociedad Cientifica ‘ Antonio Alzate.’ Milan.—Reale Istituto Lombardo di Seienze e Lettere. Montreal.—Natural History Society. Moscow.—Société Impériale des Naturalistes. Nancy.—Académie de Stanislas. New Haven (Conn.).—American Journal of Science. . Connecticut Academy of Sciences. New York.—Academy of Sciences. American Institute of Mining Engineers. Newcastle-upon-Tyne.—Institution of Mining Engineers. awe eee) okt lb eae! ‘London, Edinburgh, & Dublin Philosophical Magazine.’ North of England Institute of Mining & Mechanical Engineers, Wol. ¥7.] ANNUAL REPORT. Northampton.—Northamptonshire Natural History Society. Nurnberg.—Naturhistorische Gesellschaft. Ottawa.—Royal Society of Canada. Padua.—Reale Accademia di Scienze, Lettere & Arti. Palermo.—Annales de Géologie & de Paléontologie. Paris.—‘ Revue Scientifique.’ Société Frangaise de Minéralogie. —.. Société Géologique de France. ‘Spelunca.’ Penzance.—Royal Geological Society of Cornwall. Perth.—Perthshire Society of Natural Science. Philadelphia.—Academy of Natural Sciences. American Philosophical Society. Wagner Free Institute of Science. Pisa.—Societa Toscana di Scienze Naturali. Plymouth.—Devonshire Association for the Advancement of Science. Rochester (N.Y.).—Geological Society of America. Rome.—Societa Geologica Italiana. Rugby School Natural History Society. Salem (Mass.).—Essex Institute. Santiago de Chile—Deutscher Wissenschaftlicher Verein. —. Sociedad Nacional de Mineria. Société Scientifique du Chili. Scranton (Pa.).—‘* Mines & Minerals.’ Shanghai.—China Branch of the Royal Asiatic Society. Spezia.—Societa Gerolamo Guidoni. St. John.—Natural History Society of New Brunswick. St. Petersburg.—Académie Impériale des Sciences. —. Russische Kaiserliche Mineralogische Gesellschaft. Stockholm.—Geologiska Foérening. Stuttgart—Centralblatt ftir Mineralogie, Geologie & Palaontologie. ——. Neues Jahrbuch fir Mineralogie, Geologie & Palaontologie. ——. Verein fiir Vaterlandische Naturkunde in Wirttemberg. ——., Zeitschrift fir Naturwissenschaften. Sydney.—Australasian Association for the Advancement of Science. —. Australasian Institute of Mining Engineers. ——. Linnean Society of New South Wales. Royal Society of New South Wales. Tokio.—EHarthquake Investigation Committee. Topeka (Kan.).—Kansas Academy of Sciences. Toronto.—Canadian Institute. Toulouse.—Société d’ Histoire Naturelle. Truro.—Royal Institution of Cornwall. Vienna.—Berg- & Hiittenmannisches Jahrbuch. . Kaiserlich-K6nigliche Zoologisch-Botanische Gesellschaft. Washington (D.C.).—Academy of Sciences. ——. Biological Society. Wellington (N.Z.).—New Zealand Institute. Wiesbaden.—Nassauischer Verein ftir Naturkunde. Winnipeg.—Historical & Scientific Society of Manitoba. York.—Yorkshire Philosophical Society. III. Prrsonat Donors. Agassiz, A: Alford, C. J. Allen, H. Ameghino, F. Ami, H. Anderson, J. G. Andrews, W. Angelis d’Ossat, G. de. Avebury, Rt. Hon. Lord. Balch, E. S. Barrett, R. L. Beecher, C. K. . Belinfante, L. L. Blake, W. P. Bleicher, —. Bockh, J. Bodenbender, G. Beggild, O. B. Bogoslovski, N. Bohm, A. von. Bonney, T. G. Boule, M. Branner, J. C. Brillouin, M. Brough, B. H. Brown, H. Y. L. .Buckman, 8. 5. Carne, J. E. Choffat, P. Clark, W. B. Claypole, K. W. XVii XVili PROCEEDINGS OF THE GEOLOGICAL society. [May igo, Cole, G. A. J. Collett, O. Cooméra-Swamy, A. K. Cort, H. de. Credner, H. Crick, G. C. Dalton, W. H. Datta, P. N. Davis, W. M. Davison, C. Delgado, J. F. N. Dewalque, G. Donald, J. Donville, H. Douglass, E. Doyle, P Dunn, E. J. Duparc, L. Eginitis, D. Emmons, S. F. Evans, Sir John. Evans, J. W. Evans, T. Fletcher, H. Forir, H. Foster, C. Le N. Fox, H Francis, W. Frazer, P. Galloway, W. B. Gavelin, A. Geinitz, F. E. Gilpin, E., Junr. Gosselet, J. Gray, J. Greenwell, A. Gregorio, Marquis A. de. Gresley, W. S. Griffith, P. Groom, T. T. Grinling, F. Gulliver, F. P. Gunther, A. Harker, A. Harlé, E. Hatch, F. H. Hicks, Mrs. Hind, W. Hinde, G. J. Hingenau, O. von. Holland, T. H. Honoré, C. Hovelacque, Mme. M. Hovey, E. O. Hubbard, L. L. Hull, E. Jennings, A. V. Jensen, A. S. Jones, T. R. Karrer, F. Kayser, E. Koch, A. Keenen, A. von. Kornerup, T. Krausé, F. M. Lacroix, A. Lamarre-Olivier, A. Lambert, G. Lamplugh, G. W. Lane, A. C. Lapparent, A. de. Lebescoute, P. Lee, J. B. Lindstrém, G. Loewinson-Lessing, F’. Lohest, M. Lones, T. E. Loriol, P. de. Lotz, H. Louis, D. A. Lyell, Mrs. K. Maitland, A.G. Mansel-Pleydell, J. C. Marr, J. E. Martin, E. A. Matley, C. A. Millosevich, F. Mojsisovics, E. von. Monckton, H. W Moller, H. Mourlon, M. Nares, Sir George S. Nathorst, A. G. Newton, R. B. Nicolis, E. Nordenskidld, Baron Adolf Erik. Nordenskidld, O. Ordonez, E. Packard, A. S. Pearce, F. Perkins, H. I. Power, F. D. Radovanovich, §, Reade, T. M. Renevier, E. Reusch, H. Richthofen, Baron Ferdinand von. Ritter, E. Ritter, L. Roechling, H. A. Rosenbusch, H. Rothpletz, A. Rowe, A. W. Rudzki, P. Rutley, F. Sacco, F. Salter, A. E. Sarasin, C. Schardt, H. Scott, D. H. Seward, A. C. Sheppard, T. Sjogren, H. Smyth, B. B. Stefanescu, G. Strachey, Sir Richard. Talmage, J. E. Thompson, B. Thugutt, St. J. Tietze, E. Trener, G. B. Tucker, W. T. Upton, C. Van den Broeck, E. Veitch, A. C. Vernon-Harcourt, L. F. Vincent, M. C. Walther, J. Ward, J. Wardle, Sir Thomas. Watts, W. W. Weinschenk, E. Wellburn, E. D. Whitaker, W. Whitfield, P. P. Whitney, M. Wiman, C. Winchell, N. H. Woods, H. Woodward, Henry. Zeiller, R. Zelizko, J. V. Wael. 57.] ANNUAL REPORT, xix CoMPARATIVE STATEMENT OF THE NUMBER OF THE SOCIETY AT THE CLosE oF THE YEARS 1899 anv 1900. Dec. 31st, 1899. Dec. 31st, 1900. Compoumders .:... 6.....- 283 ite 283 Contributing Fellows...... O20 "CF ac een 924 Non-contributing Fellows. . Oa a tha ates 48 1265 1255 Foreign Members ........ A Rah titers ota 40 Foreign Correspondents... . OOM Mitre a sah 39 1344 1334 Comparative Statement explanatory of the Alterations in the Number of Fellows, Foreign Members, and Foreign Correspondents at the close of the years 1899 and 1900. Number of Compounders, Contributing and Non- contributing Fellows, December 31st, 1899 .. ae Add Fellows elected during the former year and 7 ELC J, O09 eee care cane se eerie } Add Fellows elected and paid in 1900 ........ 40 1312 Deduct Compounders deceased................ 8 Contributing Fellows deceased .......... 26 Non-contributing Fellows deceased ...... 6 Contributing Fellows resigned .......... 11 Contributing Fellows removed .......... 6 — 57 1255 Number of Foreign Members and Foreign m9 Correspondents, December 31st, 1899 .... } ‘i Deduct Foreign Members deceased ........ 3 Foreign Correspondents et 3 Horeien Members) 7). y....... — 6 13 | Add Foreign Members elected .......... 3 Foreign Correspondents elected .... 3 _— 6 — 79 1334 xx PROCEEDINGS OF THE GEOLOGICAL SOCIETY, [May 19of, Decrasep FEttows. Compounders (8). Jones, T. M., Esq. Pearce, H., Esq. Lindley, W., Esq. Prevost, Col. L. de T. Maclean, W. C., Esq. Rylands, T. G., Esq. Middleton, J. O., Esq. Young, Dr. John. Resident and other Contributing Fellows (26). Anstie, J., Esq. Pitt-Rivers, Lt.-Gen. A. H. Argyll, Duke of. Lane-Fox. Armstrong, Prof. G. F. Pritchard, E., Esq. Atkinson, H. K., Esq. Prout, T. P., Esq. Branscombe, W. H., Esq. Robinson, J. T., Esq. Candler, T. E., Esq. Ross, Capt. G. E. A. yarlick, E., Esq. Ruskin, Prof. John. Greenwell, G. C., Esq. (Duffield)..| Russell, R., Esq. Grimston, Capt. the Hon. Sladen, W. P., Esq. William. Thomson, J., Esq. Maggs, T. C., Esq. Ulrich, Prof. G. Haake Meyer, C. J. A., Esq.| Waagen, Dr. W. Petrie, Capt. F. W, H. Walker, H., Esq. Pidgeon, D., Esq. White, H., Esq. Non-contributing Fellows (6). McLandsborough, J., Esq. Morton, G. H., Esq. Tylden-Wright, C., Esq. Fletcher, W., Esq. Hill, Canon Edward. Lowe, EH. J., Esq. DecraseD Fortran Mempers (3). Geinitz, Prof. H. B. Torell, Prof. O. M. Milne-Edwards, Prof. A. Frttows Rrsrenup (11). Barham, H. G. F., Esq. Hamilton, J. J., Esq. Beaumont, W. W., sq. Main, J., Esq. Brown, T. Forster, Esq. Mosley,.G., Esq. Burrow, J. C., Esq. Scamell, G., Esq. Galton, F., Esq. Walker, G. B., Esq. . Hall, Rev. H. A. Vol. 57.] | ANNUAL REPORT, XXi Frttows Removep (6). Ashmore, I., Esq. Ford, 8. W., Esq. Campbell, Rev. J. Heussler, C. A., Esq. Davidson, W. B. M., Esq. Officer, Major C. M. The following Personages were elected Foreign Members during the year 1900 :— M. Gustave F. Dollfus, of Paris. Prof. Paul Groth, of Munich. Dr. Sven Leonhard Toérnquist, of Lund. The following Personages were elected Foreign Correspondents during the year 1900 :— Prof. Arturo Issel, of Genoa: Prof. Ernst Koken, of Tiibingen. Prof. Federico Sacco, of Turin. After the Reports had been read, it was resolved :— That they be received and entered on the Minutes of the Meeting, and that such parts of them as the Council shall think fit be printed and circulated among the Fellows. It was afterwards resolved :— That the thanks of the Society be given to Prof. J. W. Judd and Prof. W. J. Sollas, retiring from the office of Vice-President. That the thanks of the Society be given to Prof. T. G. Bonney, F. W. Harmer, Esq., the Rev. Edwin Hill, the Rev. H. H. Win- wood, and Dr. A. Smith Woodward, retiring from the Council. After the Balloting-glasses had been closed, and the Lists examined by the Scrutineers, the following gentlemen were declared to have been duly elected as the Officers and Council for the ensuing year :— VOL. LVII. Xxli PROCEEDINGS OF THE GEOLOGICAL socreTY. [May 1901, OFFICERS AND COUNCIL.—1901. PRESIDENT. J. J. H. Teall, Esq., M.A., V.P.RS. VICE-PRESIDENTS. J. EB. Marr, Esq., M.A., F.RB.S. H. W. Monckton, Esq., F.L.S. Prof. H. G. Seeley, F.R.S., F.L.S. W. Whitaker, Esq., B.A., F.R.S. SECRETARIES. R. 8. Herries, Esq., M.A. Prof. W. W. Watts, M.A. FOREIGN SECRETARY. Sir John Evans, K.C.B., D.C.L., LL.D., F.R.S., F.LS. TREASURER. W. T. Blanford, LL.D., F.R.S. COUNCIL. W. T. Blanford, LL.D., F.R.S. Prof. H. A. Miers, M.A., F.R.S. Sir John Evans, K.C.B., D.C.L.,| Right Rev. John Mitchinson, D.D., LL.D., F.R.S. D.C.L. Prof. E. J. Garwood, M.A. H. W. Monckton, Esq., F.L.S. Prof. T. T. Groom, M.A., D.Sc. E. T. Newton, Esq., F.R.S. Alfred Harker, Esq., M.A. G. T. Prior, Esq., M.A. R. 8S. Herries, Esq., M.A. F. W. Rudler, Esq. William Hill, Esq. Prof. H. G. Seeley, F.R.S., F.LS. W. H. Hudleston, Esq., M.A., F.R.S., | Prof. W. J. Sollas, M.A., D.Se., F.LS. LL.D., F.R.S. Prof. J. W. Judd, C.B., LL.D., F.R.S. | J. J. H. Teall, Esq., M.A., V.P.R.S. Lieut.-General C. A. McMahon, | Prof. W. W. Watts, M.A. F.RS. W. Whitaker, Esq., B.A., F.R.S. J. E. Marr, Esq., M.A., F.R.S. H. B. Woodward, Esq., F.R.S. Vol. 57. ] ANNUAL REPORT. Xxlli LIST OF THE FOREIGN MEMBERS OF THE GEOLOGICAL SOCIETY OF LONDON, rn 1900. Date of Election. 1857. Prof. Hanns Bruno Geinitz, Dresden. (Deceased.) 1874. Prof. Albert Gaudry, Paris. 1877. Prof. Eduard Suess, Vienna. 1880. Prof. Gustave Dewalque, Liége. 1880. Baron Adolf Erik Nordenskisld, Stockholm. 1880. Prof. Ferdinand Zirkel, Lezpzzg. 1883. Prof. Otto Martin Torell, Stockholm. (Deceased.) 1884. Prof. G. Capellini, Bologna. 1885. Prof. Jules Gosselet, Lille. 1886. Prof. Gustav Tschermak, Vienna. 1887. Prof. J. P. Lesley, Philadelphia, Pa., U.S.A. 1888. Prof. Eugéne Renevier, Lausanne. 1888. Baron Ferdinand von Richthofen, Berlin. 1889. Prof. Ferdinand Fouqué, Paris. 1889. Geheimrath Prof. Karl Alfred von Zittel, Munich. 1890. Prof. Heinrich Rosenbusch, Hezdelberg. 1891. Prof. Charles Barrois, Zvlle. 1892. Prof. Gustav Lindstrom, Stockholm. 1893. Prof, Waldemar Christofer Brogger, Christiania. 1893. M. Auguste Michel-Lévy, Pars. 1893. Dr. Edmund Mojsisovics von Mojsvar, Vienna. 1893. Dr. Alfred Gabriel Nathorst, Stockholm. 1894. Prof. George J. Brush, New ’ Haven, Conn., U.S.A. 1894. Prof. Edward Salisbury Dana, New Haven, Conn., U.S.A. 1894. Prof. Alphonse Renard, Ghent. 1895. Prof. Grove K. Gilbert, Washington, D.C., U.S.A. 1895. M. Friedrich Schmidt, St. Petersburg. 1896. Prof. Albert Heim, Tiivich. 1897. M. E. Dupont, Brussels. 1897. Dr. Anton Fritsch, Prague. 1897. Prof. A. de Lapparent, Paris. 1897. Dr. Hans Reusch, Christiana. 1898. Geheimrath Prof. Hermann Credner, Lezpzzg. 1898. Mr. Charles D. Walcott, Washington, D.C., U.S.A. 1899. Prof. Marcel Bertrand, Paris, 1899. Senhor J. F. N. Deleado, Insbon. 1899. Prof. Emmanuel Kayser, Marburg. 1899. Prof. Alphonse Milne-Edwards, Paris. (Deceased.) 1899. M. Ernest Van den Broeck, Brussels. 1899. Dr. Charles Abiathar White, Washington, D. C., U.S.A. 1900. M. Gustave F. Dollfus, Pars. 1900. Prof. Paul Groth, Munich. 1900, Dr. Sven Leonhard Tornquist, Lund. 62 XXIV PROCEEDINGS OF THE GEOLOGICAL SOCIETY, [May 1901, LIST OF THE FOREIGN CORRESPONDENTS OF THE GEOLOGICAL SOCIETY OF LONDON, rn 1900. Date of Election. 1866. Prof. Victor Raulin, Montfaucon d’ Argonne. 1874. Prof. Igino Cocchi, Florence. 1879. Dr. Emile Sauvage, Boulogne-sur-Mer. 1889. M. R. D. M. Verbeek, Buitenzorg, Java. 1890. Herr Felix Karrer, Vienna. 1890. Prof. Adolph von Keenen, Gottingen. 1892. Prof. Johann Lehmann, Kel. 1892. Major John W. Powell, Washington, D.C., U.S.A. 1898. Prof. Aléxis Pavlow, Moscow. 1893. M. Ed. Rigaux, Boulogne-sur-Mer. 1894, Prof. Joseph Paxson Iddings, Chicago, {ll., U.S.A. 41894. M. Perceval de Loriol-Lefort, Campagne Frontenex. 1894, Dr. Francisco P. Moreno, La Plata. 1894. Prof. August Rothpletz, Munich. 1894. Prof. J. H. L. Vogt, Christiania. 1895. Prof. Konstantin de Kroustchoff, St. Petersburg. 1895. Prof. Albrecht Penck, Vienna. 1896. Prof. S. L. Penfield, New Haven, Conn., U.S.A. 1896. Prof. Johannes Walther, Jena. 1897. M. Louis Dollo, Brussels. 1897. Mr. Alpheus Hyatt, Cambridge, Mass., U.S.A. 1897. Prof. Anton Koch, Budapest. : 1897. Prof. A. Lacroix, Paris. 1897, M. Emmanuel de Margerie, Paris. 1897. Prof. Count H. zu Solms-Laubach, Strasburg. 1898. M. Marcellin Boule, Parzs. 1898. Dr. W. H. Dall, Washington, D.C., U.S.A. 1898. M. A. Karpinsky, St. Petersburg. 1899. Prof. Charles Emerson Beecher, New Haven, U.S.A. 1899. Dr. Gerhard Holm, Stockholm. 1899. Prof. Theodor Liebisch, G'dttingen. 1899. Prof. Franz Loewinson-Lessing, Dorpat. 1899. M. Michel F. Mourlon, Brussels. 1899. Prof. Henry Fairfield Osborn, New York, U.S.A. 1899. Prof. Gregorio Stefanescu, Bucharest. — 1899. Prof. René Zeiller, Paris. 1900. Prof. Arturo Issel, Genoa. 1900. Prof. Ernst Koken, Tiibingen. 1900, Prof. Federico Sacco, Turia. — Vol. 57.] ANNUAL REPORT. XXV AWARDS OF THE WOLLASTON MEDAL UNDER THE CONDITIONS OF THE ‘DONATION FUND’ ESTABLISHED BY WILLIAM HYDE WOLLASTON, M.D., F.RS., F.G.S., ere. “To promote researches concerning the mineral structure of the earth, and to enable the Council of the Geological Society to reward those individuals of any country by whom such researches may hereafter be made,’—‘ such individual not being a Member of the Council.’ 1831. Mr. William Smith. | 1867. Mr. G. Poulett Scrope. 1835. Dr. G. A. Mantell. 1868. Prof. Carl F. Naumann. 1836. M. Louis Agassiz. 1869. Dr. Henry C. Sorby. 1837. ee T. P. Cautley. 1870. Prof. G. P. Deshayes. Dr. H. Falconer. 1871. Sir Andrew Ramsay. 1838. Sir Richard Owen. 1872. Prof. James D. Dana. 1839. Prof. C. G. Ehrenberg. 1873. Sir P. de M. Grey Egerton. 1840. Prof. A. H. Dumont. 1874. Prof. Oswald Heer. 1841. M. Adolphe T. Brongniart. | 1875. Prof. L. G. de Koninck. 1842. Baron L. von Buch. | 1876. Prof. Thomas H. Huxley. 1843. ie Elie de Beaumont. 1877. Mr. Robert Mallet. M. P. A. Dufrénoy. 1878. Dr. Thomas Wright. 1844. Rev. W. D. Conybeare. 1879. Prof. Bernhard Studer. 1845. Prof. John Phillips. 1880. Prof. Auguste Daubrée. 1846. Mr. William Lonsdale. 1881. Prof. P. Martin Duncan. 1847. Dr. Ami Boué. 1882. Dr. Franz Ritter von Hauer. 1848. Very Rev. W. Buckland. 1883. Dr. W. T. Blanford. 1849. Sir Joseph Prestwich. 1884. Prof. Albert Gaudry. 1850. Mr. William Hopkins. 1885. Mr. George Busk. 1851. Rev. Prof. A. Sedgwick. 1886. Prof. A.L.O. Des Cloizeaux. 1852. Dr. W. H. Fitton. 1887. Mr. J. Whitaker Hulke. 1853, es le Vicomte A.d’Archiac. | 1888. Mr. H. B. Medlicott. M. E. de Verneuil. 1889. Prof. Thomas G. Bonney. 1854. Sir Richard Griffith. 1890. Prof. W. C. Williamson. 1855. Sir Henry De la Beche. 1891. Prof. John W. Judd. 1856. Sir William Logan. 1892. Baron Ferdinand von 1857. M. Joachim Barrande. Richthofen. Herr Hermann von Meyer. | 1893. Prof. Nevil S. Maskelyne. ods. Prof. James Hall. 1894, Prof. Karl] Alfred von Zittel. 1859. Mr. Charles Darwin. 1895. Sir Archibald Geikie. 1860. Mr. Searles V. Wood. 1896. Prof. Eduard Suess. 1861. Prof. Dr. H. G. Bronn. 1897. Mr. Wilfrid H. Hudleston. 1862, Mr. R. A.C. Godwin-Austen. | 1898. Prof. Ferdinand Zirkel. 1863. Prof. Gustav Bischof. 1899. Prof. Charles Lapworth. 1864, Sir Roderick Murchison. 1900. Prof. Grove K. Gilbert. 1865, Dr. Thomas Davidson. 1901. Prof. Charles Barrois. 1866, Sir Charles Lyell. XXVI1 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. AWARDS OF THE [May 1901, BALANCE OF THE PROCEEDS OF THE WOLLASTON 1831. 1833. 1834. 1835. 1836. 1838. 1839. 1840. 1841. 1842. 1843. 1844. 1845. 1846. 1847. 1848. 1849. 1850. 1851. 1852. 1858. 1854. 1855, 1856. 1857. 1858. 1859. 1860. 1861. 1862. 1868. 1864. 1865. 1866. “DONATION Mr. William Smith. Mr, William Lonsdale. M. Louis Agassiz. Dr. G. A. Mantell. Prof. G. P. Deshayes. Sir Richard Owen. Prof. C. G. Ehrenberg. Mr. J. De Carle Sowerby. Prof. Edward Forbes. Prof. John Morris. Prof. John Morris. Mr. William Lonsdale. Mr. Geddes Bain. Mr. William Lonsdale. M. Alcide d’Orbigny. Cape-of-Good-Hope Fossils. M. Alcide d’Orbigny. Mr. William Lonsdale. Prof. John Morris. M. Joachim Barrande. Prof. John Morris. Prof. L. G. de Koninck. Dr. S. P. Woodward. Drs. G. and F. Sandberger. Prof. G. P. Deshayes. Dr. S. P. Woodward. Prof. James Hall. Mr. Charles Peach. Prof. T. Rupert Jones. i W. K. Parker. Prof. Auguste Daubrée. Prof. Oswald Heer. Prof. Ferdinand Senft. Prof. G. P. Deshayes. Mr. J. W. Salter. Dr. Henry Woodward. 1867. 1868. 1869. 1870. 1871. 1872. 1873. 1874. 1875. 1876. 1877. 1878. 1879. 1880. 1881. 1882. 1885. 1884. 1885. 1886. 1887. 1888. 1889. 1890. 1891. 1892. 1893. 1894. 1895. 1896. 1897. 1898. 1899. 1900. 1901. FUND.’ My. W. H. Baily. M. J. Bosquet. — Mr. William Carruthers, M. Marie Rouault. Mr. Robert Etheridge. Dr. James Croll. Prof. John W. Judd. Dr. Henri Nyst. Prof, L. C. Miall. Prof. Giuseppe Seguenza. Mr. R. Etheridge, Jun. Prof. William J. Sollas. Mr. Samuel Allport. Mr. Thomas Davies. Dr. Ramsay H. Traquair. Dr. George J. Hinde. Prof. John Milne. Mr. HE. Tulley Newton. Dr. Charles Callaway. Mr. J. Starkie Gardner. Mr. Benjamin N. Peach. Mr. John Horne. Dr. A. Smith Woodward. Mr, W. A. E. Ussher. Mr. Richard Lydekker. Mr. Orville A. Derby. Mr. John G. Goodchild. | Mr. Aubrey Strahan. Prof. W. W. Watts. Mr. Alfred Harker. Dr. Francis A. Bather. Prof. E. J. Garwood. Prof. J. B. Harrison. Mr. George T. Prior. Mr. Arthur W. Rowe. Vol. 57.] ANNUAL REPORT. XxXVil AWARDS OF THE MURCHISON MEDAL UNDER THE CONDITIONS OF THE ‘MURCHISON GEOLOGICAL FUND,’ ESTABLISHED UNDER THE WILL OF THE LATE SIR RODERICK IMPEY MURCHISON, Barzt., F.R.S., F.G.S. ‘To be applied in every consecutive year in such manner as the Council of jithe Society may deem most useful in advancing Geological Science, whether by granting sums of money to travellers in pursuit of knowledge, to authors of memoirs, or to persons actually employed in any enquiries bearing upon§the science of Geology, or in rewarding any such travellers, authors, or otherjpersons, and the Medal to be given to some person to whom such Council shalljgrant ~ any sum of money or recompense in respect of Geological Science.’ 1873. 1874, 1875. 1876. HOWL. 1878. 1879. 1880. 1881. 1882. 1883. 1884. 1885. 1886, 1887. Mr. William Davies. Dr. J. J. Bigsby. Mr. W. J. Henwood. Mr. Alfred R. C. Selwyn. Rey. W. B. Clarke. Prof. Hanns B. Geinitz. Sir Frederick M‘Coy. Mr. Robert Etheridge. Sir Archibald Geikie. Prof. Jules Gosselet. Prof. H. R. Goeppert. Dr. Henry Woodward. Dr. Ferdinand von Roemer. Mr. William Whitaker. Rey. Peter B. Brodie. 1888. 1889. 1890. 1891. 1892. 1893. 1894, 1895. 1896. 1897. 1898. 1899. 1900. 1901. Prof. J. S. Newberry. Prof. James Geikie. Prof. Edward Hull. Prof. W. C. Brogger. Prof. A. H. Green. Rev. Osmond Fisher. Mr. W. T. Aveline. Prof. Gustav Lindstrom. Mr. T. Mellard Reade. Mr. Horace B. Woodward. Mr. T. F. Jamieson. Mr. Benjamin N, Peach. a John Horne. Baron A. E. Nordenskiold. Mr. A. J. Jukes-Browne. [May 1001, OF THE Prof. Grenville A. J. Cole. Mr. Edward Wethered. Mr. Albert C. Seward. XXVIli PROCEEDINGS OF THE GEOLOGICAL SOCIETY. AWARDS OF THE BALANCE OF THE PROCEEDS ‘MURCHISON GEOLOGICAL FUND,’ 1873. Prof. Oswald Heer. 1887. Mr. Robert Kidston. 1874. Mr. Alfred Bell. 1888. Mr. Edward Wilson. 1874, Prof. Ralph Tate. 1889. 1875. Prof. H. G. Seeley. 1890. 1876. Dr. James Croll. 1891. Rev. Richard Baron. 1877. Rev. J. F. Blake. 1892. Mr. Beeby Thompson. 1878. Prof. Charles Lapworth. 1893. Mr. G. J. Williams. 1879. Mr. J. W. Kirkby. 1894. Mr. George Barrow. 1880. Mr. Robert Etheridge. 1895. 1881. Mr. Frank Rutley. 1896. Mr. Philip Lake. 1882. Prof. T. Rupert Jones. 1897. Mr. 8. 8S. Buckman. 1883. Dr. John Young. 1898. Miss Jane Donald. 1884. Mr. Martin Simpson. 1899. Mr. James Bennie. 1885. Mr. Horace B. Woodward. 1900. 1886, Mr. Clement Reid. 1901. Mr. A. Vaughan Jennings. Mr. Thomas S. Hall. Vol. 57.) ANNUAL REPORT. Xxix AWARDS OF THE LYELL MEDAL UNDER THE CONDITIONS OF THE ‘LYELL GEOLOGICAL FUND,’ ESTABLISHED UNDER THE WILL AND CODICIL OF THE LATE SIR CHARLES LYELL, Barr., F.R.S., F.G.S. The Medal ‘to be given annually’ (or from time to time) ‘as a mark of honorary distinction and as an expression on the part of the governing body of the Society that the Medallist (who may be of any country or either sex) has deserved well of the Science, —‘ not less than one third of the annual interest [of the fund] to accompany the Medal, the remaining interest to be given in one or more portions at the discretion of the Council for the encouragement of Geology or of any of © the allied sciences by which they shall consider Geology to have been most materially advanced, either for travelling expenses or for a memoir or paper published, or in progress, and without reference to the sex or nationality of the author, or the language in which any such memoir or paper may be written.’ 1876. Prof. John Morris. 1877. Sir James Hector. 1878. Mr. George Busk. 1879. Prof. Edmond Héhert. 1880. Sir John Evans. 1881. Sir J. William Dawson. 1882. Dr. J. Lycett. 1883. Dr. W. B. Carpenter. 1884. Dr. Joseph Leidy. 1885. Prof. H. G. Seeley. 1886. Mr. William Pengelly. 1887. Mr. Samuel Allport. 1888. Prof. H. A. Nicholson, 1889, 1890. 1891. 1892. 1893. 1894. 1895. 1896. 1897. 1898. 1899. 1900. 