. on AGE Re Aenean Testes ee ve Fae 9 tf "5 i net Se oy ash diene A Stn At nite, Wes: fata Hy ae rates eee ae rot mm sian teby * bee hy og See te take seri ise a es byt ee cesaceet Piper ee trae sar yy) ee ee eases re — wit wiper: mre eae) paee ,} soit >> + tietaert mits = Hupeibad se igs’ ea do Hayate a nts oi ae fees eet pe ee a q nd a Maes , apes 74 ott sah) roiniie data a at a if “mdowvareion!® “4 ih ya is Ane ieee a att aire fs os = i ee ao eth ys Avy re) jen) eve ) sat “i oy a iia Hd 49 corti : ‘ Sereeg se quiceantey b pepe gered meee ate sarah aie ‘ai Resin aoa entogn wrt thinatah neo aceme gt Gye tara ae tetteeat we eye age hea i > Tite vapeindaeerarae HY Hs Mattie ai He} ae . kpen seats dratetiete et Mt a hoe te feSetehadlet ide “ teehee bt rest pitta irtppees re Pao! wh ah tetoeet blog Rie tat ve Lin fe : mrpttt: SEE Syne em , Wy gpg tet ay ¢ eae f i ae hpbete . he tate bys ‘ane mis RAD TTP Pa PEL DP po. af Rian ti : Nw ¥ SE Gey we moe Se i gO any +. et Vm EL rH HeCey eawe Verges OL eh hha HLT] ye ee oo Swybhicel” Ti ph het ‘ TEL Eves tte heaegse SeEEEL EL Tit ThA. ; : vvren ha lice eeeeeergeni ct {| Pe bid Tne face raiiee Ped mult tt Hy | v SON Sete ore rc me Ue a Lt | ale Wr/w eo PELE LE Pytrrreny Deh ps we Ww v TEL EE med A | Ny yg hd S. ‘ ae a ae iLL dha ated hd de nithededalitei Vv hats bh ere] ore eeoee vit ETL TLCEELLL LT dad eQge" wee Pert oe core yr Tint iL ce WU otewaee y, ) wy ms 4 4 ; P & “W -- re =e \w ww HCI Geet ~ , 4 Se ~JjJSaSp - 4~— ‘s WELLE - CA -* , . a | PO “ . vet ' A vi ea ON vn WON, 1 ay, ar ey ‘yrs ernann a ve, 5. Seger . is ht \ Ge e Wy : Huveurrenvyccescec CNN ner Leth? ry Wii bhl tt Seer tty cee “10¥), iw” ie BAKA 202 Ule Lala | < a | im wh Th epopelu LT bebe TTP HATE Sal enti Meee ate 0 wid | LE iy if a hd 1 ecitawe wae Nyt Sore ent ¥en NaN LL ere he ae VVYO@ws Sor asceerenaeer Nae edcey “44 < i rk | , give) Se wy By | A he Ot pate hone ul Minas 4 Bk TL ee Ts Oe diel | OR | roy LAS sty & ~ © ay rads tat lalallala) WOO a NAA i a OR Ide ul er A , hs fal eres= pu Age wd I si euee dtgg? Wee. Nw e. wt AY v wa) Wee Aare ware tw atta egy Wes RAN be fe See Os ar jZ- Bars ts SU? a A wo fe futon) ral || TH Pes ~Y DAN led) DAA tld tit X Bek 8 Were aa, (VAL phd Pa. aa8 Lt eer: Me im We avy 0 ot UveeE Jota e e 4 ni yl. EAs Py) fn. ween vee. FELL BYE le AR J Ly RY adie leied CULE TT | Rey Peace ad =A RAG - ta tne ~ é ww of a! a P Se sh os = = es as & ss NS wae ae he eae hp eS y g Ve @~ 73? AR tv nynelyaresceens” Se See ya W., 2 a fvy Novo cpus re pe yt te tiny 14" WwW” : AD. se 2 -, SAS = Moun wl we SON 7 C < + s eee. Pad aid as ANTE 5 WN Le = eS SEL. . RR hs LA yf) tace LALTIMAg “h cewesry were viewer? pet Sey , PEPE Rr H Senate leg a 3 4 rt hae » ad : ae hd = Attn spate 2” : Di Nee § saat | Nua Loma) eet (Mtr ‘ ne a ol ww 4 an EY p 3 a di Pia) eee ‘ yt Oh ad, =: FE itr Hee eh. : yw . alg eth, eo Whee ibots | uM Se a atta yo" shy Pig ¥ ww "| ~_ vy wv , } a Ne ed fice PH HLL yy -- Newey vA ster. ver bh “thy Wig wah ty a tf hah ome ST A debe Te Seas rt | iL aPuve Tien wale ~ Ss wee. WN Lmaiamaauar test Ota om w 5 a q hee ve des oS ww OT JUL yet ny, TT A a on, WY Vee 1) to oe py. tpg Ww GTVESS eet? 2 4 E r w ae AA a= (2286 aa f tee Be tee = PIS ary td rid it dy we <2 e Ses Ce ; x eid Ayer Tt ib Jen See “ jygde wes. ee i rece Sime lesen -e' Moree Wie * wot hye See see 55 ey es 9 vs = ee ee ee 2 ad ; ' ce ld a oan ae ITLL Laer TT z sue <4 a = ‘~ be i _ Wy eesc wet hence ceeny ee Saha LE w' weer hy TEE /™: : ee nhl WT « wy hy wire py rw lel ey ahr § - gotta we ceni, Wy Seyse fr, tt r ofely, Jy | \o ere Ss be IDET > AP tae Bin 1 oe te a a ; a” aff. ka fie a | Bs pss. ye oan Hi ti iN i eH a ip a ah Pia ‘ wi NS Na \ ee 4 hie Tat ceed al Ht a ak i? iy rade NUCL j AMON A via Uh Une THe Mf! ans i midi AT eda eva 4 sean ie ns aN JA AMERICAN JOURNAL OF SCIENCE, JAMES D. ann EDWARD 8S. DANA. ASSOCIATE EDITORS Prorrssors JOSIAH P. COOKE, GEORGE L. GOODALE anD JOHN TROWBRIDGE, or Camprinar. Proressors H. A. NEWTON anp A. E. VERRILL, oF New Haven, Proressor GEORGE F. BARKER, or Paimapevpata. THIRD SERIES. VOL. XXXVII.—[WHOLE NUMBER, CXxXxXVII.] Nos. 217—222. JAIN OLA) LOM SWINE isso: WITH XIV PLATES. ij Ou san” sos 7 | 276 NEW HAVEN, CONN.: J.D. & E. 8. DAN AZUL 1889. New Haven, Cc i ay SE Le CONTENTS OF VOLUME XXXVILI. Number 217: Art. I.—The History of a Doctrine; Address byS. P. Lane- a TETDIN Ci Ma SN 1 ae SES PR SIG De let eg arg BN eg I II.—Description of the new mineral, Beryllonite ; by E>warp S. Dana and Horace L. Wetis. With PlateI__.__--- I11.—The Iron Ores of the Penokee Gogebic Series of Michi- gan and Wisconsin; by C. R. Van Hise. With Plate i) (sy) IV.—Recent Observations of Mr. Frank 8S. Dopes, of the Hawaiian Government Survey, on Halema’uma’u and its debris-cone;]by Jans) 1); DANSE eee eee eee 48 We Notes;on Mauna Loan July, 1888s 22 oe as? 51 VIL—A Quartz-Keratophyre from Pigeon Point and Irving’s Ausite-syemites sib Wai. UB Aen my 2 eae ee 54 VII.—On the occurrence of Hanksite in California; by pATsINSR Va Gre ET AUNTS ity ey sais ats, yes on) ah Vee aa) shi ets 63 VIII.—Sperrylite, a new Mineral; by Horace L. Wetis-__ 67 IX.—On the Crystalline form of Sperrylite; by S. L. eg OUNOHC IGE ToD) st 1) MeL gen SAR ae iN aL A SIG) SPER CN 71 SCIENTIFIC INTELLIGENCE. Chemistry and Physics—On the Vapor-density of the Chlorides of Indium, Gal- lium, Iron and Chromium; and on two new Chlorides of Indium Nuinson and PrtTERSSON: On the Vapor-density of Ferric chloride, FrrepEL and Crarts, 73.— On the Vapor-density of Gallium chloride, FRIEDEL and Crarts: On the Molec- ular Mass of Sulphur, Phosphorus, Bromine and Iodine in Solution, PaTERNO and Nastnrt: On the Atomic Mass of Osmium, SEUBERT, 74.—A Class Book of Klementary Chemistry, W. W. FISHER: Examples in Physics, D. H. Jones: Oxy- gen lines in the Solar Spectrum, M. JANSSEN, 75.—Effect of staining upon dry plates, Kunp?T: Electrical currents produced by light, SroLETow, 76. Geology and Natural History—Cambrian of Bristol County, in Hastern Massa- chusetts, N. S. SHALER, 76.—Silicified wood of Arizona, F. H. KNowiron: Dahl. lite, a new mineral, BROGGER and BAcKstrROM: Das Protoplasma als Ferment- organismus, ALBERT WIGAND, 77.—‘‘ Ringed” Trees, W. L. Goopwin: A Provi- sional Host, an Index of the Fungi of the United States, W. G. Fartow and A. B. SEYMOUR, 79.—Bibliotheca Zoologica II, bearbeitet von O. TASCHENBERG, 80. lv CONTENTS. Number 218. J 4 : 2 Page. Art.—X.—Points in the Geological History of the islands Maui and Oahu; by James D. Dana. With Plates Wand DVe: ose se EU ee XIJ.—Experiment bearing upon the Question of the Direction and Velocity of the Electric Current; by Epwarp L. Nicnorts and WiuiiaM 8. FRANKLIN -..-._.-.--.---- 103 XII.—Occurrence of Monazite as an accessory Element in Rocks; by Onvitir A. DERBY, 222 2222222 eo XIII.—Use of Steam in Spectrum Analysis; by Joun Trow- BRIDGE ANG. VWVin CaS BING mn ese sys yee aes Hotes 114 XIV.—New Personal Equation Machine; by A G. WintER- PEATE Re eas he Sa ay peg ee ory pp a) lea pepe AML IG XV.—Subsidence of Fine Solid Particles in Liquids; by CARLY DARUS Se We Se ee eer 122 XVI.—Comparison of the Electric Theory of Light and Sir William Thomson’s Theory of a Quasi-labile Ether; by Ji; WaOLGARD GIBBSY S22. 03 Meee ak les ae Oa 129 XVII.—Geology of Fernando de Noronha. Part I; by Joun C. Branner. With a map, Plate V-.___-_-_-- . 145 XVIII.— Appendix: Restoration of Brontops robustus, from the Miocene of America; by O. C. Marsu. With lategN alas oye 3 See eer 2 Ste ee ee eee 163 SCIENTIFIC INTELLIGENCE. Miscellaneous Intelligence— American Geological Society: Mineral Resources of the United States, Day: Index der Krystallformen der Mineralien, Goup- SCHMIDT, 162, + CONTENTS. Vv Number 219. Art. XIX.—Some Determinations of the Energy of the Light from Incandescent Lamps; by Ernest Merrirr_ 167 XX.—Geology of Fernando de Noronha. Part II; Petrog- eyolnnyS Ly (Cankorxeany daly WAV eI eee ee) 178 XXI.—Ophiolite of Thurman, Warren Co., N. Y., with re- marks on the Eozoon Canadense; by Gro. P. MERRILL 189 XXII.—Origin of the deep troughs of the Oceanic depres- sion: Are any of Volcanic origin? by James D. Dana, with a bathymetric map, Plate VII ...--._--- Sol Oo, XXIL.—Description of a problematic organism from the Devonian at the Falls of the Ohio; by F. H. Knownron 202 XXIV.—Some curiously developed ‘pyrite crystals from French Creek, Delaware Co., Pa.; by 8. L. PENFIELD.__ 209 XXV.—Crystallized Bertrandite from Stoneham, Me., and Mt. Antero, Colorado; by 8. L. PEnFreLp XXVI.—Mineralogical Notes; by J. 8S. DILLER SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Determination of molecular mass by means of vapor pressure,- RAOULT, 221.—Method of avoiding ‘‘ Bumping” in Distillation, Mar- KOWNIKOFF: Thiophosphoryl fluoride, THORPE and RODGER, 222.—Relation between the Absorption-spectra of Organic Compounds and their Chemica! Composition, KruUSsS, 223.-Absorption-Spectrum of Oxygen, LIVEING and DEWAR: Spectrum of Oxygen at high altitudes, 224.—Compressibility of Oxygen, Nitro- gen and Hydrogen, AMAGAT: Heat of Vaporization of Volatile Liquids, CHaP- PUIS: Combination of Oxygen and Nitrogen in Gaseous Explosions, VEITH, 225. —Dissipation of Fog by Electricity, Sorer: Magnetization of iron and other magnetic metals, Ewine and Low: Figures produced by electric action on photographic plates, Brown, 226.—Spectrum of Cyanogen and Carbon, VOGEL: Determination of the focal length of a lens for different colors, HASSELBERG, Electrodynamic Waves, Hertz, 227.—Resistance of electrolytes, THOMSON, 228. —Orthochromatic Photography, H. W. Vocen: Voltaic Balance, 229. Geology and Mineralogy.—¥ossil Plants of the Coal-measures of Rhode Island, L. LESQUEREUX, 229.—History of Volcanic Action during the Tertiary Period in the British Isles, A. GEIKIE, 230.—Geological and Natural History Survey of Minnesota, N. H. WiIncHELL and W. UPHAM, 231.—Geological Survey of Ken- tucky, J. R. ProcTER: Geology of New Jersey, G. H. Cook, 232.—Woodham Artesian Well, E. Lewis, Jr.: Bowlder-Glaciation, H. MILLER, 233.-—Archeo- cyathus of Billings, G. J. HinpE: Analyses of waters of the Yellowstone Na- tional Park, F. A. GoocH and J. KE. WHITFIELD, 234.—Elemente der Pala&onto- logie, G. STEINMANN and L. DODERLEIN: Die Stémme der Thierreichs, Nrv- MAYR: Fossil Cockroaches, S. H. ScuppER: Visual area in the Trilobite, Pha- cops rana, J. M. CLARKE: Mineralogical Notes, K. F. AYRES, 235.—Barite from Aspen, Colorado, J. F. Kemp, 236.—Serpentine of Montville, N. J., G. P. Mrr- RILL: Shipping planes and lamellar twinning in Galena, W. Cross: New York Minerals and their localities, F. L. Nason, 237. Botany and Zoology.—Certain relations of the cell-wall, Kou: Chemical nature of assimilation, T. Bokorny, 237.—Improvement of the “races” of the Sugar Beet, C. VIOLLETTE and F. DESPREZ: Primordial leaves of Abietineze, DaGurIL- LON, 238.—Notes on Cestoid Entozoa of Marine Fishes, K. LInron, 239. Miscellaneous Scientific Intelligence.—Photographic Map of the Normal Solar Spec- ‘trum, 240.—Temparature record at Hilo, Hawaii; A short Account of the His. tory of Mathematics, W. W. R. Batu, 241.—National Geographic Magazine: Bathymetric Map, Plate VII: Soaps and Candles, J. CAMERON, 242. vi CONTENTS. Number 220. ra ws ety i Page. Arr. XXVII.—Contributions to Meteorology; by Exias Loomis. «(Twenty-third paper) .-./ 2. . S2_- 1 Saeeeeee 243 XXVIII.—The Sensitive Flame as a means of Research; by W LeConre STEVENS 2 i222 522.) sen ok Le 257 XXIX.—The Denver Tertiary Formation; by W. Cross_-- 261 XX X.—Events in North American Cretaceous History illus- trated in the Arkansas-Texas Division of the South- western Region of the United States; by R. T. Hiti---- 282 XX XI.—A General Method for determining the Secondary Chromatic Aberration for a double Telescope Objective, with a description of a Telescope sensibly free from this defects by, C.'S. Hastings 522352: Bias eee 208 XXXII.—The distribution of Phosphorus in the Ludington Mine, Iron Mountain, Michigan; by D. H. Browne. Wath: Plates) iV Gil xa os oa 299 XXXIIL—Paleohatteria Credner, and the Proganosauria ; by Ge BAU Seren, yays cia tare oe pete a eee 310 XXXIV.—Appendix: Comparison of the Principal Forms of the Dinosauria of Europe and America; by O. C. MARSH sue Ba seen EL alien ee eee 323 XXXV.—New American Dinosauria; by O. C. Marsu_--- 332 SCIENTIFIC INTELLIGENCE. Chemistry and Physics.—Presence of a new Metal in Nickel and Cobalt, Kruss and ScHMIDT, 313.—Atomie Mass of Tin, BonGarTz and CLASSEN: Studies from the Laboratory of Physiological Chemistry, R. H. CHITTENDEN, 314.— Divergence of Electromotive force from Thermo-chemical data, HE. F, HEr- RoUN: Behavior of Metals to Light, Kunpr, 315.—Hertz’s experiments on Electro- magnetic Waves, FitzGERALD and F. T. TrouTon: Electrified Steam, HELMHOLTZ: Viscosity of gases at high temperatures and a new Pyrometric method, Barus, 316. Geology and Natural History.—Brachiospongide; On a Group of Silurian Sponges, C. H. BrecHEer, 316.—Waverly Group of Ohio, C. L. Herrick, 317.—Sacca- mina Eriana, J W. Dawson: Ueber eine durch die Haufigkeit Hippuritenarti- ger Chamiden ausgezeichnete Fauna der oberturonen Kreide von Texas, F. ROEMER, 318.—Shall we teach Geology? A. WincHELL: The Descending Water-current in Plants and its Physiological Significance, J. WIESNER, 319.— Certain Coloring Matters in Fungi, W. Zopr: Bacterial Forms found in Normal Stomachs, J. E. ABELOUS, 320.—Mr. Morong’s Journey in South America, 321. —Botanie Garden at Buitenzorg, Java, Dr. TREUB: Structure of the “Crown” of the Root, LEon For, 322. Obituary.—U. P. JAMES, 322. CONTENTS. vil Number 221. Page, Arr. XX XVI.—The Electrical Resistance of Stressed Glass; Eo yas CAN Toy oA Siete iat eas CP NE 7 el Ire sr 339 XXX VII.—Formation of Siliceous Sinter by the Vegetation of Thermal Springs; by Watrer Harvey WeeEp..-- 351 XXX VIIJ.—Marine Shells and Fragments of Shells in the Till near Boston ; by Warren UPHAaM-.-__-.---------- 359 XXXIX.—A Platiniferous Nickel Ore from Canada; by F. WiCruARmE andy CHAnnns CArimTT (1 nt su. eee 372 XL.—Stratigraphic Position of the Olenellus Fauna in North America and Europe; by Cuas. D. Watcortr.-_--.--- 374 XLI.—EKarthquakes in California; by Epwarp 8. HotpEn_ 392 XLII.—Chemical Action between Solids; by Wu. Hatrock 402 SCIENTIFIC INTELLIGENCE. Chemistry and Physics.—Spectrum of Magnesium, Liveing and Dewar: Lecture Experiment for showing Raoult’s Molecular depression of the Freezing Point, CIMIcIAN, 406.—Chydrazaine or Protoxide of Ammonia, MAUMENE, 407.—New Stannie Acid, Sprinc: Ethyl Fluoride, Morssan, 408.—Chemical Lecture Notes, P. T. AusteN: Elementary Text-Book of Chemistry, W. G. MrxtER: Rays of Hlectric Force, Hertz: Rotation of plane of polarization of light by the dis- charge of a Leyden jar, O. Lopez, 409.—Limit to Interference when Light is radiated from moving Molecules, EBERT, RAYLEIGH: Selective Reflection by Metals, REUBENS, 410. Geology and Mineralogy.—Recent Discoveries in the Carboniferous Flora and Fauna of Rhode Island, A. 8S. PACKARD: Annual Report of the Geological Sur- vey of Arkansas for 1888, J. C. BRANNER, 411.—Cretaceous and Tertiary Geol- ogy of the Sergipe-Alagéas basin of Brazil, J. C. BRANNER: Tertiary Volcanoes of the Western Isles of Scotland, J. W. Jupp, 412.—Nummulites up the Indus valley at a height of 19,000 feet, T. D. LaFoucweE: Sand-drift rock-sculpture, R. D. OtpHAM: Catalogue of Fossil Cephalopoda in the British Museum, A. H. Foorp: Nature and Origin of Deposits of Phosphate of Lime, R. A. F. PEn- ROSE, JR., 413.—Fulgurites of Mt. Viso, F. Ruthey: Scheelite from Idaho, W. P. Buake: Hilfstabellen zur mikroskopischen Mineralbestimmung in Gesteinen zusammengestellt von H. RosenBuscH: Les Minéraux des Roches par Livy and LAcRorx, 414. Botany.—Contributions to American Botany, XVI, SERENO Watson, 415.—Key to the System of Victorian Plants, F. von MUELLER, 416.—Revision of North American Umbelliferee, J. M. Coutter and J. N. Rose: Flora Italiana, CARUEL:’ Diagnoses plantarum novarum asiaticarum, C. J. MAxIMOWICZz: Orchids of the Cape Peninsula, H. Bouus, 417.—Handbook of the Amaryllidee, J.G. BAKER: Synoptical List of North American Species of Ceanothus, W. TRELEASE and ©. C. Parry, 418.—Multiplication of Bryophyllum calycinum, B. W. Barron: Hnumeratio Plantarum Guatemalensium imprimis a H. DeTuerckheim, J. D. Smrra: Journal of André Michaux: Annals of Botany: Herbarium of the late Rev. Dr. Joseph Blake: Outlines of Lessons in Botany, J. H. NEWELL, 419. Miscellaneous Scientific Intelligence.—Deep-sea depression in the Pacific near Ton- gatabu: Dredging Stations in North American Waters, S. SmirH: National Academy of Sciences, 420.—Proceedings of the U.S. National Museum: Exami- nation of Water for sanitary and technical purposes, H. LEFFMAN and W. Bram, 421. Obituary.— ANNIE HE. Law: HEINRICH VON DECHEN: GIUSEPPE MENEGHINI: THEODOR KJERULF: JOHN ERICSSON, 422. ® vu CONTENTS. Number 222. age. P Arr. XLIII.—Topographic Development of the Triassic Formation of the Connecticut Valley; by W. M. Davis 428 XLIV.—Analyses of three Descloizites from new Localities ; by W. B.A LEesranp- 22522... 2.2. Le XLV.—New Meteorite from Mexico; by J. E. Wurirristp _ 439 XLVI.—Contributions to the Petrography of the Sandwich Islands; by H.. 8. Dana. With Plate XIV _...-222222 44] XLVII.—Determination of Water and Carbonic Acid in Natural and Artificial Salts; by T. M. Cuararp---.---- 468 XLVIII.—Preliminary Note on the Absorption Spectra of Mixed Tiquidss by A./K: Bostwick) )) 222322 se eee 471 XLIX.—Notes on Metallic Spectra; by C. C. Hurcurns___. 474 L.—Allotropic Forms of Silver; by M. Carny Lea __-__-_--- 476 SCIENTIFIC INTELLIGENCE. Chemistry and Physics.— Composition of Water, RAYLEIGH, 492. — Diamide hydrate and other salts, Curtius and JAY: Synthesis of the Glucoses and of Mannite, E. Fiscuer and Tarren, 493.—Geometrical Isomerism, WISLIOENUS and Houz, 494.—Aluminum acetyl-acetonate, ComBes: Correction of Regnault’s results upon the weight of gases, J. M. Crarrs: Iron spectrum, H. KAYSER -and C. Run@e: Electrical currents arising from deformation, F. Braun: Elec- trical dilatation of quartz, J. and P. Curtg, 495. Geology and Natural History.—Triassic Plants of Eastern North America, 496.— Geological and Natural History Survey of Minnesota for the year 1887, 497.— Bémmeléen og Karméen med omgivelser geologisk beskrevne, H. REUSCH, 498. —Composition of a brick from the brick-yard of S P. Crafts, at Quinnipiac, three miles north of New Haven, Ct, O. H. Drak: International Congress of Geologists: Brief notices of some recently described minerals, 499.—Mazapilite, KOENIG: Gahnite, Columbite, GENTH: Stibnite from Canada, G. C. HOFFMANN: Mineralogy of Pennsylvania, J. KYERMAN: Sinter-forming Algze: Results obtained by etching a sphere of quartz and crystals of quartz with hydrofluoric acid, O. Meyer and §. L. PENFIELD, 501.—Seventh Annual Report of the Directors of the United States Geological Survey, J. W. POWELL: Journal of Morphology: Development of Manicina areolata, H. V. Winson, 502. —Anatomy of Astrangia Danaé, 503. Miscellaneous Scientific Intelligence.—International Congress of Electricians: Geo- logical Society of France: Botanical Society of France: American Geological Society, 503.—J. A. Berly’s Universal Electrical Directory and Advertiser: Stellar Evolution and its relations to Geologic Time, J. CROLL: Graphics, or the art of Calculation by drawing lines, wpplied especially to Mechanical Engineer- ing, with Atlas of Diagrams, R. H. Smrru, 504. Obituary.—F REDERICK A. P. BARNARD. INDEX TO VOLUME XXXVII, 505. Chas. D. Walcott, ~ Hees et ser = EDN ac at ole cian Spee Ua set eee U.S. Geological Survey. cae ana aaa BES sia Myon cxw * % JANUARY, 1889. Established by BENJAMIN SILLIMAN in 1818. THE mE HA Coa N JOURNAL OF SCIENCE EDITORS JAMES D. anp EDWARD 8. DANA. oe ASSOCIATE EDITORS Prorsssors JOSIAH P. COOKE, GEORGE L. GOODALE and JOHN TROWBRIDGE, or Campripes. Provesous H A. NEWTON inp A. FE. VERRILL, on New Haven, le 77 ew ae . Aas a wr tare os « “i : : ot tal Oe ese Prorrsson GHEORGHE F. BARKER, or PuinapErruta. THIRD SERIES. VOL. XXXVII.—[ WHOLE NUMBER, CXXXVII.] No. 217.— JANUARY, 1889. WITH PLATES I AND Ii, = NEW |HAVEN, CONN.: J. D. & E. 8. DANA, 1889. TUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET. Published monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- _ _ seribers of countries in the Postal Union. Remittances should be made either by money orders, registered letters, or bank checks. ° #7 LITTELLS LIVING AGE, proved in the outset by Judge Story, Chancellor Kent, President } Adams, historians Sparks, Prescott, Ticknor, Bancroft, and many others, ‘it has met with constant commendation and success. en a8 4 =| A WEEKLY MAGAZINES, it gives fifty-two numbers of sixty-four wi iee | pages each, or more than Three and a Quarter. Thousand double-— fee | column octavo pages of reading-matter yearly. 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Without such help he is lost.’’—Zpis- copal Recorder, Philadelphia. “Through its pages alone it is possible to be as well informed in current literature as by the perusal of a long list of monthlies.”— Philadelphia Inquirer. “), 1(120, 4-3), (130, 4-3), 0 (140, 4-4), m (150, 4-3), p (160, 2-6), g (1:12°0, é- 12); Moe d (102, 4-2), e (101, 1-7), f (201, 2-7) 5 brachydomes a (014, 4-7), @ (013, 4-2), y (012, 4-2), 6 (023, 3-2), e (011, 1-7), ¢ (032, 3-7), 7 (021, 2-2), F (031, 3-2), « (041, 4-2), 2 (051, 5-7), w (061, 6-2); unit pyramids w (112, 4), v (111, 1), s (221, 2), A (231, 3); macro-pyramids F (411, 4- 4); uw (212, 1-2), 7 (211, 2-2), 7 (421,. 4-2); brachy-pyramids 6 (232, 1- bearing member from the fact that all the known ore-bodies. and heavily ferruginous rocks occur within it. The upper- most member of the series is a thick layer of greywackes, greywacke-slates, and mica-schists and slates. This member is several times as thick as the three lower combined, but in its essential fragmental character it is to be considered as a unit in the series. The origin of the ferruginous rocks and ores of the iron- bearing member has been considered in a general way in a paper by Professor Irving already referred to. The funda- mental conclusion of that paper has been borne out by our later investigations, i. e. that the original rock of the iron- bearing formation is a cherty iron carbonate,t from which the various phases of rock and the ore found in it have been pro- duced by a complex series of alterations. The principal phases of rock in that part of the forma- tion in which the ore-deposits occur, aside from the cherty carbonate, are heavily ferruginous regularly banded slates, brecciated and concretionary ferruginous cherts, and the ore- * Bull. U. S. Geol. Survey, No. 8. Upon the Secondary Enlargement of Min- eral Fragments in Certain Rocks; by R. D. Irving and C. R. Van Hise. + The origin of this cherty iron carbonate is a question of great interest, but one which it would take an article of some length to discuss, so this rock is taken as a starting point. Am. Jour. Sci.—THIRD SERIES, Vou. XXXVII, No. 217.—Jan., 1889. 3 34. Van Hise—Iron Ores of the Penokee-Gogebie Series. bodies. The carbonate has proved to be far more abundant than was supposed when the paper alluded to was written, and is found at all horizons, but most plentifully in the upper ones. The regularly bedded ferruginous slates are prevalent in the middle, and the ore bodies and ferruginous cherts at the lower horizons. In this paper I have not space to add anything fur- ther to what Professor Irving has said as to the particular processes by which the different phases of rock, aside from the ores, have been produced. ° Position of the ore in the vron-bearing member.—The iron- ores are all located, as far as known at present, in that part of the iron-bearing formation between Sec. 33, T. 45 N., R. 1 W., Wis., and the east line of T. 47 N., R.45 W., Mich., a dis- tance of about 30 miles. The greater number of the larger deposits are found in the central half of this area. Also most of the known deposits le at the base, or very near the base of the iron-bearing member ; that is, they rest upon or close to the coarse-grained fragmental quartzite which constitutes the up- permost horizon of the quartz-slates. The number of impor- tant mines is about 23, and of these all have deposits upon the fragmental quartzite except five, and three of these, situated east of Sunday Lake, at the eastern extremity of the belt of mines, have exceptional characteristics which exclude them from the present-discussion. It is true that three other mines have also deposits which are north of the fragmental quartzite; but in one case, that of the Colby Mine (fig. 4), the two ore-bodies have been shown by developments to have such connections as to show that they are essentially a single deposit. It is not meant to imply that the numerous deposits resting upon the foot-wall quartzite have clean ore always in contact with it. Quite often there is a layer of what the miners denominate “aint rock,” or a layer of sand rock between the quartzite and the ore. This latter material is sometimes as much as 20 feet in thickness, although it is usually not more than a few inches, or at most a few feet. Sometimes also there is, be- tween the ore and the quartzite, a mass of greater or less thick- ness of the ferruginous chert or mixed ore of the miners; rarely a thin layer of nearly pure white chert is found between the ore and quartzite. Notwithstanding these exceptions, the south side of the ore never penetrates the quartzite and in a general way follows it, so that it may be spoken of as resting upon it. This quartzite, although subject to local variations, has an average dip to the north of 60° to 70°, and thus fur- nishes an approximately regular wall, north of which the ore lies, and is consequently called the foot-wall by the miners. The few deposits north of the foot-wall quartzite are described by Mr. J. Parke Channing as also having regular south walls Van Hise—Iron Ores of the Penokee-Gogebre Series. 35 which dip with the formation and are known as foot-walls. Whether the ore-deposits rest upon the fragmental quartzite or are north of it, they have then as their southern boundaries a plane dipping to the north at an angle of 60° to 70°. Dykes in the tron-bearing member.—Mining developments have shown that the iron-bearing member is cut by numerous greenstones, the presence of which would not have been sus- pected from natural exposures. These greenstones are much altered; many of them are so decomposed as to be soft friable matter which can be picked to pieces with the fingers, and which now contain none of the original minerals which com- pose ordinary basic eruptives. They retain, however, dis- tinctly their diabasic structure, and occasionally can be traced into comparatively unaltered phases which are true diorites. These altered greenstones are known to the miners, either as soapstones, or as diorite dykes. That they are dykes is mani- fest from their shape, and the way in which they cut across the layers of the iron-bearing member being traced at times into the foot-wall quartzite. This dyke-like character is well shown by figs. 2 to 7. The association of the ores and these soapstones was found to be so constant, that Mr. J. Parke Channing, Inspector of Mines for Gogebie County, Mich., was secured to work out the relation of the ore-bodies and dyke-rocks. What follows as to the position of the dykes themselves, and as to the position of the ore-bodies with refer- ence to them, is wholly the result of data furnished by his in- vestigations. The position of the dykes is given with reference to the iron formation in which they occur. This formation has a northern dip and a general east and west strike. As used in reference to the dykes, an east and west direction means parallel with the iron formation, a north and south direction transverse to it. The important thing for the present purpose, is not the abso- lute direction in which the dykes run, but their relations to the containing formations. The dykes vary a good deal in their dip and strike in different mines, and the same dyke at times in the same mine also varies in dip and strike. However, certain of their elements are quite constant. The dykes always dip to the south, and generally the southern dip, or its component transverse to the formation, is from 20° to 30°, The northern dip of the iron formation has been said to be from 60° to 70°. Lt follows from this, that of the stratified rocks were placed again in a horizontal position, the dykes would be vertical. The true dip of the dykes is usually, how- ever, not exactly transverse to the formation, but east of it; so that a component along the dykes, parallel to the strike of the rocks, has usually an eastern pitch (figs. 2 and 5). This pitch 36 Van Hise—Lron Ores of the Penokee-Gogebie Series. may be as high as 85°. From this amount it varies to hori- zontality, or even to a western pitch of 10°. The position of these dykes with reference to the foot-wall quartzite will be better understood by figs. 2 to 8. The thickness of the dykes varies greatly, running from those of but a few inches in thickness, to those nearly 90 feet thick, fig. 4. In most of the mines in which the ore-deposits dre of any magnitude the dykes are six feet or more in thickness ; while it is noticeable that the three largest mines have dykes of considerable thickness. At least one dyke has been found in connection with every deposit west of Sunday Lake, with the single exception of the Tronton-Puritan ore-body, and it is possible that when the workings of these mines penetrate deeper they will come in contact with a dyke—one is known to come to the surface three or four hundred feet west. As to the three mines east of Sunday Lake, it has already been noted that their character is quite exceptional. From the eastern pitch of the dykes, it is evident that they must, if they continue in their observed directions, reach the surface to the west of the present work- ings of each of the mines. As these workings are but a few hundred feet deep, it follows that when these dips are high the dykes would reach the surface but a short distance from the ore-deposits. It thus becomes probable that there are as many dykes in the lower horizon of the iron-bearing member as are seen in all of the different mines, while doubtless there are many more. In some mines there are as many as three or four parallel dykes. In those cases in which there are several dykes In a single mine, one is generally known as the main dyke. The smaller ones are in some cases clearly offshoots from the larger, the actual connections between them being traced. Position of the ore in reference to the dykes.—The ore has been spoken of as resting upon the fragmental quartzite as a foot-wall, and in exceptional cases as resting upon a non-frag- mental quartz-rock, which belongs in the iron-bearing member, but which nevertheless forms a foot-wall for the ore deposits, dipping north with the formation. From the description of the position of the dykes and the quartzites, it is evident that the two rocks form V-shaped troughs, which have at the apices right angles, and the south arms of which are nearer vertical tlian the north arms; the first being upon an average 20° to 30° from a vertical, while the second is from 20° to 30° from a hori- zontal position. The relation is that of a right angled trough tilted toward the north until it lacks 20° to 30° from having its arms in horizontal and vertical positions. In one or two. mines, for a short distance, these troughs do not incline either east or west, but at most of them, from what has gone before, Van Hise—Iron Ores of the Penokee-Gogebie Series. 37 - it is evident they incline to the east. The ore-bodies lie in the apices of these roughly shaped troughs, figs. 3,4, 7. Each deposit of ore in following a trough will evidently be at differ- ent depths at different places east and west, depending upon the nearness of the dykes to the surface. All ore-deposits in the position described would reach the surface if the underlying dykes dip to the east or to the west. As a matter of fact, many of them were found at the rock-surface, but others were found after cutting an overlying rock. However, at present (October, 1888), mining developments have traced all deposits which are large enough to warrant working, with two exceptions, to the surface, and these exceptions are newly discovered deposits, which in all probability will be traced to the surface in the future. As would be expected, it is also true that the devel- opment of the deposits which were originally found at the surface have carried them, in every case in which they are of any magnitude, below the surface of the country rock. Both of these facts, the tracing of the ore-deposits discovered at depth to the surface, and those discovered at surface beneath rock, are inevitable deductions from what has preceded. Lock above the ore.-—The rocks which are found above the ore-deposits are the ferruginous cherts—the rocks which have been spoken of as the characteristic ones near the base of the iron-bearing member throughout the area in which the ores occur. The upper boundary of the deposits differs from the quartzite and dyke-boundaries, in that the change from ore to the cherty rock is a transition instead of an abrupt one. In passing upward through an ore-deposit, as its border is reached, the ore becomes mixed with chert until so poor in iron as to become unsalable. In passing still farther upward, the amount of chert becomes greater, until a fractured chert and iron ore, known to the miners as “ mixed ore,” is found. In passing up still farther this mixed ore grades into the ordinary ferrugi- nous chert of the lower horizons. To summarize then, the boundaries of the ore-deposits are to the south, either fragmental quartzite or ferruginous quartz- rock in the ore-formation—generally the former; under the ore, the dyke rocks; and above the ore, the typical ferrugi- nous cherts of the region.* The horizon above the ferruginous cherts, is in most cases a regularly banded red ferruginous slate. This slate is composed of chert and iron peroxide and is as regularly bedded as the unaltered carbonates. Above this slate, constituting the upper horizon of the ore formation, are often found cherty iron carbonates. While this section is known to occur at several of * Hyident, practical deductions for carrying on prospecting and mining follow from the foregoing, but in this paper my space is too limited to give them. 38 Van Hise—Iron Ores of the Penokee-Gogebic Series. the more important mines, it cannot certainly be said te be common to all of them. Also the respective thicknesses of the ill-defined belts are very different at different mines. A gen- eral statement may be made, that at most of the mines a cross section of the iron formation shows the proportion. of un- altered iron carbonate to increase in passing from lower to higher horizons. It is true that almost solid carbonate occurs at three places at relatively low horizons, although none of them are known to be at the base of the member, while one is certainly underlain by a ferruginous chert Also at several localities a typical chert is found at very high horizons. Figs. 2 to 8 illustrate as wide variations of the relations of the ore- bodies to the surrounding rocks as is anywhere found; yet all are alike in essential points. Character of the ore.—The iron ore is a soft, red, somewhat hydrated hematite. By chemical analyses it is shown to be more or less manganiferous, the manganese occasionally run- ning to a high percentage. Much of it is so friable that it can be broken down with a pick, although as taken from the mines it is compact enough to hold together in tolerably large lumps.. These lumps are porous, often more or less nodular, and also often roughly stratiform. The strata conform in a general way to the strike and dip of the formation. Mingled with this soft hematite, in a few mines, is a small quantity of aphanitic steel-blue hematite. The south deposits carry upon an average more manganese than the north deposits, the average in the South Iron King being above !0 per cent, while from the South Colby, ore has been taken which contained as much as 30 per cent metallic manganese. TuE ORIGIN OF THE ORES. We have before us the character of the iron ores, the shape of the deposits, their relations to the rocks surrounding them, the nature of the rocks of the iron formation above the ore horizon, and the character of the formations above and below that bearing iron. An attempt will now be made to suggest an explanation of the character and location of the ore-bodies. The shape of the deposits and their relations to the strata of the iron formation are such as to exclude the idea of original _ sedimentation in place; neither can they be considered as the result of oxidation of iron carbonate in place alone. All of the unaltered iron carbonate now found contains a much larger quantity of silica than the ores, so much as to make them entirely valueless. Also the red banded slates found at the middle horizons give every evidence of being a material which has resulted from the oxidation of the bedded carbonate in place. Van Hise—Iron Ores of the Penokee-Gogebic Series. 39 Further, the large amount of manganese which the ores, espe- cially the south deposits, contain is greater than that found in any carbonate from which analyses have been made; and the average content of manganese in the ore is much greater than the average of the carbonates. While it is thus true that the ores are not carbonates of iron which have altered in place, it is almost as certainly true that the iron carbonates of the belt have been the source whence the iron oxides for these ores have been derived. The nature of the evidence upon which this statement is based has been suggested; but the conclusion would be much clearer if there were place to give a detailed description of the rocks of the iron formation as a whole. Since, then, the iron ores cannot be explained by oxidation of carbonate alone in place, and since the carbonate was the source whence they were derived, they are necessarily concen- trations of iron oxide, combined perhaps with iron oxide fur- nished by oxidation of carbonate in place. If this explanation is adopted, however, it is not only necessary to explain the presence of the iron oxide in its peculiar position, but the nature of the whole lower part of the formation. The explanation must account for the great increase in the amount of silica in the lower horizon of the ore formation as compared with the original cherty carbonate; for its almost total absence in the ore; for the concentration of the iron oxide; for the almost complete absence of carbonate of iron at the lower horizons; for the red banded slates and carbonates in the middle horizons ; and for the relatively much more abundant unaltered carbonate in the upper horizons. A particular occurrence of won ore.—Before attempting to give a general explanation of these facts, it will first be well to refer to one of several occurrences of narrow belts of iron ore in natural exposure. At Sunday Lake outlet, in Sec. 13, T. 47 N., R. 46 W., Mich., the actual transformation from cherty iron carbonate to iron ore is seen in all its phases. In clefts, joints and partings along the bedding of the exposure are nar- row seams of hematite. In passing from the seams, the hema- tite becomes mingled with some chert; going still farther, the chert increases in quantity until a groundmass of silica contains many rhombohedra of iron oxide. The iron oxide then grad- ually passes into siderite. This siderite is in perfect rhombo- hedra, and it is evident, in thin section, that the iron oxide adjacent is pseudomorphous after it. The rock has now passed from an ore into a sideritic chert, which is of a light-gray color, aphanitic texture, and breaks with conchoidal fracture. The latter rock is manifestly in its original condition. The pro- cesses by which the seams of iron oxide occupied the space once taken by sideritic chert are plain. The iron carbonate has de- 40 Van Hise—Iron Ores of the Penokee-Gogebie Series. composed in place to iron oxide, the rock becoming a hematitie chert. Along the seams, waters bearing iron in solution have passed. These waters have particle by particle dissolved out the chert and replaced it with iron oxide, and where once was lean sideritic chert is rich ore. A part of the iron oxide is due to the oxidation in place of iron carbonate, but the larger part has come from a greater or less distance there to be deposited. The seams of iron oxide at this point are but a few inches in thickness, but it is probable that the series of changes which have here taken place upon a small scale, will upon a large scale explain the concentration of workable ore-deposits. Time at which concentration of the main ore-bodies occurred. —It has been stated that the iron belt rocks are much less altered as a whole in the upper horizons, being there composed largely of unaltered cherty carbonate, while the lower hori- zons contain very little carbonate and are mostly composed of ferruginous chert and iron ore. It follows as a deduction from this succession, that the series of changes which have so completely altered the lower horizons of the formation have occurred subsequently to the uplifting of the series. The al- terations can only be explained by the action of percolating waters bearing oxygen, and which therefore came from above. If the layers were horizontal when the changes occurred, the waters passing downward would have altered most that part of the formation nearest the surface. The reverse would be the case if the alteration was subsequent to the tilting, for the up- per layers of the member would partially escape the action of percolating waters, as will readily be seen by glancing at figs. 1 and 9, and taking into consideration the nature of the belt of rock above the ore formation. It is a membér composed of black and gray clay-slates, greywacke and greywacke-slates, all of which contain a large amount of clay, rocks particularly im- pervious to water. A rock underlying any great thickness of such a formation in a horizontal position could not be greatly affected by waters from above. However, when the series had been uplifted and eroded, this upper impervious member would have been removed, and the waters would come directly in contact with the lower horizons of the ore formation, while the upper horizons of the belt would still be somewhat protected. Before going farther, it is necessary to consider the porosity of the rocks which underlie the ore formation. They have been said to be composed of quartzites and feldspathic quartz- slates. Included in the latter are clay-slates; consequently the rocks of this member are also almost impenetrable to pereo- lating waters. The uppermost layer of the member, the quartzite, is not itself a perfect barrier to the passage of water, on account of the jomts which are always found in such a brit- Van Hise—Iron Ores of the Penokee-Gogebie Series. 41 tle rock. These joints do not affect the underlying slates, for these thinly laminated clayey rocks are so. flexible that under the slight bowing which they have received, they are scarcely fractured at all. Process of Concentration.—An attempt will now be made . to trace the passage of percolating waters through the inclined layers of the iron formation. Fig. 9 is a section showing the condition of this member at the present time at the surface, and illustrating how this state of affairs was reached. The strata of the formation are now exposed by their dipping at a high angle, 65°, to the north. The whole Penokee-Gogebic series, more than 13,000 feet thick in some places, of which the iron formation is a part, is exposed in the same fashion. Therefore thousands of feet of the iron member have certainly been carried away by erosion. The figure assumes that about 2000 feet have been eroded from this member since it was upturned. It would, however, make no difference with the argument if this erosion occurred during the time of the upturn- ing. The upper part of the figure represents the surface of the iron formation, and a part of the underlying and overly- ing rocks at some past time. Near the bottom of the figure is the present land surface, Showing the succession of rocks from north to south which are now actually found. A tran- sition from unaltered cherty carbonate to completely decom- posed carbonate is noted. At the time when the upper sup- posed land surface was an actual one, the present surface would be but little exposed to the action of percolating water. It could not pass through the slates which overlie the iron forma- tion; neither could it get in through the underlying feld- spathic quartz-slates. Therefore, most of the water which at that time was able to reach the present land surface, must have done so by passing down, along and through the layers of the iron formation itself. The dotted broken line repre- sents a perpendicular course which the water would follow were its passage not deflected by the laminated character of the rocks; but there would be a tendency for this water to follow the bedding, so that, entering the iron formation at its uppermost horizon, it would follow an irregular course marked by a broken line and would reach the foot-wall quartzite at the line of the present surface of the country. It is immaterial to the argument whether this line ought to vary farther from the perpendicular than marked or not; for, in any case, nearly the whole of the present surface of the iron formation would escape the percolating waters, or if not this surface, some other yet lower down. It is, however, probable that the lowest horizon would not thus escape until a great depth was reached; for the waters entering the formation, would 42. Van Hise—Iron Ores of the Penokee-Gogebie Series. steadily work their way to a greater and greater depth along the foot-wall, until such depths were reached as to prevent its farther penetration. Now, suppose erosion to gradually sweep away the rocks which are between the old surface of the countr y and the present surface. Beginning at the base of the formation the rocks at_ . the present surface would be more and more exposed to the action of percolating waters, which would in turn affect the middle, and finally the higher layers until its whole width was subject to the agencies of alteration. There is, then, a gradual increase in the time that percolating waters have acted upon the various layers of the formation in passing from south to north. The difference in time to which the highest and lowest layers have been subjected to such action, is at least the length of time that it has taken erosion to remove the thickness of rock between the old surface of the country and the present surface; therefore the slower the erosion is taken to have been, the greater the difference in time. Next suppose that erosion had continued until the surface of the land is at some intermediate point. In tracing the per- colating waters, it is necessary to take into account the deflec- tion to which they would be subjected by its layers, and the impenetrable character of the underlying slates and intersect- ing dykes. The relative position of the ore-bodies, quartzites and dykes has already been given. The water which fell upon the layers of the iron formation near its base, would readily pass through the rock, it being here already much altered and broken by the long action of water. Passing through these ferruginous cherts, the water would quickly reach a dyke or the fragmental quartzite, and would follow along this barrier, deflected to the north if upon the quartz- ite, and to the south if upon a dyke, until it reached a trough made by the dyke and quartzite, along which it would follow, traveling toward the east as it penetrated deeper. Such water would be likely to contain oxygen in solution, and would be capable, if it contained alkalies, which might be readily obtained from the alteration of the basic dykes, of tak- ing up a small amount of silica. Other water falling upon higher layers would make its way slowly and with difficulty through these less altered parts, and would oxidize iron carbo- nate until all oxygen had been extracted from it. This oxida- tion of a part of the iron carbonate would liberate carbon dioxide, which would be taken into solution and added to the carbon dioxide which the water already contained.* Such * In this discussion carbonated water is taken as the agent of solution. It is likely enough that organic acids have helped to take the iron carbonate in solution and bear it to the points of precipitation. Van Hise—Iron Ores of the Penokee-Gogebie Series. 43. water would take into solution unaltered iron carbonate. It would also in its upper course take up what silica it’ was able to carry. As it penetrated farther and took more carbon dioxide in solution, and consequently also more iron carbonate, it would be less able to carry silica, and would deposit that material as chert in the lower horizons. The water thus travel- ing on with an increasing amount of iron carbonate, would finally reach a dyke and be deflected toward the foot-wall quartzite. It would follow this dyke until the apex of the trough was reached; here it would mingle with a larger amount of water more directly from the surface bearing oxy- gen, and therefore capable of oxidizing the iron carbonate. The iron would then be precipitated in the apex of the trough as more or less hydrated sesquioxide of iron. Upon the other hand, the silica would here be dissolved ; for the carbon dioxide solution containing iron carbonate would be greatly diluted by the large amount of water which bore the precipitating agent for the iron, and the resultant abundant dilute solution of carbon dioxide bearing perhaps alkalies with it, would be capable of taking up silica which was either origi- nally present or had been subsequently deposited in the apex of the trough. Such solutions may have furnished the silica which has enlarged the particles of quartz in the foot-wall and thus indurated it. The result of this leaching would be to steadily add iron oxide to and remove the silica from the apices of the trough formed by the quartzite and dyke, and thus to form ore-bodies. At the same time the other parts of the formation would be steadily impoverished in iron content. Much of that which remained disseminated through the forma- tion would have been changed from carbonate to oxide. In its lower part, the silica which was taken into solution in the upper part of the water’s course would be precipitated.* The processes thus outlined would penetrate to deeper parts of the formation as erosion steadily advanced until the present surface of the country is reached, and the ore-bodies thus formed at depth are now found at surface. It follows that a large amount of iron found in the ore-bodies was originally in rock which has been removed by erosion. So far as the deposits are at the surface, all of the iron oxide, except that * The chemistry of the processes thus outlined assumes the following: that the oxygen of percolating waters is sufficient to oxidize iron carbonate not in solution and set carbon dioxide free; that the resultant carbonated waters are sufficient to take iron carbonate in solution; that if such waters bearing dissolved carbonates are mingled with other waters bearing oxygen, the iron carbonate or a por- tion of it will be precipitated; that silica may be carried in percolating waters; that carbon dioxide is sufficient to precipitate silica from such solutions; and that a carbon dioxide solution strong enough to precipitate silica. by dilution, may be made so weak in carbon dioxide that it would be capable of taking silica into solution. All of these facts and principles of chemistry are so well known that no discussion of them or reference to authorities is needed. 44. Van Hise—TLron Ores of the Penokee-Gogebic Series. which came from the oxidation of carbonate in place, must have come from such a source, while it is probable that a large part of the deposits located at considerable depths have been stored from rock which has been broken down and seattered far and wide. These are not so much concentrations of iron oxide which were originally deposited as a carbonate above them, as from the layers which stretched to the southward, but which were subsequently by upturning placed over the ore-bodies. Also the large proportion of silica now found near the surface, and particularly in the southern half of the belt, is probably much greater than was here originally present. The silica of these highly cherty rocks associated with the ores may represent a concentration from many hundreds, or even thousands of feet of rock which have been swept away, just as the ore-bodies are concentrations from the iron carbonates which these same rocks contained. A portion of the silica may have come from the alteration of the dyke-rocks contained in this removed material, but doubtless most of it came from the original cherty carbonate. The only exceptions of moment to the facts as assumed in the above discussion, are the occurrence of iron ore at a higher horizon than the foot-wall quartzite, and the ore-bodies east of Sunday Lake, which, so far as present developments go, are not known to be associated with dyke-rocks. It has been said that those ore-bodies in the main part of the range which are north of the fragmental quartzite have a well-defined cherty quartz foot-wall of a regular character. In these cases, this quartz-rock has served as the plane which checked the waters in their downward passage before reaching the fragmental quartz- ite. Here the relation of the ore to the dykes, and its other characters, are the same as when the ore is found upon the fragmental quartzite. It is of interest to note that in one of the largest mines of the region, the Colby, as shown by Fig. 4, the north and south deposits have as their basement the same great dyke, the two ore-bodies being separated merely by a gigantic horse of rock which served as the impervious layer to form the foot-wall of the north deposit. The explanation given of the origin of the ore found upon the fragmental quartz- ite, applies perfectly to these north deposits with the modifica- tions above indicated. That there are layers of the iron-bearing formation which are not readily pervious, and therefore become basements along which the down-flowing waters passed, is not at all strange. It would be stranger if, in a thickness of water- deposited sediments of 800 feet, there were no layers which, at least for a short distance, were effectual barriers to the passage of percolating waters. The chemistry of the process of con- centration of the ore-deposits east of Sunday Lake, in all Van Hise—Iron Ores of the Penokee-Gogebic Series. 45 probability, is like that of the typical deposits of the range. Their concentration is apparently, however, more nearly analo- gous to the narrow seams of ore described in the early part of this paper than to the typical deposits. The formation here appar- ently being cut by no impervious dykes, the waters have not been carried over to the quartzite, thus forming main channels of percolation, but the comparatively small ore-bodies have developed here and there as favorable conditions for concen- tration occurred.* : The above explanation of the origin of the ore-deposits ac cords well with the facts of their occurrence, and also with the . idea that the iron formation deposits were originally an impure cherty carbonate of iron. It explains perfectly the peculiar posi- tion of the ore-bodies with reference to the dykes and the foot- wall quartzite; it explains their presence in a similar position in the few instances in which the deposits are north of the fragmental quartzite ; it explains the flat wedge-shaped charac- ter of the ore-deposit; it explains the nature of the ore, a soft somewhat hydrated hematite, bearing more or less of manga- nese; it explains the excess of manganese which the ore car- ries beyond the amount found in the unaltered carbonates, and its relatively greater abundance in the south deposits; it ex- plains the presence of large quantities of unaltered carbonates in the upper horizons of the iron formation, the gradual lessen- ing of this carbonate in passing to lower horizons, and_ its absence at the base of the formation ; it explains the large per- centage of silica contained in the greater part of the lower horizons and the low percentage at the apices of the troughs. Probable extent in depth of ore-bodies.