1901. Prof. W. Boyd Dawkins. Prof. T. Rupert Jones. Prof. T. McKenny Hughes. Mr. George H. Morton. Mr. E. Tulley Newton. Prof. John Milne. Rev. J. F. Blake. Dr. A. Smith Woodward. Dr. George J. Hinde. Prof. Wilhelm V*¥ aagen, Lt.-Gen. C. Af. McMahon. Mr. John E¢tward Marr. Dr. RamsafY H. Traquair, OF THE Dr. C. I. Forsyth-Major. Mr. George W. Lamplugh. Mr. Edwin A. Walford. Miss Catherine A. Raisin. Mr. Percy F. Kendall. Mr. Benjamin Harrison. Dr. William F. Hume. Dr. Charles W. Andrews. Mr. W. J. Lewis Abbott. Mr. William H. Shrubsole. Mr. Frederick Chapman. Miss Gertrude L. Elles. Mr. Alexander McHenry. Xxx PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, AWARDS OF THE BALANCE OF THE PROCEEDS ‘LYELL GEOLOGICAL FUND.’ 1876. Prof. John Morris. 1891. 1877. Mr. William Pengelly. 1891. 1878. Prof. Wilhelm Waagen. 1892. Prof. J. W. Gregory. 1879. Prof. H. A. Nicholson. 1892. 1879. Dr. Henry Woodward. 1893. 1880. Prof. F. A. von Quenstedt. 1893. Mr. Alfred N. Leeds. 1881. Prof. Anton Fritsch. 1894. Mr. William Hill. 1881. Mr. G. R. Vine. 1895. 1882. Rev. Norman Glass. 1895. 1882. Prof. Charles Lapworth. 1896. 1883. Mr. P. H. Carpenter. 1896. 1883. M. Ed. Rigaux. 1897. 1884, Prof. Charles Lapworth. 1897. Mr. Joseph Lomas. 1885. Mr. A. J. Jukes-Browne. 1898. 1886. Mr. D. Mackintosh. 1898. Mr. Henry Woods. 1887. Rey. Osmond Fisher. 1899. 1888, Mr. Arthur H. Foord. 1899. Mr. John Ward. 188. “ixXMr, Thomas Roberts. 1900. 19. M. Lounis Dollo. 1901. Dr. John W. Evans. 190. Mr. C. Davies Sherborn. 1901. Vol. 57.] ANNUAL REPORT. | Xxxl AWARDS OF THE BIGSBY MEDAL, FOUNDED BY THE LATE Dr. J. J. BIGSBY, FBS. F.GS. To be awarded biennially ‘as an acknowledgement of eminent services in any depart- ment of Geology, irrespective of the receiver’s country; but he must not be older than 45 years at his last birthday, thus probably not too old for further _ work, and not too young to have done much.’ 1877. 1879. 1881. 1883. 1885. 1887. 1889. Prof. Othniel C. Marsh. Prof, Edward D. Cope. Prof, Charles Barrois. Dr. Henry Hicks. Prof. Alphonse Renard. Prof. Charles Lapworth. Mr. J. J. Harris Teall. 1891. 1893. 1895. 1897, 1899. 1901. Dr. George M. Dawson. Prof. William J. Sollas. Mr. Charles D. Walcott. Mr. Clement Reid. Prof. T. W. Edgeworth David. Mr. George W. Lamplugh. AWARDS OF THE PROCEEDS OF THE BARLOW. JAMESON FUND, ESTABLISHED UNDER THE WILL OF THE LATE Dr. H. C. BARLOW, F.G.S8. ‘ The perpetual interest to be applied every two or three years, as may be approved by the Council, to or for the advancement of Geological Science.’ 1879. 1881. 1882. 1884. 1884. 1886. 1888. 1890. ' 1892. Purchase of Microscope. Purchase of Microscope-lamps. Baron C, von Ettingshausen. Dr. James Croll. Prof. Leo Lesquereux. Dr. H. J. Johnston-Lavis. Museum. Mr. W. Jerome Harrison. Prof, Charles Mayer-Eymar. 1893. Purchase of Scientific In- 1894, 1896, 1896. 1898. 1900. 1900. struments for Capt. F. E. Younghusband. Dr. Charles Davison. Mr. Joseph Wright. Mr. John Storrie. Mr. Edward Greenly. Mr. George C. Crick. Prof. Theodore T. Groom. XXXil PROCEEDINGS OF THE GEOLOGIOAL socleTy. [May 1gor, Estimates for INOOME EXPECTED. £ 8s. ad. Sate Compositions). gee. sivas soe Cereb seers Bo - 90 0 0 Due for Arrears of Admission Fees ..... saawe LOMO Admission Bees, fO01 yee ic cite nc a seek 207 18 O ——_———— 327 12 0 Arrears of Annual Contributions ............ 168 -0)20 Annual Contributions, 1901, from Resident Fel- lows and Non-Residents... cc. . ce esos 1700 "O70 Annual Contributions in advance ............ 45 0 0 — 1918 0 0 Sale of Quarterly Journal, including Longmans’s ACCOUNG 2), cairn ee eye clot et a minh alsl ede eae Mies he ae 150 0 0 Sale of Transactions, Library Catalogue, General Index, Hutton’s ‘ Theory of the Earth’ vol. iii, Hochstetter’s ‘New Zealand,’ and List of HM OWS oi anjs ca oe wanker nara cotesajuibee « sehciy tan Rene od OO Dividends on £2500 India 8 per cent. Stock .. 75 0 O Dividends on £300 London, Brighton, & South Coast Railway 5 per cent. Consolidated Pre- FETENEe SLOG. Hejske aise sl hia cin es clane Get ofa ete 15 0 0 Dividends on £2250 London & North-Western Railway 4 per cent. Preference Stock ...... 90 0 0 Dividends on £2800 London & South-Western Railway 4 per cent. Preference Stock ...... 112" Ow Dividends on £2072 Midland Railway 23 per cent. Perpetual Preference Stock .......... 5116 0 ——_— 34316 0 2829 8 0 Balance against the Society . ...<..s)d.ems eae eee ike 467 5 0 £3296 13 0 Note.—The following Funds are available for Extraordinary Expenditure :— Sy OSes Balance in the Bankers’ hands at December 31st, 1900: On ‘Current Account: 0-2 .cissh, scnch esterase sees ee erect 122 17 me On Deposit Account’ y(n sce -neeeeestocce eet ee 250 0 0 Balance in the Clerk’s hands at December 31st, 1900 ............ 15 Seas £388 14 10 Vol. 57.] FINANCIAL REPORT. XXxUi the Year 1901. EXPENDITURE ESTIMATED. pa Pi Ate oe House Expenditure : UPR cig vir wb a0 caiisiele Sabiduesatedibeiddedascetvandedded 15 0 MT EM UGS RIVCE (fies 00 ot eanapisiia Siaee-beeeavceiieenins 15: 00 TEL SG 7G) LUTE Oa Ra nese eer Ce eae 40 0 0 BEE erst ecient vied O Piptary (books and, Windiney. 6.5 6. bce s es oe os wa tnt aki 280° 0.10 International Catalogue of Scientific Literature .......... 60 0 0 PRISER SEMI) atest eigi a) Noesretie) s atore'e'> 8S vee c aw biel eee hs os 5 0. 0 Publications : Quarterly Journal, including Commission on RS ees cia ecient dn Aston s eine daideat oult 900 0 0 Record of Geological Literature ............... 130 0 0 IGE AO EMMI LO WERE ccrccclncorccrercecsee re ences see 35 0 0 Postage on Journal, Addressing, ete. ......... UN Ua Abstracts, including Postage ............cessesee 110) 0-0 1265 0 0 Estimate of Ordinary Expenditure .............-0e.ee: 2770 8 O Cost of Redecoration of the Society’s Apartments........ -500 0 0 Slee mie Lipit mstalahOn. sek ce al nee eee owen ae 26 5 O £3296 18 0 W. T, BLANFORD, Treasurer. January 26th, 1901. XXXIV PROCEEDINGS OF THE GEOLOGICAL society. [May 1go1, Income and Expenditure during the REOEIPTS. To Balance in hands of Bankers at January Ist, 1900: On Current Account ............ 146 5 10 On. Deposit Account ............ 250 O 0 ,, Balance in hands of Clerk at January 1st, OOO peeks Sieh sea on ek cae Caras 24 8 0 420 13 10 », Compositionss 34.) 3a. fe. foo eo oe ke oe 103 0 0 ,, Admission Fees: INEEGAES \ fo aicccckGnnenenmeae Gece nee 44 2 0 Carrent 4 i: cehe eae ee 245 14 O — 289 16 © ,, Arrears of Annual Contributions .... 169 2 0 ,, Annual Contributions of 1900, namely: Resident Fellows .................. 1693 13 0 Non-Resident Fellows ............ 6 6 0 ,, Annual Contributions in advance .... 5412 0 — 1923 13 0 ,, Publications : Sale of Journals, Vols. i to lv *............... 102, 0.6 <5, sournal, Viol, vi) Goeth ei ss Ack 47 197 16 » ‘teolosieal Wan’. i252, s dubrary Ostalopue =. (cccsces sc. te 1 ead jo {Mast OPMeH Owes een csasacce co cicscce as 4 0 », General Index to Quarterly Journal, VOLS tOAL esc eeccchakkl oman S: 15) 16 ,, Hutton’s ‘Theory of the Earth’ MOL, MR Res eee eek ace ee eee 16:49 ; Hochstetter’s ‘New Zealand’ ...... 60 —-————. 156 13 9 ~ nimcome. Tax Repayment) 9.000 eee. eae il 12a », Dividends (less Income Tax) on £2500 India 3 percent. Stock .. 7117 6 £300 London, Brighton, & South Coast Railway 5 per cent. Consolidated § Preference SDE Eh pA eager 3-2! 14 8 9 £2250 London & North-Western Railway 4 per cent. Pre- ference Stock .......... 86 12 6 £2800 London & South-Western Railway 4 per cent. Pre- ference Stock ..:.. 2... 107 1620 £2072 Midland Railway 22 per cent. Perpetual Preference Stock 2s. heutnem ewe 4917 2 ——_———— 330 11 11 » Interest on Deposit: 2i¢c.25. ese aoe ee eee 1412 7 », Amount refunded by H.M. Office of Works for alterations to Wavatory . "2c tios ess ae ee 200 0 0 * Due from Messrs. Longmans, in addition to £3450 18 1 the above, on Journal, Vol. lvi, etc. ...... £85 1 0 ee Vol. 57. FINANCIAL REPORT. XXXV Year ended December 31st, 1900. : PAYMENTS. By House Expenditure: Pre os Be Ed Mee re ors on cats 2 soem wdtsdleeadeldesiss sebaaeaees 15,0 LDS, LESTE 20 a en ee ae Ls 0: 0 EMINENT 5 oes cecucad-cselesesadedecane 16154 Legacy Duty on Prestwich Bequest of Books 1 0 O LEAS sc ssel0d: SURG Se ACE Ieee 24.19 O NNR Sed see's We ann Suicidclanva ese ovdcededies 35 10 6 Braiiieo aNd LC PAITs <2. .5 04. tecc.cccscsssessves 29 8 6 House-repairs and Maintenance ............... 20°15, 6 Paar leaMN GS Fo. ccspeensesececesdsccsccdons 12 14 6 Washing and Sundries:..........2.cccacscovsorees 33 16 10 BRCM COMES (hic... lndac.deecsevansasccesiae 20 10 11 ——— 216 6 1 » Salaries and Wages, ete. : PRARIS EMG SCCECUALY. < .ccek aie occas ai ceCecceacssceu’ 325 0 0 mf Half Premium of LifeInsurance 1015 0O PBA AGHOEATAAIY 2. cies cfecies 8 FEO JO 4800) — ‘qu00 red g AVMITEY UTO}SO AA -YON F Wopuo'yT FESls > ET BG Tt sduruuer ueysned poyT Vy “TIC s e UL po}SeaAUl pun oy} UO (xB, PULODU]T sse[) SpUSpLAT(T ue O OL OL ‘TePOW Pur ‘PIOLysuepIoN YAMA FOP V worse oF Prvay kg ]/9 8106 °*°°'''' OOGT ‘3ST Axenuer ye sroyTE” oY} 78 COUUTPY OL, pes. > "SINGWAV "8 = ‘SLdIHOaY ‘ENNOOOY Lsnuy, “ano TVOINVOTOUL) NOSIHOUATA, , 1) | ia 4215 5 ILL v9F © SL Ie °°'' OOGT ISTE tequicseg 48 stoyus_ oy} 4B coURTeT Net ee Xb oumvomy & tues ou zo quowdedey 8 ELIS ‘th MOM puvpanyy, es100p) “IP OF preay “ 1TT ol og (°°°'* 40039 “quea tod g Aqun0( eitysdueEy SLOLF Cer laOlese ce ee ee Seg) 1B Ul poySoaUl pun oy} Uo (xBy, PWODU] sso) SpUoprAld us QAOIK) ‘JOG 0} popleae [epoy PlOH SULyLIys Jo ys0H fg}g ¢ @& °''°''° OOGL 481 Arenuve ye sioyuLg ot} 48 eoUBlLa OL, pate ‘SINAWAV p ‘8 ¥ ‘SLaIHONY “ENNODOY LST , GNOY NOILVNOG NOLSV'TTIO MA s ‘0061 ISTE aquasag < spung ysn4y fo puawaznjs : f hiuonun ‘stonpny | _ Old NOLTH ‘9 “a | ie NOLMONOW ‘M HOVYOH : iL GUOANV TE LM ‘20188 0} Way} pug pure ‘sn 07 pojueserd syunvd0V puUv SYOOg oY} YILA 4U9UIEZeIG S14} peredutoo QAR 9 AA. 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XXX1x AWARD OF THE WoLLASTON MEDAL. In handing the Wollaston Medal, awarded to Prof. CHARLES Barrors, F.M.G.8., of Lille, to Sir Arcursatp Gerxie, for trans- mission to the recipient, the PrestpENntT addressed him as follows :— Sir ARCHIBALD GEIKIE,— In these days of specialization few men are endowed with those faculties which enable them to contribute with marked ability to all branches of our many-sided science; but among those few Prof. Barrois must unquestionably be ranked. In the Monograph on the Calcaire d’Erbray and many other papers he has established his reputation as a paleontologist ; in numerous memoirs on the Granitic and Metamorphic Rocks of Britanny he figures as an accomplished petrologist ; while in the many geological maps of the same district he has constructed a lasting monument to his skill and energy as a geological surveyor. His published work represents a vast accumulation of facts carefully observed, clearly described, and lucidly arranged. More than this, it is often full of suggestiveness. He has had the satis- faction of initiating lines of research which have been followed up with great success by others. It was he who first taught us how to zone our English Chalk by | the aid of the fossils which it contains, and the friendships which he formed during the progress of that work have been strengthened by the lapse of time. He might repeat with truth the words of another visitor to these Islands from the other side of the Channel : vent, vidi, vrcr. In his recent publications on Britanny he has correlated the breadth and character of the metamorphic zones surrounding the granitic masses with the thickness of the cover under which the intrusions took place, and has suggested ideas that may prove of great importance in connexion with such questions as the origin of the crystalline schists and igneous magmas, But he has aided the progress of geology in other ways than as an original worker. The illustrious pupil of an illustrious master, he has contributed to maintain the great reputation of Lille as a centre of geological teaching; while his extensive knowledge and exceptional organizing ability have ever been at the disposal of the International Geological Congress and kindred associations. Many years have elapsed since I had the privilege of making his d 2 xl PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, acquaintance, and it is, therefore, with the greatest pleasure that I now ask you to transmit to him the Wollaston Medal, which has been awarded to him by the Council as a mark of their appreciation of the great services that he has rendered to all branches of geological science. Sir ARCHIBALD GEIKIE replied in the following words :— Mr. PResipENT,— It has been to my friend Prof. Barrois a matter of very keem regret that he is prevented from being here to-day, to renew his personal relations with the Fellows of the Geological Society, and to receive from them the highest distinction which it is in their power to bestow. We must all deeply sympathize with him in the causes that deprive us of his presence. Bowed down by one of the greatest afflictions that can befall a father—the death of a son in the full bloom and promise of early manhood—he has man- fully struggled with his numerous duties, until at last his health has given way under the strain. Let us hope that he may soon be restored to his former vigour, and be able to resume the researches: in Britanny and the detailed description of them on which he has: so long been engaged. He has asked me to receive this Medal for him, and I count it a great privilege and honour to be the inter- mediary between the Geological Society of London and one of the most distinguished and widely esteemed geologists of Europe. Prof. Barrois has sent a letter of thanks, which I will now read :— ‘Mr. PRESIDENT,— ‘Allow me to express my gratitude for the new honour which the Geological Society has bestowed upon me, by the award of the Wollaston Medal, as I cannot but recall that the Council has on a former occasion encouraged me in my scientific work by the award of the Bigsby Medal. ‘I have since made long wanderings along the Channel cliffs on both sides, from Chalk to granite, for the sake of science, in the steps of De la Beche, Fitton, Godwin- Austen, and the founders of stratigraphical geology; and it is for me a very un- expected event to see my name written to-day, for ever, with theirs, in the Proceedings. of the Society. ‘No distinction can be more gratifying to a geologist than to receive its highest award from the Council of the illustrious Society which for nearly a century has extended our knowledge in every branch of geology, and promoted progress in every part of the earth. I so greatly appreciate this great honour, that I feel as if the work that I have been able to accomplish was too small to merit the Wollaston Medal, granted as a reward, but rather as a friendly incitation to go on in my labour— “ypward and onward.”’ ‘Lille, February 9th, 1901. ‘CHARLES BaRROIS.’ Pe oe Vol. 57.] ANNIVERSARY MEETING—-WOLLASTON DONATION FUND. Xli AWARD oF THE Wo .taston Donation Funp. _ The PresipEent then presented the Balance of the Proceeds of the ‘Wollaston Donation Fund to Mr. Arraur Watton Rows, M.B., M.S., of Margate, addressing him as follows :— Dr. Rowr,— It will, I am sure, be a source of gratification to you to be associated with Prof. Barrois on the present occasion, for you have ‘done much to confirm and extend the principles which he first applied to the elucidation of the structure of the English Chalk. ‘We recognize, however, that, although your work has been of very great stratigraphical importance, your main object is biological, and that the task you have set yourself is that of working out the evolution of organic forms during the Upper Cretaceous Period. In your paper on Micraster you have set an example which I trust will be followed. You have shown how it is possible to deal with a vast mass of material, so as to bring out the main facts of evolution, without burdening science with hosts of new names and Jong lists of synonyms. By the application of the dental engine to the preparation, and of microphotography to the illustration, of fossils, you have also rendered signal service to science. The Council of the Geological Society, in making this Award, have been desirous of expressing their gratitude to you for the work that you have already accomplished, and their lively sense of favours ‘to come. AWARD OF THE MurcHison MepDAt. In handing the Murchison Medal, awarded to Mr. Atrrep JoHN JuKEs-BRrownE, B.A., of H.M. Geological Survey, to Mr. W. Wurraxer for transmission to the recipient, the Presrpenr addressed him as follows :— Mr. WHITAKER,— Mr. Jukes-Browne, whose absence we all deeply regret, has ‘aided the progress of geology in many ways. His numerous writings on the Upper Cretaceous Rocks are too well known to = xl PROCEEDINGS OF THE GEOLOGICAL socieTY. [May 1901, make it necessary for me to refer to them in detail. He has, from the first, recognized the enormous importance of associating paleontological with stratigraphical work, and by original research, as well as by a critical study of the writings of others, has made himself master of the geology of that period to which he has especially devoted himself. But he possesses also a good all-round knowledge of geology. His Handbooks on Physical and Historical Geology have been of great service to students, and his suggestive work on the Building of the British Isles has been the means of directing attention to many problems of considerable theoretical interest. There is yet another way in which he has rendered great service to geology, and that is as a stimulator of work in others. I am sure that no one will be more ready to acknowledge this than Mr. William Hill, with whom Mr. Jukes-Browne has been so long associated. In recognition of these many services to our science, the Council have awarded to him the Murchison Medal, which I, an old College friend and fellow-student, now ask you to transmit to him with our heartiest good wishes. Mr. WuitakeER, having expressed his gratification at the privilege of receiving the Medal on behalf of an old colleague and valued friend, read the following extracts from a letter which he had received from Mr. Juxrs-BRrownE :— ‘I beg you to convey to the Council of the Geological Society my deep appreciation of the honour conferred upon me by the award of the Murchison Medal, and my great regret that the state of my health makes it impossible for me to be present in person to express my acknowledgments. ‘That such work as I have been able to accomplish should be thought worthy of this high reward is not only a present gratification, but will be an incentive to show myself more worthy of such recognition. I feel also that I have been specially fortunate in my friends, and that without the assistance of two of them in particular—Mr. W. Hill and Prof. J. B. Harrison—many of the investigations in which I have been concerned would have been incomplete. - ©J should like further to say that the pleasure of receiving the Murchison Medal on. the present occasion is much enhanced by the knowledge that the Wollaston Medal is at the same time awarded to my old friend, Prof. Barrois, whose zonal work among: the Cretaceous Rocks of England and France has added so much to our knowledge of those rocks.’ ——— Vol. 57.] ANNIVERSARY MRETING—-MURCHISON GEOLOGICAL FUND. xliii AWARD oF tHE Murcuison GroLoeicaL Funp. The PrestpEent then handed the Balance of the Proceeds of the Murchison Geological Fund, awarded to Mr. Tuomas SarcEanT Hatt, M.A., of Melbourne, to Prof. J. W. Jupp, for transmission to the recipient, addressing him as follows :— Professor Jupp,— In awarding the Balance of the Proceeds of the Murchison Fund to Mr. Hall, the Council is desirous of recognizing the value of his many contributions to Australian geology, and especially of his detailed researches on the Zonal Distribution of the Graptolites of Victoria. His work has thrown much light on the Lower Paleozoic history of Australia; while his discovery of the coincidence of the Ordovician auriferous belts with certain graptolitic zones is an illustration of the bearing of paleontological research on economic questions. His application of the zonal method of research to the Kainozoic deposits of Victoria has done much to elucidate the later geological history of the Colony, and his bibliographic labours have, I am told, greatly facilitated the work of his scientific colleagues in Victoria. We hope that this Award will be of some assistance to him in further researches. AWARD OF THE LyeELt MEDAL. In presenting the Lyell Medal to Ramsay Heartey Tragqvair, M.D., F.R.S., of Edinburgh, the Presrpenr addressed him in the following words :— Dr. Traquarr,— The Council of the Geological Society, in presenting you with the Lyell Medal, desires to express its sense of the great value of your many contributions to paleontology. More than thirty years have elapsed since the publication of your first papers on Fossil Fishes, and during the whole of that period you have been giving evidence of your keen insight into the structure of these interesting forms of life. I can only refer to one or two of your more important works. Your memoirs on the structure of the Paleoniscide and Platy- somide are, I believe, masterpieces of descriptive paleontology, and must for ever remain most valuable works of reference. Of great importance, from a geological point of view, have been your researches xliv PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, bearing on the Fish-Fauna of the Old Red Sandstone of Scotland. You have not only shown the complete divergence between the fauna of the Orcadian Series and that of the Lower Old Red Sandstone south of the Grampians, but you have also pointed out that in certain areas the fishes in different divisions of that formation are arranged in life-zones—a fact which has been of service to the field-geologist. Your last, and perhaps your greatest, work is your monograph on che remarkable Fossil Fishes from the Silurian Rocks of the South of Scotland. Your keen insight and wide knowledge of fossil ichthyology enabled you to show, among other points, that the group of the Heterostraci, which hitherto contained only the Pteraspide, must be considerably enlarged, and that a transition could be seen from the shagreen-covered Ccelolepide to the plate-covered Pteraspide. You have also arrived at the conclusion that the Heterostraci, though not actual Selachians, had in all probability a common origin with the primitive Elasmobranchs. These results must be of the highest interest to biologists. I have great pleasure in handing to you the Medal, together with our best wishes that you may long be spared to carry on your most valuable researches. Dr. Tragvarr replied as follows :— Mr. PREsrDENT,— Permit me to thank the Council of the Geological Society for the honour which they have this day conferred upon me, and you, Sir, for the kind words which you have spoken regarding my work. | Tf am much gratified to hear that some of that work has been of use to the stratigraphical geologist, as it is indeed impossible for the paleontologist who has himself collected in the field, to avoid taking an interest in his subject from the geological standpoint also. The impulse, however, which led me to take up Fossil Fishes as a speciality was entirely biological. While still a boy at school I broke open an ironstone-nodule containing a piece of a Paleoniscid fish, and was thereupon seized by an intense curiosity to know how the bones of its head were arranged. As I did not find the information that I desired in the books, I resolved some day to try and work out the problem myself. Need I remark that, when in due time I got fairly to work on the subject, I found that fossil ichthyology presented a field sufficient to supply not only myself, but many others, with original work for our lifetimes ? : Vol. 57.] ANNIVERSARY MEETING—LYELL GEOLOGICAL FUND. xlv If the work that I have accomplished in this field falls far short of the realization of early dreams, it is still gratifying for me to find that I have been able to do enough to merit this expression of the Society’s approbation. AWARDs FROM THE LyELL GroLogicaL Funp. In presenting one half of the Balance of the Proceeds of the Lyell Geological Fund to Joan Witti1am Evans, D.Se., LL.B., the PRESIDENT addressed him as follows :— Dr. Evans,— Half the Balance of the Proceeds of the Lyell Fund has been awarded to you, in recognition of the importance of your geological work during the last ten years. Your visit to an almost unknown part of Brazil, and several years’ residence in India, have enabled -you to make observations and to collect specimens of great value to our science. The papers which you have already published in our Journal on the Matto Grosso District, and on the Calcareous Sand- ‘stones and Monchiquites of North-western India, are evidence of your capacity for original work. We trust that this Award may aid you in publishing the results of investigations that you are known to have carried out while engaged — in the Survey of the State of Junagarh (Kathiawar), and will encourage you in further work. In handing the other half of the Balance of the Proceeds of the Lyell Geological Fund, awarded to Mr. Atexanper McHenry, of the Geological Survey of Ireland, to Sir Arcursatp Gxrkie for transmission to the recipient, the PrestpEnr addressed him in the following words :— Sir ARCHIBALD GEIKIE,— Mr. McHenry’s claims to recognition are well known to you, and the fact that you receive the Award of a moiety of the Balance of the Proceeds of the Lyell Geological Fund on his behalf, isa proof that you cordially endorse the action of the Council. For forty years he has laboured to advance our knowledge of Irish Geology as a member of the Geological Survey ; first as a collector of fossils and rock- ‘specimens, and afterwards as a member of the Surveying Staff. _ Most of his work has been published in the Maps and Memoirs of xlvi _ PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, the Geological Survey, to which he has devoted himself, as you yourself have said, with admirable loyalty and enthusiasm. One of his most useful labours has been the preparation, in conjunction with his former colleague, Prof. Watts, of a Guide to the Collection of Rocks and Fossils belonging to the Geological Survey of Ireland. His extensive and accurate knowledge largely contributed to make this work a most valuable compendium of Irish Geology. We hope that this Award will act as an encouragement to him, and be of some assistance in further work. Sir ARCHIBALD GEIKIE, in reply, said :— Mr. Presipent,— On the part of my old colleague, I have to express to the Geological Society his best thanks for the recognition of his work which is expressed in this Award. Next to myself he is the member of the Geological Survey who has been longest on the staff. His whole life has been devoted to his official duties, and he has * only now and then ventured to make his appearance in non-oflicial print. His labours are thus chronicled in the Maps, Sections, and Memoirs of the Geological Survey of Ireland, and are probably familiar to comparatively few geologists. He has been content honestly and strenuously to do his duty, with a loyalty that has never flinched, and with an enthusiasm that seems to wax higher as the years go past. To such a man you may well believe that recognition from the Geological Society is as precious as it 1s un- looked for. It will nerve him with fresh energy for the task of revision of the Superficial Deposits of Ireland on which the Survey is about to enter; for it will show him that his work is not only known to his colleagues, but is appreciated by the leaders of geological science here. AWARD oF THE Biesspy MEDAL. In presenting the Bigsby Medal to Mr. Grorez WiLLIAM LametueH, of H.M. Geological Survey, the Presrpent addressed him as follows :— | : Mr. Lamprven,— In 1891 the Council of the Geological Society recognized the value of your work on the Glacial Deposits of Yorkshire and on the 1 nel Vol. 57.] ANNIVERSARY MEETING—BIGSBY MEDAL. xlvil Speeton Clay by an Award from the Lyell Fund. Since that time you have still further extended our knowledge of the Lower Cretaceous Rocks of Yorkshire and Lincolnshire, and have furnished Prof. Pavlov with material which has enabled him to throw con- siderable light on the physical conditions and migrations of the Cephalopod Fauna during the period represented by these rocks. Your early work was done in the midst of an active and successful business career, which you gave up, somewhat against the advice of your friends, to join the Geological Survey and devote all your energy to the progress of science. Of late years you have been working in the Isle of Man, and the map of that island which you have produced is a striking proof of your skill as a geological surveyor. Its publication leads us to look forward with great expectations to the forthcoming memoir. In awarding to you the Bigsby Medal, the Council feel that they are placing it in safe hands. You have done much, and they confidently expect that you will do more. Mr. Lamptvexu replied in the following words :— Mr. PREsIDENT,— | It is not without a proper sense of responsibility that I receive this Medal. The terms of the Award leave no doubt that, while it is intended to some extent as a recognition of work already done, it is essentially intended as an incentive to further work, and implies a certain obligation in this respect—which you, Sir, in your en- couraging words have not attempted to lighten. The recipients of this Medal in the past have always fulfilled the obligation, and it will indeed be a satisfaction to me if it be in my power to prove my fitness for the trust reposed in me by this Award. You have made reference to my altered circumstances since the time, ten years ago, when my earlier work received kindly recognition from the Council of this Society ; and it may, therefore, be permitted to me to confess that, in deciding to devote my whole energies to geological research, I felt some misgiving lest the studies which had proved so congenial as a recreation should take on another aspect when made the main occupation of my life. But the misgiving has proved groundless ; the wider opportunity, so far from blunting my interest in these studies, has brought fresh zest, and on every side has opened up vistas of promising work for the future. xlvili PROCEEDINGS OF THE GEOLOGICAL sociETy. [ May 1gor, THE ANNIVERSARY ADDRESS OF THE PRESIDEN qT, J.J. Harris Tear, Esq., M.A., V.P.R.S. The greatest loss that we have sustained during the past year is one which we share in common with the nation and the world. Our noble QUEEN Vicroria, of ever-glorious memory, has passed away, Robed in the simple splendour of her life. As a Society we have to deplore the loss of a past-President, two Foreign Members, and many Fellows who have contributed to the progress of geology during the Victorian era, now, alas! for ever closed. His Grace the late Dux or ARGYLL was too well-known in other spheres of activity to render it necessary that we should record the ordinary biographical details of his life in the pages of our Journal. Born in 1823, he was elected a Fellow of this Society in 1850, and in the following year communicated his classic paper on the Tertiary Leaf-beds in the Isle of Mull. - The intercalation of the plant-bearing strata with the sheets of basaltic lava was clearly established in this communication, and thus a fact of vital importance in connection with the chronology of the volcanic eruptions of the Inner Hebrides was placed beyond dispute. _ The clearness and accuracy with which the details of this occur- rence are described and illustrated, by pen and pencil, make one regret that the numerous claims on his time by affairs of State and by the duties connected with the administration of a large domain, prevented him from following up a line of research for which he was obviously so well qualified. His later communications were, for the most part, of a polemical character. He stood out boldly as a champion of the older faiths in opposition to the rapidly-growing ideas on such subjects as Glaciation, Earth-Sculpture, and Evolution; andit must be admitted that on many occasions his keen critical faculty, combined with his extensive knowledge, enabled him to find weak places in the armour of his opponents, while his literary skill and great eloquence often enabled him to drive home his attacks with striking effect. The two addresses delivered during his presidency of this Society are illustrations of his attitude towards the tendency of geological thought at the time. He combated with great force the extreme Vol. 57.] ANNIVERSARY ADDRESS OF THE PRESIDENT. xlix forms of the Glacial Theory, and many of his arguments find supporters at the present day—probably in this very room. _ He has left his mark on the history of our age, and we are proud to think that, in the midst of a busy public life, he found time to carry out at least one original research of great importance, and kept up his general interest in our science till the end. AtpHonse Mitye-Epwarps, the renowned son of an illustrious. father, Henri Milne-Edwards, was born at Paris in 1835, and died, after a brief illness, on April 21st, 1900. He, like so many celebrated zoologists, was trained for the medical profession, and took his degree in 1859. He became Assistant Naturalist at the Muséum d'Histoire Naturelle in 1862, and Professor at the School of Pharmacy in 1865. In 1876 he was appointed Professor of Zoology at the Muséum d’Histoire Naturelle, and in 1892 became Director of that institution, a post which he filled with great distinction until the time of his death. Essentially a zoologist, and as such justly celebrated for his many labours among both vertebrate and invertebrate animals, he brought his wide knowledge to bear upon the problems of paleon- tology. In 1863 he published a paper on fossil birds :—‘ Mémoire sur la Distribution Géologique des Oiseaux Fossiles,’ and his work on the Osteology of the Dodo appeared in 1866; but it was in 1867 that the first part of his great work appeared, ‘ Recherches’ Anatomiques & Paléontologiques pour servir 4 |’ Histoire des Oiseaux Fossiles de la France,’ which was completed in four folio volumes in 1871. This work is a monument of the labour and research of the writer, and still remains a classic of reference: He also wrote the ‘History of the Birds of Madagascar,’ in the great work published by A. Grandidier in 1876-85. Alphonse Milne-Edwards became a Member of the French Academy of Sciences in 1879; and in 1884 he received the gold medal of the Geographical Society of France for his deep-sea explorations. He was elected a Foreign Member of the Zoological Society of London in 1876, a Foreign Correspondent of our own Geological Society in 1882, and a Foreign Member in 1899. (ET. Wy Orro Marrin TorELt was born in Varberg (Sweden), on June 5th, 1828. At the age of 16 he entered as a student at Lund, where he took up the study of natural science, intending to become, like his PROCEEDINGS OF THE GEOLOGICAL SocIETY. [May 1901, father, a physician. In 1858 he became Med. Kand.; but then devoted himself to zoological work, especially to the Geographical Distribution of the Lower Marine Animals. In this field Sven Lovén had already undertaken his epoch-making researches on the difference between present and past times, shown by the fossil fauna of the Bohusland shell-banks. These studies, carried on by Torell under Lovén’s guidance, were the starting-point of his life’s work. During a journey to Switzerland, made in 1856, he was struck by the resemblance of the Alpine moraines to the Drift of Sweden. Thenceforward Torell became a geologist. Combining enthusiasm with the technical knowledge of the true naturalist, he attacked the difficult problem of the Former Submergence of Scandinavia and of the neighbouring lands. At that time he accepted the popular idea of the diluvial origin of the Drift-deposits; but, on closer examina- tion, he gave up this view, though satisfactory evidence was not easy to obtain. | It should not be forgotten that Lund, in Torell’s student days, was deficient in collections, books, and geological instruction. Torell himself largely made up this deficiency. He saw that a true understanding of the bygone Glacial Period could only be gained through the study of the unexplored and still ice-clad Arctic regions. He therefore devoted the following years to this explora- tion, visiting Iceland in 1857, Spitsbergen (in company with Prof. Nordenskidld) in 1858, and Greenland in 1859, thus commencing the long series of Swedish Arctic expeditions. His own latest and most important Arctic voyage was that undertaken, again in conjunction with Prof. Nordenskidld,in 1861. To the cost of these expeditions he devoted a considerable part of the property inherited from his father. Torell devoted the following years to Quaternary geology, gathering around him at Lund a band of enthusiastic disciples. In 1860 he had become Adjunkt in Zoology, and in 1866 Professor of Zoology and Geology. The value of his work, however, caused him to be appointed, in 1870, Chief of the Swedish Geological Survey, in this post following Axel Erdmann. On his transference to the capital he took the initiative in the foundation of the Geological Society of Stockholm. For over a quarter of a century, till 1897, he retained his official post, labouring both for science and for the practical application of geology to Swedish industries. He died on Sep- tember 11th, 1900. Both in England and in Germany Torell was well known and liked ee. Vol. 57.] ANNIVERSARY ADDRESS OF THE PRESIDENT. hi for his enthusiasm and the ready courtesy with which he imparted his great store of experience. In Germany he showed that the Drift was mainly of glacial or fluvio-glacial origin, not marine, as had been thought. To England he made several visits, and pointed out how large a proportion of our East-coast Drift was probably of Scandinavian origin. He recognized various erratics found in Norfolk and Yorkshire as belonging to rocks peculiar to scattered islands in the Baltic, or to the neighbourhood of Christiania. Torell was not a ready writer, and his publications scarcely represent the work that he accomplished. This is to be measured rather by the commanding position which Scandinavia has taken in Arctic Exploration and in Glacial Geology. [C. R.] Joun Awnstiz, B.A., was an Associate Member of the Institute of Civil Engineers, and is best known to geologists by his work on ‘The Coalfields of Gloucestershire & Somersetshire, & their Resources, 1873. He gained his knowledge of these districts while working under the direction of Prestwich, who, as one of the members of the Royal Coal Commission, had been requested to report on the quantities of coal, wrought and unwrought, in the coalfields. Mr. Anstie prepared materials for some of the vertical and hori- zontal sections published by the Geological Survey, in illustration of the same coalfields. He died on January 8th, 1900. (LES E. We H. Kresy Atkinson, who joined the Society in 1886, was associated with the ‘Colliery Guardian’ for more than forty years, and had been for twenty-four years its Editor. He died on March 15th, 1900, aged 83. Grorce CLemMENTSON GREENWELL, M.Inst.C.E., became a Fellow of this Society in 1858. He was distinguished as a mining engi- neer, and his ‘ Practical Treatise on Mine Engineering,’ of which the first edition was published in 1855, has always been regarded as a.standard work. Born at Newecastle-upon-Tyne on July 25th, 1821, he was educated partly in that city, and partly at the University of Edinburgh. In 1844 he commenced work among the collieries in County Durham, and in 1853 was appointed sole manager of the Countess Waldegrave’s collieries at Radstock. Here he made a particular study of the Somerset Coal-Measures, concerning which hi PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, but little had been published since the famous paper by Buckland & Conybeare which appeared in our Transactions (1824). Mr. Greenwell’s observations were printed in the Transactions of the North of England Institute of Mining Engineers, in those of the South Wales Institute of Engineers, and of the Manchester Geological Society. The most important of his works on the dis- trict was that published in conjunction with his friend, Mr. James McMaurtrie, F.G.S., on ‘The Radstock Portion of the Somersetshire Coalfield’ (Svo, Newcastle-upon-Tyne, 1864). Leaving Radstock in 1863, Mr. Greenwell was occupied for some years in the management of collieries in Cheshire, until 1879, when he devoted himself entirely to consulting practice. He died in November 1900, in his 80th year. [HB We Commander the Hon. Wit1i1am Grimston was the second son of James Walter, second Earl of Verulam. He was born on January 7th, 1855, and entered the Royal Navy in 1868, from which he retired in 1885 through ill-health, brought on by a gallant action which resulted in the rescue of a seaman who had fallen overboard. He was elected a Fellow of this Society in 1897, and died on May 10th, 1900. Cuartes Jonn Aprian Meyer was a Fellow of old standing, having been elected into the Society in 1869, though of recent years we have had him rarely among us. He was born on May 28rd, 1832. His inherent love of natural history was fostered by the residence of his family in the country, near Godalming, where his interest was at first especially attracted to bird-life. He there com- menced to collect fossils from the Lower Greensand of the district,. and in so doing laid the foundations of that intimate knowledge of the Lower Cretaceous Rocks of the South of England which enabled him afterwards to add to our literature a valuable series of papers. which will ever remain as a permanent memorial of his labours. As in the case of many another worker who is gratefully remembered in our science, it was only the leisure spared from other duties that. he could devote to his geological investigations, for in July 1857 he entered upon a post in the Civil Service, in the Accountant-General’s Office, in a division which was subsequently transferred to the Chancery Courts under the title of the Supreme Court Pay Office. During his holidays he repeatedly visited such localities as promised to yield fresh information respecting the rocks in which he was Vol. 57; | ANNIVERSARY ADDRESS OF THE PRESIDENT. liit particularly interested, and was thus able in his papers to look beyond the limits of the object of his immediate investigation and to indicate its general relations. As a fossil-collector he was remarkably successful, and in this respect his services to science are not yet concluded, as his large collection has been presented by the generosity of his sister, Miss C. Meyer, to the University of Cambridge, where no doubt it will continue to supply valuable material to paleeonto- logical workers in the future, as it has already done to Davidson, Lycett, and others in the past. Mr. Meyer’s first paper was a note ‘On the Age of the Black- down Greensand, published in the ‘ Geologist’ for 1863; and this was the first of a series which appeared, at the rate of one or more almost every year, in the same publication and its successor, the Geological Magazine, from 1863 to 1869. Of these papers, three dealt with the Brachiopoda of the Lower Greensand, of which some new species were described ; one gave a careful account of the Lower Greensand of the Farringdon District ; another described, for the first time, the passage of the Red Chalk of Speeton into the underlying clay ; and another discussed most ably the correlation of the Lower Cretaceous Rocks of the South-East and West of England. In the last-mentioned paper Mr. Meyer expressed opinions as to the classification of these rocks differing in some points from those currently held, and his views will require the respectful consideration of future workers in the same field. In 1869 his well-known paper on the Lower Greensand of Godalming was published as a separate pamphlet by the Geologists’ Association, and remains the most detailed account of that neigh- bourhood which has yet been attempted. His first communication to this Society was contributed in 1871, and was a description of Lower Tertiary deposits exposed in excavations at Portsmouth. This was followed by papers in 1872 and 1873 on the relations of the Lower Greensand and Weald Clay, having particular reference to the supposed passage-beds or Punfield forma- tion, respecting which he cleared up some difficulties and miscon- ceptions. In 1874 he contributed to our Journal a most valuable account of the Cretaceous Rocks of Beer Head and the Devon Coast, which has already become one of the classic papers on that district. In 1878, in the pages of the Geological Magazine, he discussed the Micrasters of the English Chalk with that catholicity of view that distinguishes all his work, and marked out the lines of research which have since been pursued with such excellent results. VoL, LVII. € liv PROCEEDINGS OF THE GEOLOGICAL society. [May root, to paleontological science. His latest contribution was a joint paper with Mr. A.J. Jukes-Browne on the Chloritic Marl and Warminster Greensand, in the Geological Magazine for 1894. His papers were evidently written with great care, and are characterized by lucidity of expression and arrangement. Mr. Meyer was quiet and unassuming in manner, and ever courteous and ready to impart any information that he possessed. He served on the Council of this Society between the years 1871 and 1876. He died on July 16th, 1900. [G. W. L.] GroreE Hieurietp Morton, born in Liverpool on July 9th, 1826, was educated at the Paddington Academy, and subsequently at the Liverpool Institute. Though from an early age engaged in business, he devoted all the leisure-time of a long life to geological pursuits, and exerted an influence upon the growth of geological knowledge in his native city which it would be difficult to overestimate. His earliest specimens, collected during boyhood, he identified for himself at the Museum of the Royal Institute, with the aid of the few men who at that early date possessed the requisite knowledge. In 1845 he was mainly instrumental in forming the Liverpool Natural History Society, which, however, had but a short life. In 1859 he organized and temporarily housed the Liverpool Geological Society, holding the office of Honorary Secretary until the year 1885, and that of President during the sessions 1868-69, 1869-70, 1885-86, and 1886-87. During the forty years of his membership he read no less than sixty-two papers before the Liverpool Geological Society, nearly all of which contained original observations on the geology of the neighbourhood; while he found time also to contribute several communications to the Literary & Philosophical Society of Liver- pool, the earliest dating so far back as 1856. In 1863 he collected his observations in one volume, under the title of ‘The Geology of the Country around Liverpool.’ In 1891 he brought out a second edition of this work, which was followed by an Appendix in 1897. This great record of work did not pass unrecognized, and in 1887 he received from the members of the Liverpool Geological Society a handsome testimonial, in appreciation of the great services which he had rendered to local geology. During and after 1864 he had also performed the duties of lecturer at Queen’s College, Liverpool, in a manner which led, in 1868, to the presentation of a testimonial from his students ‘in appreciation of the great assiduity of their teacher of geology.’ Vol.57:] ANNIVERSARY ADDRESS OF THE PRESIDENT. lv In 1899 he put the finishing touches to a work which had occupied much of his life. Few of the exposures of rock made in and about Liverpool had escaped his notice. By systematically recording upon the 6-inch Ordnance map the faults and boundaries of formations thus revealed, he was in a position, after more than forty years’ work, to map the geology of the city with a degree of accuracy unattainable by any other means. In 1899 he allowed copies of those 6-inch sheets to be made for the use of the Geological Survey, the Liverpool Free Library, and the Liverpool Geological Society. He was elected a Fellow of this Society in 1858, and was pre- sented with the Lyell Medal in 1892, in recognition of his long and meritorious services to Geology in the work done around Liver- pool, both on the Triassic rocks and on the Glacial phenomena. He read two papers before this Society, one on Glacial Surface-markings on the Sandstone near Liverpool, published in Quart. Journ. Geol. Soe. vol. xviii (1862) p. 377, and the other on the Carboniferous Limestone of the Country around Llandudno, published in the same Journal, vol. liv (1898) p. 382. He was a constant attendant at the Meetings of the British Association, and served as Secretary to Section C at Liverpool in 1870, and as Vice-President at Southport in 1883. Among Mr. Morton’s latest and most important researches were those in which he established and traced along the North Wales border a zonal and stratigraphical classification of the Lower Carboniferous Rocks, the last contribution to that series of papers being ‘On the Carboniferous Limestone of Anglesey,’ which was read before the Liverpool Geological Society eight months after his death. His field-work was conducted on a true method, for he combined the qualities, self-acquired but of no mean order, of a stratigraphist and paleontologist. His papers embody the history of a long and painstaking career in the field; he wrote simply and briefly, for the purpose of recording original observations, and his writings will place future generations of geologists under a lasting obligation. He died at Liverpool on March 30th, 1900. [A. 8.] A distinguished investigator in that department of Science where Geology borders on Archeology, has passed away by the death of Lieutenant-General Aveustus Hunry Lane-l'ox Pirr-Rivurs, F.R.S. To geologists he is probably best known by his discoveries of flint- implements and bones of Pleistocene mammals in the Thames- Valley gravels at Acton and Ealing. At the time of these e2 lvi PROCEEDINGS OF THE GEOLOGICAL sociETY. [May rgo1, discoveries, which were described in our Journal in 1872, he bore the name of Lane-Fox ; but, on inheriting the Rivers estates at the death of the sixth Lord Rivers, in 1880, he was compelled to assume the name and arms of Pitt-Rivers, in accordance with the will of his great-uncle, the second Baron. Born in 1827, the son of Mr. W. A. Lane-Fox, of Hope Hall, General Pitt-Rivers was educated at Sandhurst, and entered the Army in 1845, During the Crimean War he saw much active service. As a young man he became a great collector of weapons and implements, and ultimately formed an ethnological collection of unrivalled interest. This collection he arranged on scientific principles, so as to illustrate the gradual development of form and, ornament. After publicly exhibiting the collection for some years. in London, under the auspices of the Department of Science & Art, he presented it to the University of Oxford, where a special building was erected for its reception. In 1886 General Pitt- Rivers received from Oxford the degree of D.C.L. It was during his residence at Kensington, some thirty years: ago, that Pitt-Rivers, keeping a careful record of excavations for buildings in his neighbourhood, was led to his interesting discoveries in the Thames gravels. It is noticeable, too, that when visiting Egypt in 1881, he discovered worked objects in chert, embedded. in the indurated gravel of the Nile Valley, on the site of ancient Egyptian tombs at Koorneh, near Thebes. General Pitt-Rivers was an indefatigable explorer of prehistoric: remains, having received his introduction to barrow-digging on the: Yorkshire Wolds, under Canon Greenwell. When he succeeded to: the Rivers estates, he devoted his attention to the exploration of his own property, and his researches are described in four magni- ficent quarto volumes, under the title of ‘ Excavations in Cranborne Chase.’ These volumes were privately printed, and generously vresented to archeological friends and public libraries General Pitt-Rivers imported into his archeological explorations. the scientific methods of the geologist. He observed and recorded the: exact position of every object which was unearthed, taking rigid care to avoid the commingling of relics from different layers. No object, however small or seemingly unimportant, was neglected. Before commencing work, he carefully contoured the ground, so that accurate sections could be drawn ; and at the close of his investiga- tion, he restored the surface to its original form. At the bottom of most of his excavations he deposited a copper medal, designed by Vol. 57.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lvil Sir John Evans, indicating to future explorers that the ground had been disturbed. General Pitt-Rivers held the office of Government Inspector of Ancient Monuments under the Act of 1882. He was elected a Fellow of this Society in 1867, and of the Royal Society in 1876. After many years of declining health, he died at his seat, at Rushmore, near Salisbury, on May 4th, 1900. [BR OoW. eg Rozert RussELt, born on May 24th, 1842, was educated as a civil engineer, and joined the staff of the Geological Survey in 1867. For some years he was occupied, under the late Prof. A. H. Green, in the survey of the Yorkshire Coalfield, and afterwards in the Whitehaven Coalfield. He died at St. Bees on May 9th, 1900, aged 58. Water Percy Siapen died on June 11th, 1900, at the com- paratively early age of 51. He was born near Halifax (Yorkshire) in 1849, and was educated at Marlborough, under Dean Bradley. Apparently without any regular scientific training, his innate love of zoology led him to acquire a wide knowledge of this and collateral sciences. His earliest paper was published in 1877, and for the next 17 years he devoted himself to the study of the Echinoderma, and more especially to the Starfishes. Much of his work was done in conjunction with his friend Martin Duncan. Although his labours were chiefly among the living forms, his intimate acquaintance with these gave him the greater power to deal with the fossils which came under his notice. The outcome of his work was published in the Proceedings of the Royal Society ; in the ‘ Annals & Magazine of Natural History’; in the Journal of the Linnean Society; and in our own Journal; but his great work was doubtless the magnificent volume, of 900 pages and 118 plates, in which he described the Asteroids of the Challenger Expedition. His work among the fossil Echinoderma was of no mean order, as shown by the memoir, produced in collaboration with Martin Duncan, on the collections of the Geological Survey of India, and also his continuation of Thomas Wright’s Memoir on the Cretaceous Asteroids, published by the Palzontographical Society in the volumes for 1890 and 1893. Mr. Sladen was for many years Secretary of the British Asso- ciation Table at the Naples Biological Station; for 10 years he was Secretary of the Linnean Society, and afterwards Vice-President. Iviii PROCEEDINGS OF THE GEOLOGICAL socreTY. [May 1901, He was a Fellow of the Zoological Society, and since 1872 a Fellow of the Geological Society. He was a generous, loving, and trust- worthy friend, and will be much missed by those who knew him best. (ER. Ts Na James THomson, so well known for his researches among the Scottish Carboniferous Corals, was born at Kilmarnock on December 18th, 1823. Of humble parentage he had, when quite a child, to seek employment, and thus contribute to the general support of the family. His education, in consequence, was the outcome of his own strong and earnest nature. The business of his life came to be that of a commercial traveller, in which he continued until upwards of 70 years of age; but his interests were early in life concentrated. on natural-history subjects, and on geology in particular. He became a Fellow of our Society in 1868, and was an old member of the Glasgow Geological Society, to whose Transactions he con- tributed papers on the geology of Campbeltown, Islay, Arran, etc. His chief work, however, was the collection and description of the Corals from the Carboniferous Rocks of Scotland, and his treasures: were presented by him to his native town, where they are preserved in the Museum buildings at Elmbank. He was for many years an attendant at the Meetings of the British Association, and there, as elsewhere, his hearty, genial nature won him numerous friends. He died on May 14th, 1900, in his 77th year. [HOBO Wels Cuartes Tyitpen-Wrieut, J.P., who died on August 8th, 1900, was an eminent mining-engineer, whose name had been on our roll of Fellows since 1857. The son of the Rev. E. C. Wright, of Pitsford (Northamptonshire), he assumed the name of Tylden- Wright, by Royal licence, on his marriage, in 1860, with Elizabeth, the only child of Sir John Maxwell Tylden. Mr. Tylden-Wright received his education at Marlborough College, and at the Royal School of Mines. For twenty-six years he was Managing Director of the Shireoaks Colliery ; at one time he was Chief Agent to the Earl of Dudley, and he also held the position of viewer to the Duchy of Lancaster, to the Duke of St. Albans, and to Mr. Webb, of Newstead Abbey. Mr. Tylden-Wright’s only communication to this Society was a description of the sinking through Permian rocks to the Barnsley coal, at Shireoaks, in 1859. He died at his residence at Mapperley Hall, Nottingham, at the age of 68. Vol. 57.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lix Grorer Henry Freperick Uxricu, Professor of Mining and Mineralogy in the University of Otago, was born at Zellerfeld (Prussia) in 1830. He was educated in the High School of his native town, and subsequently graduated at the Royal School of Mines at Clausthal. After four years’ service in the Mining Department of the Prussian Government he went to Victoria, where, in 1857, he received an appointment in the Royal Mining Com- mission. He subsequently joined the Geological Survey of the Colony under the directorship of Dr. Selwyn, and held the office of senior field-geologist at the time of its abolition in 1869. He then became the curator of the mineral section of the Industrial & Technological Museum in Melbourne. In 1875 he paid his first visit to New Zealand, the colony in which he was destined to end his days, and reported on the Otago Goldfields. Two years later he was appointed Professor of Mining and Mineralogy, in the newly-created Mining School connected with the University of Otago. It was uphill work for some time, but by dint of energy, perseverance, and enthusiasm, he succeeded in getting together the necessary appliances, and finally established’ a flourishing school whose students are now found in responsible positions, not only in the various States of the Australian Common- wealth, but also in New Zealand, South Africa, and the United States. He communicated papers to this Society on the Nuggetty Reef of the Mount Tarrangower Goldfield (1870), on the Tin-Ore Dis- coveries in New South Wales (1873), and on the Nickel-Iron Alloy, Awaruite, from New Zealand (1887 & 1890). Though hampered of late years by ill-health, his zeal continued unabated till the end, and was, indeed, the cause of his death. On May 26th, 1900, he lost his footing while examining the geology of Flagstaff Point, Port Chalmers, and fell a distance of 100 feet. He never recovered consciousness, and passed away some few hours afterwards. Wituetm Waacen, Professor of Paleontology at the University of Vienna, died in that city on March 24th, 1900. He was born at Munich, on June 23rd, 1841, and received there, and at Zurich, a sound scientific education, in which the guidance and influence of his distinguished teacher, Oppel, may be recognized as a leading factor. This was shown by Waagen’s early writings ; and we must place him, with Neumayr, among the most renowned represen- tatives of Oppel’s school. lx PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1901, Following two works on the Jurassic rocks, there appeared three important papers on Jurassic Ammonites, in one of which, ‘Die Formenreihe des Ammonites subradiatus’ (1869), striking out in a then somewhat novel line, the author brought forward the idea of the ‘developmental series,’ and introduced the term ‘ mutation.’ After serving for some time in the capacity of scientific tutor to Prince Arnulph and Princess Therese of Bavaria, Dr. Waagen, in 1870, joined the staff of the Geological Survey of India, but ill-health forced him after a few years to retire from that position, and in 1875 he returned to Europe. The principal results of Dr. Waagen’s work in connection with the Indian Geological Survey were the voluminous and important monographs on the Palontology of Cutch and of the Salt Range, published in the ‘ Paleontologia Indica.’ In the former of these (1873-76) the author described the rich Jurassic Cephalopod Fauna of Cutch, and sought to correlate the life-sequence with that recognized in Europe. His work on the Salt-Range Fossils included the description of the Productus-Limestone Fauna (1879-87), the excellent ‘ Geological Results’ (1889-91), and an incomplete study of the Ceratite- Formation (1895). Dr. Waagen subsequently held a position as Lecturer at Vienna University, but in 1879 was appointed Professor of Mineralogy and Geology in the German Technical High School at Prague, and became a contributor to the great work on the Silurian fauna of Bohemia, continued after the death of Barrande. In 1890, on the death of Neumayr, he succeeded to the Chair of Paleontology at the University of Vienna, a position which he occupied until his death. In addition to the above-mentioned works, Dr. Waagen was the author of numerous papers of less importance, and the unfailing courage and whole-hearted devotion with which, in face of many adverse circumstances, he sought to further the development of paleontological knowledge, never failed to receive fitting recog- nition. In 1878 the balance of the proceeds of the Lyell Geological Fund was awarded to him, and he became the recipient of the Lyell Medal in 1898. He had been a Fellow of this Society since 1881 . Endowed with a delicate constitution, Dr. Waagen was con- tinually forced to struggle against ill-health; but this, and the many difficulties which befell him, he manfully strove to overcome, until seized by a paralytic stroke in 1896, from the effects of which he never succeeded in rallying. Vols 7.) ANNIVERSARY ADDRESS OF THE PRESIDENT. lxi Although Dr. Waagen’s researches led him to regard the broad problems of organic development from a point of view with which, perhaps, a majority of his fellow-workers in science are little in agreement, the great value of his labours will be readily conceded. His careful descriptive work, together with many able and suggestive generalizations, form contributions of high importance to inverte- ‘brate paleontology. [Be Bethed JoHn Youne, LL.D., the Curator of the Hunterian Museum in the University of Glasgow,’ was born in 1823 at Lennoxtown, in the parish of Campsie. When but 10 years old he left school to act as errand-boy at a calico-printer’s, in whose employ- ment he remained for 26 years. Meanwhile he had spent his leisure-hours in study, stimulated by the Mechanics’ Institute, and had given especial attention to geology. In 1855 he was called upon to assist in arranging, for the meeting of the British Asso- ciation at Glasgow, a collection of rocks and fossils from the West of Scotland. This work, on which he was engaged for five months, brought him under the favourable notice of the scientific men assembled at Glasgow, and led to his being appointed, in 1859, to the Curatorship of the Hunterian Museum, where he worked under the direction of Prof. John Young, M.D. His geological researches were carried on chiefly among the ‘Carboniferous Strata of Scotland, and he did excellent service in collecting and mounting the Microzoa, and in studying the Polyzoa and other fossils. He aided largely in the preparation of the useful ‘Catalogue of the Western Scottish Fossils,’ which was published at Glasgow in 1876, and he contributed papers to the Transactions of the Glasgow Geological Society, the Geological Magazine, and to our own Journal. He joined the Geological Society of London in 1874; and in 1883 he received an Award from the Murchison Geological Fund, in recognition of his long-continued researches among the Polyzoa and other minute fossil organisms of the Carboniferous Strata of the West of Scotland. He died on March 13th, 1900, aged 77. 1 We are indebted to an obituary notice by Prof. T. R. Jones in the Geolo- gical Magazine, August 1900, p. 382, for some of the sbove particulars. lxil PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, THE EVOLUTION OF PETROLOGICAL IDEAS. INTRODUCTION. The nineteenth century, whose obsequies we have so recently cele- brated, was born in what has been aptly termed by Prof. Zittel, our latest historian, the heroic age of geology. Geological Societies and Geological Surveys did not then exist. Cooperative work was unknown ; but a few individuals, of great power and originality, were laying the foundations of our science on a firm basis of accurate observation. Pallas had recently carried out his remark- able researches in Eastern Russia, and had noted the extraordinary abundance of the remains of the mammoth, rhinoceros, and bison in the superficial deposits of the Siberian plains. De Saussure had climbed Mont Blanc, and published his unrivalled descriptions of Alpine scenery and Alpine structure. Werner was still acting as an exponent of the science which he had done so much to foster, and had fired his two most illustrious pupils, L. von Buch and Humboldt, with that enthusiasm for natural knowledge which was destined to produce such glorious results. Hutton had just passed away, after giving to the world his Theory of the Harth, the main features of which form the basis of modern geology. Smith and Cuvier, both born in the same year (1769), were in the prime of life, and actively engaged in those researches which placed stratigraphical geology on a secure foundation. These are some of the heroes of our science. The early history of geology is mainly a record of fantastic speculations ; but in the heroic age it was beginning to be recog- nized that no solid advance could be made, except on a basis of carefully observed fact. A reaction against the wild speculations of the seventeenth and the greater portion of the eighteenth centuries had set in, and this led, among other things, to the foundation of our Society—the parent of all such societies—in 1807. | That it was necessary to put a curb on the unbridled licence of geological speculation, and to emphasize the importance of diligence and accuracy in the observation of facts, will be admitted by all students of the history of our science; but it is well to remember that there is a scientific, as well as an unscientific, use of the imagination. The chief glory of science is, not that it produces an amelioration of the conditions under which we live, but that it Vol: 571 ANNIVERSARY ADDRESS OF THE PRESIDENT. lxili continually enlarges our view, introduces new ideas, new ways of looking at things, and thus contributes in no small degree to the intellectual development of the human race. It is now generally recognized that the state of advancement of a science must be measured, not by the number of facts collected but by the number of facts coordinated. Theold Baconian idea that it was only necessary to collect facts and pigeon-hole them according to rule, in order to make the most brilliant discoveries, has been somewhat discredited by the history of scientific progress. Speaking on this subject, De Morgan says :-— ‘Modern discoveries have not been made by large collections of facts, with subsequent discussion, separation, and resulting deduction of a truth thus rendered perceptible. A few facts have suggested an hypothesis which means a supposition proper to explain them, the necessary results of this supposition are worked out, and then, and not till then, other facts are examined, to see if these ulterior results are found in Nature. .... What are large collections of facts for? To make theories from, says Bacon; to try ready-made theories by, says the history of discovery ; it’s all the same, says the idolater; nonsense, say we.’ Hutton appears to have been of De Morgan’s way of thinking. He pondered over the facts that he had observed in England, France, and Scotland, and formulated his theory of the earth. He then went again into the field to test the consequences of his theory, and verified them. He never seems to have thought it worth while to describe isolated facts, or the structure of particular districts, except in so far as they illustrated his theory: although no one was better qualified to do this, as all readers of his description of the unconformity at Siccar Point, of the granite-veins in Glen Tilt, or of the geological features of Arran, will readily admit. His joy at the discovery of the granite-veins in Glen Tilt can be easily understood. His theory required that they should exist, and they were found, not by chance, but because they were looked for. And we may be sure that the joy did not arise from gratified vanity, for, as Playfair says, he was one of those who took more delight in the contemplation of truth than in the praise of having discovered it. In thus calling attention to the importance of ideas in scientific research, I trust it will not be thought that I am advocating a return to the condition of things which prevailed in the early days of geological history. Armchair philosophizing, apart from actual work in the field, the laboratory, and the museum, is by no means to be commended. But the worship of fact, as fact, may easily be overdone. The number of discoverable facts is practically infinite, xiv PROCEEDINGS OF THE GEOLOGICAL society. {May 1go1, and it is therefore possible to get into such a condition as not to be able to see the wood for the trees, to lose the due sense of propor- tion, and to become mere machines for tabulating interminable trivialities. On the other hand, it should be remembered that every worker endowed with imagination must formulate, in his own mind, many theories that will not stand the test of verification, and that it is quite unnecessary for him to trouble other workers with such theories. He can test them for himself, and relegate them to oblivion if necessary, without burdening our overcrowded book- shelves with crude speculations and unverified hypotheses. | It is only when a theory has proved its usefulness as a coordinator of fact that it becomes worthy of the dignity of publication. It may be true, or false, most likely the latter; but if it coordinates more facts than any other, it is at any rate useful, and may be conveniently retained until replaced by a better. Controversy as to the truth or falsity of a theory often seems to me beside the mark, for if a given theory coordinates more facts than any other, it is at least worthy of respect, and may be tentatively held as a working hypothesis, along with the conviction that it is not true, or only partially true. Indeed, the controversial spirit is, in my judgment, inimical to the best interests of science. It makes a man more eager to refute than to understand the views of his opponents ; it tends to check the flow of sympathy, and thus often prevents that friendly cooperation which is so desirable in the interest of scien- tific progress. When controversy becomes acute, I always feel inclined to exclaim ‘a plague on both your houses !’ Every branch of our many-sided science has benefited by the zeal for collecting facts which manifested itself during the early years of the nineteenth century. Methods of observation have been perfected, national surveys and private individuals have examined, and are examining, the geological structure of every civilized State, and explorers have penetrated to almost every quarter of the globe. Our libraries and museums are being rapidly filled with records of all this scientific activity. Side by side with the registration and cataloguing of facts there has taken place an evolution of scientific ideas, and it is on this aspect of the subject, so far as my own special branch is concerned, that I propose to offer a few remarks. Rocks may be studied from two more or less distinct points of view, the descriptive and the etiological. But it is well to note Vol sz] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixy that the distinctness of these two points of view is but the expres- sion of our ignorance as to the genetic relationships of the different types. Facts as to composition, structure, and the like, accumulate faster than they can be interpreted; and our classifications are, therefore, necessarily more or less artificial. But there is that within us which compels us to bring our classifications into accord with our views as to genesis. Phylogeny must in the end control classification, both in the organic and inorganic worlds. As soon as we realize that any scheme of classification places together objects which have no genetic relationship, or groups them irrespective of such relationship, we become dissatisfied with it. The old classi- fications need not be thrown over the moment that their imper- fections are glimpsed ; but in the end they have to be discarded, and the new ideas find expression in a new classification. Thus Thro’ the ages one increasing purpose runs, And the thoughts of men are widened with the process of the suns. - How far Hutton was in advance of his time on matters relating to petrogenesis is illustrated by the fact that more than half a century elapsed before his ideas found expression in systematic treatises. Yet the separation of rocks into igneous, sedimentary,. and metamorphic, and the further subdivision of the igneous rocks. into plutonic and volcanic, follow naturally and logically from his. fundamental conceptions. The reason for the tardy recognition of what is now generally admitted to be the true basis of classification is not far to seek. Hutton was no systematist. Werner, on the other hand, was not only a keen observer, but he possessed in quite an exceptional degree the power of describing what he observed in precise and definite terms, and of grouping his facts according to their supposed relationship. He was, in short, a born systematist, and this, com- bined with his eloquence and enthusiasm, gave him a commanding influence. In looking back at these two striking figures of the heroic age, Werner and Hutton, it is almost impossible to avoid a feeling of regret that the one did not possess what the other lacked.. But such regrets are useless. Let us honour them both. The authors of systematic treatises on rocks published during the first half of the century were all under the spell of Werner, and they were still further hampered by their ignorance of the com- position of those rocks which are of so fine a grain that their constituents cannot be determined with the naked eye, or with the aid of a simple magnifying-lens. The treatises of Hatty, Brongniart,,. Ixvi PROCEEDINGS OF THE GEOLOGICAL sociEry. | May rgot, and Leonhardt clearly recognized the great natural group of frag- mental rocks; but the true limits of the other equally natural groups were, so far as general treatises are concerned, brought into prominence for the first time in the work by Von Cotta, the English translation of which appeared in 1866. PROGRESS DURING THE First HALF oF rHE CENTURY. Igneous rocks played but a small part in the Wernerian system. ‘They were regarded as stratified rocks melted by heat, due to the burning of coal beneath volcanic districts. We now recognize that they are of great importance, and probably represent the original source of all the other rocks. The clearing up of our ideas as to their nature and mode of origin centres round two controversies : one as to the origin of basalt, the other as to the origin of granite. It is difficult for us to realize the condition of things which prevailed during the early years of the century, when the martial spirit of the age seems to have affected the scientific world, and a furious controversy raged between the Neptunists and the Vulcanists as to the origin of basalt. We look with a feeling of astonishment at the controversialists, condemn their methods, and admire the calm figure of the old man Desmarest as he sits there refusing to be dragged into the controversy, and quietly replies to his chal- lengers ‘Go and see.’ Now and again, in looking through some neglected cabinets of our museums we come across dust-covered specimens labelled ‘ Ammonites in Basalt from Portrush,’ and are thus forcibly reminded of those stirring times. The controversy as to the origin of granite lasted longer, and during its later stages, at any rate, was conducted with dignity and a due regard to the amenities of scientific discussion. It resulted, moreover, in a very decided enlargement of our conceptions as to subterranean phenomena. The Wernerian view that granite was a precipitate from a primordial ocean was compelled to give way as soon as the tectonic relations of granitic masses, so well described by Hutton, Playfair, and Sir James Hall, were clearly realized. The phenomena of granite-veins, the occurrence of inclusions of the surrounding rocks, and the sharpness of the junctions between granite and the strata with which it is in contact, prove beyond all doubt that the material of which many granite~masses are composed must have been intruded from below in a plastic state. Towards the mil Volk 57: | ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixvii middle of the century these facts were generally recognized for all those masses which occur outside areas of erystalline schist. But their recognition, although conclusive as against the view that granite was everywhere a primordial sediment, by no means involved the necessity of accepting the Huttonian theory that it resulted from the consolidation of a mass of matter in a state of pure igneous fusion. The earlier phases of the discussion as to the origin of granite centred mainly round the tectonic relations of the rock-masses ; but the later phases had reference rather to the composition and struc- ture of the rock itself. The papers on this subject, and especially the discussion between Scheerer and Durocher, are well worthy of the attention of modern petrologists. j Scheerer maintained that the purely igneous origin of granite was disproved by three lines of argument. Thus he contended that the very presence of quartz was opposed to the theory, for this mineral could not be formed by igneous fusion, and was absent from lavas containing an excess of silica, such as obsidian, even when these lavas must have cooled more slowly than some granite-veins. Again, the order of consolidation of the minerals, as determined by mutual interference, was not the order of their fusibilities. Fournet had endeavoured to remove this objection by supposing that quartz, like water and sulphur, could be cooled below its proper melting- point. But this theory of the surfusion of quartz was untenable, because the amount of overcooling was too great and the complete rest which was necessary could not be postulated. Scheerer ad- mitted that the objections to Fournet’s theory were rendered less forcible by a consideration of the fact, pointed out by Durocher, that the magma of granite did not contain the material of the separate minerals in a fused state, but consisted of a homogeneous liquid— a solution as we should say—so that the overcooling did not affect quartz as such. This, however, in his opinion, did not justify the theory, for, to use a free translation of his own words, ‘it is evident that the point of solidification of the silicate forming the magma out of which the different compounds are separated, ought to approach the fusion-point of silica as the quantity of bases in the liquid portion decreases.’ According to Durocher’s view, the ultimate base of granite should consist, not of quartz, but of a substance like petrosilex. A third line of argument, founded on the occurrence in some granites of the peculiar pyrognomic minerals, such as gadolinite, was also brought forward by Scheerer. If a chip of isotropic gado- Ixvill PROCEEDINGS OF THE GEOLOGICAL sociuTy. [May 1901, linite be heated to redness, a sudden and remarkable change takes. place. It glows brightly for a few moments, and after cooling is found to have become denser and strongly birefringent. Thus gadolinite occurs in two phases: a lighter isotropic phase, and a denser birefringent phase. The change from the former to the latter takes place at a red heat, and the reaction is accompanied by a considerable loss of energy, but little or no loss of material.. The occurrence of this mineral in some granites proves, therefore, according to Scheerer, that they must have consolidated below a red heat. These three lines of argument, based on the presence of quartz,. on the mutual relations of the constituents, and on the presence in some granites of pyrognomic minerals, concur, he considers, in dis- proving the theory of pure igneous fusion. Scheerer then propounds his own theory of aqueo-igneous fusion,, basing it on the fact that some of the granitic minerals, such as mica, contain water. The presence of even small quantities of water would, he maintains, lower the consolidation-point consider- ably, and during consolidation the water would concentrate in the mother-liquor, and ultimately in the silica. Final consolidation would take place on the escape of the water. Thus the paradoxical order of crystallization would be explained, and the granite might consolidate at a temperature which would admit of the formation of the pyrognemic minerals. 7 The theory of Scheerer was opposed by Durocher, and the con- troversy between these two distinguished men extended over a period of three or four years. Durocher considered that a close examination of the structure of granite does not bear out the view that there is a well-defined order of consolidation. The minerals. mutually interfere one with the other, sometimes one, and sometimes: another, having the advantage. The magma appears to have cooled down to a comparatively low temperature, and then to have sepa- rated into definite compounds which did not solidify instantaneously. The relative perfection of form would, on this view, be largely determined by the relative power of crystallization of the different constituents. In this respect quartz is at a disadvantage. It possesses, moreover, as shown by M. Gaudin, a great range of viscosity, and when fused can be drawn into threads like glass and sealing-wax. He agrees with Scheerer in rejecting Fournet’s theory of surfusion, and considers that the paradoxical order of consolida- tion can be explained by taking into consideration the wide range Vol. 57.| ANNIVERSARY ADDRESS OF THE PRESIDENT. lxix of viscosity of quartz and its slight tendency to crystallize. A similar view has recently been advocated by Prof. Joly. Durocher replies to Scheerer’s argument derived from the absence of quartz in obsidians, by pointing to its presence in trachytes, and attempts, somewhat unsuccessfully, to explain away the presence of the pyrognomic minerals. In his criticisms of Scheerer’s views as to the amount of water present in granite he is often effective, for he shows that sufficient allowance had not been made for the effects of alteration. Scheerer’s view became the popular one, and is now generally held. It was greatly strengthened by Dr. Sorby’s discovery of the widespread distribution of liquid cavities containing water in the quartz of granites, and by the well-known synthetic experiments of Daubrée and others. The failure of all attempts to produce granite is also still felt to be a strong argument against the theory of dry fusion. Scheerer concludes the discussion with some observations which I cannot refrain from quoting. He says :— ‘To avoid misunderstanding, I desire to make some remarks on the value which I attach not only to my theory of the origin of granite, but also to geological theories in general. I am far from believing that the igneous theory, which M. Durocher defends with so much vigour, is finally disposed of, or that my theory is completely satisfactory. Such definite conclusions cannot be reached in the present state of our science. More than one point of view is possible on almost every subject: of this kind, and thus it must ever be, for mathematical certainty is unattainable. ‘A short time ago it seemed as if the Neptunean theories had completely abandoned the field in favour of those volcanic theories which appeared so absurd to our ancestors. Now the Neptunean theories are beginning to show signs of life. I have endeavoured to conciliate the two sister-enemies by suggesting that water may play an important part in the formation of fused rocks. . . . I do not pretend, however, that my theory is unassailable, or that it has been absolutely demonstrated. . . . In my opinion a geological theory should not be considered as absolute; but it becomes probable when a con- siderable number of facts group themselves around it, and its degree of probability can be measured by its power of assimilating the new facts brought to light by the progress of science.’ These are wise words, and may well be remembered when dif- ferences of opinion tend to become sharply accentuated. The path of science is littered with discarded theories, and this fact should serve to remind us that ‘ we are none of us infallible, not even the youngest.’ In the discussion between Scheerer and Durocher attention was VOL, LVII. Fé lxx PROCEEDINGS OF THE GEOLOGICAL sociETY. [May 1901, directed to the mutual relations of the constituents of granite and to the inferences which could be drawn from a study of those relations as to the order of consolidation of the minerals. THE ConsoLIDATIoN oF Ienzous Maemas. At the time when the discussion took place this kind of reasoning could be applied only to coarse-grained rocks, but with the advent of the microscope it became possible to extend it to the important group which had been designated, in the earlier classifications, as ‘apparently homogeneous rocks.’ In the early part of the century Cordier had proved, by the microscopic examination of the powder of basalt, that this rock was heterogeneous, but it was not till the examination of thin sections had been introduced that the mutual relations of the constituents of the finer-grained rocks could be studied. In those rocks which have resulted from the consolidation of homogeneous silicate-magmas, and in which the consolidation has been unaccompanied by the phenomena of resorption—that is, in which there has always been equilibrium between the constituents during the process of consolidation—the order of separation can be inferred from the microscopic structure. It has thus been established that the process of consolidation cannot be divided into a number of sharply-defined periods, each characterized by the separation of some one mineral only; but that the times during which the different minerals are separating out overlap to some extent. The amount of overlapping varies in different cases, and, in one and the same magma, is most marked in plutonic masses ; whence we conclude that it is largely determined by physical.conditions, and especially pressure. The order of consolidation, as determined by an examination of the mutual relations of minerals, is, therefore, the order in which they commence to form, and this order may or may not agree with that in which they cease to form. The laws which express the order of formation of minerals, and the chemical and physical conditions which control that order, have not as yet been definitely established. One of the most important papers on theoretical petrology is undoubtedly that by Prof. Rosenbusch on the significance of the granular and porphyritic structures in massive rocks. The import- ance of this paper must not be judged simply by the amount of truth in the principles enunciated, but rather by the stimulus: which it gave to theoretical considerations and to researches Vol. 57.] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxi directed towards a particular end. The constituents of massive rocks are divided by Prof. Rosenbusch into four groups :— 1. The ores and accessory constituents (magnetite, hematite, ilmenite, apatite, zircon, spinel, and titanite). 2. The ferromagnesian constituents (biotite, hornblende, pyroxene, and olivine). 3. The felspathic constituents (felspar, nepheline, leucite, melilite, sodalite, and hatiyne). 4. Free silica. Prof. Rosenbusch pointed out that members of the first group precede those of the other groups; that in granites and syenites the members of the second group precede those of the third; but that in the diabases and gabbros the order is inverted, and that in both groups silica is the last. The general conclusion is reached that ‘the order of consolidation of the silicates and, consequently, their crystallo- graphic development (idiomorphism), corresponds to a law of decreasing basicity; the ores and accessory minerals are the earliest, and quartz is the latest, product of the rock-forming process.’ This empirical law expresses, in a broad and general way, the main facts observed with regard to the sequence of minerals in thelarge and important group of intermediate rocks, but it breaks down when applied to the most acid and the most basic rocks; quartz is often formed before felspar in the former, and iron-ores © are not infrequently formed after felspar in the latter. The views that we hold regarding the laws which express the order of consolidation in igneous magmas will necessarily be coloured by our conceptions as to the nature of these magmas. A great advance in the evolution of ideas on this subject is marked by a short letter, written by Bunsen to Streng; and published in the Journal of the German Geological Society for 1861. In this letter Bunsen points out that the arguments against the igneous origin of granite, so far as they rest upon the so-called anomalous order of consolidation of the minerals, are based on a misconception of the nature of the process of consolidation. He says :— ‘The temperature at which a substance consolidates from a state of fusion is never that at which it separates from a solution in another substance. The temperature at which a definite substance crystallizes from its own liquid depends only on the substance and on the pressure to which it is subjected; whereas the temperature at which the same substance separates from its solution in another substance depends principally on the relative proportions of the two substances, No chemist will fall into the error f2 Txxil PROCEEDINGS OF THE GEOLOGICAL socizTy. [May 1go1, of assuming that a solution ceases to be a solution at 200°, 800°, 400°, 500°, or even when heated to a temperature at which it becomes self-luminous ; or will suppose that a crystalline aggregate of ice and calcium-chloride which has become fluid is a solution, but that a mixture of quartz and felspar which has been fused is not.’ He then proceeds to point out that the laws which govern the solidification of aqueous solutions must hold good also for igneous solutions; that by the addition of a certain amount of calcium- chloride to water the temperature may be lowered to —10° C., without the separation of any solid substance; that by the addition of further amounts the temperature of consolidation of water may be lowered. as much as 59°, and that of calcium-chloride 100°. Other salts, such as the sulphates and nitrates of potassium, may be made to separate from aqueous solutions at temperatures from 600° to 800° below their freezing-points ; moreover, the order of consolidation is determined by the relative amounts of the two substances present; thus water may be made to consolidate before or after a dissolved salt, by varying the concentration of the solution. I have given a somewhat full abstract of this important letter, because I believe that the expansion of the idea which it contains will be the characteristic feature of the next great advance in petrological science, an advance which will come about, not so much by adding to our already large store of facts, as by dint of experi- ment controlled by the modern theory of solutions, and carried out for the express purpose of testing the consequences of that theory and discovering the modifications which may be necessary to adapt it to igneous magmas. Almost all recent writers on theoretical questions relating to the igneous rocks have accepted the solution-theory, and the condition of formation of minerals has been discussed from this point of view. Crystals tend to form in a homogeneous liquid mass when the liquid becomes supersaturated with any definite compound. As soon as crystals arc developed the liquid in their immediate neighbourhood ceases to be supersaturated, and there is thus established an osmotic force producing molecular flow from the supe portions towards the growing crystals. From a consideration of the work of Pelouze on glasses, com- bined with his own work on igneous rocks, Lagorio arrived at the conclusion that the ordinary rock-forming compounds tend to separate out in the following order: oxides, pure iron-silicates, magnesian and ferromagnesian silicates (olivine and rhombic ad Vol. 57. | ANNIVERSARY ADDRESS OF THE PRESIDENT. ]xxul pyroxenes), calc-magnesian silicates (monoclinic pyroxenes and hornblende), silicates of magnesium and potassium or of iron and potassium (biotite), calcium-silicate (anorthite), silicates of sodium and calcium (plagioclase), sodium-silicates (nepheline and albite), and lastly potassium-silicates (orthoclase) in conjunction with quartz. In his important work on slags, Prof. Vogt has clearly established the influence of the relative proportions of the bases to each other and to silica in determining the nature of the compounds which separate out. Thus in slags in which the ratio of bases to silica corresponds approximately to that found in bisilicates, the ratio of CaO: MgO determines the formation of such minerals as enstatite, augite, and wollastonite. When the ratio of Mg0+ FeO: CaO is greater than 2:44: 1, enstatite forms; when the same ratio is less than 1:4:1, augite separates out, and continues to do so, until this ratio becomes less than *85:1; with a still further diminution in the ratio of magnesia to lime, wollastonite is formed. In slags having approximately the composition of monosilicates the ratio of MgO+Mn0O+Fe0O: CaO determines the formation of olivine or melilite. When the above ratio is greater than 1: 1-1 (in slags with about 20 per cent. of alumina), olivine is formed ; but when it is less than 1: 1-25, melilite is produced. The general conclusion arrived at as a result of the work of Vogt, Lagorio, and others, is that mass-action and the affinities of the bases to each other and to silica are the two factors of primary importance in determining the molecular grouping, so long as the pressure remains constant. The action of alumina may be especiallv referred to, as illustrating the influence of the mutual affinities of the so-called bases. In the sorting of partners in accordance with the law of mass-action, this substance, when present in sufficient quantity, practically takes the whole of the alkalies and as much of the lime as is necessary to make felspathoid molecules. So marked is this action that M. Michel Lévy and M. Osann, in caleula- ting the results of analyses, combine the whole of the alumina with the alkalies, when the latter are present in sufficient quantity, and associate any excess of alumina with lime in the form of felspathoid molecules. It is only in those rocks that contain an abnormal per- centage of alkalies that minerals like egirine and riebeckite occur. This controlling influence of alumina, which has also been emphasized by Prof. Iddings, has the most far-reaching effects in determining petrographical species. Itis asif there were a kind of Ixxiv PROCEEDINGS OF THE GEOLOGICAL society. [May rg07, repulsion between the ferromagnesian and alumino-alkaline con- stituents. Dark rocks rich in the former, and light roeks rich in the lattér, represent the extreme forms of many mtermediate types; and Prof. Brogger has recently proposed that this should receive expression by the application of the terms melanoeratie and leucocratic to these two strongly-contrasted varieties. The results already obtained leave no doubt that a properly- directed series of experiments will throw great light on the laws which control the formation of minerals during the consolidation of igneous rocks. The classic researches of Prof. Fouqué and M. Michel Lévy on the synthesis of such rocks as basalt, andesite, and nephelinite by pure igneous fusion show that we can control the necessary physical conditions, and that the whole subject, so far at least as these rocks are concerned, lies within the range of experiment. The work of Morozewiez, to which I have directed attention in another place, may be mentioned as proving that a rch harvest of results may be confidently anticipated from experimental work in this direction. To return to the question of the order of consolidation of minerals in igneous rocks. If the solution-theory be true, no order based solely on a consideration of the properties of the minerals can hold good in all cases. In the case of aqueous solutions of two sub- stances the order of separation, as pointed out by Bunsen, depends on the relative proportions of these two substances. This subject, so far as alloys, fused salts, and aqueous solutions are concerned, was investigated with great skill by Prof. Guthrie, the import- ance of whose work on alloys has been brought into prominence of late by the researches of Roberts-Austen, Le Chatelier, Osmund, J. EK. Stead, Heyeock & Neville, Alder Wright, and others. It is too early yet to discuss the full bearmng of this recent work on petrographical questions, but it is impossible to examine the beautiful photographs which illustrate the structure of alloys, such, for example, as those accompanying the Fifth Report of the Alloys Research Committee,’ or those illustrating Stead’s paper on iron and phosphorus,? or Heycock & Neville’s paper on gold-aluminium alloys,’ without being struck by the resemblance of many of these structures to those met with in rocks. 1 Fifth Report by Sir a Roberts-Austen, Proc. Inst. Mech. Eng. 1899, p. 85. = Journ. Iron & Steel Inst. ae lviit (1900) p. 60. * Phil. Trans. Roy, Soc. vol. exciv (1900) A, pp. 201-3 Nok 's 7] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxv Some years ago I directed attention to the possible application of Guthrie’s work on cryohydrates and eutectics to petrographical questions, and the experience since gained has tended rather to con- firm me in the views which I then expressed. Fused salts which do not act chemically upon each other show, when mixed in eutectic proportions, a marked tendency to form spherulitic, and what may be called micropegmatitic, intergrowths. It has since been proved that the same is true of alloys. Thanks to the kindness of Mr. J. E. Stead, [ am able to give two figures, drawn from photographs, which illustrate this fact, and side by side with these are placed figures of micropegmatitic and spherulitic structures copied froin Prof. Iddings’s memoir on the rocks of Obsidian Cliff. Figs. 1 & 8 = Spherulitic and micropegmatitic structures in obsidian. (After Iddings, VIIth Ann. Rep. U.S. Geol. Surv. 1885-86, pl. xv.) Figs. 2 & 4 = Similar structures in eutectic alloys: from microphotographs by Stead. 2—A simple spherulite in the eutectic of lead and antimony bse 4 = Micropegmatitie structure in magnolia-metal (lead, 80 per cent. ; antimony, 15 per cent. ; and tin, 5 per cent.), 1 The outlines of this spherulite are somewhat.too sharply drawn, Ixxvi PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, In the case of the alloys the spherulitic structures are charac- teristic of rapid cooling, and the micropegmatitic structures of slow cooling. The mode of occurrence of the same structures in rocks is strictly in accordance with this view. A comparison of the structures in the two cases makes. it almost impossible to believe that the resemblances are merely accidental, and if not, they point to the conclusion that micropegmatite is an eutectic compound. From this point of view it becomes of interest to determine the melting-point of fused micropegmatite. This was kindly done for me by Prof. Joly, by observations with the meldometer. He found that fused micropegmatite melted somewhat more readily than orthoclase, but less readily than fused orthoclase. These observations do not support the eutectic hypothesis, but they can scarcely be said to negative it, as the conditions of the experiment are certainly very different from those under which the rocks are produced. Quartz and orthoclase have not as yet been formed by pure igneous fusion. The melting-point, at atmospheric pressure, of a mixture of quartz and orthoclase is above that of basalt, and yet we know from the occurrence of angular fragments of basalt in grano- phyre, that the consolidating-point of the mixture under certain conditions of pressure is below that of the fusing-point of basalt under the same conditions. If, as Prof. Loewinson-Lessing’s calculations suggest, the formation of felspathic minerals is accom- panied by an increase in volume, and the formation of ferro- magnesian minerals by a decrease in volume, pressure will lower the fusing-point of the former and raise that of the latter, so that, under plutonic conditions, the relative order of consolidation of acid and basic magmas may be the reverse of that under volcanic conditions. Magmas usually contain water, and sometimes other volatile constituents (such as chlorine, boron, fluorine, etc.), whose importance in determining the fluidity and the molecular grouping of the constituents has been generally recognized since the publica- tion of the classic paper ‘Sur les Emanations Volcaniques & Métal- liferes’ by Elie de Beaumont. When separated from the magma, these constituents exercise most important metamorphosing and mineralizing effects, as is well seen in the phenomena accompanying the formation of tinstone and apatite-veins, in the development of zeolites, and in the production of large masses of kaolin. But, so Yok. 57-1 ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxvli long as they remain in the magma, they must be regarded as belonging to it, and playing their part along with the other con- stituents in producing the final result. The application of the theory of solutions to igneous rocks is com- plicated in many ways. We are ignorant of the manner in which the constituents revealed by analysis are distributed in the molten magmas, and of the changes which take place in the molecular groupings as the temperature approaches the point of saturation. M. Le Chatelier has recently suggested that granite furnishes an illustration of the phase-rule, and may be regarded as a stable system of three phases (quartz, felspar, and mica), made up of the three components—silica, alumina, and potash. Few petrographers will admit that the case can be put as simply as this. No doubt the consolidation of igneous magmas is governed by the phase-rule, but in the majority of cases the number of components, on any view as to their nature, is too great to make the rule of much practical value. Another cause of complication arises from the fact that the physical conditions have often changed during the process of consolidation, thus giving rise to the phenomena of resorption ; and yet another from the absence of assurance that the minerals seen in a rock have in all cases been developed from a magma having the composition represented by the bulk analysis. I cannot leave this portion of the subject without calling attention. to the recent work of Prof. Joly on the melting-points of the rock- forming minerals, and his proof of the enormous range of viscosity possessed by quartz and-other minerals. Whatever view we take as to the nature of silicate-magmas, there can beno doubt that in general the process of consolidation is a process of differentiation. Definite compounds separate out, either successively or simultaneously, from a homogeneous magma, and at the time of their formation are in equilibrium with the surrounding liquid; but owing to changes in temperature and pressure the equilibrium established at one period may be destroyed at another, and the igneous rock as we see it may not contain a record of all the operations which have taken place during the process of consolidation. So far as individual rocks are concerned, we look to experiment, rather than to observation, to give precision and definiteness to our ideas regarding the nature of the changes which accompany solidification. Ixxvill PROCEEDINGS OF THE GEOLOGICAL society. [May got, THE ORIGIN OF SPECIES. The geologist, however, has to deal not only with igneous rocks as individuals but as groups, to consider their mutual relations, their geographical distribution and mode of origin. But to give anything like a full account of the growth of ideas on this subject would expand this address to an inordinate length, and would, moreover, be a work of supererogation, for the whole question has been admirably reviewed by Prof. Iddings and Prof. Leewinson-Lessing. The germs of all the theories which are now struggling for existence can be discovered in the writings of our predecessors. Scrope (1825) held the view that lavas were formed from previously crystallized rocks, such as granite, and maintained that in the process of eruption, or intumescence as he termed it, a kind of differentiation might take place, giving rise to trachyte and basalt. Darwin (1844), in his important work on Volcanic Islands, also discussed the origin of petrographical species. He directed attention to two causes of differentiation which may ultimately prove to be of great importance—(1) the movement of crystals in a magma under the influence of gravity; and (2) the squeezing or leaching-out of the more fusible constituents from a partially consolidated or partially fused mass. The first of these he illustrated by the well- known Pattinson process for desilverizing lead, and the second might be illustrated by another metallurgical process often known ~as liquation (but quite distinct from the process referred to by Durocher under the same name), by means of which silver is separated from blister-copper. The copper is fused with a certain proportion of lead, and the bars are maintained at a temperature above the fusing-point of the silver-lead alloy and below that of copper. The silver-lead alloy is thus leached out of the copper, which remains as a solid porous mass. Such a separation might be effected in the case of a plutonic mass, if a partially solidified magma, were subjected to pressure under conditions which admitted of the escape of the still liquid portions into the surrounding rocks, As a matter of fact it has been so applied by Mr. Barrow, who thus explains the relation between pegmatites and certain oligoclase- biotite-gneisses in the Southern Highlands of Scotland. The eurite- veins in granite are generally supposed to owe their origin toa somewhat similar action, but in this case the separation is due to the leaching-out of the still liquid eutectic into cracks in the nearly consolidated mass, and not to orogenetic movements. It is com- parable, therefore, to the liquation-process above mentioned. Vol. 57.] ANNIVERSARY ADDRESS OF THE PRESIDENT. lxxix Bunsen explained the varieties of igneous rock revealed by his analyses by assuming the independent existence of two magmas—- the ‘normal pyroxenic’ and ‘ normal trachytic’—and supposing a process of intermixture to account for the intermediate varieties. Von Waltershausen thought that igneous magmas were arranged in a series of concentric shells, according to specific gravity. Durocher, in his celebrated essay on Comparative Petrology, maintained ‘that ail igneous rocks, modern and ancient, were derived from two niagmas which co-exist below the solid crust of the globe, and occupy there each a definite position,’ His two magmas—basic and acid—do not differ materially from those of Bunsen, and his idea of their arrangement in the earth’s crust is practically the same as that of Von Waltershausen. He compared the two magmas to baths of fused metals, which separate into distinct alloys on cooling. He does not give actual illustra- tions, but we may consider one, in order to give precision to the idea. A mixture of 43-64 per cent. of bismuth and 56-36 per cent. of zine separates at a temperature between 700° and 800° C. into two alloys, which arrange themselves according to specific gravity. On cooling, the heavier is found to contain 84°82 per cent. of bismuth and 15°18 per cent. of zinc; the lighter 2°47 per cent. of bismuth and 97°53 per cent. of zinc. If silver be added to the mixture, there is also a separation into two alloys, so long as the amount of silver is less than about 40 per cent. ; when it exceeds this amount, there is no longer any separation. Durocher speaks of eruptions which derive their supply from the primary magmas as belonging to the first order, and those which draw their material from more or less isolated magma-basins as belonging to the second order. The latter furnish rocks which depart from the normal type, and this he explains, in part at least, by assuming a process of separation analogous to that by which the primary magmas were produced. Thus he says :— ‘It is therefore probable that phonolitic and trachytic porphyry are only the two opposite products of a liqguation which took place in the midst of the fluid mass; they are, as it were, the two inverse alloys into which we so often see a metallic bath divide itself.’ The type of magmatic differentiation conceived by Durocher may be illustrated by a very simple experiment. Place some phenol and water in a Florence flask: two immiscible conjugate solutions will be formed—a solution of water in phenol at the bottom, and a solution of phenol in water at the top. Now heat the mixture to [e6.O.0 PROCEEDINGS OF THE GEOLOGICAL society. | May Igor, 69°C., and a perfectly homogeneous solution will be produced. On cooling, this will again break up into two. Clouds are first formed in the cooler portions of the liquid, and after the coalescence of the minute drops, gravity is able to effect a perfect separation of the two solutions. Do silicate-solutions behave in the same way? Backstroém has recently argued that they do; but until the fact has been definitely established by experiment, there will always remain a certain element of doubt. The sharp separation of basalt and granophyre, which is so striking a feature of the Brito-Icelandic province, suggests that the two magmas represented by these rocks may separate in the manner just described. But the great viscosity of fused granophyre at atmospheric pressure and easily accessible temperatures would probably prevent the attainment of any decisive result. Clarence King maintained that local lakes of fusion were formed by relief of pressure, and that differentiation took place partly by liquation in Durocher’s sense, and partly by the rise or fall of erystals. The physico-chemical speculations, which played so important a part in the science of rocks during the middle of the century, were neglected for a time, in consequence of the opening up of a new field of observation by the introduction of the microscope; but of late years we have returned to these speculations with renewed vigour, and with a wealth of facts at our disposal which the earlier theorists would have envied. The mineralogical composition and microscopic structure of all kinds of igneous rocks have been determined, reliable chemical analyses have been made, and the problem of the origin of petro- graphical species has resolved itself into the question of the evolu- tion of the magmas. Especially noteworthy is the stimulus given to the chemical side of petrology by the magnificent work of the. United States Geological Survey. We have now some four or five new and original classifications of igneous rocks largely based on the analyses of Clarke, Hillebrand, and their assistants, and the cry is— ‘still they come!’ But the authors of these analyses have hitherto refrained—perhaps wisely—from attempting any general classifica- tion of rocks from a chemical point of view. The number of constituents is so large that there is no reason, so far as I can see, why every petrographer should not have his own classification and his own method of graphical representation. Vol. 57. | ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxi The idea that petrographical species have originated by differentia- tion from homogeneous magmas, and possibly in the first instance from some one primordial magma, has been greatly developed during the last decade of the century, especially by American and Nor- wegian petrographers. Thus Prof. Iddings, in the introduction to his important memoir on the Origin of Igneous Rocks, says :— ‘The object of the present paper is to give the writer’s reasons for concluding that all of the voleanic and other igneous rocks of any region are so intimately connected together by mineralogical and chemical relations that they must have originated from some single magma whose composition may be different in different regions; and, further, that it is the chemical differentiation of this primary magma which has given rise to the various kinds of igneous rocks.’ The fact that the diverse igneous rocks of certain districts are often bound together by common mineralogical and chemical characters which distinguish them from the corresponding rocks of certain other districts was clearly recognized by Prof. Judd in his well-known paper on the Volcano of Chemnitz, and subsequently erystallized by him in the happy expression petrographical province, as applied to any district in which the igneous rocks have certain common characteristics. The idea has been still further extended and elaborated by Prof. Iddings, who sees in the common characteristics the indications of a kind of blood-relationship or consanguinity, which can only be explained on the assumption that the different species of one and the same province have originated by differentiation from a single homogeneous magma. Prof. Brégger, in his remarkable series of studies on the rocks of the Christiania district, has still further generalized this idea, and much of his work is directed towards the evolution of a genealogical tree, in which the twigs shall correspond to the final products of differentiation, the larger branches to some of the plutonic masses, and the trunk to the primordial homogeneous magma. The idea is a fascinating one: se non é vero, é ben trovato. But it must be admitted that we know very little about the causes of the assumed differentiation. These are supposed to be of two types: (1) those which affect the liquid magmas, and (2) those connected with the separation of the minerals. Magmatic differentiation is generally regarded as the most important, but it is the type of which we know least. Soret’s principle, to which I have appealed, will, I fear, help us very little, though it is undoubtedly a vera causa. Mr. Harker has clearly shown that, as applied to a mass like the Carrock-Fell — gabbro, it breaks down hopelessly when subjected to a quantitative Ixxxll PROCEEDINGS OF THE GEOLOGICAL SocrETY. [May Igor, test. The principle of Gouy & Chaperon is even more unsatis- factory. Durocher’s liquation-theory is, perhaps, more promising, but until it has been proved by actual experiment that there is a real analogy between baths of fused metals and silicate-magmas it cannot be said to rest upon an assured basis. Faraday’s researches on lead-glass certainly suggest that gravity may act differen- tially on the constituents of silicate-magmas, independently of the principle of Gouy & Chaperon. Thus he found that glass taken from the top of pots not more than 6 inches deep might have a density of 3°28, while that from the bottom might have a density of 3°85; but there is some doubt as to whether the consti- tuents were ever uniformly mixed in the molten state, and if not, whether sufficient time was allowed for diffusion to establish homo- geneity. It is certain, however, that they were uniformly mixed in the solid state, and the experiments are therefore of great interest ; for, if they do not prove differentiation in a molten mass, they prove that an uniform solid mass may become differentiated as it liquefies, by a kind of liquation-process analogous to that which takes place in the extraction of silver from copper. Prof. Iddings has carefully considered the chemical compositions of groups of rocks, belonging to several different petrographical provinces, from the point of view of the differentiation-hypothesis, and has arrived at the conclusion that ‘ the simple-oxide molecules shift about independently of one another to a great extent.’ If this conclusion be correct, it is clear that the phenomena cannot be explained by the hypothesis of a differentiation solely connected with the formation of known minerals ; but this view does not appear to be accepted by Prof. Brogger, who believes ‘that the process of differentiation must be referred to magmatic diffusion of definite chemical compounds to and from the cooling surface; further, that these diffusion-phenomena in all probability stand in direct relation to the order of crystallization of minerals in the corresponding magma; and lastly, that the order of crystallization, the nature of the differentiation, and the sequence of eruptions are all closely related phenomena.’ Differentiation dependent upon crystallization rests on a somewhat firmer basis, and it was this kind of differentiation that first attracted. my attention. Mr. Clough, while mapping the Cheviot district, proved that the widespread series of andesitic lavas is cut by a number of quartz-felsite dykes. Why did quartz-felsite succeed andesite in the Cheviot district? This was the question which kept continually recurring to me during my examination of the rocks of Vol. 57.] ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxill the district. Now, a microscopic examination of the andesites proved that the phenocrysts taken together must have the composition of a basic rock, for they were composed of labradorite, augite, and hypersthene, and therefore the glassy base present in some of the | andesites must be allied to quartz-felsite in composition. The sequence established by Mr. Clough could therefore be explained by the assumption that the quartz-felsite magma represented the mother- liquor of the andesitic magma, after the phenocrysts had separated out. Thus, if crystallization had progressed in the plutonic mass to the stage represented by the phenocrysts of the lava, or a little further, and the mother-liquor had then been squeezed out as one squeezes water out of a sponge, or separated in any other way, and forced upwards into cracks in the overlying series of andesitic lava- flows, the question above referred to could be satisfactorily answered. I was fortunately able to test the theory quantitatively, for Mr. Waller had already analysed one of the quartz-felsites and Dr. Petersen had published analyses of the glassy base of one of the andesites and of the devitrified base of another. On comparing the mean of the two analyses of the base with the analysis of the quartz- felsite, it was found that of the eight constituents, six differed by less than 4 per cent., silica differed by 2°2, and soda by 1°46." Differentiation dependent on crystallization is a fact which can- not be denied ; for the igneous magma, except when it cools as a 1 As the figures were not placed side by side in the original paper (Geol. Mag. 1885, p. 106), I so place them now :— ie 10% III. IV. Diff. SiO Ge actus ea: 66°25 65:16 65710) .'. -6F9 2-20 AICO eee ne 13:59 17-49 15°54 Nore +016 Ba rel. S11 3-01 3:06 3:0 —0:06 GAO. Eee. 2°75 0-84 1:79 14 — 0:39 NBO Te 0-28 2°34 rot 15 +0:19 TO en 4-95 5:54 5:24 56 +0:36 Mar aceare-t 2-25 3°68 2:96 i —1-46 i ree 5:89 1:76 3°82 3°7 —012 99:07 99:82 99-42 100°3 I = Glassy base of hypersthene-andesite from Fairhaugh, Usway Burn, Cheviots. (Ebert.) II = Devitrified base of andesite, 2 miles up Allerhope Burn. (Wulf.) TIT = Mean of the two analyses. IV = Quartz-felsite from dyke on the Coquet, 3 mile above Shillmoor Farm, Cheviots, (Waller.) Ixxxiv PROCEEDINGS OF THE GEOLOGICAL society. [May 1907, glass, separates into distinct minerals which do not, as a rule, con- solidate simultaneously. But the acceptance of this fact does not involve the acceptance of the differentiation-theory of the origin of petrographical species, for, as M. Michel Lévy points out, the erystal- lization of a magma under ordinary circumstances does not com- mence until it has reached a pasty state. MM. Fouqué & Lévy observed no tendency to differentiation, of the kind required to produce petrographical species, in their celebrated synthetical expe- riments. The centres of crystallization were uniformly distributed throughout the masses, which were too viscous to allow of any appreciable movement of the first-formed minerals. Nevertheless, the facts observed by Darwin and others clearly prove that in large masses of lava, even at the surface of the earth, movement of crystals is possible in igneous magmas, and M. Michel Lévy himself admits that such movement may become an important factor under certain — circumstances, Mr. Harker has suggested another way in which crystallization may operate, so as to produce variation in a mass of rock. He has shown that the Carrock-Fell gabbro varies in composition from the centre to the sides, and that, as so frequently happens in eruptive masses, the latter are more basic than the former. He considers ‘that the differentiation took place by diffusion in a fluid magma, but not as a process distinct from and quite anterior to crystallization. It was, as I believe, effected in a quasi-saturated magma, concurrently with the crystallization of the earlier-formed minerals; .... the characteristic of all [such occurrences] is that the several constituents are concentrated in a definite order, which is identical with the order in which they crystallize out from the magma.’ All theories which depend on diffusion or molecular flow have been criticized by Mr. Becker on the ground that the rate of diffusion is too slow to produce the results attributed to it in any reasonable time. He shows that, in the case of a column of water resting upon a layer of copper-sulphate, the lapse of 1,000,000 years would be required to produce sensible discoloration at a height of 350 metres, or semisaturation at a height of 84 metres; and he considers that the molecular flow of any compound in a silicate-magma would © probably be at least 50 times less rapid, so that a mass of lava 1 cubic kilometre in volume ‘would not have had time to segregate into distinetly different rocks by molecular flow if it had been kept melted since the close of the Archean period.’ Vol. 57.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. xcV In addition to the exhibits mentioned on p. xciv, the following specimens, photographs, and maps were exhibited :— Specimens exhibited by the Rev. R. Ashington Bullen, B.A, F.L.S., F.G.S., in iNustration of his paper. Specimens of Rocks and Fossils from Antigua, from the Geological Society’s Museum, collected by Dr. N. Nugent, Major-Gen. Sir Patrick Ross, G.C.M.G., and Mr. Guilding, exhibited in illustration of Prof. J. W. Spencer’s paper on that island, Photographs of probable Moraine on which Scratched Boulders are found, near Lea Schools, Matlock Bath (Derbyshire), exhibited by W. J. P. Burton, Esq., F.G.S. Photographs showing the Conformity of the Witteberg Series to the Bokkeveld Series, and of the latter to the Table-Mountain Sandstone, by E. H. L. Schwarz, Esq., A.R.C.S., of the Geological Survey of Cape Colony, exhibited by Prof. J. W. Judd, C.B., LL.D., F.R.S., F:G.S8. Five Sheets of the Geological Map of Rumania, presented by the Director of the Museum of Geology, Bukharest. May 8th, 1901. J.J. H. Tuart, Esq., M.A., V.P.R.S., President, in the Chair. Frecheville Joseph Ballantine-Dykes, Esq., Kwala Lumpor, Selangor (Straits Settlements); and George William Roome, Esq., B.Se., Normal College, Bangor (North Wales), were elected Fellows of the Society. The List of Donations to the Library was read. The following communication was read :— ‘The Influence of the Winds upon Climate during the Pieistocene Epoch; a Palzeo-Meteorological Explanation of some Geological Problems.’ By F. W. Harmer, Esq., F.G.S. The following specimens, photographs, and maps were exhibited :— Specimens from the Cretaceous of Texas, exhibited by E. A. Martin, Ksq., F.G.8. Six Photographs of the Contorted Glacial Drifts of the Norfolk Coast, between Cromer and Sheringham, taken and exhibited by A. T. Metcalfe, Esq., F.G.S. Four Sheets of the Geological Map of the Grand Duchy of Hesse, scale us by G. Klemm and C. Chelius, 1901, presented by the Director of the Grand Ducal Survey. VOL. LYII. x¢eV1 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Aug. 1901, May 22nd, 1901. J.J. H. Teatz, Esq., M.A., V.P.R.S., President, in the Chair. The List of Donations to the Library was read. Mr. Groren Axsort, in exhibiting some specimens of Cellular Limestone from the Permian beds at Fulwell, Sunderland, which he proposed to present to the British Museum (Natural History), remarked that their interest depended upon the assumption that they were entirely inorganic. Although showing a remarkable resemblance to corals, yet no zoologist or geologist had yet claimed them as organic. If this surmise were correct, the carbonate-of- lime-molecules—probably when amerphous—must have had some inherent molecular directive force which produced the numerous distinct patterns in their structure. These fall into four distinct classes :—honeycomb (two kinds), coralloid, and pseudo-organic, the last-named being remarkable for having a constant discoidal shape, and therefore those of this class must have had their external form also controlled by the hypothetical force. Each class appears to have passed through four stages of ‘crowth’ and to have undergone some marvellous rearrangements of the particles while in the solid condition. So far as he knew, no one had previously attempted to classify the different patterns, nor had anyone, except William King, in his work on ‘ Permian Fossils,’ offered any theory as to the formation of this cellular structure in the Magnesian Limestone. The following communications were read :— 1. ‘On the Skull of a Chiru-like Antelope from the Ossifcrous Deposits of Hundes (Tibet).’ By Richard Lydekker, Esq., B.A., F.RSS EGS: | 2. ‘On the Occurrence of Silurian [?] Rocks in Forfarshire and Kincardineshire along the Eastern Border of the Highlands.’ By George Barrow, Esq., F.G.S.' 3. ‘On the Crush-Conglomerates of Argyllshire.’ By J. B. Hill, Esq., R.N.* (Communicated by R. 8. Herries, Esq., M.A., Sec.G.S.) In addition to the specimens described above, the following specimens and map were exhibited :— Skull of a Chiru-like Antelope from the Ossiferous Deposits of Hundes (Tibet), from the Geological Society’s Museum, and a Skull of a recent Antelope, exhibited by R. Lydekker, Esq., B.A., F.R.S., F.G.S., in illustration of his paper. _ Rock-specimens and Microscope-sections, exhibited by G. Barrow, Esq., F.G.8., in illustration of his paper. * Communicated by permission of the Director of H.M. Geological Survey. Vol. 57.] | PROCEEDINGS OF THE GEOLOGICAL SOCIETY. x¢vll Six specimens of the so-called ‘ Clay-Concretions’ from Vermont (U.S.A.), possessing unusual symmetry. They are really calcareous concretions (containing about 50 per cent. of calcium-carbonate) from the river-drift clays of the Connecticut Valley. Exhibited by George Abbott, Esq., M.R.C.S. Geological Survey of Norway Map, = No. 25D. Lillehammer, by T. Muenster, 1899, presented by the Director of that Survey. — June Sth, 1901. J.J. H. Toart, Esq., M.A., V.P.R.S., President, in the Chair. Henry Johnson, Esq., Castledale, Dudley (Worcestershire), was elected a Fellow of the Society. The Names of certain Fellows of the Society were read out for the first time, in conformity with the Bye-Laws, Sect. VI. Art. 5, in consequence of the non-payment of the Arrears of their Contri- butions. The List of Donations to the Library was read. The following communications were read :— 1. ‘On the Passage of a Seam of Coal into a Seam of Dolomite.’ By Aubrey Strahan, Esq., M.A., F.G.S.’ 2. ‘On some Landslips in Boulder-Clay near Scarborough. By Horace Woollaston Monckton, Esq., F.L.S., V.P.G.S. The following specimens, photographs, and lantern-slides were exhibited :— Specimens and Microscope-sections of Dolomite from the Wirral Colliery (Cheshire), exhibited by A. Strahan, Esq., M.A., F.GS., in illustration of his paper. Photographs and Lantern-slides, exhibited by H. W. Monckton, Esq., F.L.S., V.P.G.S., in illustration of his paper. June 19th, 1901. J. J. H. Teart, Esq., M.A., V.P.R.S., President, in the Chair. George Abbott, Esq., M.R.C.S., 33 Upper Grosvenor Road, Tunbridge Wells; William John Ball, Esq., 33 Hungerford Road, Crewe; and Prof. Edward Thomas Mellor, B.Sc., Vaynor, Belmont Road, Portswood, Southampton, were elected Fellows of the Society. 1 Communicated by permission of the Director of H.M. Geological. Survey. | xX¢cVill PROCEEDINGS OF THE GEOLOGICAL socIFTY. [ Aug. IgoOl. The Names of certain Fellows of the Society were read out for the second time, in conformity with the Bye-Laws, Sect. VI. Art. 5, in consequence of the non-payment of the Arrears of their Contri- butions. The List of Donations to the Library was read. The following communications were read :— . ‘On the Use of a Geological Datum.’ By Beeby Thommen ts F.G.8., F.C.S. . ‘On Intrusive, Tuff-like, Igneous Rocks and Breton in Ireland.’ By . ames R. Kilroe, Esq., and Alexander McHenry, Esq., M.R.J.A.* (Communicated by R. S. iene Esq., M.A., Sec.G.S.) | The following specimens were exhibited :— Rock-specimens of Tuff-like Igneous Rocks from Ireland, exhibited by J. R. Kilroe, Esq., and A. McHenry, Esq., M.R.I.A., in illus- tration of their paper. Drift-worn Paleolithic Implement: found at Orpington (Kent), exhibited by George Clinch, Esq., F.G.S. Rock-specimens from the Salcombe district (South Devon), show- ing crumpling and folding, exhibited by William P. D. Stebbing, Esq., EGS. ‘ Communicated by permission of the Director of H.M. Geological Survey. Vol. 57. ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxxy IT am by no means ayerse to making heavy drafts on the bank of time for geological purposes, but unless some effective answer to Mr. Becker’s arguments can be found, I think that we shall have to give up unaided molecular flow as an important factor in the origin of petrographical species. Mr. Becker has not, however, simply confined himself to destructive criticism. He has proposed a theory of differentiation dependent on ‘fractional crystallization.’ During the cooling of a mass of molten matter in a dyke or laccolite, convection-currents will be established ; these will act as stirrers, and, aided by diffusion, will tend rapidly to restore homogeneity in the liquid mass after it has been destroyed by, the deposition of the first-formed crystals on the walls of the cooling surfaces. He compares a laccolite in which the marginal parts are different from the centre, to a barrel of cider which has been frozen from the outside. During the earlier stages nearly pure ice is formed on the walls, while the alcohol is concentrated in the central portion ; from this a liquor, gradually increasing in strength, may be drawn off as consolidation progresses. Here we see a further — development of the idea originated by Darwin. All forms of the differentiation-theory take as their starting- point a homogeneous magma, and then proceed to derive from it the different varieties of igneous rocks as we now see them by magmatic or some other form of differentiation. Are we justified in taking this view? As applied to certain districts, and especially to the Christiania district which Prof. Brégger has done so much to elucidate, it has proved of great value. But if we look at the general question, there are many facts which should give us pause. The earth’s crust is certainly heterogeneous, and if magmas are, in any case, formed by the refusion of solid rocks, it is probable, as Mr. Becker has pointed out, that such magmas would be hetero- geneous at the start. Even the refusion of homogeneous rocks may give rise to a heterogeneous magma, comparable to that produced by Faraday in his experiments on glass. The cause of some of the variations in igneous rocks is therefore probably to be sought for in actions which antedate the formation of the magmas. But even homogeneous magmas may become modified by the absorption or assimilation of the rocks through which they pass. This point has been clearly established and especially emphasized by M. Michel Lévy, Prof. Barrois, and Prof. Lacroix in France, and by Dr. Johnston Lavis, Prof. Sollas, Prof. Cole, and Mr. Harker in this country. VOL. LVII. g Ixxxvi PROCEEDINGS OF THE GEOLOGICAL socieTy. [May 1901, That it is a vera causa is admitted on all hands, but differences of opinion exist as to the extent to which it should be applied in explaining the origin of petrographical species. If we study igneous rocks which have appeared at the surface as lavas, or have been intruded at moderate depths as dykes, sills, laccolites, or bosses, the evidence of absorption is, in my judgment, so slight as to be practically negligible; but if we pass from such regions to others in which plutonic rocks are found in relation with crystalline schists and study ‘les appareils granitiques 4 racines profondes’ of M. Michel Lévy, the case is different. It may be that the final solution of the problem of the origin of igneous magmas will be found in these regions; but here we touch a question which belongs to the future rather than to the past, and hes, therefore, beyond the scope of this Address. So far as | am concerned, I will confess that my ideas are not fixed. At present I am not disposed to attach much importance to theories involving differentiation a situ by unaided molecular flow in dykes and laccolites ; but rather to attribute such variation as does occur to successive eruptions, or to a continuous change in the nature of the material during the process of intrusion. The great difficulty in applying any theory that involves differentiation am situ to such cases arises from the slight effect of the igneous magmas on the containing walls—a fact which negatives the idea that the material arrived at the place where we now find it in a condition of super- fusion, or that it remained fluid long enough to enable any con- siderable diffusion to take place. Our ideas as to the origin of igneous rocks are still ‘en pleine évolution.’ Conditions are rapidly changing in consequence of dis- coveries in geology and physical chemistry. Rival theories are struggling for existence, and although it is safe to predict that some will become extinct, that others will be modified, and that natural selection will finally bring about the survival of the fittest, it is impossible to determine, at present, the relative importance of those which claim our attention. The origin of petrographical species, so far as the igneous rocks are concerned, is a problem the final solution of which has been handed on by the nineteenth century to its successor. Vol. 57.] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. Ixxxvii February 20th, 1901. J.J. H. Tear, Esq., M.A., V.P.R.S., President, in the Chair. George William Sawyer Brewer, Esq., Ryeworth Villa, Charlton Kings, Cheltenham ; James Carter, Esq., 1 Granville Road, Black- burn; Louis Charles Deverell, Esq., F.C.S., 104 Upper Thames Street, E.C.; Percy Hawkins, Esy., Beswada, Kistna District (Madras Presidency); and L. Clements Henry, Esq., F.R.G.S., Axim, Gold Coast (West Africa), were elected Fellows of the Society. The List of Donations to the Library was read. The Appress which it was proposed to submit to His Majesty the King, on behalf of the President, Council, and Fellows, was read as follows, and the terms thereof were approved :— ‘TO THE KING’S MOST EXCELLENT MAJESTY. ‘May iT preasE Your Magszsty, ‘We, Your Majesty’s most dutiful and loyal subjects, the President, Council, and Fellows of the Geological Society of London, humbly beg leave to offer to Your Majesty our most profound and heartfelt sympathy in the great sorrow which has fallen on You in the death of our late beloved Sovereign Queen Victoria, and to most respectfully express the deep grief that we, in common with all Your Majesty’s subjects, feel at the great loss which has befallen the Nation. ‘While thus expressing our grief, we most humbly beg leave to offer to Your Majesty our most sincere and unfeigned congratulations on Your Majesty’s Accession to the Throne of Your Ancestors. Our knowledge of the great interest _ which Your Majesty has always taken in all matters relating to the welfare of Your subjects makes us feel with confidence that Science will continue to advance during Your Reign as in that of Her late Majesty of beloved memory. We recall with pride that Your Majesty’s Father, the late Prince Consort, was for many years a Fellow of this Society. ‘ And we shall ever pray that Your Majesty may long be spared to reign over a happy and contented people.’ Prof. J. B. Harrison, alluding to a series of views of parts of the interior of British Guiana, which he laid on the table, remarked that the photographs had been taken by his colleague, Mr. H. I. Perkins, F.G.8., Acting Commissioner of Mines in British Guiana, during their recent geological investi- gations into the structure of the goldfields of that colony. The views well illustrate the general characteristics of the densely wooded country in which the gold-bearing areas occur, and give some idea of the difficulties which affect the work of the mining prospector and of the field-geologist in that colony. Several of the photographs illustrate rapids, cataracts, and falls which so frequently occur along the courses of some of the vast rivers of that part of South America, and show the differing forms of weathering of various igneous rocks and of horizontally-bedded sandstones and conglomerates in the tropics. Among the photographs are several fine views of the Kaieteur Ixxxvill PROCEEDINGS OF THE GEOLOGICAL Society. [May 1gor1, Falls on the Potaro River, a tributary of the Essequibo. These falls, which were discovered by a Fellow of the Geological Society, Mr. C. Barrington Brown, in the course of his geological recon- naissance of the colony about thirty years ago, occur near the escarpment of the great sandstone-formation which is so largely developed in the Guianas and in Brazil. The falls are over a ledge of very coarse siliceous conglomerate, some 18 or 20 feet thick, which overlies a thickness of about 1000 feet of almost horizontally- bedded sandstones. The river above the ‘falls 1s about 400 feet broad and from 18 to 20 feet deep, and plunges vertically, as a great curtain of water, for 740 feet, into a vast chasm at the extremity of a deep valley which it has eroded for a distance of about 17 miles from the escarpment of the sandstones. During the first 3 or 4 miles of its course from the falls through the valley, the river descends for about 400 feet by a series of cataracts and rapids. The valley, which is eroded in places through the sandstones into the underlying igneous rocks, is of surpassing beauty, and offers many features of marked geological interest. One of the views, taken when the water was low after a long-continued drought, ‘shows very clearly the great cave which the spray of the falling water has cut out from the softer sandstone-strata. Others of the views show the somewhat primitive methods employed in prospecting and in working the placer-claims for gold. With reference to a few rock-specimens exhibited, Prof. Harrison stated that they were of diamond-drill cores from the Omai-Creek claims on the Essequibo River, and that they fairly represented the principal auriferous rocks of that district. Omai Creek is a small stream flowing into the Essequibo at about 1350 miles above its mouth, and the country through which it flows is usually diabase (dolerite) and its. decomposition-products. From a part of the bed of one of the tributaries of this stream (Gilt Creek), about 500 feet in length by 50 in breadth, some 60,000 ounces of gold and some hundreds of small diamonds have been recovered by the somewhat crude methods of working hitherto in use. The specimens shown were of quartz-diabase and of a massive epidiorite, the oldest auriferous rocks in the district; of an in- trusive aplite or possibly altered albite-granite, the con- tents of which in gold (apparently of secondary origin) vary from 1 to 15 dwts. per ton, but in places where it is intersected by veins of secondary quartz may rise to 40 or 50 ounces per ton of the rock; of diabase or dolerite, so far as is at present known the rock of most recent origin in the colony, and it is, in the speaker’s experience, invariably auriferous, appearing in fact to be the principal source of gold in the Guianas; and of highly- altered porphyroids, in parts changed almost completely to epidote-chlorite rocks, in others to sericite-rocks wherein the original porphyrites and quartz-porphyrites can be discerned only with difficulty, and these in that district form the practically non auriferous country-rock. The so-called placer-deposits of British Guiana form a Volis 7] PROCEEDINGS OF THE GEOLOGICAL SOCIETY. Ixxxix striking exception to the generally received text-book view of the origin of placer gold-deposits. In the speaker’s experience the Guiana deposits have not been derived to any great extent from pre-existent quartz-reefs containing gold, but from the degradation in situ of diorites, epidiorites, and hornblende-schists originally more or less auriferous, or in places of mineralized masses and dykes of acidic or of intermediate rocks ; but principally of bosses, sills, and dykes of an intrusive diabase or dolerite of at present unknown geological age, which appear to be always gold-bearing to a minute extent, while in places the selvages of the dykes may contain as much as 5 ounces of gold per ton of the rock. He hoped at some future opportunity to return to the subject, and to lay before the Society the evidence which he had obtained for the above statements, and also the results of many observations bearing on the genesis of placer gold-deposits, and on the concentration of the minute amounts of the precious metal contained in igneous rocks in their degradation-products by processes of chemical solution and redeposition under tropical conditions. _ Finally, he reminded the meeting that the area in which he is at present working forms but a small portion—some 300 miles in breadth—of that great, though almost undeveloped, mineralized belt which extends from El Callao in Venezuelan Guiana to near the mouth of the Amazon in Brazilian Guiana. Prof. Epwarp Hutt made a communication, illustrated by lantern-slides, on the submerged valley opposite the mouth of the River Congo. The position of this submerged valley has been ascertained by Mr. Edward Stallybrass and Prot. Hull, by contouring the floor of the ocean with the aid of the soundings recorded on the Admiralty Charts. The sides of the valley are steep and precipitous and clearly defined, the width varying from 2 to 10 miles, and the length across the Continental platform being about 122 miles. It is continuous with the Valley of the Congo, and its slope is uninterruptedly downward in the direction of the abyssal floor. The steepness of the sides indicates that they are formed of very solid rocks. Several other submerged valleys off the coast of Western Kurope were described for comparison. In most cases the landward end of the submerged river-channel is filled with silt, etc. for some distance from the mouth of the actual river; but, farther out, its course becomes quite distinct towards its embouchure at the edge of the Continental platform. Among the valleys specified were those off the mouth of the Tagus and the Lima, the Adour, and the Loire, and those in the English and Irish Channels. ; The following communication was read :— ‘On the Beds between the Millstone Grit and Mountain Lime- stone of Pendle Hill, and their Equivalents in certain other Parts of Britain. By Wheelton Hind, M.D., B.S., F.RCS., F.G.8., and J. Allen Howe, Esq., B.Sc., F.G.S. xe PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, In addition to the photographs and specimens described on p. Ixxxviii the following were exhibited :-— Specimens of Rocks and Fossils from the Millstone Grit Series, with Rock-sections and Lantern-slides, exhibited by Wheelton Hind, M.D., BS., F.R.C.S., F.G.8., and J. Allen Howe, Esq., B.Sc., F.G.S., in illustration of their paper. Vertical Sections, Geological Survey of England & Wales, Nos. 83 & 84: South Wales Coalfield, by A. Strahan & W. Gibson, presented by the Director-General of H.M. Geological Survey. March 6th, 1901. J.J. H. Teatz, Esq., M.A., V.P.R.S., President, in the Chair. Joseph Alfred. Bean, Esq., Moot Hall, Newcastle-upon-Tyne, was elected a Fellow of the Society. The List of Donations to the Library was read. The Presipent read the following resolution, which had been passed unanimously by the Council at their Meeting that after- noon :— ‘That this Council desire to place on record their deep sense of the loss occasioned to Geological Science by the death of Dr. GuORGE M. Dawson, C.M.G., and to express their sincere sympathy with his family in their bereavement.’ The Presrpenr announced that Sir ArcurBatp Grtxie, D.Sc., D.C.L., LL.D., F.R.S. (President from 1890 to 1892), had presented to the Society a large framed photographic portrait of himself. The following communications were read :— 1. ‘Recent Geological Changes in Northern and Central Asia.’ By Prof. George Frederick Wright, F.G.S.A. (Communicated by the President.) 2. ‘The Hollow Spherulites of the Yellowstone and Great Britain.’ By John Parkinson, Hsq., F.G.S. The following specimens were exhibited :— Rock-specimens and Microscope-sections exhibited by John Parkinson, Esq., F.G.S., in illustration of his paper. Limestone bored by a Species of Worm (?), from Hempstead Beach (Isle of Wight), exhibited by W. P. D. Stebbing, Esq., F.G.S. | Wel, 5921 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. x¢l March 20th, 1901. J.J. H. Tuart, Esq., M.A., V.P.R.S., President, in the Chair. George Edward Blundell, Esq., Wellington College (Berkshire), and Thomas Andrew Oliver, Esq., Southfield House, Bramcote (Nottinghamshire), were elected Fellows of the Society. The List of Donations to the Library was read. Mr. H. B. Woopwarp called attention to a polished slab of Landscape Marble, or Cotham Stone, from the Rhetic Beds near Bristol, which had kindly been lent for exhibition by Mr. Frederick James, Curator of the Maidstone Museum. The specimen showed that, after the arborescent markings had been produced in the soft mud, some irregular and partial solidification took place in the upper layers of the deposit; and then, during contraction, a kind of subsidence occurred, of the upper and harder portions into the lower and softer materials. This subsidence was accompanied by a breaking-up of the harder portions, suggesting a comparison (in miniature) with ‘ broken beds’ and even crush- conglomerates. The specimen was of considerable interest, as illustrating the mechanical changes produced during solidification. The following communications were read :— 1. ‘On a Remarkable Volcanic Vent of Tertiary Age in the Island of Arran, enclosing Mesozoic Fossiliferous Rocks.’ {Communicated by permission of the Director-General of H.M. Geological Survey. | Part I.—‘ The Geological Structure.’ By Benjamin Neeve Peach, Ksq., F.R.S.L. & E., F.G.8., and William Gunn, Esq., F.G.S. Part II.—‘ Paleontological Notes.’ By Edwin Tulley Newton, Esq., ERS. E.G.S. 2. ‘On the Character of the Upper Coal-Measures of North Staffordshire, Denbighshire, South Staffordshire, and Nottingham- shire; and their Relation to the Productive Series.’ By Walcot Gibson, Esq., F.G.S. [Communicated by permission of the Director of H.M. Geological Survey. ] The following specimens, etc. were exhibited, in addition to that described above :— Rocks and Fossils from Arran, exhibited by permission of the Director of H.M. Geological Survey, in illustration of the paper by x¢li PROCEEDINGS OF THE GEOLOGICAL society. [May 1901, Messrs. B. N. Peach, F.R.S.L. & E., F.G.S., W. Gunn, F.G.S., and HK. T. Newton, F.R.S., F.G.S. Rocks and Fossils of the Upper Coal-Measures of North Stafford- shire, etc., exhibited by Walcot Gibson, Esq., F.G.S., in illustration of his paper. A copy of the 1st Edition (1873) of the Geological Sketch-Map of Cape Colony, drawn up and presented by E. J. Dunn, Esq., F.G.S. March 27th, 1901. Special General Meeting: 8 P.M. J.J. H. Treats, Esq., M.A., V.P.R.S., President, in the Chair. This meeting was convened on the requisition of the following five or more Fellows, namely :—The Rey. J. F. Braxz, Dr. Henry Woopwarp, Dr. A. Smira Woopwarp, Sir Henry H. Howorrts, Dr. F. A. Barner, Mr. R. Burren Newton, Mr. H. A. Anten, Mr. C. Davies SuErzory, Dr. F. L. Kircuin, Mr. Uprrenp Green, and Mr. G. EK. Dinter ; for the purpose of considering the following matters :~— 1. The present state of the Society’s Museum. 2. The steps necessary to be taken for putting the collections therein contained into a satisfactory condition, if retained in the Museum; or otherwise the desirability and conditions of their disposal elsewhere, as may be decided on. 3. The arrangements necessary to be made, in order to keep the collections constantly in a satisfactory condition, if their retention is decided on. 4. The amount necessary to be expended (a) in the first instance, and (6) annually, to carry out the decisions of the Meeting. Also to authorize the Council to incur this expenditure; and finally to make such order concerning the estates or revenues of the Society as to the Fellows assembled in such General Meeting shall appear useful for the purpose of carrying out their decisions. The Rev. J. F. Brake proposed, and Mr. R. Butten Newton seconded, the following resolutions :— 1. That the general collection in the Society’s Museum be limited to such specimens as have been or may hereafter be definitely referred to, by name, description, or figure, in the Society’s publications, or in such other works as may be agreed upon by the Council. 2. That the specimens retained be thoroughly cleaned, provided with fresh labels additional to the old ones, placed in drawers or boxes designed to exclude dust, and arranged with reference to the papers or works wherein they are referred to, and that a catalogue of such retained specimens be printed. 3. That the remaining specimens be disposed of in such a way as the Council may direct. Vol. 57.] | PROCEEDINGS OF THE GEOLOGICAL SOCIETY. XClii 4, That the Council be authorized to expend, either out of capital or income, so much as Ny be necessary to carry these resolutions into effect. The following Amendment was moved by Sir Henry Howorrs, F.R.S., and seconded by Prof. W. Boyp Dawkins, F.R.S. :— That in the opinion of this Meeting the time has now come when this Society shall transfer its collections to some other Museum, The Amendment was put, and there voted for it 22, against 19. The Amendment was therefore carried, and on being again put as a Substantive resolution there voted fan it 26, against 19. The Amendment was therefore declared carried as the Resolution of the Meeting. April 3rd, 1901. Horace W. Monoxton, Esq., F.L.S., Vice-President, in the Chair. Joseph 8S. Bridges, Esq., B.Sc., 45 Thistlethwaite Road, Clapton, N.E.; and Thomas Birch Freeman Sam, Esq., C.E., c/o Messrs. F. & A, Swanzy, 147 Cannon Street, E.C., and Cape Coast Castle (Gold Coast), West Africa, were elected Fellows of the Society. The List of Donations to the Library was read. The following communication was read :— ‘The Igneous Rocks and Associated Sedimentary Beds of the Tortworth Inlier.’ By Prof. Conwy Lloyd Morgan, F.R.S., F.G.8., and Sidney Hugh Reynolds, Esq., M.A., F.G.S. The following specimens and maps were exhibited :— Specimens, Rock-sections, and Lantern-slides, exhibited by Prof.C. Lloyd Morgan, F.R.S., F. G.S. ang) S.) HH. Reynolds, Ksq., M.A., F.G.S., in illustration of their paper. Curiously-worn Bunter Pebble from the Drift at Woolmer Green (Hertfordshire), exhibited by A. E. Salter, Esq., B.Sc., F.G.S8. Relief-Map of Canada and the United States (1 inch=250 miles), 1900, presented by the Director of the Geological pe of Canada, Carte Géologique du Massif du Mont-Blanc, a5 a drawn up and presented by L.. Dupare and L. Mrazec. , VoL, LVII. h XC1V PROCEEDINGS OF THE GEOLOGICAL socieTy. [May root. April 24th, 1901. J.J. H. Tear, Esq., M.A., V.P.R.S., President, in the Chair. Vaughan Cornish, Esq., M.Sc., F.C.S., F.R.G.S., 72 Princes — Square, London, W.; Ronald Audiey Martineau Dixon, Esq., 46 Marlborough Avenue, Huli; and Charles Kenelm Digby Jones, Esq., 12 Chester Street, Edinburgh, were elected Fellows; and Prof. Friedrich Johann Becke, of Vienna, was elected a Foreign Correspondent of the Society. The List of Donations to the Library was read. The Secretary read the following letter, which had been received from H.M. Secretary of State for the Home Department :— a Home Office, Whitehall, 8rd April, 1901. ‘Sir, I am commanded by the King to convey to you hereby His Majesty’s thanks for the Loyal and Dutiful Address of the President, Council, and Fellows of the Geological Society of London expressing sympathy on the occasion of the lamented death of Her late Majesty Queen Victoria, and congratulation on His Majesty’s Accession to the Throne. ; ‘I am, Sir, J. J. H: Tran, Esq: ‘Your obedient Servant, Geological Society of London, ‘Cuas. T. RiTcHTE.’ Burlington House, W. The Prestpent drew attention to a framed and glazed copy of the Table of the British Strata by Dr. Henry Woodward, F.R.S., F.G.S8., and Horace B. Woodward, Esq., F.R.S., F.G.8., which the former had kindly presented to the Society. In exhibiting a specimen of Crioceras occultus from the Snettisham Clay of Heacham, near Hunstanton, Prof. H. G. Szztny said that he had no doubt that the Trigonia hunstantonensis and Crioceras occultus, originally described as from the Hunstanton Limestone, were from the clay at Heacham. The example of Crioceras now shown was found by Mr. F. Deighton, of Cambridge. It only differs as a variety from the type figured in 1865. The following communications were read :— 1. ‘Notes on Two Well-Sections.’ By the Rev. R. Ashington Bullen, B.A., F.LS., F.G.S. 2. ‘On the Geological and Physical Development of Antigua’ ; 3. ‘On the Geological and Physical Development of Guadeloupe’; 4, ‘On the Geological and Physical Development of Anguilla, St. Martin, St. Bartholomew, and Sombrero’; and 5. ‘On the Geological and Physical Development of the St. Christopher Chain and Saba Banks’: the four last-named papers being by Prof. J. W. Spencer, Ph.D., M.A., F.GS. ADMISSION AND PRIVILEGES OF FELLOWS OF THE GEOLOGICAL SOCIETY OF LONDON. Every Candidate for admission as a Fellow must be proposed by three or more Fellows, who must sign a Certificate in his favour. The Proposer whose name stands first upon the Oertificate must have a personal knowledge of the Candidate. Fellows on election pay an Admission Fee of Six Guineas. The Annual Contribu- tion paid by Fellows is Two Guineas, due on the Ist of January in eyery year, and payable in advance; but Fellows elected after the month of February are subject only to a proportionate part of the Contribution for the year in which they are elected, and Fellows elected in November or December pay no Contribution for the current _ year, The Annual Contribution may at any time be compounded for by a payment of Thirty-Five Pounds. The Fellows are entitled to receive gratuitously all the volumes or parts of volumes of the Quarterly Journal of the Society that may be published after their election, so long as their Annual Contributions are paid; and they may purchase any of the pu blications of the Society at a reduction of 25 per cent. under the selling prices. The Library is open daily to the Fellows between the hours of 10 and 5 (except during the fortnight commencing on the first Monday in September; see also next page), and on Meeting Days until 8 p.m. Under certain restrictions, Fellows are allowed to borrow books from the Library. Publications to be had of the Geological Society, Burlington House. Reduced Price Reduced Price TRANSACTIONS. tothe Helloee TRANSACTIONS. to the 7 : 8. d. 8. d. em pe ALD ins sneecadcccvensccdsvcassesecs EAS OF) 2 Vols JV ip sh aut ls cireceststestesaseteceesree 010 0 Ole Eee Parti bovcse,saiccecs