—This explanation of the origin of the ores may throw some light upon the depth to which the ore-bodies extend. The fact that all of them have been traced to the erosion surface, is favorable, rather than otherwise, to their extending to a considerable depth. The ore-bodies, at the depths now penetrated, must have formed almost wholly before the sweeping away of the rocks of the iron formation above them. They could, then, have received but little of the iron they contain since the end of the Glacial epoch, for erosion was then terminated by the mantle of drift dropped over the region. The deposits, with some degree of proba- bility, may be said to continue to a depth at which the agencies of concentration could effectively work. Whether this distance will be found to be measured in hundreds or thousands of feet, the data at present are too scant to indicate. I am inclined to believe, however, that they may be depended upon to con- * As bearing upon the truthfulness of the above theory as a whole, it is an interesting fact that the practical miners, in prospecting, eagerly follow under- ground water channels, hoping that they will lead to ore-deposits. 46 Van Hise—Iron Ores of the Penokee-Gogebie Series. tinue for a considerable depth. While they may extend in unimpaired richness and magnitude to a depth as great as can be penetrated by workings, it is certain that they do not continue to an indefinite distance. There is also a possibility that the deposits may become poorer than at the surface at comparatively small depths; for it may be that percolating waters, since the termination of the Glacial epoch, have been able to remove from the upper parts of the deposits a small percentage of silica. Such a removal, even to the extent of five per cent, or less, would have an important influence upon the value of the deposits. Emmons on Ore-deposits.—It is of interest to compare the. conclusions reached, to those of Emmons* as to the origin of the silver-lead-deposits of Leadville, Colorado. He finds that the ore did not form in pre-existing cavities, but by a gradual replacement of the rock materials by substances brought in solutions ; and also that these solutions did not come up from below, but have reached their “immediate locus” by pass- ing downward through the rocks above. In his discussion upon ore-deposits in general, he maintains that a like origin is much more common than has been believed. It will be seen that mv conclusions as to the origin of the iron ore of the Penokee-Gogebic Series, arrived at independently of Mr. Emmons’s work, are in exact harmony with his general conclusions. Lron ores in other parts of the Lake Superior country.— Before closing this paper, some allusions must be made to the nature and origin of the iron ores which are found in other regions in the Lake Superior country. Large deposits of ore are found in rocks remarkably like those of the Penokee- Gogebic series, in the Vermilion Lake, Marquette and Meno- monee regions. These ores are associated in almost every mine with a somewhat varying peculiar rock, universally known as soapstone. The connection between the ore and these soapstones is so constant that the appearance of this peculiar greasy altered material is considered as a very favor- able indication in prospecting. It is true that the rock which miners denominate soapstone, in different localities has quite different appearances, and frequently schists are called soap- stones which have no essential likeness to the material with which the ore is found associated. These so-called soapstones, in the regions referred to, are at times peculiar green banded schists, at other times are compact strongly foliated sericite- schists, and only occasionally do they retain the structure of * U.S. Geol. Survey; Monograph x11; Geology and Mining Industry of Lead- ville; Samuel Franklin Emmons, pp. 375-379. Trans. Am. Inst. Min. Eug., vol. xvi, pp. 804-839. Structural Relations of Ore Deposits, S. F. Emmons. Van Hise—Iron Ores of the Penokee-Gogebic Series. 47 an eruptive rock; but in the few cases of which we have defi- nite knowledge, the manner in which the soapstones cut the adjacent rocks is that of dykes. This is particularly well shown at the large open pits at the Jackson Mine, Negaunee, Michigan, and at the Champion Mine, Champion, Michigan. This same dyke-like character of the peculiar schistose rock at one mine in the Vermilion Lake series is described and figured by Pro- fessor Alexander Winchell.* Mr. James R. Thompson, Min- ing Engineer for the Iron Cliffs’ Mining Company, of Negaunee, Michigan, also finds in quite a number of mines in the Mar- quette region, that the soapstones have a dyke-like character. With most of the soapstones of these regions, the only evidence that they are of eruptive origin is their relations to the rocks which they intersect. They have not been shown in many eases, as in the Penokee-Gogebic region, to have the typical structure of eruptive diabases; but the transition phases between these much altered rocks and the comparatively unaltered massive eruptives have in some instances been found, and it is probable that many of them are altered eruptives. At any rate, the close association between the soapstones and the ores can hardly be accidental, and, taken in connection with what has been given in reference to the Penokee-Gogebic ores, it is very sug- gestive that they, in some way, and perhaps in a way similar to that in the Penokee-Gogehic region, have influenced the con- centration of the iron in the ore-bodies at the places found. To certainly determine the origin of all these ‘“ soapstones,” and their stratigraphical and other relations to the ore-bodies _will require a detailed investigation. It would, however, be an interesting illustration of the uniformity of nature’s processes, if such future investigation should show that the iron ores in the otner regions of the Lake Superior country have an origin like those of the Penokee-Gogebic series. Madison, Wisconsin, October, 1888, DESCRIPTION OF FIGURES. PLATE II. FiguRE 1.—Cross-section of the Penokee-Gogebie series at Penokee Gap, show- ing the relations of this series to the underlying Laurentian and the over- lying Keweenaw series. The figure also shows the conformable succession of the four menibers of the series itself. At this particular place, the quartz- slate member, as compared with the iron-bearing member, is thicker than usual. Scale 1’=40007. FIGURE 2.—Eleyation of First National mine, looking south. The eastern pitch of the dyke is shown, and the resultant greater depth of the ore in passing to the eastward. Scale 1”.=130’. FIGURE 3.—Cross-section of same mine, looking east. Scale 1"=130’. * Geol. and.Nat. Hist. of Minn.; 15th annual report, pp. 24-25. 48 Dana—Observations of FS. Dodge on Halem@uma@u. FicurE 4.—Cross-seclion of Colby Mine through both north and south ore-depos- its. The perpendicular line running through the figure is drawn because the two parts of the section are not exactly upon the same plane. They differ from this so slightly, however, that the true relations of the ore-bodies to the surrounding rocks are shown by the combiued figure. Scale 1”=210’. FigurE 5.—Elevation of Pence Mine, looking north, The eastern pitch of the dyke is again observable. The right-angled trough made by the dyke-rock and quartzite is in this case not filled with ore throughout the whole figure. At the eastern end of the figure after passing through a heavy bed of drift, the ore constitutes the rock surface. Seale 1"=210/. FIGURES 6, 7 and 8.—Cross-sections of same at No.1, 2 and Father Hennepin shafts respectively. In figure 8, the shaft has not yet passed through the ore. Scale 1"=210’. FIGURE 9.—Section designed to show the variation from unaltered carbonate to ferruginous chert and ore-bodies in passing from higher to lower horizons, and to illustrate the manner of ore-concentration: S=Upper Slate, Q=Quartz- ite, FQ = Feldspathice Quartz-slate. Scale 1"=1230/. Figures 2 to 8 inclusive are from surveys made and blue-prints furnished by Messrs. J. Parke Channing and C. M. Boss, of Bessemer, Mich. Art.' 1V.— Recent Observations of Mr. FRANK S. Dopes, of the Hawanan Government Survey, on Halema@uma@u and its debris-cone ; by JAMES D. Dana. Mr. Frank 8. DopGeE has recently made a new survey of Halema’uma’u, the great South Lake basin of Kilauea, which gives definite facts as to the gradual lifting of the debris-cone of the basin, and sustains his conclusions from previous obser- vations that the cone has been floated upward on the column of lavas beneath the floor of the basin. The accompanying map and the sections 2 to 5, reduced from copy recently received by the writer from him, present the chief results of his survey. In addition I have from him a brief letter of explanations. The scale of the map is 2000 feet to the inch, which makes the distance across the basin from east to west (New Lake not included) a little over 3000 feet. The outline of the debris-cone at base is approximately indi- cated by the dotted line. The numbers give the level, below the Voleano House datum, of three points at the top of the cone as well as of the floor of the basin and of the crater out- side. At m,n, 0,p.q,7 are small discharging cones, ten to twenty feet high. Two of these small cones, m and n, were at such a height, owing to the rising of the floor of the basin, that their lava streams overflowed the rim of the basin; and from 0, the lavas had flowed into New Lake. Figures 2 to 5 are four profile sections by Mr. Dodge, AB, CD, EF, GH, of the basin and its cone. The height in these sections is exaggerated five times, but in fig. 2, the profile a } has the true proportions. In 2 and 3, p is the pit within the Am. Jour. Sci., Vol. XXXVII, 1889. Plate II. ined t gnowidnagay Soret ——S i ferruginous SECTION SS es ee —— ree Ss ——— = ke sock TRON ORES OF THE PENOKEE-GOGEBIC REGION. Dana— Dodge's Observations on Halem@uma u. 49 debris-cone. No attempt to obtain the depth could be made on account of the discharging vapors. The projection above the ASN J B ee \ae B %. Sas C Rae} Faster oo SOOT yA Sa rate pase (Ce? -331 € p a C Fig. 1. Map of Halema’uma’a in July, 1888, by Mr. F. S. Dodge, reduced to one-fourth. AB, CD, EF, GH, courses of the sections in Figs. 2 to 5; m, N, 0, P, 7, 7, Small cones; s, highest summit; ¢, next highest; New L., New Lake. Figs. 2-5. Sections by Mr. Dodge of Halema’uma’u in July, 1888, along the lines AB, CD, EF, GH, vertical scale 400 feet to the inch, horizontal, 2000 feet ; e, edge of basin of Halema’uma’u; J, active lava lake at west foot of debris-cone ; p, pit in debris-cone; s, highest summit of cone. Fig. 6. Diagram sections of the Halema’uma’u basin and its debris-cone, pre- pared from the descriptions and maps; p, the pit of the cone; ee, edges of the basin; A, condition in May, 1886; B, Oct. 1, 1886; C, Aug., 1887; D, July, 1888. floor of New Lake in fig. 2 is due to the “stranded floating island.” Am. Jour. Sct.—THirRD Series, Vout. XXXVI, No. 217.—Jan., 1889. 4 50 Dana—Dodge’s Observations on Halem@uma@u. It will be remembered that in April, 1886, a month after the eruption, Mr. J. S. Emerson found the basin 570 feet in depth at middle and 175 to 200 feet deep over a broad border re- gion. The condition is represented approximately (from Mr. Emerson’s measurements) in the profile section, A. Three months later, July 20th, Prof. Van Slyke reported that “a cone of loose blocks” had been formed within the basin “perhaps 150 feet high.” ‘This is the first notice of the cone.* In the first week of the following October (1886), less than six months after Mr. Emerson’s survey, Mr. Dodge made his first survey. He found the cone standing at the center of the basin, with the “ broad border region” around it little changed from the condition observed by Mr. Emerson ; but owing to its depth, the top of the cone at s was only 2 to 5 feet above the level of the western rim and at ¢, 28:7 feet below the same level. The width of the cone at top on an east-and-west line was found to be 1100 feet. The general profile, deduced from the survey, is shown in section B. Ten months later, in August, 1887, the writer found the position of the cone, judging from his estimates, as represented in fig. C. After another eleven months, in July, 1888, Mr. Dodge made his recent survey. The basin was very nearly obliterated, and some parts, as already mentioned, were higher than the level of the rim; asa consequence the debris-cone stood with its whole height emerged. This is illustrated in the fourth of the above sections, D. From the levels obtained by Mr. Dodge at his two surveys in October, 1886, and July, 1888, and by Mr. Emerson in April, 1888, we have data for determining the rate of change of level. (1) The change in the western rim of Halema’uma’u was nothing; (2) in the summit s, 167-2 feet; in the sum- mit ¢, 171:4 feet. The time during which this rise of ap- proximately 170 feet took place was about 650 days, giving for the mean daily rate of rise 3°15 inches. The small ejections, going on over the basin outside of the -cone during the two years past, raised to some extent the level of the floor. But whatever the amount it does not affect the calculation, this being based on changes in the level of the summit, which received no additions from ejections or any other source. The conclusion of Mr. Dodge that the cone within Hale- ma’uma’u, and the floor of the basin about it had been “ floated upward” on the rising lavas appears, therefore, to be the only satisfactory explanation of the change of level. * Emerson, this J., III, xxxiii, 87; Van Slyke, ibid., 95, 1886. Notes on Mauna Loa in July, 1888. 51 Art. V.—Wotes on Mauna Loa in July, 1888. I. On an Ascent of Mount Loa by W. C. Merritt, President of Oahu College. From a letter to J. D. Dana, dated July 28. PRESIDENT MERRITT reached the summit of Mt. Loa at noon of the 18th of last July, and encamped near the southeast angle of the crater. The spot was considerably lower than the highest point on the west side of the crater, and probably about 13,400 feet above tide-level. Water boiled at 185° F. between 7® and 8" in the morning when the temperature was at 56° F. The thermometer was at 62° F. at noon, 40° F. at 7 P. M., 30° F. at 11 P. mM. and 26° F. at daybreak, so that during the night water froze in a large crack, ten feet below the surface. About half a mile south-by-west from the southern end of the crater of Mokuaweoweo (see map, Plate II, vol. xxxvi), there was a small but deep pit-crater. Having descended the east wall of the central pit of Mokuaweoweo to its bottom, a small cinder cone was found not far from the eastern wall; and just southwest, a pumice cone in the midst of an aa flow, the sum- mit of which was very hot and reddish from the action of va- pors. In the southwest corner of the pit, there was a cone at F (for all positions see same map), from which vapors were escaping, and south of it, at m, a circular pit 300 and 400 feet in diameter by estimate, and 150 to 175 feet deep. The walls of the pit consisted of the edges of layers of basaltic rock one of which was 40 to 50 feet thick, and vertically columnar in structure. The floor of the central pit had, as a whole, a slope from the southwest to the northeast, confirming the view that the southwest part of the pit had been the seat of great- est activity, as it is in Kilauea. Southwest of m, the outer wall of the central pit was cut through from top to bottom by two parallel fissures, which had a §.8.W. direction, and thence pointed nearly toward the place of chief eruption of 1887. East of m and near the wall in the direction of L, there were great numbers of small fumaroles, from which sulphur vapors were escaping freely, and large deposits of sulphur had been made about them. Near / two dikes, 2 to 23 feet thick, intersected the walls, crossing one another at a small angle, the rock of which had a feldspathic aspect. From a rough measurement, the depth of the crater on the east side was made not over 350 feet. If this small depth is sustained by careful observations, a great change of level had taken place since the survey of Mr. Alexander in 1885. Such a change might have been among the effects of the eruption of February, 1887. 52 Notes on Mauna Loa in Suly, 1888. In Prof. Dana’s paper of July last, accounts are cited of a fountain of lavas in the summit crater in 1873—in June, by Mr. W. L. Green and Miss Bird, and in August, by Dr. O. B. Adams. President Merritt obtained from Mr. E. G. Hitch- cock the following facts observed by him and Mr. H. R. Hitch- cock on a visit to the summit in October, 1873. They spent one night at the summit near the site of Wilkes’s camp, on the east side of the central crater or pit. At the time a fountain of lavas was playing in the southwestern end of the crater, toa height of 600 feet. The height was ascertained by lying upon the brink and looking across the pit to the top of the opposite wall; the column of fire ascended at least one-half higher than the distance from the floor to the top of the walls, and taking this distance at 400 feet, the height of the fountain was de- cided to be approximately 600 feet. Moreover the descending lava of the fountain, fallmg into the basin, flowed off north- ward nearly the whole length of the western side of the pit. President Merritt also visited Kilauea on July the 14th. His letter speaks of the walls of Halema’uma’u as in part wholly obliterated, as represented by Mr. Dodge; it was 15 to 20 feet high in some places. The nearly circular lake (at 2) on the west side of the cone (which he calls ‘‘ Dana Lake”) was in ebulli- tion, but not more active than in August, 1887. The enclos- ing walls of this small lake were 10 to 15 feet high above the liquid lava within, and 15 to 20 feet above the floor outside. With regard to the rising of the cone in Halema’uma’u Mr. Merritt expresses full confidence in the view of Mr. Dodge. II. Notes on Mount Loa by Rey. E. P. Baker. In the month of July, Rey. E. P. Baker of Hilo, made an excursion to the summit of Mt. Loa, and also to the sources of several of its great eruptions, and, in addition, visited the lava stream of Kilauea of 1849 and the Kau “desert.” Mr, Merritt’s trip to Mokuaweoweo was made with Mr. Baker. The following notes are from a letter on his excursions ad- dressed to the writer. Mr. Baker also made a valuable collec- tion of rock-specimens which will add much of interest to the paper on Hawaiian lavas soon to be published by Prof. E. 8. Dana. J. DaaDe To the facts respecting the summit of Mt. Loa, reported by President Merritt, Mr. Baker adds that he observed six parallel fissures ten to twenty rods apart at the south end of Mokuaweo- weo which had a course toward the place of eruption of 1887, and which were probably there produced at the first outbreak, be- fore the outflow of the lavasin Kahuku. (See vol. xxxvi, p. 24.) A descent was made into the southern crater of Mokuaweoweo —probably the first ever made—and the depth found to be Notes on Mauna Loa in Suly, 1888. 53 seventy-five feet greater than that of the central crater. A fresh-looking lava stream descended into it down the northern wall, which may have been made in 1887. Mr. Baker, speaking of the source of the lava streams of the great eruption of 1880-81, states that the two streams from the source, the Kau or southern and the Hilo or eastern (see map, Plate I, vol. xxxvi) originated together at the extremity of along fissure. This fissure follows the course of a “ divide,” so that.a small obstacle was sufficient to turn the flow to one side or the other. The outflow took place on this divide; a northern stream flowed first, then the Kau stream, and then the Hilo. The fissure ran by the north side of Red Hill, a cone with a deep crater which is still giving out vapors, and this hill was apparently the occasion of the turn off southward of the Kau stream, it standing at the point of their divergence. Water boiled near this hill at 196° F. This Kau stream is in general aa, but near the source it is pahoehoe. At the upper extremity of the fissure there is a pit crater, Pukauahi, which is described as the source of the lavas and is still smoking. At this place also water boiled at 196° F. On the route from Ainapo to the source of the outflow of 1852, the lavas of the 1852 stream, where they were first reached, were of the aa kind; but after awhile there was a change to pahoehoe, and soon after this the source was reached —a red cone in the midst of an extensive bed of pumice. Long ditches or trenches occur in the surface of the region which were evidently the beds of lava streams, their sides hav- ing been the banks. The flow appears to have had a single outlet. Water boiled at the source at 200° F. Going from Ainapo to the source of the eruption of 1887, in Kahuku, about 6000 feet above the sea-level, Mr. Baker passed through regions of woods and grass and saw seven run- ning streams and three or four ponds of water. There had been heavy rains. The fissure of 1887, about 400 feet above the place of outflow, was still giving out vapors. No deep erater marked the place of discharge. Over the wide region beween Mt. Loa and Mt. Hualalai it is hard to tell where the slope of one ends and that of the other begins. The 1859 flow of Mt. Loa as it came down ~ heading northwestward, turned just enough northward to fetch by the northeastern flank of Hualalai. The Kaw desert, lying to the south and southwest of Ki- lauea, has a surface of whitish or light colored sand with areas of pahoehoe lava, which is decomposing at places into a red- dish soil. Itis about eight miles by six inarea. It is desti- tute of vegetation and owes its dryness to its being under the lee of Kilauea. 54 OW. S. Bayley—Rocks of Pigeon Point, Minnesota. Art. VL—A Quartz-Keratophyre Pin Pigeon Poimt and Irving's Augite-Syenites ; by W. 8. BAYuEY. (Published by permission of the Director of the U. 8. Geological Survey.) (I.) Iyrropucrory. ONE of the most striking features in the geology of Pigeon Point,* Minnesota, is the occurrence there of a bright red rock along the borders of the large mass of olivine-gabbro, which forms the main portion of the point. This rock is best seen along the south or Lake Superior side of the point near its eastern extremity, where its brilliant color when moistened by - the water, forms a beautiful contrast to the dark gray of the gabbro with which it is in contact. The first mention of the rock was made by Dr. Norwood,t Assistant U. 8. Geologist, in 1851, who described it as a red- dish colored syenitic rock,. containing but a small amount of quartz. About thirty years later Professor N. H. Winchell, of the Minnesota State Survey, saw a red rockt associated with gabbro near the extremity of Pigeon Point, and a rock§ red with orthoclase, from its north shore about a mile from its eastern extremity, which latter he mentions as having probably originated by the fusion and recrystallization of the sedi- mentary beds through which the gabbro cuts. A microscop- ical examination of this rock has very recently been made by Dr. M. E. Wadsworth,| who regards it as an altered phase of some eruptive, the original nature of which he is unable to de- cide from the single section at his command. Professor R. D. Irving in 1881, described a red rock from Brick Island, one of the smaller of the Lucille group of islands, about a mile south of Pigeon Point. He says: “Its thin section reveals a rock very close to those red rocks of the Keweenaw Series which I have described under the names of augite-syenite and granitic porphyry.” On Pigeon Point also Professor Irving found a red rock which “resembles in every particular the rock from Brick Island.” Similar red rocks have been observed by several geologists at various other places in the Lake Superior region, but no careful study has been made of any one of them. * For exact location see this Journal. June, 1888, p. 388. + Report of a Geological\Survey of Wisconsin, Iowa and Minnesota. By D. D. Owen, U.S. Geologist, Philad., 1852, p. 399. t Geol. and Nat. Hist. Survey of Minnesota for 1880, p. 70. § Ib. for 1881, p. 57. Geol. and Nat. Hist. Survey of Minnesota, Bulletin 2. Preliminary De- scription of the Peridotytes, Gabbros, Diabases, etc., oe Minnesota, 1887, p. 81. | Copper Bearing Rocks, ete. Monog. V., U.S. G. S., 1883, p. 369. W. S. Bayley—Locks of Pigeon Point, Minnesota. 55 (II.) MacroscopicaL AND Microscopical. The red rock of Pigeon Point presents several phases differ- ing in some respects from one another. In its most typical aspect it is a brick-red, fine grained, drusy rock, speckled with little spots of a dark green color. Scattered through the pre- vailing red feldspar are small grains of white quartz, which sometimes’ present well-defined crystal outlines. The feldspar itself is occasionally observed with a well marked cleavage and rarely with a crystal outline. Usually it has no distinctive morphological characteristics. In some cases a small quantity of alight colored feldspar can be detected intermingled with the red variety. The green spots consist of little plates of chlori- tized mica. Under the microscope the coarser grained of these non- porphyritic varieties are seen to be composed essentially of an hypidiomorphie granular aggregate of at least two feldspars, quartz and chlorite, with a few subordinate constituents—mus- covite, rutile, leucoxene, magnetite, hematite and apatite. The feldspars embrace a striated plagioclase, twinned accord- ing to the Carlsbad law, and in one instance according to the Manebach law, and a second, less well individualized feld- spar, which is younger than the plagioclase, but slightly older than the accompanying quartz. It surrounds the plagioclase and is intergrown with the quartz in micro-pegmatitic and granophyric forms. Both the plagioclase and the granophyre feldspar are colored by numerous little plates of hematite, the plagioclase, however, containing fewer of these than the grano- phyre variety. When the latter occurs with its own outlines, as it occasionally does, it appears to be unstriated, though fre- quently in Carlsbad twins. After hematite, apatite, leucoxene, and little plates of muscovite or kaolin, are the most com- mon inclusions of both varieties of feldspar. In no case could erystals be found fresh enough to yield measurements of suffi- cient accuracy to determine their true nature. The quartz is in irregular areas filling in the interstices between the other constituents, and is also intergrown with red feld- spar as has already been described. It contains numerous fluid cavities with little dancing bubbles, and also inclusions of a dust-like substance and little areas of red feldspar. The chlorite owes its origin principally to a formerly exist- ing biotite. It occurs both in little radiating spherulites crowded close together, and in plates enclosing quartz and feldspar. Calcite, rutile and leucoxene are its most common inclusions, while the little pleochroic halos* (Héfe) character- istic of this mineral when derived from biotite, are not rare. *For the discussion concerning the nature of these halos, see Neues Jahrb. f. Min., etc., 1888, i, p. 165. 56 W.S. Bayley—Rocks of Pigeon Point, Minnesota. Associated with the chlorite is oftentimes a very light green fibrous mineral, which from its bright polarization colors is probably to be referred to sericite. Rutile forms quite a prominent constituent. in some specimens. It is found in irregular masses of a dark brown color, and also in long rod- like forms, in both cases intermingled with leucoxene and fre- quently with chlotite. A second phase of the red rock resembles quartz-porphyry. Well terminated quartz crystals and occasional brick-red and greenish-white feldspars are scattered through a very fine grained groundmass of a dark red or purplish color. This variety is characterized under the microscope by the beauty of its granophyre structure. All gradations between the granular structure just described, and the typical porphyritic structure have been examined, and in all there is more or less of the true granophyre. In the most typical porphyritic varieties the porphyritic crystals are both quartz and feldspar. In the less perfectly developed phases the quartz occurs in round, ellipti- cal and even crescent-shaped areas, and includes in many places portions of the groundmass. This quartz is perfectly clear and is free from inclusions other than the little fluid cavities with movable bubbles (see fig. 1.) A very few irregularly outlined feldspar areas represent the porphyritic crystals of this mineral in their earliest stages of development. They are now so altered as to prevent the identification of their species. Other areas which appear in the hand specimen as crystals are seen under the microscope to be composed of granophyre substance in which the feldspathic portion is very highly col- ored by little plates of hematite. The groundmass, in which these crystals are imbedded, con- sists of quartz and highly altered feldspathic substance in granophyric intergrowths. This is in part sometimes replaced by coarser areas in which the two minerals form a micropeg- matite. The fine granophyre is found more particularly around the distorted and corroded porphyritic quartzes, and in the undeveloped feldspars mentioned above. It radiates from all porphyritic quartzes forming a zone, which in ordinary light resembles the ‘“ quartz globulaire” of Lévy, but in which the quartz fibers, between crossed nicols, are seen to be optically independent of the orientation of the substance of the crystals. Chlorite, iron hydroxides, leucoxene, and tiny flakes of a dark brown biotite are the accessory constituents of the ground- mass, Calcite is quite abundant as an alteration product of some of the fibres intergrown with the quartz, and also in the little cavities contained in the rock. Green alteration-products are also common. Fig. 1 is an ideal representation of the most W. S. Bayley—fRocks of Pigeon Point, Minnesota. 57 characteristic peculiarities of the groundmass and its porphy- ritic ingredients as exhibited by several thin sections. The microscopical characteristics of both the porphyritic and the granular varieties of this red rock indicate the probability of the identity of the two. Although the most typical quartz- porphyry is quite different in structure from the typical gran- ular variety, all gradations between the two types can be recog- nized. Their mineralogical L. composition is the same, and, as will be shown later, _their chemical composition is identical. There can be little doubt that the por- phyritic variety is a true eruptive rock. It presents all the features of Rosen- |); busch’s* “ Vogesen grano- | phyres.” Since the granular varieties are so similar to this, it is also probable that these also are eruptive. No trace of fragmeutal struc- ture could be detected in any one of them, nor is there any field evidence that they are altered fragmentals. All the field relations seem to point to the original character of the rocks. They occur in dykes and veins intersecting other rocks, and the contact between them and the quartzites which they cut, is sometimes clearly seen. It must be confessed, however, that without microscop- ical and chemical evidence of the identity of these rocks with the quartz-porphyry their true nature would be difficult to dis- cover from the field relations alone. A more careful examina- tion of the stracture of the point than has thus far been possi- ble, will probably reveal facts which will place beyond doubt the conclusions reached by the microscopical examination. The quartz-porphyries are very similar in macroscopic and microscopic appearance to the Keweenawan quartz-porphyries described in Irving,t as flows in the copper-bearing rocks on both sides of Lake Superior. The granular red rock ap- proaches more nearly this_author’s augite-syenites, though the ' best developed and most characteristic augite-syenites are more nearly allied to the third phase of the red rock. The rock of Brick Island, which is classed by Irving among the augite- syenites agrees in most of its minute features with the rock described above as the most prevalent type of the red rock on Pigeon Point, as Irvingt himself states. * Die Steiger Schiefer, etc. Strassburg, 1876. + Copper-Bearing Rocks, p. 95. tals Ch ps9: 58 W.S. Bayley—Rocks of Pigeon Point, Minnesota. The third variety was noticed more particularly at the con- tact with an olivine gabbro, which occurs on the point in larger masses. As the red rock approaches the gabbro it is clearly seen to be affected by the latter in such a way as might be expected if both rocks were in a pasty condition at the same time, or if one had been intruded in or next to the other under enormous pressure. The red rock becomes darker as it approaches the gabbro. The green spots, which are scattered over the 7 ved groundmass, become more prominent. They y @ ave larger in size and more abundant in number - /7 than in the two varieties above described, and XQ’ sin some cases are united into red-like bodies and arborescent forms (fig. 2). A light colored feld- spar is also much more frequently discernible in this variety. Still closer to the gabbro a rock is observed which is very dark in color, and can be distinguished from the gabbro only by the possession of a reddish feldspar among its components. The darkest of these rocks resembles very closely the orthoclase gabbros* of Irving, which are supposed by Dr. Wadswortht to be but altered forms of olivine-gabbro. , A discussion of this point can not be entered upon in this place, but it is hoped soon to obtain results from the work now being earried on, which will determine whether or not the orthoclase gabbros may have been derived by the action of an acid magma upon a basic gabbro with which they are always associated. The lighter colored of these intermediate rocks (as we shall call them for the sake of brevity) when examined under the microscope are found to differ but little from the red rocks de- scribed above. They contain a larger amount of plagioclase (oligoclase ?), of chlorite, and of biotite, and much more mag- netite and apatite than do the latter, but otherwise resemble them very closely. Micropegmatite is more frequent than is the granophyre intergrowth of quartz and feldspar, and it is es- pecially to be remarked that in almost every case examined the extinctions of the little quartzes are in the direction of their longer axes. The most noticeable fact in relation to them is the freshness of their plagioclase, which is usually in large tabular or lath-shaped crystals. When examined carefully and compared with sections of Irv- ing’s augite-syenites they are seen to bear a strong resemblance to some of these—a resemblance so strong that pictures{ repre- senting the augite-syenites might as well be used to illustrate the appearance of the Pigeon Point rocks under the microscope. * Copper-Bearing Rocks, p. 50. +L.c., p. 54. Cf. also Herrick et al., American Geologist, June, 1888, p. 340. + Copper-Bearing rocks, p. 112, and figs. 1, 2, 3, 4, Pl. XIV. W. S. Bayley— Rocks of Pigeon Point, Minnesota. 59 After a careful microscopic examination of every one of the thin sections of rocks described by Irving as augite-syenites and a comparison of these with the typical red rock of Pigeon Point and its associated intermediate varieties, the conclusion is established beyond doubt that some of the former are in every respect similar to the typical red rock of the point, while the others are as certainly identical in all essential particulars with those varieties which have been called its intermediate varieties. (III.) CHEMICAL AND GENERAL. From a mere microscopical examination of different sections of the various phases of the red rock on Pigeon Point, one would naturally be lead to regard them as portions of the same magma which had erystallized under different conditions, and then had undergone more or less decomposition. They both possess the same mineralogical composition and present grada- tion in structure from the granular to the porphyritic, with granophyric groundmass. In order to obtain more positive evidence on this question, analyses of the quartz-porphyry and also of the granular rock were made by Mr. W. F. Hillebrand in the laboratory of the U. 8. Geological Survey, with these results: I. Analysis of the powder of seven of the freshest specimens of the granular rock. II. Analysis of the powder of three of the quartz-porphyries. JIf. Analyses of the granite from Bejby, Sweden; contain- ing red orthoclase, gray and brownish gray quartz, black mica, and a few flakes of a golden yellow mica.* its Il. TI SiO ees 72°42 74:00 73°32 Oe eyes oe “40 34 Ue eae TWA) Sa gl i ii 13-04 12°04 14:25 Be On oat eo 68 78 aes MeO te 2°49 2°61 2°60 10 io @), eee saad 2s A “09 05 09 CAO 2 ae 66 85 83 AO es Nas 15 12 he VO ae) LISS 58 “42 Ba BO Msi) 4:97 4°33 4°96 INGA Oye Era) 2) 3°44 3°47 3°21 BOVE ees: a in tr sal TO Ree Ser shi 2a 86 M222 EO) Payee 20 06 day S LO) Pane Sea Pett tire ti fi 100°37 99°93 100°48 Sp. Gr. 2°620 2°565 * Gerhard: Neues Jahrb. f. Min., etc., 1887, ii, p. 271. 60 W.S& Bayley—Rocks of Pigeon Point, Minnesota. After an inspection of these figures there can be no rea- sonable doubt that the two rocks from Pigeon Point are parts of the same mass. The very slight differences in amount noted in the case of the silica, alumina and potash are not greater than are frequently found in different portions of the same hand specimen of most rocks. The slight differ- ence in specific gravity are what might be expected from a study of the structure of the rocks. Unfortunately no complete analyses of Irving’s Keweenawan quartz-porphyries are given by that geologist, but a few sil- ica determinations have been recorded, which are of interest in showing the close agreement, in this respect, between these rocks of undoubted er uptive origin and the Pigeon Point rock. The percentages of silica in three Minnesota quartz-porphy- ries* are respectively 71:10, 73°87 and 76°83; thus differing but slightly from the 74 per cent. of the Pigeon Point rock. In consideration of the large amount of sodium indicated in analysis I, it was thought interesting to separate the feldspar from one of the freshest of the red rocks and subject it to a chemical examination. This was done in the usual way, and it was found that the greater portion fell when the specific grav- ity of the solution used was 2°577. This was analyzed by Mr. Whitfield of the U. S. Geological Survey with the following result: Si0. Al,Os; Fe,03; CaO MgO K.O Na,O Ion 65°00 18°22 2°64 1°06 0°06 84°18 8°40 *46=100°12 When examined under the microscope the powder of this mineral is seen to be free from quartz and quite homogeneous, although slightly altered and filled with little plates of hema- tite. Its optical constants could not be accurately determined, but from the figures given above there can be but little doubt that the feldspar is an anorthoclase.t+ If this be true the rock would fall into the quartz-kerato- phyre group as defined by Rosenbusch.t Its microscopical characteristics correspond to those of the quartz-keratophyres, as described by Giimbel and Lossen, and the composition of its feldspar is that of an anorthoclase. Many of the quartz-porphyries of the Keweenawan series, as well as some of the augite-syenites will probably be found to belong to this same class of rocks—a class which up to the pres- ent time has not been known to have a representative on this side of the Atlantic. One of the most interesting points in the study of the red rocks of Pigeon Point, has reference to the origin of those * Copper-Bearing Rocks, pp. 108, 109, 100, 441. + Anorthoclase separated from a liparite of Pantelleria, has a composition (according to Férstner, Zeitschr. f. Kryst., 1883, p. i125) as follows: Si0.=66°06, Al.O3 19°24, Fe.0s 0°54, CaO 1°11, MgO 0-11, Ks0 6:45, NasO 7°63. ¢ Rosenbusch: Mikroskopische Physiographie, 1887, ii, pp. 434-442. W.S. Bayley—Rocks of Pigeon Point, Minnesota. 61 phases which are found upon the contact with olivine-gabbro. As has already been stated, the macroscopical and microscop- ical characteristics of these rocks are such as would lead to the supposition that they were produced by the mutual interfusion of the basic and acid rocks at their points of contact. The field relations of the three rocks leave no doubt as to the fact that the intermediate rock is the result of contact action. That this action took place at some distance below the surface is proved by the perfect crystallization of the constituents of the intermediate rock. That it was not confined to the effect of solutions passing from the gabbro to the keratophyre, or the reverse, is shown by the perfect freshness of the plagioclase, and its well-defined crystal outlines in both rocks. The best place upon the point at which to study these rocks is on its south side, near its eastern extremity. Here the space between the fresh olivine gabbro and the typical quartz-kerato- phyre is occupied by a series of rocks which exhibit in the field a gradual transition between the heavy, dark basic rock, and the light red keratophyre. _ Analyses and specific gravity determinations of several of these intermediate products substantiate the conclusions arrived at above. IV. Olivine gabbro, analysed by Mr. Hillebrand. V. Intermediate rock (No. 11211) near the gabbro. _ VI. Intermediate rock (No. 11209) midway between the red rock and the gabbro. VII. Intermediate rock (No. 11210) near the keratophyre, analyzed by Mr. Hillebrand. VIII. Quartz-keratophyre, as given on p. 59 IV. Vv. VI. Vil. VIII. LOAF este 49°88 50°69 57°88 57°98 72°42 Mi Ox c.2) . 1°19 ea uD 1°75 “40 KOM ee S55 ee ie 13°58 13°04 Ble, Oe 222 5, 2°06 Snes Aas 3°11 ‘68 Me@ rier nf: 8°37 epee wi ie 8°68 2°49 Mn@Oe 23 09 Spt ipa 13 09 CaO =" Saie 7°94 4°68 2°01 66 SiH O) ee eae Ur Nt ay ty ee Baie eal 02 See ete 04 15 IMO we any nae rahe 2°87 58 ON “68 aah pth 3°44 4:97 Na OE ais 2°59 ia te ss 3°56 3°44 Ose ares Me aohes 2 beh tr tn EC OPA 1-04 Mie sen 2°47 hepa POe Baan iG cour est 29 20 a eae ti as Nap 2 eel 3 100°12 99;0n 100°33 Sp. Gr. __. 2923 2-741 2°620 62 W.S. Bayley—Rocks of Pigeon Point, Minnesota. In these results can be traced the gradual transition from the basic gabbro, rich in calcium and magnesium, and poor in potassium, to the acid keratophyre, which is poor in calcium and magnesium and rich in potassium. We can hardly imagine ‘the conditions under which a rock of the composition of the gabbro (LV) could be changed into a rock of the com- position of the intermediate rock (Vil), by means of solutions* emanating from the keratophyre, unless these solutions con- tained in them the materials of the keratophyre in about the proportions in which they are present in that rock, a sup- position which is not at all probable. It would seem, then, that we are justified in regarding the intermediate rock as due to the fusion and recrystallization of the materials of both the keratophyre and the gaboro, in con- sequence of the irruption of one of these rocks into the other at some considerable depth below the surface of the earth, where the conditions were such as to produce a rock with the characteristics of a plutonic rock. In other words the inter- mediate rock is the result of deep seated contact action. Analyses of Irving’s augite-syenites are not given, so that a comparison of their composition with that of the intermediate rock (No. 11,209) cannot be made. Their thin sections, how- ever, aS has already been stated, exhibit a very close similarity to many of those of the contact rocks. Further, those with these characteristics are always, so far as could be determined, in close association with gabbro, and in many: cases are also very near a more acid red rock resembling the quartz-kerato- phyre in one of its phases. The augite-syenites of Irving, then, may be divided into two classes, those which are like the quartz-keratophyre, de- scribed above, and those which are similar to the contact rock. In neither case are they altered eruptives, in the sense that they owe their present characteristics to the alteration of a more basic eruptive. They have both resulted from the solidi- fication of a molten magma. Of course it is not affirmed that no alteration has taken place in any of the augite syenites, for such is not the ease. Some of them have suffered the kaolinization of their feld- spar, and the chloritization of their augite and mica, with the production of secondary silica. Their most characteristie properties, however, are not due to this alteration, but are due to the chemical composition of the magma by whose cooling they were formed. * Cf. American Geologist, June, 1888, p. 343. Messrs. Herrick, Clarke and Dem- ing: Some American Norites and Gabbros. Il. G. Hanks Hanksite in California. 63 : (IV.) Conciustons. The red rock on Pigeon Point is not an altered gabbro nor an altered sedimentary rock, but is the result of the solidifi- cation of a magma, which under certain conditions gave rise to a rock with the characteristics of a granophyre. These two rocks contain a sodium-potassium feldspar, and thus should be classed among the quartz-keratophyres. Upen the contact of the quartz-keratophyre with an olivine- gabbro is a series of rocks, which possess a composition inter- mediate between those of the keratophyre and the gabbro. They may be regarded as the result of contact action at great depths Irving’s augite-syenites are similar to the Pigeon Point quartz-keratophyre, in some instances, and in others are like the intermediate rocks. They are neither altered gabbros nor altered forms of a previously existing augite-syenite. Geological Laboratory of Colby University, June 25, 1888. Art. VII.—On the occurrence of Hanksite in OCS by Henry G. Hanks. THE best known locality of hanksite in California is Borax Lake, owned by the San Bernardino Borax Company. This lake lies in township twenty-five South, range forty three East, Mount Diablo base and meridian, and in the northwest corner of San Bernardino county, the largest in the state, very near the Inyo county line. This vast deposit of soluble salts was- discovered and located February 14, 1873, by Dennis Searles and E. M. Skillings. Up to the present time it has produced 10,500 tons of borax, and is still far from being exhausted. When the state becomes more populous, and facilities for cheaper transportation multiply, other minerals will also be ex- tracted, to the benefit of those interested, as well as to the State. The so-called « Diy lake.) Alkali lat? ior“ Salt Marsh,” is a pan-like depression in the desert, ten miles long and five wide more or less. It is the sink of a wide spread water-shed and a small stream which heads some fifty miles south. It is the opinion of those who have long resided at or near the locality, that it is a secondary sink of ‘Owens Valley and is partly fed by seepage from Owens and Little Lakes. The climate is generally very dry, but during some seasons, considerable water finds its way to this depression. Having no outlet, the water spreads out and forms a shallow lake or marsh. In the dry season the surface is covered with an alka- line incrustation, which is principally common salt. On the 64 H. G. Hanks—Hanksite in California. western margin of the large depression lies a small basin known as “ Borax lake proper,” which has approximate dimen- sions of one mile and a half in length by half a mile in width. From this secondary lake, and the dividing ridge referred to below, most of the borax produced has been taken. Between Borax Lake, which is a few feet higher than the general level, and the wide alkali flat, there is a slight ridge, which acts as a natural dam and prevents the water from flowing away. It is covered with crude borax which is be- lieved to be of semi-voleanic or solfataric origin. This barrier prevents the water of the borax lake from flowing to still lower depressions on the great alkali flat beyond. The water of Borax Lake is a dark brown highly concentrated alkaline liquor, having a density of 28 degrees Beaumé. The salts obtained from it by erystallization contain carbonate, chloride and bi-borate of sodium, with much organic matter. There has never been an exhaustive analysis made, which would, no doubt, be very interesting. For a number of years it was planned to explore or prospect the underlying formations both as a matter of general inter- est, and in the hope of finding the source of the borax and other salts. After much delay, work was finally commenced in 1887, and carried on under many difficulties, owing to the nature of the ground. The bottom of the lake was found to be of a remarkably sticky, tenacious, plastic clay, described as being “tough as wax.” ‘To avoid the difficulty of keeping back the alkaline water by coffer dams or other similar con- trivances, the first experimental well was commenced on the ridge before mentioned. It was sunk by sprimg-pole drills to a depth of three hundred feet. The following is a section carefully kept by Mr. Searles: 1. Two feet salt and thenardite. 2. Four feet clay and volcanic sand containing a few crystals and bunches of hanksite. 3. Eight feet volcanic sand and black tenacious clay with bunches of trona of black shining lustre from inclosed mud. 4. EKight-foot stratum, consisting of volcanic sand in which is found glauberite, thenardite and a few flat hexagonal crystals of hanksite. 5. Twenty-eight feet of solid trona of uniform thickness. Other borings show that this valuable mineral extends over a large area. 6. Twenty-feet stratum of black, slushy, soft, mnd, smelling strongly of hydrosulphuric acid, in which there are layers of glauberite, soda and hanksite. The water has a density of 30° Beaumé. 7. Two hundred and thirty feet (as far as explored), of brown clay, mixed with volcanic sand, and permeated with hydrosul- phuric aeid. H. G. Hanks—Hanksite from California. 65 Overlying No. 5, is a thin seam or stratum difficult to pene- trate, to which the name “hard stuff” has been given, the exact nature of which is unknown. Borax is produced at these works by three different methods. By evaporating natural solution of borax; by lixiviation of crude material; and by solution and re-erystallization of tincal. What is known as ‘‘erude material” is a somewhat pulveru- lent, shghtly yellowish, amorphous incrustation which yields about eight per cent. of borax when worked on a large scale. Borax is obtained from this crude material by solution and evaporation The plant, which is very extensive, and owing to the distance and isolated position of the deposits, costly, con- sists of a large steam flue boiler, and a multitude of boiling and crystallizing tanks, of wood and boiler iron, Steam is conveyed in pipes to the various tanks, instead of utilizing the heat of the sun, which would be more economical and the yield and quality quite as good. The peculiar dryness of the climate is specially favorable for solar evaporation and gradu- ation. Fifty men and thirty-five animals are employed in these works. The product is hauled in wagons to Mohave station, a distance, of about seventy miles, over a sandy desert, so dry and sterile that a supply of water must be hauled in other wagons for the use of men and animals. The fuel used has been generally the sage-brush which is gathered at heavy cost, and thrown under the boilers with pitchforks, like hay into a barn: but recently, California crude petroleum has been substituted. Hanksite first came to San Francisco in the massive form and was called by the borax miners “Ice,” which it certainly resembled. It was examined in the usual manner and found to be an anhydrous sulphate of soda, and was labelled thenar- dite. No analysis was made and the small proportion of car- bonic acid was overlooked in the blowpipe examination. The next specimens received were small hexagonal plates, found in the highly concentrated waters of the lower lake. These went to New Orleans with the California exhibit, and were shown at the exposition of 1884-5, where they attracted the attention of Mr. William Earl Hidden, who was the tirst to suspect a new species. ‘Thie results of his study of the erystals led to a paper by him, which he read before the New York Academy of Sciences, May 25, 1885.* The magnificent crystals recently discovered were taken from the sandy clay No. 2 of the section, and No. 7, seventy feet or more below the surface. There were not more than * This Journal, xxx, 133, 1885. Am. Jour. Sc1—TuHirRpD SErins, VoL. XXXVII, No. 217.—Jan., 1889. 5 4 66 | Hl. G. Hanks—Hanksite in California. thirty in all. About the time of their discovery, work was suspended. It will not be resumed for several months, when it is to be hoped that enough will be obtained to supply the scientific world with specimens. The form of these erys- tals is shown in fig- ure 1,* the planes present are: ¢(0001, Q~), m (1010, 2), o (1071, 1), s(2031, 2). What Mr. Searles calls “bunches of hanksite” are ag- gregations of flat hexagonal plates joined together in a confused irregular manner. ‘They vary in size from an inch or less in diameter to eight inches or more. One of these crystals is shown in figure 2. The crystals also vary in size, the largest being three inches, and the smallest half an inch or less in diameter. Some of the bunches have been accidentally subjected to the action of comparatively pure water, by which partial solution has taken place, not only marring the beauty of the individual crystals, but leaving the clusters in a dilapidated, cavernous condition. In the dark, concentrated, amber-colored water of the borax lake, they remain unchanged. Ue V.—Notes on Mauna Loa in July; 18885" ." 2s ae eens 5 VI—A Quartz-Keratophyre from Pigeon Point and Irving’ s Augite-Syenites; by W.S,. Bavnupy._-....--2_2... 22 VII.—On the: occurrence of Hanksite in California; — by ee TIENRY Gt TIANKSS Seg yo aa VIIL.—Sperrylite, a new Mineral; by Horace L. Wants. a IX.—On _ the nce form of Sperrylite; by S Lit PEG TD Sega ee oes os ee Bee : SCIENTIFIC INTELLIGENCE. : Chemistry and Physics—On the Vapor-density of the Chlorides of Indium, Ga lium, Iron and Chromium; and on two new Chlorides of Indium Ni~son and PETTERSSON: On the Vapor-density of Ferric chloride, FRIEDEL and Orarts, 73.— fy On the Vapor-density of Gallium chloride, FRIEDEL and CRAFTS: On the Molee- | ‘ular Mass of Sulphur, Phosphorus, Bromine and Iodine in Solution, PATERNO and Nastnr: On the Atomic Mass of Osmium, SEUBERT, 74.—A Class Book Elementary Chemistry, W. W. Fisher: Examples in Physics, D, H. JonES:— gen lines in the Solar Spectrum, M. Janssen, 75.—Effect of staining upo plates, KuNDT: Wleciical currents ee i light, Sey 76. lite, a new ane eoeeed and BACKSTROM: Das Protoplacnts als Fe organismus, ALBERT WIGAND, 77.—‘ Ringed” Trees, W. L. GoopwiN: A sional Host, an Index of the Fungi of the United States, W. G.. FAaRLow and. SEYMouR, 79.—Bibliotheca Zoologica II, bearbeitet von O. TASCHENBERG Chas. D. Walcott, U. S. Geological Survey. ae ; z j ¢ oe i ; av. PEBRUARY, 1889. Established by BENJAMIN SILLIMAN in 1818. THE AMERICAN JOURNAL OF SCIENCE. EDITORS JAMES D. ayn EDWARD §. DANA. ASSOCIATE EDITORS | Proressors JOSIAH P. COOKE, GEORGE L. GOODALE AND JOHN TROWBRIDGE, or Camspripnge. Proressors H. A. NEWTON anv A. E. VERRILL, oF New Haven, Prorzessorn GEORGE F. BARKER, or PuitapErputa. THIRD SERIES. VOL. XXXVIIL—[WHOLE NUMBER, OXXXVIL] No. 218—FEBRUARY, 1889. WITH PLATES III-VI . NEW HAVEN, CONN.: J. D. & EH. 8. DANA. 1889. TUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET. Published monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- cribers of countries in the Postal Union. Remittances should be made either by money orders, registered letters, or bank checks. ‘ ) “d ‘a B.. A. y Be -MINERALS. ne je Me Send for Catalogue. Free to any Address. The following will convey some idea of the superior quality of oe our stock: i a Prismatic Phenacites from Colorado; Hiibnerite in terminated _ erystals from Colorado; Tyrolite, Clinoclasite, and other arsen- 2 — ates from Utah; Dioptase from the Urals; Topaz Crystals, j highly modified, from Mexico; Calcite Twins from Egremont— very fine; Iridescent Dolomites from Frizington; Celestite, trans- ie parent tabular crystals, from Yale; Vanadinite in superb crystals | A from Arizona; Colemanite, very choice crystals; Beegerite, Ala- ie bandite, Freislebenite, Milarite, Minium, Axinite, Barrandite, . Bementite, Brochantite, Cacoxenite, Kudialyte, Hanksite, Kjerul- fine, Lansfordite, Gadolinite, Descloizite, Szaboite, Samarskite, — i Stromeyerite, Sussexite, ete. Minerals by the pound for Blowpipe Analysis. Illustrative Collections of all kinds. f CORRESPONDENCE SOLICITED. GEO. L. ENGLISH & CO., Dealers in Minerals, 1512 Chestnut Street, - - Philadelphia, F d 7 + THE AMERICAN JOURNAL OF SCIENCE [THIRD SERIES] Art. X.—Points m the Geological History of the islands Mavi and Oanu; by James D. Dana. With Plates III and LV. THE subjects prominently illustrated by the islands Maui and Oahu are: the conditions of extinct volcanoes in different stages of degradation; the origin of long lines of precipice cutting deeply through the mountains; the extent and condition of one of the largest of craters at the period of extinction; and the relation of cinder and tufa cones to the parent volcano. The other islands of the group present facts bearing on these subjects, but the writer’s knowledge of them is too imperfect for review in this place. I. Istanp or Matt. The accompanying map, Plate 8, reduced from the recent large government map,* shows the general features of the island of Maui: (1) The voleanic mountain of East Maui, Haleakala, 10,032 feet in height, having at summit, a crater 2500 feet in great- est depth and twenty-three miles in circuit. * On this Plate, as on that of Hawaii in the last volume of this Journal, most of the lettering of the original map is omitted, with necessarily also minor details as to erosion and topography. Am. Jour. Sct.—Tuirp Series, Vout. XXXVII, No. 218.—Fsp., 1889. 6 82 J. D. Dana—Geological History of Maui. (2) The abrupt depression of Kipahulu, to the southeast of the summit, surveyed but not geologically studied, which looks as if it were the site of another great crater. (8) The slopes of eastern Maui, little gullied by erosion, but most so on the side facing northeast—the windward side; and here the longest valleys scarcely reaching to the summit. (4) The mountain of west Maui, a voleano in ruins, being profoundly cut up by valleys, and the original height reduced to 5788 feet as the maximum. (5) The low intermont area of Maui, made of the united bases of the two volcanoes, but covered for the most part by the lava-flows of Haleakala, whose fires continued in action long after the western voleano was turned over, dead, to the dissecting elements; the width from north to south at the nar- rowest part, near the line reached by the lavas of Haleakala, about six miles, and the height at the survey station near its middle, 156 feet. From my use of the maps of the Hawaiian government sur- vey through the preceding memoir, and my frequent refer- ence to them for facts about the volcanoes, craters and lava- flows, as well as the topography of the island, it has been appa- rent that they have been a very prominent basis for the con- clusions presented. The government map of Maui has still greater geological importance; for Prof. Alexander, the sur- veyor-general, has made it, by his accurate work and his appre- ciation of the importance of details, a contribution to science of the highest value and interest. What I have to say of the extent, depth, form and discharge-ways of the great crater, of the heights and positions of cinder cones, and of the erosion of the mountains, should be put mainly to the credit of the map, which was Prof. Alexander’s work not only in superin- tendence and geodetic measurement, but largely also in the details of the survey. The survey of the island, which is still in progress, reflects great credit on the Hawaiian people, and we trust it may be continued until in all parts complete. Every cone, or precipice, or fissure, terrace-level, or lava-stream located is a contribution to the history of the island and to physical and geological science.* * T am, moreover, personaily indebted to Prof. Alexander’s kind providings, guid- ance and instructions for the success of my trip in 1887 (August 4 to 6) up Halea- kala and into the crater, where a night was spent—an exceptionally brilliant night after a day of clear views from the slopes and the summit; and also for my ex- cursion up Wailuku valley on western Maui. IT owed much also, while on the island, to the hospitality of Mr. Henry Baldwin of Haiku, Mr. Edward M. Walsh and Rey. Thomas Gulick of Paia, and Mr. Bailey and Rev. Mr. Bissell of Wailuku. An excellent model of the island of Maui has been made by Prof. C. H. Hitch- cock, who devoted much time to it during his recent visit to the Hawaiian Islands. The government map was the chief source of data for the details. The verti- J. D. Dona— Geological History of Maui. 83 1. Hast Maui. I. The Mountain.—The crater of Haleakala has been many times described, but first with a detailed map in illustration by Captain Wilkes. Captain Wilkes states that he is indebted for the map to his artist, Mr. Joseph Drayton ;* and consider- ing that it was from an artist’s survey, not that of a surveying party with instruments, it is a remarkable piece of work. The expedition owes much to Mr. Drayton, not only for his excel- ‘ent labors as draftsman in all departments at sea, but also, after his return, for his management of engravers, printers, etc., dur- ing the publication of the various Reports. The mountain is usually ascended from Paia, a village on the north coast. The path (see map) passes Olinda and reaches the edge of the crater where the nearly vertical western wall bounding it is not less than 2500 feet in height. Thence it follows the summit southwestward to the southwest angle pass-, ing Pendulum Peakt on the borders of the crater just before reaching it. Here are three cinder cones, and the top of one is the culminating point of the mountain, 10,032 feet above tide. They stand at the head of a long line of cinder cones extend- ing southwestward down the mountain to the sea; and near the sea at the foot of this line are three or four comparatively recent lava-streams, enough to illustrate the process of seashore extension by such sea-border outflows. From the. southwest angle of the crater and the base of one of the three cinder cones, a cinder-made slope of rather easy grade descends into the crater, making a convenient place of descent; and thence the path continues eastward to the usual place of encampment, 44 miles from the top. 2. The two great discharge-ways of the crater.—Besides its lofty walls and great area, the most remarkable features of the crater are the two openings, a northern and a southern, a mile to a mile and a half wide between precipitous walls of rock— the walls of the northern 2,000 feet and over, of the southern, 1,000 to 2,000 feet—through which poured the lava of prob- ably the last of the great eruptions. The Kaupo lava-stream, the southern, has much the smoother surface, as if more recent; but the broader Koolau stream descended the wind- cal height is increased four times, and the craters and valleys are thus strongly brought out. All such exaggerated relief maps, whether of a mountain or sea- basin, need a note of warning attached to prevent wrong conclusions as to slopes and heights; for the ratio of 4 to 1 instead of 1 to 1 changes a slope of 14° to one of 45°,a low to an acute cone. The light shading used on the map of Hawaii in the last volume of this Journal and here on that of Maui, is intended to bring out the idea as nearly as may be of a mean slope of 7 to 10 degrees. * Wilkes’s Narrative, vol. iv, p.255. In the Exploring Expedition I had no chance to visit Maui, and saw it only from ship-board when passing it. + The Pendulum station of Mr. H. D. Preston, of the Coast Survey, in 1887 This Journal, last volume, page 305, 84 J. D. Dana—Geological History of Maui. ward slope, and the consequent erosion may have made all the difference. 3. The Cinder-cones and Lavas at the bottom of the crater. —Another striking feature of the crater is the group of red and gray cinder-cones which stand over the bottom, sixteen in number; the highest 900 feet above its base and all over 400, and yet looking small in the view from the summit of the great area. The sight to the northward, when half way to the bottom, comprising the northern discharge-way in the dis- - tance, the highest of the cinder-cones in the foreground, and beyond these and two other cones the broad stream of lava of the erater-floor as level apparently as a river, stretching away between precipices of more than 2,000 feet and then terminat- ing in an even line at the limit of vision as if there began the plunge to the sea, is wonderfully like the real river of lava on its downward way. The cinder-cones of the bottom were evidently the last work of the fires. The ashy surface of the cones is without a trace of erosion and thus bears no distinct marks of age. The slopes are mostly 25° to 30° and less, and hence they may have had the itch diminished somewhat by the winds and rains and earth- shocks, but there are no channelings by descending waters. The material is scoria in coarse fragments and sands, and though in part originally reddish and purplish, the red color has generally been deepened by oxidation from exposure. Besides the scoria, there are on some of the cones, es- pecially those toward the borders of the pit, numerous large blocks of gray, compact, scarcely vesiculated rock. Some of the masses about a cone near the place of descent meas- ured over a hundred cubic feet. The masses must have been torn off from the throat of the voleano’s conduit, this being the only conceivable source. They indicate therefore the action of vast projectile force at these isolated centers when the cones were in progress, and its continuation even to the close of the ejections; and they also are probable evidence of very rapid work in the cone making. A few of the other cones were grayish in color as if from the abundance over their slopes of these projected grayish stones; but I was unable from want of time, to verify this supposition. The cones stand, or appear to stand, on the rough, fresh- looking, scoriaceous lavas of the bottom, these lavas spreading away from beneath them. It was evident that the opened fis- sures or vents which gave exit to the cinders, first poured out the lavas; and then followed the cinder ejections as the fires declined and the liquid lavas of the vent became somewhat stiffened. The cinder material is proof of powerful projectile work; for the fragments of the exploding bubbles were thrown J. D. Dana—Geological History of Maui. 85 upward, as the heights of the cones prove, many hundreds of feet—more than nine hundred to make the highest cone. The fresh-looking lavas, occurring about the base of the more western of these cones, were found to continue eastward through- out the erater, with little change of features and with the same relation to the bases of the several cones, as if all were of one epoch of eruption—the epoch of the Jast outbreak of Halea- kala; the lavas seemed to have come from the latest outflows of several subordinate vents, after the crater had made its great discharge through the two gateways down the mountains. This scoriaceous lava of the crater contained in many places much augite and chrysolite in largish grains or crystals, be- ing both augitophyric and chrysophyric. 4. Lavas of the walls and summit.—The lava of the walls was in part scoriaceous; but, where examined on the south and southwest sides, it was commonly a very compact, rather light gray variety of basalt, like that of the projected blocks about ~ some of the cones. The layers of compact basalt had often one or more parallel planes of fine or coarse vesiculation, sometimes at intervals of one to three or four feet. At one locality on the ascent of the mountain the solid gray rock had been found to be’a convenient stone for stone imple- ments of various kinds, anda large manufacture had appa- rently been carried on there; and yet near by, the lavas that were so solid had occasional planes of coarse vesiculation, each one to three or more inches thick. Pendulum Peak, near the summit, just north of the southwest corner of the crater (the place of descent) consists largely of this compact light-gray basalt, with rarely any vesiculation visible without the aid of a pocket lens. This compact basalt or doleryte is a common rock also over the lower slopes toward Paia. It appears thus to be to a large extent the material of the older lavas; yet not only of the older. But at the summit on the west side, along the two miles passed over before reaching the place of descent, the compact variety of the basalt was rather the exception. There were large areas of the same scoriaceous lava that covers the bottom of the crater, and in some places it was equally augitophyric and chrysophyric, the augite in well-defined crystals. One of these areas was just north of Pendulum Peak; and a large region on the west border of the crater, looked as if successive streams of lava had recently flowed one over another, piling up layer on layer; so that by this means the surface for a breadth of a mile or more westward from the summit line had derived its unusual steepness of 15° to 16°. The lava-streams of the sur- face had the appearance of being overflows from the crater; as if the great pit had been full to the brim before the outbreak 86 J. D. Dana—Geological History of Maui. and had poured out from time to time small streams like those of a full lava-lake in Kilauea. But they more probably came from fissures cut through to the summit at the time of the last or some one of the later eruptions. The fact that lavas of the summit are so very chrysolitic, even at a height of nearly 10,000 feet, has an important bearing on the question as to the effect of high specific gravity in determining the distribution of materials in liquid lavas. Crystals of augite and large grains of chrysolite are common in the loose material at the base of the cinder cones at the sum- mit, near the place of descent, and colored glassy crystals of labradorite occur with them—facts first learned from Rev. T. L. Gulick after our return. These summit cones have the recent appearance and other features of those over the crater’s bottom, and appear to be of the same series and time of origin ; and the cinder-slope of that side of the crater was probably made in part from the ejections of these summit cones. 5. The probable nature of the last eruption.—The great dis- charge-ways of Haleakala, one to one and a half miles wide, with the walled valleys confining them, look as if the results of enormous rents of the mountain, made when the moun- tain emptied itself by the wide channels. But they may have been in existence before, and have been simply used for the last of the outflows. They are, nevertheless, evidence of rents at some time, and of a vast amount of removal of material some way—by subsidence, or otherwise. The height of the walls at the gaps, 2000 feet and over at the Koolau gap, and 1000 and over at the Kaupo, are a minimum measure of the amount of material removed. In my Exploring Expedition report I suggest that the mountain was fissured across along the lines of the two discharge-ways, and the eastern block shoved off a mile or two. Buta subsidence of the masses that occu- pied them into caverns below, leaving the walls as fault planes, may be more probable. The abyss which received them in this case had been prepared during a long period of undermining through ejections. Still there is some reason to believe in the grander view of a subsidence of the whole east- ern block, after the cross-fracturing. The island, as is seen on the map, is abruptly narrowed (instead of widened) at the spots where the Koolau and Kaupo streams reach the sea; and the part to the eastward is small, as if narrowed by such a subsidence. Moreover, the mean height of the eastern crater- wall is lower than that of the opposite or western by 500 to 1000 feet. A subsidence of 1000 feet increasing in amount to the eastward would account for the narrowing and for the very short eastern radius of the eccentric volcano. The question merits consideration. J. D. Dana—Geological History of Maw. 87 The evidence that the lavas were discharged in both direc- tions at once at the last eruption consists in the nearly uni- form appearance of the fresh lavas over the bottom of the crater from one end to the other, and their continuing into and ap- parently being the streams that descend the Kaupo and Koolau discharge-ways. Mr. J. M. Alexander has remarked that the crater is probably a double one, a combination of two great craters, as Mokuaweoweo at the summit of Mt. Loa is compound in structure. This is no doubt historically true; but at the latest of the eruptions there was probably one ac- tion over the whole; the distinction for the time obliterated. The period of the last summit eruption is unknown. I learn from Mr. Bailey of Wailuku, Maui, that, according to an island tradition, a lateral eruption of the mountain occurred about 150 years since in the district of Honuaaula of the southern part of East Maui, at an elevation above the sea probably of about 400 feet. 6. Activity of the Crater ending in Cinder-ejections.—The origin of the crater of Haleakala needs, I believe, no explana- tion beyond that given in the remarks on the origin of craters generally: that a volcanic crater and the mountain containing it commence to form together about an opened vent which discharges both vapors and lavas; that the crater is a result of the projectile action and the discharge of material from below, and generally also of subsidence into the cavity which is made by the discharge ; and that it does not become closed before the central vent ceases to discharge, and commonly is not then closed.* Haleakala is an example of a basaltic voleano which reached its end, through declining fires, in cinder ejections ; but it left its great crater open, and 2000 to 2500 feet deep, with the greater part of the bottom free from the cinders notwith- standing the amount discharged. The latest down-plunge or subsidence by which the vast pit and perhaps also its dis- charge-ways were made, may therefore have filled full the empty subterranean chambers which former outflows had pro- duced, and left the mountain solid instead of hollow. Mt. Kea on Hawaii, 13,805 feet in height, also ended its work with cinder eruptions; but the ejected material of lavas and cinders obliterated so far the old crater that no visitor of the region has yet found traces of its former limits. Whether Mt. Kea is a hollow mountain or not remains to be ascertained. Since the above was written, the results of the pendulum in- vestigations of Mr. E. D. Preston at the summit of Haleakala have been made known in a paper published in the number of _ * This J., xxxv, 33, Jan. 1888. The view is the same published in my Explor- ing Expedition Report, 40 years since. — 88 J. D. Dena—Geological History of Maui. this Journal for November last,* and have afforded unex- pected evidence on these doubtful points. They have led him to the important conclusion that “the density of the moun- tain is at least equal to its surface density,” and that, therefore, unlike some results obtained on the continents, “it is a solid mountain,” so that the interior must have been left filled by the subsidence of rock that made the great crater at the sum- | mit. He states also that “the zenith telescope observations at the foot of the mountain indicate the same fact.” Mr. Preston states further that at Kohala, on the north coast of the island Hawaii, the plumb-line deflections were half a minute southward, which, he adds, is well explained by the po- sition to the southward of all the great mountains of Hawaii. He records also that at Hilo, on the east coast, the deflection was a fourth of a minute to the northward. Mr. Preston remarks that “there is no explanation” of this result at Hilo “unless we assume that the south side of Hawaii, where the volcanoes are active, is much less dense than the north side where the fires have been slumbering for centuries.” But to the north of Hilo is a long reach of ocean, the coast of Hawaii there trending northwest ; the summit of Mt. Kea, 13,805 feet high, is 25 miles distant and bears N. 75° W.; and that of Mt. Loa, 13,675 feet high, is 35 miles distant and bears 8. 63° W.; and the center of gravity of the combined mass (the lowest level over 5000 feet) bears probably a little south of due west. It appears, hence, that we have here evidence that Kea is like Loa, not solid; that it is a hollow mountain, as inferred above from the absence of a summit crater; but Mr. Preston is prob- ably right in his inference that Mt. Loa is the more cavernous of the two. Additional plumb-line and pendulum observations are, however, much to be desired. 2. West Maut. West Maui has lost the original slopes of its great cone and its crater through erosion. It has been supposed that remains of three great craters may be distinguished in the mountains: the largest at the head of Wailuku or Iao valley on the north border of which rises the highest peak, Puu Kukui, 5788 feet high; another in the less deep valley of Waihee, just north of this; and a third at the head of the Olowaiu valley, to the south. . I examined only the Wailuku valley, the largest of the three, —so named from the village on the coast near its entrance. The valley is a deep cut into the mountains, remarkably grand in its precipitous walls with thin crested summits. It widens * Vol. xxxvi, 305. J. 1D). Dana— Geological. History of Maw. 89 somewhat toward its head, and in this upper part an extensive plateau occupies the center. The torrent of the valley is here divided between two tributaries, one running either side of the plateau. The height and rather bold sides of the plateau at the head of the valley, and its size and position, taken in con- nection with its location near the center of the mountain range, appear to make it pretty certain that the plateau represents the floor, or rather what is left of the central area, of the great erater. I looked for the edges of lava streams in the en- closing walls in order to make out their pitch and the thickness of the beds. But dense vegetation so covers everything that distant views are of no geological value, and one day’s excur- sion was not sufficient for a climb of the heights. As to the former crater condition of the other two valleys mentioned, | know nothing from personal observation. The idea of their having been craters is based on the size, depth, and boldness of the walls and the ampitheater-like head. But these features are common results of denudation in old volcanic islands, and therefore, in the question here considered I give them little weight. 3. The Eccentric form of the Maui Volcanoes. The map of Maui illustrates a Hawaiian feature of volcanic mountains which may be common in other regions. The chief crater of the mountain is not at its center. In Haleakala the ratio of the radii east and west of the crater is 2:3; and in West Maui, 8:11. The shorter radius is to the south-south- east of the crater in one and to the southeast in the other. In Hawaii it is not easy to mark off the true base of Mt. Loa. But we have the fact that in both the summit crater and Kilauea, the form is oblong, and each has its intenser activity in the more southern portion—the south-southwestern in one, and the southwestern in the other. The effect is not due to the to the winds, for the mountains consist almost solely of lava- - streams. 4. Drift-made ridge of consolidated coral sand. The positions of the high ridge of consolidated coral sand of Wailuku are indicated on the map. Whether proof of eleva- tion or not is yet undecided. I wasinformed that the sands are at the present time drifted by the trade-winds to the farther inland limit of these ridges and over their surfaces—a fact which seems to show that present conditions are sufticient for their production. 90 J. D. Dana—Geological History of Oahu. Il. IshAnD OF OAHU. From the map of Oahu, Plate 4, it is apparent that the island (a) consists of two eroded mountain regions, an eastern and a western, separated by a plain sloping gently downward to the opposite coasts and upward toward the eastern mountains. A more remarkable feature (4) is the long and high precipice fronting northeastward, and thus facing the tradewinds. Be- sides these characteristics (c), there are lateral or subordinate voleanic cones on the sea-border, of which Diamond Head and its companions, Punchbowl, and the Koko Head craters on the eastern cape (Plate 4, figs. 1, 2, 3), are examples. The island is the only one of the group that has (d) a nearly continuous coral reef fringing the shores. It owes to this reef the harbor of Honolulu, the one good harbor of the group, and also the possibility of a much larger and better one at Pearl River, seven miles west of Honolulu; the cutting of a channel through the reef is all that is needed, as has long been recog- nized, to make these capacious inner waters available for ship- ping®. Another interesting feature (e) is the existence of an elevated coral reef on the borders of the island, having its in- ner limits approximately indicated on the map by a dotted line. The facts on which the following account of the island is based and the views deduced from them are for the most part contained in my Expedition Geological Report. The visit in 1840 gave me nearly a month for study, which was indus- triously employed in excursions over and around the island. The accompanying map, on Plate 4, differs little, excepting in improvement in outline and topography, from the colored geo- logical map of my Report, and the outline of the elevated coral reef and its coral rock and sand bluffs are copied from it. The view of the tufa cones on the same plate are simply new drawings from some of my old sketches. For fuller particu- lars and some views not reproduced—as those of Kaneohe Point and Aliapaakai, I refer to the Report. My recent visit (in 1887) gave me an opportunity for another excursion around a large part of the island (taken with President Merritt), and * Honolulu, the capital of the Hawaiian Kingdom, was a collection of thatched huts in 1840, with exceptions only in a Custom House, an unfinished coral-rock church, and a few dwellings of civilized aspect. To-day it is city-like in its houses, its streets electrically lighted, its public squares, large Hospital grounds, spacious Government buildings—among them a palace good enough for any po- tentate—and its excellent hotel; and, through the addition of groves and avenues of introduced palms and tropical trees (some of which are always in flower or fruit) it is fast becoming a place of ideal beauty. Honolulu is the center of all the island activities, including inter-island navigation. It is not out of place to Tepeat here that steamers start every week or two for Hawaii and Kilauea—one route by Hilo to Keauhou, and thence up by horseback and wheels, the other by Punaluu on the south coast, where there is a good hotel and a carriage road all the way to the voleano. A carriage road from Hilo to Kilauea is in prospect. J.D. Dana— Geological History of Oahu. ol for further explorations, refreshing old memories and adding new facts; and this return to the subject affords an occasion also for reconsidering former conclusions. 1. Features, structure, and origin of Oahu. 1. General features ; Contrast with the island of Mawi.— Like Maui, Oahu is in origin a volcano-doublet—that is, as re- gards rock-structure, it was the united work of two great vol- canoes, a western and an eastern. But unlike Maui, its two vol- canie cones or domes have suffered so great loss that the posi- tion of either crater is wholly a matter of conjecture. A large part of the loss Oahu has suffered is due to denud- ing agencies. Kast Maui, as the map on Plate 3 illustrates, has lost in this way comparatively little of its original evenness of surface owing to the recency of its extinction. Its windward gorges are narrow, and only shallow gulches occur over the lee- ward surface. The ratio of its diameters at base, 1:1°3, is probably very near the original ratio. West Maui is pro- foundly gorged on all sides and most deeply so to windward, illustrating results of longer wear than East Maui has had. But something of the old slopes remain, and in the base we have still the ratio of its old diameters, 1: 1°74, with the outline little indented. The double lesson is taught: (1) what denud- ation from descending waters does to a voleanic cone 5° to 10° in slope in the region of the trades; (2) what, on the contrary, the sea cannot do, no encroachments of note existing to attest to its power, notwithstanding the length of the era of denudation. Oahu resembles Maui in having the western mountain-cone the most time-worn and the smaller in area, but here the like- ness ends. Both of its mountains are deeply eroded. Further, East Oahu has only part of its old slopes left. They remain only on its southern, western and northern sides; the north- eastern are cut off by the great precipice, twenty miles long, which is made for the most part of the edges of the lava- streams that slope southward and westward. The sharp-edged serrated ridge, making the summit of the precipice, is from 1000 to 3000 feet in height, and at its northeastern base, from - Kualoa eastward, there is in general only a narrow strip of low land with low hills, the width but three or four miles except in the Kaneohe peninsula. The precipice continues beyond Knaloa northwestward, but not the low land at its base. These features have occasioned peculiarities in the results of denudation on East Oahu. The leeward or south and southwestern sides have long and deep valleys, some of them heading in broad amphitheaters under the crested mountain ridge. The windward side, along the 20-mile precipice, on the contrary, has buttresses and shallow alcoves, with a but- 92 J. D. Dana—Geological History of Oahu. tress here and there lengthening out into a ridge; and only far- ther northwest, beyond Kualoa, are there the longer valleys or gorges and ridges and the mountain architecture characteristic of deeply worn windward slopes. The only broad valley of the leeward or south and southwest- ward slope that is continued upward with gradual ascent to the very edge of the precipice is that of Nuuanu, behind the city of Honolulu. It is the valley to the left in fig. 2 on Plate 4. Six miles up it ends in the “pulz,” or precipice, and overlooks the northeastern sea-border plains and hills. The height of the “ali” is only 1207 feet above the sea; but on either side are the highest peaks of the range, Konahuanui 3105 feet in height, and Lanihuli, 2775 feet. Great denudation on the /eeward side of an island is an ex- ception to the usual rule. It is a consequence, on Oahu, of the sharp-crested 20-mile precipice. The trade winds become chilled on striking the summit of the precipice and ready, therefore, to drop their moisture ; but as they are moving on, they get beyond the summit before much of the moisture falls, and so the leeward slopes receive the water. In the upper part of the Nuuanu valley, within two miles of the palz, 182 inches of rain fall a year, and nearly 100 inches less than this at Honolulu, although brief sprinklings occur almost daily over the city. Konahuanui and Lanihuli, as seen from Hono- lulu are generally under clouds, but from Kaneohe they are usually uncovered. A nearly similar condition exists in West Maui, owing to the thinness of the rocky walls at the head of its great valleys. Very broad valleys are consequently made on the leeward side, as in Oahu; but these valleys soon end below in a slender gulch, which may be, for the most of the year a “dry run;’ the excessive dryness and heat of the lower plains evaporating powerfully and supplying no water. 2. Orographic condition of Hast Oahu.—F¥rom the facts mentioned, it appears to be plain that the chief structural dif- ference between East Oahu and East Maui is that the latter is a whole volcanic mountain, and the former a piece of one. By some means the Oahu mountain-cone or dome has lost, as I concluded in 1840, a large piece from its mass—all that once existed northeast of the 20-mile precipice. The size of the lost piece it is not easy to determine. The lava streams of the leeward slopes, which dip away from the precipice mostly at an angle of 3° to 5° (as seen in the intersecting valleys), must have come from some point or points beyond it to the north- eastward. Following the leeward slopes around westward and north- ward we find all pointing upward toward the higher part of J. D. Dana—Geological History of Oahu. 93 the mountains, as if the source were somewhere in that direc- tion; but just where, remains in doubt; and it may be even questioned whether there may not have been two or more great craters along the line. No point or region has a more reasonable claim for consider- ation in this respect than the head of Nuuanu valley. In situ- ation and width, and the features at its head, it is just what should be looked for in a great discharge-way. On my recent visit I sought for facts bearing ou the question and found the dip of the beds to diminish from 38° to 1° toward the top, and at the “ pali,” the beds were very nearly or quite horizontal. This is favorable to the conclusion that the crater was either at its head or near by it, just beyond the precipice. The low land below, over the Kaneohe peninsula and between this pe- ninsula and the “ pali,” is a region of tufa hills and other small cones, unlike any part elsewhere of the north or northeast coast. In addition, at the head of Nuuanu valley, very near the top of the “ pali,” there are the remains of a red cinder cone. Besides this, on descending the steep “pali” by the path, there is to the east of the path a long broad slope, 35° to 40° in angle, consisting of reddish layers of volcanic cinders, scoria, earth and stones—indicating cinder ejection from some point above. It is therefore most probable that the center of volcanic ac- tivity for East Oahu was in the vicinity of the “pali,” above the low region a little to the northeast of it. The cinder cones above mentioned may have been results of the last efforts of the declining fires, like those of Haleakala and Mt. Kea. In 1840, I was led to locate the central crater on the Kan- eohe peninsula, because the head of the “ pali” was so near the southern foot of the mountain; I thought it must have been farther off. But the fact that the volcanic mountains of East and West Maui are eccentric in ground-plan, and that the same feature quite certainly characterized this Oahu cone, makes the position near the “pali” the most probable. In Haleakala the center of the crater is only six miles from the southern shore; and this distance in the Oahu crater, on the above supposition, would be about seven miles. The idea of an eccentric cone fourteen or fifteen miles in the transverse diameter through the crater is thus strongly favored. On fur- ther comparison with Haleakala, we find that the part of the longer diameter of the mountains which lies northwest of the center of the crater is about 19 miles in length on Maui, and on Oahu it would be nearly 25 miles. The small dip of 1° to 3° prevails widely about the mountains at Kualoa point and to the northward, as well as in the upper part of the Manoa valley, west of the Nuuanu; and from this it may be inferred 94 J. D. Dana—Geological History of Oahu. that the East Oahu mountain was a dome, like Mt. Loa, rather than a cone like Haleakala. The existence of one or more craters west of the “pali” has been urged, and is possible. I know of no special facts sustaining it. The amphitheater at the head of Manoa valley is referred to by Mr. Brigham as probably the site of a crater; but I was more inclined from my examination to make it an amphitheater of erosion. 3. Origin of the long precipice on Oahu.—The long preci- pice of East Oahu has been attributed to erosion. But I have found no evidence that such’ transverse walls are legitimate effects of erosion, either fluvial or marine. As illustrated on Maui (p. 91), the sea works with extreme slowness in batter- ing lava-cliffs, and cannot work at all below the limit of force- ful wave-action—a level not twenty feet beneath the surface. Fluvial action makes long valleys in the long descending mountains and capes which the sea is incapable of obliterating. Land waters have done grand work in alcoving the long preci- pice, and carving battlements and temples out of the rocky piles that were left, as is well exhibited in the Kualoa bluffs, while the sea has not even scraped away the small tufa cones on its borders. It might be said that the cones of Kaneohe and the “pali” have been made since the era of erosion; but this disconnects their origin by a very long era from the period of activity in the crater. Another view with regard to the origin of the precipice is that of my Expedition Report, namely that it was made by a profound fracturing of the mountain-dome across from south- east to northwest, and a drop-down of part of the outer or eastern section. ‘The line of fracture was irregular—the course rather of a series of fractures; and subsidences of varying extent may have taken place along the line, becoming smaller to the northwest, where high ridges are left between the preci- pice and the coast. The amount of displacement was not less than the height of Konahuanui, 3105 feet, and probably much exceeded this. Great catastrophic subsidences are not uncommon in voleanic regions. In the account of Maui and its crater the fact of a subsidence not less than 2500 feet, accompanying and follow- ing some one of its eruptions, appears to be placed beyond doubt. Hawaii has plain evidences about its crater of subsi- dences hundreds of feet in amount of displacement if not thousands; and there are high precipices, like that at Kealake- kua Bay, for which there appears to be no other probable source of origin. The small western island of the Hawaiian group, Niihau, has a bold precipice as its eastern face, 1500 to 1800 feet in height above the sea, and the lava-streams of the island pitch J. D. Dana—Geological History of Oahu. 95 from the precipice to the westward, showing that the streams flowed from a point to the eastward, and that a large piece, perhaps the larger part, of an old volcano has disappeared. Kauai, north of Niihau, has its Napali cliff, a dozen miles long, along its southwest side, in a line with the Niihau cliff. Molo- kai, to the east of Oahu, was once, as its lava-streams prove, a doublet of volcanoes, like Maui; but it has been shaved down to a strip of land 35 miles long, and not a fifth of this in mean width. The eastern part has an alcoved precipice facing the north, which rises to a height of 2500 feet above the sea. It encloses a strip of land along the sea shore, and on ‘this spot, thus walled in, it has been found convenient to locate the Leper quarantine-ground of the islands. Lanai, a narrow island south of Molokai about 20 miles long, has a bold front to the south and gradual slopes from it in other directions. Thus such precipices are rather the rulein the Hawaiian group ; and if seashore erosion is not the origin—as an island like Tahiti, with its profound radiating gorges asa result of fluvial action and its non-gorged coast, appears to show*—fractures and subsidence must be. A great voleano is a disgorger of lava in vast floods and so it makes its mountain; and it may make also empty cavities at the same time and asa consequence. As long as the ascensive force keeps the liquid lava-column of the active volcano fully up to the summit crater, the mountain may have only local cavities. But whenever a great discharge takes place, a coequal cavity may result; and if the discharge is from fissures at the base of the cone, 15,000 to 18,000 feet below the sea level (not a greater depth than exists in the neighboring seas) an enormous cavity may be left, which only the renewed action of the ascen- sive force would fill. If the mountain then became extinct with no return of the liquid, it would be a hollow mountain ; and the greatest of subsidences which the Hawaiian facts seem to indicate, are small compared with the possible consequences of such a condition. 4. The Tufa and other Lateral cones of Hast Oahu.—Several of these cones, as already stated, are represented on Plate 4. Punchbowl, fig. 2, stands on the northern border of Hono- lulu (at P on the map).t Its highest point is 498 feet above tide-level. The tufa of the beds constituting it, though rather feebly consolidated, is quarried on the west side of the cone, and specimens may there be conveniently obtained. It is a yellow to brown, in part resin-lustered, palagonite-like rock, bearing evidence in its constitution and in the dip of the beds, * This Journal, xxxii, 247, 1886. + The sketch was taken in 1840 from the deck of the ship Peacock as she lay in the harbor. The native huts at its foot are omitted. : 96 J. D. Dana— Geological Llistory of Oahu. that mud-making warm waters were concerned in the deposi- tion: and its being of brown, in place of red, color, is probable evidence that the temperature of the water was below 200° F. Diamond Hill, fig. 1, makes the prominent cape east of the city; its bold southern brow has a height of 761 feet above the sea at its base. It is, like Punchbowl, a fine example of the typical tufa-cone in its broad and shallow, saucer-shaped erater, with the stratification parallel to the bottom of the sau- cer and to the original outer slope. These slopes have become deeply trenched, as the view shows, by descending waters ; and since 1840, the southern brow has lost something of its bold- ness. Two other cones stand in a line to the north of it, the first, a place of lava outflow. The three vents appear to be sit- uated on a single line of fracture. The Koko Head tufa-cones are situated at the east extremity of the island. The view (fig. 8) was taken from the east- ward at sea. The larger or more northern of the two cones is much denuded inside and out. The other low cone, situated on the Point, is worn to its center by the sea, and has thereby been made to exhibit to the passing vessel (as it goes from or toward Honolulu) the dip of its tufa beds inward and outward, and thereby the true structure of such a cone. Artesian borings on Oahu afford some facts bearing on the history of Diamond Head and Punchbowl. The borings ' were made by Mr. J. A. McCandless of Honolulu, and records of a number of them have been received from him through Prof. W. D. Alexander. The following section is from James Campbell’s well, at the west foot of Diamond Head, not far from the sea-level. Thickness. Depth. Gravel and beach'sand {7222-22 ees. eee 50htecty ae Tufa like that of Diamond Head __-__---_-- 270 320 feet Harp coRAL ROCK, like marble ---------- 505 825 Darkiorowmnicla ye ie Nk ao eee See iee 75 900 WiashedwWeraviel <1 Sli u ho ce eee 25 925 Deepmediticlay: sss) tea Shea Ng MNGi NEO ep 95 1020 SOFT WHITE CORAL ...---.-- Paper e ay es ets 28 1048 Soapstone-likemmockue (02. ais 20s ee ae 20 1068 Brown clay and BROKEN CORAL-_..------- 110 1178 lar. diolwe awa, Seer te hela ie cu Ca pe ae 45 1223 Blackiandjrediclayeie. sas: Be eee ee 28 1251 Brown) Wawa Sey ee i aig ap ke witae (249 1500 The well went down 1178 feet before reaching the solid lava of.the bottom. In its upper part it passed through 270 feet of tufa, indicating that the tufa-cone extended below the sea- level to this depth, and therefore had a total height of over 1000 feet. Below the tufa, between the 320-foot and 825-foot Am. Jour. Sci., Vol. XXXVII, 1889. Plate Ill. : : — » Oo Sh Lee is 40) =) RN I56r 35! iat iN? EW OMI, 7 7, IN ( LY \ 4 ean Geka hig ZS a ere ail ys\ iy Lee 10 FROM THE GOVERNMENT MAP miles Am. Jour. Sci., Vol. XXXVII, 1889. Plate IV. FROM THE GOVERNMENT MAP SiG yc 8, yailes Sy CE y Ge = 2 = C] g | = | | Mokapuw Pt che Peninsula } I | | | | js | 3 } az | Barkers Pt. | | or Kalaeloa 2 e | | Koko Head | 1551 5 10" 5 158 40’ 15" 1. The volcanic cones: a, Diamond Head, or Leahi; b, Kaimuki, or Telegraph Hill, andc, Maaumae. 2. Punchbowl, or Puowaina, with Nuuanu valley to the left, id ule peaks Konahuanui and Lunahili, right and left of the pali. 8. The Koko ead craters. J.D. Dana—Geological History of Oahu. 97 levels, there are 505 feet of hard coral rock ; and then on the 1045-foot level, a 28-foot layer of soft white coral and at a greater depth, brown clay and broken coral. As the well is close by the west foot of the Head and passes through so much of its tufa, it is quite certain that the 505-foot stratum of lime- stone was made before the tufa-eruption; and that the beds underneath it mark earlier conditions over the site. As regards a supply of fresh water the well was a failure— an exception to the usual experience. The water came up salt and a much stronger brine than sea-water. It was under some pressure, as it stood a foot above the level of surface wells near by. i Other borings have been made in Waikiki—the sea-border district just west of Diamond Head. The section afforded by the deepest of the Waikiki wells is here inserted for compari- son. It is that of the King’s well, No. 2—about half a mile west of Diamond Hill and 850 yards from the seashore. : Thickness. Depth. SAMOA G CORA ea epee palene seaman Rerteetiom 22. VV Geeuriy ICORAT ROCK 2. 22 us sla Se 22, 60 NecllOwisand te coe Raa 43 103 MER Vary: aaa agate oS ON Sh N 47 150 WHE COR Ale ROCK sate a ate a oe 110 260 pluen clay = see ae eee 25 285 Touch clay sands CORALS =32): 22.542 65 350 IBN es. Cle na aa eae re ae cy US rant et 30 380 ELAR DE COR AT EROCK 2hesey 4, tee obs oe 40 42.0 SOMITE CORAM pes Sai sey Oh Ne 30 450 Mouol Cla yer ata cea Set oe a Baas 5 455 VW VGEnER nie OF ATR OOKury 5. oy genta aia 40 495 Mou hiclavecame seat cena teal hae 30 525 WVSENI EE COAT ROCK sense erin 100 625 Mouobrs Clavie ie srk sue woe) nailer 5 630 Conauandeclays seem. - kn wus 70 7100 (oughe clayey sansa Sone a Oo wa 28 728 ISIE VoL SSP y c6 bas nee Oh Lara alin na Ste 2 730 BIE A Vai hi Chet ee Os Sg by eC 120 850 In this well, the upper 320 feet probably correspond approx- imately to the upper tufa-made portion of the preceding. It is remarkable that tufa is wholly absent, although the distance from the active vent was so small; but this is accounted for by the direction of the trade winds, which would have carried the ejected material seaward—the direction in which the hill is elongated. Moreover the tufa-cone although 1000 feet high may have been thrown up in a single year or less. Instead of tufa for the upper part, there are, underneath 88 feet of sand and Am. Jour. Scl—Tuirp SeRizs, VoL. XX XVII, No. 218.—FerEs., 1889. 7 98 J. D. Dana—Geological History of Oahu. coral, 22 feet-of white coral rock; 110 feet more of the coral rock above the 260-foot level, and 65 feet of “tough clay and coral” next above the 350-foot level. Further, beginning with the 385-foot level, coral rock is continued to the 700-foot level, , or for 315 feet, with the exception of 40 feet of clay divided between three layers ; and this 315-foot layer of limestone ap- pears to correspond to the 505-foot layer between 320 and 825 feet in the other section. The solid lava-stream of the bottom of the well was reached at 730 feet. The amount of water obtained proved that the lava-stream was one of those from the mountain. It is overlaid by 2 feet of volcanic sand and 28 of tough clay, the sand serving to contain the water and the clay to confine it, conditions suited to make the well a success. In these sections the intercalated beds of so-called “ clay” vary widely in position and thickness, and appear to be, in gen- eral, local deposits from mountain streams, or tufa deposits from one source or another. In another boring in Waikiki, a bottom of solid lava was reached at 375 feet; and in a third, Goo Kim’s well, at 475 feet. The former had an intercalated lava-stream at a depth of 206 feet, and the other at 150 feet. In Goo Kim’s well, which was nearly a mile from the seashore, there were 26 feet of coral rock above the 150-foot level, and 194 feet of coral rock above the 430-foot level but with two intercalations of a 20-foot layer of “clay” in the stratum. The facts as to the varying levels of the “clay” beds and the intercalation of lava-streams show what accidents the living species of the sea and its reefs were exposed to. They make the existence of a continuows 505-foot stratum of coral lime- stone underneath the tufa of Diamond Head the more re- markable. The artesian wells made within the limits of the city of Honolulu might be expected to throw light on the history of Punchbowl. 1. A well in “Thomas Square,” just south of Punchbowl, afforded the following section. Soil 6 feet, with 6 of black sand and “clay” 4.-.. 16 ft. _-- Wihite wCOnal stocker hie 2s ak Lee CO a che eae 200 SiN Gusto Bro wale lay tee ye ees oie 2 a eed eee 44 260 Coral roe kero: eae Leche cs te eer ee a A ate 10 270 Brown clay, Sx ley: eee Be oS Neen Ra TE pe Ble 60 330 Wibitetcoralirock)2552 ee ae eae Aa cu FS dies 50 380 Brow nt clay): Ae) U WC INeete Ree hy eek i Cua Shee 80 460 Bed rock or lava, penetrated _--:.----.-------- 49 509 2. In “Mr. Ward’s well,’ below Thomas Square, on King street, there were at the top 15 feet of loam and sand, then 180 feet of “hard coral rock,” carrying the depth to 195 feet; again 24 feet of coral and shells above the 219-foot level; and J. D. Dana—Geological History of Oahu. 99 then, underneath 109 feet of “yellow clay” which may be Punchbowl tufa, 23 feet of coral rock above the 393-foot level, and 107 feet of white and yellow sand below it; with the bot- tom lava at 508 feet covered by 4 feet of quicksand. An abundant flow of water was obtained. 3. South of the last, in the “ Kewalo well,’ begun near the sea-level, beneath 6 feet of black volcanic sand, there were 50 feet of coral rock over a 40-foot layer of hard lava; then 190 feet of coral, divided in two by an intercalated 30-foot layer of “clay,” over the 350-foot level; with the bottom lava-bed at 620 feet. 4, Section from a well in the Palace yard : Soil 4 feet, black sand 4---........ 8feet. --- CORA O Keser ete cel ey a aa 64 72 feet. lardulavia serge sie ee ee ct ae 6 78 Wihitecoraliroclke. sees nee a 60 138 (OG i SP a Iona es) ia Reta 240 378 Woraliprock eee enna eee ay 75 452 Clayzandvoravels ee 2 cae eae 254 707 Lava or bed rock penetrated ------- 55 762 Of the above sections 1, 2 and 3 have a thick bed of clay on the 260-foot to 280-foot level; 1, 2 and 4 on the 330-foot, 370-foot and 378-foot levels; 1 and 2 and 3 on 460-foot, 500- foot and 535-foot levels; and No. 4, a layer 254 feet thick on the 707-foot level or the bottom rock. It is possible that one or more of these of “clay” may be decomposed tuta of Punch- bowl origin. But to refer all to this source would make the period of eruption of very improbable length. The “black sand” below the soil in Honolulu is naturally referred to this source. But more investigation is required for a decision. There is no evidence that Diamond Head and Punchbowl were of simultaneous origin. 5. West Oahu.—The mountains of West Oahu cover at the present time a much smaller area than those of East Oahu. Their original dimensions we have no data for estimating. The highest peak, Kaala, in the northeast part of the group of sum- mits, has a height, according to the government survey, of 3586 feet—which is 681 feet greater than that of Konahuinui ; and besides this, there are, in the southeastern part, peaks of 3105 and 3110 feet. These elevations, and the deep and open valleys divided off by sharp ridges, are sufficient evidence that the mountain range is but a small remnant of the once great volcanic mountain, probably a loftier mountain than that of East Oahu. Denudation has had a far longer time for its dis- secting work, and has done much to diminish the area it covers. Whether great loss has resulted also from subsidence is not ascertained. 100 J. D. Dana—Geological History of Oahu. The fact that the voleano of East Oahu was in full action long after the extension of the western cone, is shown (as I first observed in 1840 and again in 1887) by the encroachment of the eastern lava-streams over its base, and the burial in part of the valleys. The accom- panying sketch is a view, yq looking westward from the \.. | plain made by the encroach- » =| Ing lavas, showing how the ~~ =| lavas dammed up the al- | ready made valleys of West Oahu, and forced the drain- 3 age waters to take a north or south direction, nearly parallel with the base of the mountain, in order to reach the sea. The courses of these streams are shown on the map. The depth of burial by the East Oahu lavas was probably some hundreds of feet. 2. Evidence of recent change of level. 1. Elevation.—Evidence of recent upward change of level is afforded by the elevated coral reef along the sea-border. The dotted line on the map (Plate 4) has already been pointed to as approximately the inner limit of the raised reef; the small dotted areas about Kahuku Point, the prominent north cape of the island, and in Laie, the district next southeastward, besides others west of Waimanalo, are the positions of hills or bluffs made of the reef rock and consolidated drift sands. The rock is in some parts a beautiful white, fine-grained building stone; but generally it has sudden transitions in texture and firmness, and much of it is a consolidated mass of broken corals, or else of standing corals made compact or nearly so with coral sand. Along southern or southwestern Oahu the height of the reef is fifteen to thirty feet; and I estimated the amount of elevation indicated by it in 1840 at 30 to 40 feet. At the Kahuku bluffs, which I visited anew in 1887 (see figure 2), the solid coral reef rock extends up in some places to a height by estimate of fifty to sixty feet above tide level; and this is surmounted by drift-sand rock, made of beach coral sands that were drifted into hills on the coast when the reef- rock was submerged, adding twenty feet or more to the height. There are large caverns in the bluffs, which are mostly within the upper layer of the coral reef-rock and_have the drift-sand rock as the roof. In the sketch, a faint horizontal le may be seen passing by the top of the cavern; it separates the beds _ of different origin. The coral reef-rock consists mostly of ce- mented masses and branches of corals of the kinds common in J. D, Dana—Geological History of Oahu. 101 the modern reef, and also has often the corals in the positions of growth. But the wind-drift beds show the quaquaversal or variously-striking dip common in wind-made drifts, as rep- resented in the two sections below. 2. Kahuku bluffs of coral rock and drift-sands, with two sections of the . drift-sand rock. The change of level along northern Oahu, according to the facts from Kahuku, appears to have been at least sixty feet, or twenty feet greater than on its southern side. Even with an accurate measurement of the height of the reef-rock about Oahu the amount of elevation would remain doubtful because the coral reefs off the island are at present nowhere up to low-tide level; and this may or may not have been the fact before the change of level took place. . The surface of the elevated reef of Oahu is exceedingly un- even from unequal construction and erosion, and its interior has in some places large and winding caverns, so that an overlying formation, were there one, would afford an example of wncon- Sormability by denudation. It is obvious that with greater elevation, the unevenness would be as much greater, large enough to get the credit, perhaps, of representing an interval of many thousands of years, although results of the “modern” period in geology. Denudation works rapidly among lime- stones and especially so when the limestones have just left the water, with the usual irregularities of upper surface and texture. 2. Subsidence.—A gradual subsidence of the island is appar- ently indicated by the coral reefs, through the depth to which they have been found to extend in Artesian borings. In these borings, described on page 96, a depth of 700 to 800 feet was 102 J. D. Dana—Geological History of Oahu. found for the coral rock, and more than 1,000 for broken corals; and over 700 is reported by Mr. McCandless from a well in the Eua district, about five nriles west of Honolulu. The facts lead to the inference that the subsidence amounted to at least 800 feet, and that it corresponds to the coral-reef subsidence which Darwin’s theory requires. Mr. McCandless informed me that fragments of corals like those of the modern ~ reefs were brought up from the various levels. This evidence of subsidence to the amount stated is not, how- ever, complete. Doubt remains because the corals brought up in fragments have not been examined by any one competent to decide on their actual identity with existing species; I could not find that any of them had been preserved. The import- ance of their preservation and careful study is now understood, and we may hope before long to have the doubt removed. As the case stands, the probability is that the limestone is to the bottom true coral-reef rock and that the depth to which it ex- tends is, therefore, a measure of actual subsidence. Darwins Coral Island theory.—In the above statements the present condition of Darwin’s theory of Coral Islands, is fully and fairly recognized. Much has been recently written about the theory’s having been set aside or proved to be without foundation. But in truth, no facts have been published that prove the theory false, or set aside the arguments in its favor. The facts and arguments from Tahiti brought out by Mr. Murray I have shown, in my review of the subject in this Journal in 1885* (published also at the same time in the Lon- don Philosophical Magazine), to have no weight and more than this, to sustain Darwin’s theory, instead of opposing it. The idea of the excavation of the lagoon-basins of coral islands by sea-waters I have also proved in the same paper to be not a possibility. : The only suggestion of real importance that has been pre- sented is not against Darwin’s explanation, but simply in favor ~ of a possible substitute. Mr. A. Agassiz and others have sug- gested that deep-sea organisms may build up limestone over the sea-bottom, and thus raise the rock to the level where reef- forming corals may grow, or within 100 to 150 feet of the sur- face; and that, in this way, coral reefs and islands may have been formed without subsidence. Mr. Guppy has shown that some coral-made limestone, in the southwest Pacific, actually has a base of limestone that had been made by other life than that of reef-corals. This is all the foundation for setting aside Darwin’s conclusions. It is good ground for doubting, and a good reason for investigating the nature of the coral limestone in the various coral-reef regions of the Pacific at * Volume xxx, pp. 89 and 169. Nichols and Franklin—Direction of Electric Current. 108 depths below the level of 100 to 150 feet—as I state in the article referred to, where I propose that deep borings should be made, under government authority, on a sufficient scale to settle the question. The borings have been made on Oahu; but, as I say above, the fossils of the reef-rock passed through below the coral-growing limit have not been examined and the subsidence therefore is not positively proved. There are many collateral arguments in favor of the Pacific coral-island subsi- dence reviewed in my paper which still remain strong; but they may be held in abeyance until the borings have been sat- isfactorily made. These and other points are discussed at length in the paper to which I have above referred. I took no part in the controversy with reference to the state- ments of the dogmatic Duke of Argyll, knowing that the subject was in good hands. But I may here say that the charge which he made that no one had dared to bring for- ward and discuss the facts and views published by Mr. Murray and others against Darwin’s theory was the more inexcusable that my paper had appeared as recently as in 1885 in the Lon- don Philosophical Magazine. The charge was based on ignor- ance of the facts on all sides, and on incapacity to appreciate the spirit actuating men of true science. One other paper—on the question whether volcanic action ts a cause or not of trough-making over the Ocean’s bottom, with a review of the ocean’s depths ulustrated by anew bathymetric chart—will close this series with the exception of the promised paper on the rocks of the islands by E. 8. Dana. Art. XI.—An Experiment bearing upon the Question of the Direction and Velocity of the Llectric Current ;* by Epwarp L. NicHous and WILLIAM 8. FRANKLIN. [Contributions from the Physical Laboratory of Cornell University, No. III.] In one of his recent articles in the Annalen der Physik und Chemie, Fcepplt has described an, experiment in which the de- flection of the galvanometer needle under the influence of a stationary coil of wire carrying an electric current, was compared with the deflection produced when the coil was given a high velocity of rotation; the axis of the coil being the axis of revolution. If the current traversing the coil had possessed direction and a finite velocity, a change in the de- * Read before the American Association for the Advancement of Science ; Cleveland meeting; August, 1888. + A. Foeppl; Wiedemann’s Annalen, Bd. 27, p. 410. 104 Nichols and Franklin—Direction and flection of the needle might have been looked for as the re- sult of the revolution of the coil; the deflection being greater when the coil was revolving in the direction in which the current was flowing than when at rest, and less when the direction of the current was opposed to that of the coil. The result of the experiment was a negative one, the deflection of the needle being just the same when the coil was at rest as when it was in rapid rotation. , Feppl’s apparatus was inadequate to the end in view, for had the current consisted in a motion of translation of a sin- gle fluid, its velocity need not have greatly exceeded 300,000 centimeters per second to have rendered the difference between the deflections due to the stationary and to the rotating coil indistinguishable. The method is, however, capable of very much greater refinement than that attained in his experiment, and while modern views of the nature of the electric current are such as to lead us to look for a negative result, whatever the delicacy of the apparatus, the present condition of electrical theory is not such as to render a repetition of the experiment under improved conditions devoid of interest. The present writers, by whom the details of a similar method had been developed before they became acquainted with Feeppl’s work, have repeated his experiment with an appara- tus capable of indicating the direction and velocity of the current, supposing it to have direction, even though that ve- locity were very large indeed. A flat bobbin of hard rubber was carefully turned upon a lathe. It was 8°25 in diameter and 1°6™ in thickness. The periphery was provided with a groove of rectangular cross-sec- tion. This groove was wound differentially with sixty-four turns of insulated copper wire. The winding was very com- pact and the wire was held in place within the groove by means of a brass tire or collar. Brass dises of slightly smaller diame- ter than the bobbin were screwed to the faces of the latter and well centered steel axles were inserted in these discs. Two brass supports, fastened to a hard rubber block which served as a base for the apparatus, carried bearings of Babbitt metal in which the steel axles of the bobbin rested. Each of the sup- ports likewise bore two brushes of spring brass which could be so adjusted as to make contact with brass collars upon the axle of the coil. When the supports were connected with the ter- minals of a storage battery or other source of current, the cir- cuit was completed through the coil; the current passing from one support to the axle upon that side by means of the bearing and brushes, thence to the brass disc upon the same side of the bobbin. From this disc, with which one terminal of the coil Velocity of the Electric Current. 105 made contact, the current traversed the windings and made exit through the opposite dise, axle and support. The coil thus mounted was driven by a belt. It could be given a very high velocity of rotation and could be supplied with current equally well whether at rest or in motion. In some preliminary trials to determine the rate at which it could be driven with safety the source of power was a small high- speed water-motor. It was found that four hundred revolu- tions per second could be readily obtained and that such a velocity could be maintained without undue heating of the bear- ings. Upon one occasion a speed of nearly six hundred revo- lutions was reached, when the brass retaining band parted with a loud report and the bobbin was instantly stripped of every vestige of wire. The coil was then rewound and balanced anew, and the rate of four hundred revolutions per second, al- ready determined as lying well within the limits of safety, was not exceeded during the remainder of the investigation. The rate of revolution was readily and accurately determined from the pitch of the note emitted by the revolving coil, this determination being verified from time to time by two inde- pendent methods; namely from the siren-like note uttered by four screw-holes situated 90° apart upon one of the brass discs attached to the bobbin, and by estimating the velocity of the driving belt. The needle, by means of which variations in the magnetic moment of the coil were to be detected, was placed immedi- ately above the latter and as near to the windings as possible. It consisted of a steel wire, about 1° long and 1 millimeter in diameter, hardened and magnetized. It was suspended within a cylinder of copper and was rigidly connected with a precisely similar needle, by means of an aluminium support, the two needles being parallel, in the same vertical plane and about 5™ apart, their poles in opposition. The aluminium support also carried a plane mirror and was suspended in the usual manner by a silken fibre. The astatic pair thus mounted was com- pletely neutral and it was necessary to give it directive force by means of a governing magnet,.the position of which was so selected as to give the system a fixed zero point and at the same time a very high degree of delicacy. Deflections.were noted by use of a telescope and scale. The figure of merit of the apparatus was determined by substituting a coil of direct windings and known area, for the differentially wound coil, and reading the deflection due to ‘00001 amperes of current. Since, for the effect in question, the figure of merit was the same as though the revolving coil also were directly wound, it could then be derived from a comparison of the total areas of the two coils. 106 Nichols and Franklin—Direction and The most serious defect of this apparatus lay in the imper- fect balancing of the differential windings. The position of the needle when a current traversed the coil always differed considerably from that which it assumed when the current was broken, and with one ampére of current the deflection amounted to several centimeters. The difficulty was however not of a nature to interfere altogether with the progress of the inves- tigation and a series of readings were accordingly made with coil at rest and in motion. The rate of revolution during the determinations was 380 turns per second. ‘The direction of the current through the coil and the direction of rotation of the latter were repeatedly reversed while the position of the needle was under observation. The result was an entirely negative one, no measurable effect upon the needle resulting from the motion of the coil. The current traversing the coil was meas- ured upon a Moler’s “swinging-arm” galvanometer. During a portion of the time it exceeded one ampére. A determina- tion of the figure of merit of the apparatus made immediately after the conclusion of the series of observations gave as a result : 1™™ deflection=0°0000164 ampéres. When one ampére of current traversed the coil, therefore, a change in the apparent magnetic moment of the latter (due to rotation), inthe ratio 1:1-:0000164 would have shown itself in a change of deflection amounting to 1™™. Such a variation could not have escaped notice. The mean circumference of the windings of the coil was 23°939™, so that at 880 revolutions per second the wire had an average velocity, in the direction of its own length, of 9096°82™. If we suppose the current to consist in the movement of electricity along the wire in a given direction, the velocity, relative to the conductor, being the same whether the coil is at rest or in motion, and the deflection of the needle to be due to the translatory movement of electricity with reference to the needie and proportional to that movement, it is easy to caleu- late the change in deflection, for any assumed current-velocity, which will be produced by a given rate of rotation of the coil. Let V,, be the linear velocity of the conductor, V, the velocity of the current, C, the current traversing the conductor, C, the current necessary to produce a given deflection when traversing a directly wound coil of the same total area. VEC. Ci. a Then V,= Velocity of the Electric Current. 107 In the case in question, a current-velocity of 554,680,000 per second would have been indicated by 1™ change of deflec- tion when the coil reached 380 revolutions per second. In these preliminary measurements, the highest degree of sensi- bility attainable by the method in question had beeu approached only in so far as the velocity of the revolving coil was con- cerned. It was evident that the number of ampére-turns in the revolving coil could be greatly increased without corres- ponding loss of speed, and that the question of further increas- ing the sensitiveness of the astatic pair, depended only upon our power to eliminate the disturbance due to the lack of com- plete balance in the differential windings of the coil. To meet these ends a new coil was made for us by Mr. F. C. Fowler, the mechanician of the department of Physics, to whose skillful workmanship the excellent performance of the coils already described was due. This new coil was of the same diameter as the original one, and it was constructed in the same general manner. It was wound upon a box-wood spool, however, which was thick encugh, axially, to admit of 390 turns of wire without changing the mean area of the wind- ings. To avoid the very great difficulty of constructmg a dif- ferentially wound coil so perfect that when earrying large cur- rents, its effect upon the delicate astatic needle should be neg- ligible, we resolved upon a modification in our method which should make the complete electrical balancing of the coil un- necessary. For the current from the storage battery used in our preliminary observations we substituted that generated by a small alternating-current dynamo giving 40,000 reversals a minute. The advantages of this change were very great, for there was no appreciable effect upon the needle, even when a much heavier current than we had attempted to use in our first experiment was traversing the coil. Under these conditions the sensitiveness of the astatie pair could be increased to the highest degree compatible with the maintenance of a perma- nent zero point, and the current traversing the coil was limited only by the heating of the wires. The current from the alternating-current machine was meas- ured by its heating effect upon a phosphor-bronze wire about fifty centimeters long, stretched vertically within a cylinder surrounded by a water-jacket. The elongation of the wire was made to move a small mirror by means of a simple device which need not be described here, and the angular movement of the mirror was read with a telescope and scale. This wire had been previously subjected to extended investigation and its reliability as an indicator of current was well established.* It * See the Thesis of P. P. Barton and F. R. Jones: “The Measurement of Al- ternating Currents.” MS. in the Library of Cornell University. 108 Wichols and Franklin—Direction of Electric Current. had been found that its indications when heated by an alterna- ting current of the character used in our experiments agreed very closely indeed with those obtained by calibration with con- tinnous currents of known intensity. Such a ealibration was made in the present case, covering deflections from zero to 300 scale-divisions, which last-named reading corresponded to 5-00 amperes. The new coil of 890 turns was now driven at 380 revolutions per second, the circuit being opened and closed and the cur- rent direction through the coil being repeatedly reversed, as in the former experiments. The amount of current traversing the coil was increased from time to time until the stretched wire indicated 4:26 ampéres of alternating current, which was the largest quantity which it was deemed safe to permit the coils to carry, even for the few seconds necessary to the com- pletion of an observation. The direction in which the coil re- volved was likewise reversed from time to time. No change in the position of the needle due to the motion of the coil, nor to a reversal of the direction of the coil, nor to a reversal of the direction of the current within the coil could be detected, although’ the sensitiveness of the needle had been increased, about eight times, the current more than four times and the number of turns in the ratio of 390 to 64. A re-determination of the figure of merit of the apparatus showed that 1™ deflection now corresponded to :000000438 am- peres. An effect of much less than 1™™ due to the revolution of the coil, would have been clearly observable under the con- ditions of the experiment. The absence of such an effect seemed to warrant us in the conclusion, that if direction be as- cribed to the electric current, its velocity must be such that the quantity of electricity conveyed past a given point in a unit of time, when the direction of the current was that in which the coil was travelling, did not differ from that transferred when the current and coil were moving in opposite directions by as much as one part in ten million—even when the linear velocity of the wire, as in our experiment was 90968 centi- meters. _ Now the velocity at which such a current must needs have traveled, in order that the revolution of the coil should in- crease or diminish the quantity of electricity passing the needle by an amount corresponding to a deflection of 1™™, or in the case of the reversal of the direction of the current within the moving coil, corresponding to 2"™, is found as before by multi- plying the current in the coil by the linear velocity of the latter and dividing the product by the figure of merit of the apparatus. O. A, Derby—Monazite as an Element in Rocks. 109 We thus have 9096°8 K 4°26 eee 9 LOS SalOs centimeters: 00000043 an mires It is quite within safe limits to say therefore that we should have been able to detect a change of deflection due to the mo- tion of the coil, even though the velocity of the current had been considerably in excess of one thousand million meters per second. Physical Laboratory of Cornell University, August 1, 1888. Art. XIL—On the occurrence of Monazite as an accessory Element in Rocks ; by ORVILLE A. DERBY. Some five or six years ago Mr. John Gordon, an American mining engineer now engaged in commerce in Rio de Janeiro, brought to my attention a peculiar heavy yellow sand which had been sent to him from the province of Bahia under the supposition that it was tin sand. This on examination proved to be monazite with the composition, according to an analysis by Prof. Henri Gorceix of the Ouro Preto Mining School (Comptes Fendus, 1885): Phosphoric acid 28-7 per cent, oxide of cerium 31°38 per cent, oxides of didymium and lanthanum (?) 89°9 = 99-9. Inquiries instituted by Mr. Gordon and myself in regard to the locality and mode of occurrence of this sand revealed the fact that it occurs in con- siderable patches on the sea beach near the little town of Alcoba¢a in the southern part of the province of Bahia, where it seems to have- been accumulated by natural concentration through wave action. Attention having been thus drawn to this mineral, Prof. Gorceix has since detected yellow grains in the diamond sands of several localities of the provinces of Minas Geraes and Bahia which from giving the didymium lines in the hand spectroscope have been referred to monazite, and I have my- self identified it by the same process in gold sands from sev- eral points in the provinces of Minas, Rio de Janeiro and Sao Paulo. The wide distribution of the mineral in the sea and river-sands of Brazil was thus established, but under circum- stances that gave no clue to its origin. Recently Mr. Gordon informed me that in examining with a lens the sands of the beaches about Rio de Janeiro he found always yellow grains similar in appearance to the Bahia mona- zite and that on concentrating the sands in a copper miner’s pan, he obtained a small quantity of white and yellow sand that 110 O. A. Derby—Monazte as an Element in Rocks. hung to the bottom of the pan behind the black iron minerals. Under the microscope the white grains show the charac- teristic form of zircon while the yellow ones, aside from their physical resemblance to the Bahia mineral, give like that, the didymium band in the hand spectroscope and the microchemi- eal tests for phosphoric acid and cerium, so that their identity with monazite seems clearly established. As gneiss is the only rock that is at all abundant about Rio de Janeiro, it was natural to suppose that the mineral so widely distributed in the sands might have come from that rock. About the same time Prince Pedro Augusto de Saxe Coburg Gotha discovered in an apatite-bearing streak of the gneiss of the Serra de Tijuca a minute yellow crystal with the physical aspect of monazite, but too small for chemical tests. This suggested the idea that, notwithstanding the small proportion of the mineral and the microscopic size of the grains, it was not altogether hopeless to look for it in the rock itself, while Mr. Gordon’s method of concentration by panning was nat- urally suggested as the simplest and readiest mode of in- vestigating the question. Under Mr. Gordon’s instruction I soon acquired sufficient facility in the use of the pan to make a satisfactory concentration and with his aid some scores of tests have been made of the rocks in the vicinity of Rio and from about a dozen points in the provinces of Rio de Janeiro, Minas Geraes and Sao Paulo. Where decomposed rock was obtainable the tests were made on this by washing a quantity equal to a heaped double handful, care being taken to obtain material decomposed 7m s¢tw and carefully freed from any extraneous wash. Where decomposed material was not at hand pieces of sound rock were ground in a mortar, a fragment the size of the fist or even smaller proving sufficient for a satisfactory test. All the tests made on gneiss, granite and syenite have given, in addition to zircon, a greater or less quantity of mi- croscopic crystals of a heavy yellow mineral apparently identi- eal with the Bahia monazite. As no erystallographic study could be made, the identification has been based on the general appearance of the grains, their high specific gravity, and mi- crochemical tests for phosphoric acid and cerium. In some few cases the yellow grains are lighter in color and duller in luster than the Bahia mineral, but as they give the phosphoric acid and cerium reactions they are presumed to represent a variety of monazite, or perhaps some other cerium-bearing phos- phate. Their high specific gravity is proved by their behavior in the pan where they remain with the zircon, behind the other minerals, so that, after extracting the magnetite with a magnet, it is possible by careful manipulation to obtain these two min- O. A. Derby—Monazite as an Element in Rocks. 111 erals nearly free from titaniferous iron and garnet when these are present. The separation of the zircon is presumably favored by the minute size of the grains and by their pris- matic form as it remains behind minerals as heavy or even heavier than itself when, as is generally the case, these are in larger grains. The yellow mineral, however, is frequently in as large grains as the titaniferous iron and of a similar rounded form and appears to hang back in virtue of its greater specific gravity. A few tests were made with fused chloride of lead (sp. gr. 5), which on cooling showed the yellow grains at the bottom of the ingot while the zircon and titaniferous iron were near the top. A number of the samples were tested with the hand spectroscope giving the didymium band, but owing to the difficulty of bringing together a sufficient num- ber of such minute grains to give a perfectly satisfactory test, this means of identification was abandoned in favor of micro- chemical processes. All of the samples have been tested by treatment with sulphuric acid and molybdate of ammonia. In some eases crystals appeared in the sulphuric and oxalic acid solutions, along with those referred to cerium, which probably represent some other elements. It is possible that a more complete chemical and crystallogical study of the yel- low grains of these residues may prove some of them to be- long to minerals other than monazite, but in the impossibility of making such investigations here, they are all referred pro- visionally to that species. Samples of rock and residue from the granite of the Serra do Tijuca in the outskirts of Rio de Janeiro, in which the yellow grains are particularly abundant, have been placed in the hands of Prof. George H. Williams of Baltimore, in the hope that he may find them of sufficient in- terest to make such studies as, from the lack of appliances and the necessary training, are out of the question here. The gneisses examined were obtained from a score or more points in and about the city of Rio, including porphyritic, granulitic and schistose varieties; from Kilometer 78 (ascent of the Serra do Mar), on the Dom Pedro IL. railroad, and the station of Barra do Piraley on the same line; the station of Socego on the Uniao Mineira railroad in the province of Minas Geraes ; and the towns of Cutia, Piedade, Santos and Iguape in the province of Sao Paulo representing an extension of about 300 miles along the axis of the great gneiss region of the maritime group of mountains of Brazil. In every case zircon and the yellow mineral were found there, proving to be the most constant accessories since ; of the ordi- nary accessory elements, garnet, rutile and the iron minerals, magnetite and ilmenite—the first two were frequently abseat, while rarely only one of the iron minerals seemed to be pres- 112 O. A. Derby—Monazite as an Element in Rocks. ent. Rutile appears to be a comparatively rare element in these gneisses since the transparent red titaniferous grains re- ferred to it were found only in two or three places in peculiar highly micaceous schistose layers, unusually rich in iron min- | erals. If, as is possible, these grains belong to some other mineral, then rutile is entirely lacking in the rocks examined. The gneiss from Socego and Cutia contains an abundance of sillimanite. All the gneisses examined belong to the class of biotite gneiss, except that from Santos which contains both muscovite and biotite and in this the yellow grains are rare in comparison with the zircon. No oppartunity for examining a purely muscovite gneiss has yet been afforded. The relative proportions of zircon and the yellow mineral vary considera- bly in these tests, sometimes the one sometimes the other pre- dominating. In the rock from Socego and from Kil. 78 D. Pedro II. railroad, the yellow mineral is particularly abundant. A small number of granites have been examined with a similar result, that is to say, all of them give zircon with a heavy phosphate which in most cases appears to be identical with the Bahia monazite. The greater number of tests have been made on fine-grained biotite granites which give residues identical in appearance with those from the gneiss. The two specimens of muscovite granite examined from the station of Caieiras on the Sao Paulo railroad and from Sorocaba in the province of Sao Paulo gave a small quantity of lusterless whitish grains, quite different in appearance from those which we had become accustomed to refer to monazite, but on sub- jecting them to microchemical tests these also proved to be cerium-bearing phosphates. Yellow grains of the ordinary aspect are quite abundant in the small dykes of biotite granite in the gneiss about Rio and also in the larger masses of the Serra de Tijuca near Rio and at Pridade in the province of Sao Paulo, where Mr. Henry Bauer has kindly made a test for me. It is also abundant in uncommonly brilliant and per- fect crystals in a small dyke in the gneiss of the Serra de Tin- gua, a peak of the Serra do Mar range near Rio. They are rare, in comparison with the zircon, in the large dykes near Campo Grande on the Santa Cruz branch of the Dom Pedro II. railroad, and near Bassa do Pirahy on the main line of the same roads, and in a small dyke at a place called Boa Vista on the Ribeira river in the Iguape region. It is interesting to note that the first two of these rocks carry cerium as a silicate in the form of orthite. The Tijuca granite is one of the rich- est rocks yet examined in the yellow mineral and a rough quantitative test was made on it as follows: A quantity of the rock disintegrated but not completely decomposed was dried in the sun and ground in a mortar to pass through a sieve O. A. Derby—Monazite as an Element in Rocks. 118 containing ‘45 holes to the linear inch. As the decayed feld- spar and mica, which may be presumed to carry the rarer and first formed minerals of this rock, went much finer than this, it was assumed that all of these were set free. From 1906 grams of the ground rock 0°557 grams or 0-029 per cent of residue consisting mainly of the yellow grains were obtained. As the small quantity of zircon and ilmenite in this residue is, probably, but little if any in excess of the loss in washing, the proportion of the yellow mineral can be safely put down as from 0°02-0:03 per cent of the entire mass of this rock. A red syenite from the Serra do Stauba in the province of Bahia gave the yellow mineral in comparatively large grains, but these were few in number in comparison with the zircon. A mass of clay from the station of San Joas on the Sorocaba railroad in the province of Sao Paulo which is presumed to rep- resent the syenitic rock of the vicinity, but which may be from gneiss, gave, with abundant zircons, a mineral giving the same reactions as those from the other rocks but lighter in color and duller in aspect than is usual. he basic eruptives thus far examined, representing diabase, quartz-diorite mica-diorite and minette have afforded no trace of the yellow mineral. It should be mentioned that in all these tests care has been taken to select samples representing the principal mass of the rock free from veins and mineral aggregates. In the course of these investigations grains which appear to represent several other rare minerals have been met with, but these have not yet been fully examined. Since the above was written, a test has been made on a rock richer in monazite than any hitherto examined. This isa fine grained granitite exposed in a large dyke in the road from Engenho Noro to Jacarepagua in the outskirts of Rio de Janeiro. After thorough drying in the sun 3002 grams of the clay resulting from the decomposition of the rock was washed and the residue cleaned by the use of a heavy solution (sp. gr. 3°5), and of the electro-magnet. The residue weigh- ing 2°24 grams, or U:0746 per cent of the entire mass, consists principally of monazite in exceedingly fine grains with a small amount of zircon and a much smaller amount of other impurities that could not be completely separated without loss of material. The mixed monazite and zircon can safely be put down as 0-07 per cent of the rock. In a recent excursion to the Argentine Republic Mr. Gor- don obtained residues of zircon and monazite from the river- sands at Buenos Ayres and from gneiss and granite decom- posed in situ at Cordoba. Am. Jour. Sc1.—TuirpD Series, Vou. XXXVII, No. 218.—FeEp., 1889. j 8 114 Trowbridge and Sabine—Steam in Spectrum Analysis. Art. XITL—On the use of Steam in Spectrum Analysis ; by » JOHN TROWBRIDGE and W. C. SABINE. AmonG the difficulties with which the investigator in spec- trum analysis must contend is that of obtaining a source of light which is free-from constituents other than those which are under examination ; and at the same time sufliciently powerful to enable him to photograph the spectra of the latter. The voltaic are gives a sufficiently strong light to enable one to pho- tograph throughout the visible spectrum; the electric car- bons, however, are full of impurities, and it is difficult to in- terpret the spectra obtained by these means. Moreover, it is not easy to employ the are spectrum for researches in the ultra violet portion of the spectrum. On the other hand the spark from a Ruhmkorff coil taken between terminals of metals, the spectrum of which we wish to examine, gives us in general spectra comparatively free from impurities, but its light is very feeble compared with that of the electric arc, and even when the spark is obtained by means of a powerful coil which is ex- cited by an alternating dynamo machine an hour is necessary to obtain with a concave grating of 21 feet radius of curvature, on the most sensitive dry plate a photograph of the ultra violet spectra of copper at the wave length 2100. It becomes an important question then to ascertain whether the time of exposure of the sensitive plate can be shortened by any process; for the outlay in obtaining one photograph in the ultra violet by the means hitherto at our command is very large, involving as we have said the running of an engine of at least two horse power for an hour. In our experiments with a jet of steam we find that the time of exposure of the sensitive plate can be shortened to at least one-third. We were led to employ steam for the purpose of obtaining the spectra of oxygen and hydrogen with a more powerful electrical excitation than is possible in Geissler tubes. During the winter of 1886, when engaged upon the subject of oxygen in the sun, one of us in connection with Mr. C. C. Hutchins tried to obtain a powerful electric spark in an atmosphere of steam, but the experiments were unsatisfactory. The difficul- ties were chiefly in the way of proper insulation. Experi- ments showed that no containing vessel could be employed for the sides of the vessel conducting the electricty from one ter- minal of the Ruhmkorff coil to the other. No spark could be obtained, and the experiments were abandoned. During the present winter the experiments were renewed. The contain- ing vessel was abandoned and the jet of steam was allowed to Trowbridge and Sabine—Steam in Spectrum Analysis. 116 impinge directly upon the spark. No effect could be perceived when there were no condensers in the secondary circuit, and with the introduction of small condensers the effect was not marked ; but when the number of Leyden jar condensers. was - increased to four the effect of the jet of steam upon the elec- trie spark was surprising.. Its light immediately became com- parable with that of the electric arc, enabling us to see the metallic spectra with the naked eye upon the ground glass of the photographic camera without the use of an eye piece. The chamber in which the spark and steam jet were placed became rosy red from the hydrogen arising from the dissociation of the steam. The hydrogen and oxygen lines in the air spectra became very much strengthened, a continuous spectrum showed itself in the neighborhood of the C line and also in the yellow, and a photograph of the air line and metallic line of the ter- minals employed could be taken in a third of the time which was necessary when the steam jet was not employed. The apparatus consists merely of a tin box which is placed opposite the slit of the spectroscope. Steam enters at one side and is blown across the terminals of the Ruhmkorff coil which are placed in the box opposite the slit, an outlet on the side op- posite from the place of entrance of the steam allows the waste steam to escape into the outer air. The change of color of the spark is undoubtedly due to hy- drogen. The light filling the box above referred to is decidedly red, and the hydrogen line C flashes out with great brilliancy in the midst of a continuous band of red in the spectrum. The metallic line from the terminals are greatly strengthened. The light from iron terminals is especially brilliant. Without the steam the spark between iron terminals seemed to consist of a single line of discharge. When the steam was turned on a great bundle of sparks appeared in the midst of a flaring light and the noise of the spark was greatly increased. This effect can undoubtedly be traced to increased conduction of the air space between the terminals of the Ruhmkorff coil. The appearance of the spectra led us to examine the ques- tion of the spectrum of the Aurora Borealis and its connection with that of aqueous vapor. We believe that the theory that the shifting nature of the northern lights may be due to elec- trical discharges following strata of air more or less laden with aqueous vapor has been advocated. The appearance of the spectra of the electric spark in steam certainly leads one at first to favor this hypothesis. We have spoken of the marked brill- jancy of the hydrogen line and of a continuous red band near this line. The continuous spectrum in the yellow is no less prominent. The observations which have been made on the northern lights do not enable one to make exact comparisons. 116 Winterhalter—Personal Equation Machine. The lines given by different observers, however, do not appear to coincide with the prominent lines and bands observed in the air spectrum heightened by steam. Other observers, among them Professors Liveing and Dewar, have employed steam to obtain steam lines, but we have been unable to find any reference to the remarkable economy in time and in waste of apparatus which results in the use of a jet of steam in spectrum analysis, when the spark method of obtaining the spectra of metals is employed. Jefferson Physical Laboratory. Art. XIV.—A Wew Personal Equation Machine, for use with the Meridian-Cirele; by A. G. WINTERHALTER, Lieut., U. 8. Navy. Doctor WALTER F. WISLICENUS, in charge of the merid- ian-cirele at the Strassburg Observatory, has lately given an account of his investigations, by means of an apparatus devised by himself, of his personal error in recording transit observa- tions, The salient features of the machine are its attachment directly to the meridian-circle and the capability of using it in almost any position of the telescope. These warrant a brief exposition of the contents of Dr. Wislicenus’s paper.* The idea of determining the personal error in transit obser- vations by means of an apparatus appears to have been first enunciated by Professor Kaiser in 1851 in the 5th volume of the Tijdsschrift voor de Wis- en Natuurkundige Wetenschap- en. Prazmowski, in Warsaw, seems to have been the first to publish (in Cosmos, vol. iv, p. 445), in 1854, a scheme for a per- sonal equation apparatus. The author, after a more or less detailed study of the appa- ratus designed, successively, by Mitchel, Plantamour and Hirsch, C. Wolf, F. Kaiser, E. Kayser, Harkness, Hilgard and Suess, Eastman, R. Wolf, Br edichin, Christie, has arrived at the conclusion that in all previous instruments the disadvantage is presented of a horizontal position of the telescope used and, therefore, of an upright one of the observer, conditions not found in transit observations. From this and other considera- tions, the author lays down the following features to be com- plied with by such an apparatus : 1. The personal error should be determined with the same instrument with which observations are made. * Untersuchungen tiber den absoluten persdnlichen Fehler bei Durchgangs- beobachtungen. Von Dr. Walter F. Wislicenus, Privatdocent and Assistent an der Sternwarte zu Strassburg. Leipzig, 1888. Pp. 50, 9"x12”; one plate, with 3 figures. (Wilhelm Engelmann). Winterhalter— Personal Hquation Machine. 117 2. The apparatus should allow the error to be determined in various positions of the observer. These two requisites are found in an apparatus arranged by Professor Bakhuyzen, but the second is secured by a disposi- tion, which is not convenient and which requires much time for adjustment, i. e., for reflecting into the tube of the transit- circle telescope (placed at a determined elevation), the image of the artificial star by means of two mirrors, one of which is secured to the object-end of the telescope. Of the good points of the Leyden apparatus, as described by the author, I had the opportunity of satisfying myself on a recent visit to that obser- vatory. The task to be accomplished, according to the author, was the fulfillment of three conditions, viz: 1. The apparatus must be capable of application to a transit or meridian circle of the larger class. 2. It should not hinder the free movements of the telescope. 3. The artificial star should traverse the whole field and sc imitate as faithfully as possible the motion of a true star. _ The design of a machine of this character was facilitated by the fact that in the instrument used an artificial star was already present, namely, the small luminous image which is seen in telescopes with a central field-illumination, produced by the little mirror attached to the inner surface of the object. glass. This method of illumining the field, now always used in the Repsold constructions, is, therefore, the first essential to the apparatus. The machine designed was fitted to the Cauchoix transit of 132 millimeters aperture, an old instrument left by the French Faculty and later modernized for the Strassburg Observatory by the Repsolds. The apparent motion of the artificial star over the wires is secured by causing the ocular to slide laterally, when the image appears to move in the direction of motion of the ocular and is found in the center of its field. The machine’s breaks are recorded as followed: On the ocular slide, insulated by a layer of caoutchoue, is a brass plate secured by two scews running into sockets of hard rubber. This bears, at right angles to the line of motion of the ocular, a steel spring having a small brass terminal, carrying a platinum-point, which touches another brass plate secured to the fixed ocular- head on top of an insulating layer. With an electric wire run- ning to each of the insulated plates mentioned, the current is closed, when the platinum-point touches the brass underneath it. In the last-named brass plate a number of parallel lines, corresponding as accurately as possible to the position of the reticule-wires, have been drawn by a dividing engine and filled up with an insulating substance. The platinum-point in pass- 118 Winterhalter—Personal Equation Machine. ing breaks the current successively for each artificial transit. It can be so set that the machine’s break and the observer’s break shall differ by a constant amount, allowing them to appear in succession on the chronograph sheet and be recorded by one pen. The motor used was the clock-work of a Hipp chronograph. On one end of the horizontal axis of the telescope the two halves of a wheel are clamped. This wheel has a double row of teeth, one row gearing into the chronograph-train used as the motive power, the other into the connections for moving the ocular. At the latter, the arrangement contemplates, by means of the raising of a cain, the alternate engagement of a pinion in upper and lower racks for motions forward and back- ward. This change of direction can be made without the eye leaving the eye-piece. By combining wheels of different num- bers of teeth, a large number of different speeds can be given to the clock-work. I pass over a number of interesting experiments, such as those with a flat platinum-point for slow motions and a fine one for fast motions, experiments with various insulating substances for filling the grooves representing the wires, and will mention that the application of the apparatus to the Cauthoix instru- ment in question restricts the motion of the telescope through 116° of the 360° of a complete revolution, of which only about 26° are above the horizon. This facility of movement enables the observer to take up any desired position on or off the observing-couch. Designed for a new instrument, still more ample motion might be secured. ‘The motive power should impart a regular motion and should be capable of regulation without the insertion of various wheels. The author gives the results of numerous observations made for the determination of his personal error, using the equation Q) eat where x is the absolute personal error; a, the difference taken from the chronograph record between the machine’s and the observer’s breaks for motion in one direction; }, the same for motion in the opposite direction. All instrumental inaccura- cies are eliminated, as may be seen from the two equations (a), (b), from which (1) is derived : (a) a=ae2+ce+d+f, for forward motion ; (b) 6=e—c=d—f, for backward motion ; where, in seconds of time, ¢ is the error introduced by a slight eccentric displacement of the image produced by the motion of the ocular; Winterhalter—Personal EHquation Machine. 119 d, the time by which the machine’s break occurs earlier or later than the transit ; J; the time by which the machine’s break precedes the transit for all threads, by reason of the adjustment of the platinum-point ; +, prefixed according as the machine’s break occurs “iit” than the corresponding transit of the artificial star. The time elapsing between a transit and the corresponding automatic break must be the same for both directions of the motion of the ocular, which must be assured by the use of a uniformly acting clock-work. 207 —0 ‘046 +0 *323 — 45 —0 °127 +0 °041 +0 410 —90 +0 °140 +0 :497 +1 -772 In this table, the first column indicates the position of the telescope, counting from the horizon, + above it, — below; 120 Winterhalter—Personal Equation Machine. the remaining columns give the personal equation with rates of motion of the star corresponding, respectively, to 11° 2170, | 60° 8/5 and 80° 19’-0 declination. The general deduction is: In the author’s personal equation a dependence is proved on the position of the telescope, 1. e., on the corresponding position of the body. Second Group. il, 2. SB) CY? —05:'115 26 1) 0) —0 :096 aes) 240) Uf, ©), JQ, Oil +82 40L.C. +0 +463 +59 40 L.C. +0 +040 In this table, the first column gives the setting in declination as read off on the circle, with an indication of upper and lower culminations, the motion being, as stated, that of a star of that declination ; the second column, the personal equation. The general deduction is: the amount of the personal equa- tion is algebraically increased and changes sign (becoming posi- © tive) for slow motions ; this is also shown by the first group. Besides, the second group indicates, although not as plainly as the first, the dependence of the equation on the position of the observer. The author finds also that in time his equation changes. For a star of equatorial motion, it was found 1886. Dec. 138-22 : —0°°178; 1887. May 23-27: — 0-105); 1888. March 17: +0 148. A comparison of the two groups with results obtained in Leyden in 1886 is interesting, but does not safely show a varia- tion depending on varying positions of the telescope. Physiological. investigations were not attempted nor were generalizations for others, but the author draws two conclusions applicable to his own ease. The absolute personal error is with stars of a mean speed of transit a minimum, increases with an increase and decrease of the speed and, in the latter case, in general more rapidly than in the former. The absolute personal error is, in general, dependent on the position of the telescope and the requisite position of the body of the observer, as also on the observed object,—star or limb. An ingenious disposition of the apparatus permitted the au- thor to examine his personal error in observing the limb of disks of various diameters. A brass ring was blackened and Winterhalter—Personal Equation Machine. 121 fastened to the cell of the eye-piece on the side nearest the reti- cule, leaving, however, the entire aperture free. On this ring a gilass-plate, 0° millimeter thick, was secured with shellac. This plate had a circular opening in its center and was attached in such a position that the edge of the opening passed through the center of the ring. It is obvious that the illumination of the field was now divided into a bright and a somewhat darker part by an arc passing through the center of the field. There is seen, then, a part of a bright disk on a half-bright ground, transiting the wires by the motion’ of the ocular, as before. By using plates of different-sized openings, disks were obtained corresponding to angular radii of NGm Qe emily Orie tut I, Oe On: The motion in one direction gives the transit of either the preceding or the following limb ; to get the same limb for the reversed motion, it would be necessary to turn the ocular through 180°. Owing to a limited time, the observations were made only so as to take the mean between errors of preceding and following limbs. For a motion corresponding to that of a star of 11° 21’ de- clination, the personal equations in observing the limbs, in the order of angular radius above given, were: + 05089, +05:259, +0213, +0%183, +0157, while for a star the equation in the same position of the tele- scope was found to ‘be +0%148. Forming the differences limb — star, in the same order, we have: —05:059, +0111, +0%-065, + 08-035, +0%-009. The observations in this last investigation are not complete, but it seems to be established that the author’s personal equa- tion is different for observation of limb and of star, the differ- ence generally increasing with the increase of the size of the disk observed. The advantage of the author’s apparatus remains in the fact that with it the circumstances of transit observations can be closely imitated, both as regards the position of the observer and the fulfillment of other desirable conditions. Objections of complication can scarcely be made, as it is not likely that an apparatus of an entirely simple character will be devised to - permit a complete investigation of the peculiarities of the personal error. 122 0. Barus—Subsidence of fine Particles in Liquids. Art. XV.— Zhe Subsidence of Fine Solid Particles in Liquids ;* by CARL Barvs. 1. THRovGHOUT this paper the motion of the corpuscles through the liquid is of the kind premised in treating capillary transpiration : in both eases solid and liquid move relatively to each other under conditions by which eddies are excluded, and the whole kinetic energy is at once converted into molecular kinetic energy, or heat. In my earlier work I endeavored to analyze the phenome- non of sedimentation into parts such that the conditions under which the subsidence is to be explained from a chemical, or from a physical, point of view, may be better discernible. To do this I first considered the question in its purely mechanical aspects.t If P be the resistance encountered by a solid spher- ule of radius 7, moving through a viscous liquid at the ratew, and if & be the frictional coefticient, then P=6zkrxv: Again, the effective part of the weight of the particle is P’ =trr(p-p' \9; where g is the acceleration of gravity and p and p’ the density of solid particle and liquid, respectively. In case of uniform motion P=P’. Hence “= oor"(o—p')g vigil weal io gets lg) In any given case of thoroughly triturated material the par- ticles vary in size from a very small to a relatively large value ; but by far the greater number approach a certain mean figure and dimension. An example of this condition of things may be formulated. To avoid mathematical entanglement I will select y= Aw?e-™ . .. . . (2) where y is the probable occur- rence of the rate of subsidence x. If now the turbidity of the liquid (avoiding optical considerations) be defined as propor- tional to the mass of solid material particles suspended in unit of volume of liquid, then the degree of turbity which the given * The present article, being a continuation of Bulletin U. 8. G. 8., No. 36, 1886, is largely based the experimental evidence there tabulated. Mr. William Dur- ham (Chem. News, xxx, p. 57, 1874; id. xxxvii, p. 47, 1878) was the first to give an incentive to this class of experiments. Much of our knowledge of the effect of precipitants is due to him. Moreover, the theoretical views at which he ulti- mately arrives may be regarded as a definite point of departure. In this country Prof. T. 8. Hunt (Proc. Boston Soc. Nat. Hist., Feb., 1874), Prof. W. H. Brewer (National Acad. Sc., 1883; Am. Journal, (3), xxix, p. 1, 1885) and Prof. C. R. Stuntz (Cincinnati Soc. Nat. Hist., Feb., 1886) have occupied themselves with similar work. Prof. Stuntz’s paper contains further references among others to Waldie’s results (Journal Asiatic Soc., of Bengal, 1873; Chem. News, 1873). Meanwhile Mr. W. Hallock has made experiments on the subsidence of lamp- black in connection with his work on the density of that substance (Cf. Bull. U. 8. G.S., No. 42, p. 132, 1887). I may add that my own experiments were sug- gested by Prof. Brewer’s memoir. + Cf. G. Kirchhoff, Mathematische Physik, lecture 26, § 4, 1876. C. Barus—Subsidence of fine Particles in Liquids. 123 ydex particles add to the liquid is, caet. par., proportional to r°ydx, where 7 is the mean radius. Hence the turbidity, 7; at the outset of the experiment (immediately after shaking) is @ T=T, [| r°ydw=T,, where equations (1) and (2) have been in- corporated, If the plane at a depth d below the surface of the liquid be regarded, then at a time ¢ after shaking the residual turbidity is 2 d 7 Date (BAe aan eed rydxe= T, (7 —( 1 +5)¢ ): The equation describes the observed occurrences fairly well. In proportion as the time of subsidence is greater, the tube shows opacity at the bottom, shading off gradually upward, through translucency, into clearness at the top. If instead of equation (2) there be introduced the condition of a more abrupt maximum, if in other words the particles be very nearly of the same size, then subsidence must take place in unbroken column capped by a plane surface which at the time zero coincided with the free surface of the liquid. Again suppose one-half of the particles of this column differ in some way uniformly from the other half. Then at the outset there are two continuous columns coinciding, or as it were interpénetrating throughout their extent. But the rate of subsidence of these two columns is necessarily different, since the particles, each for each, differ in density, radius and frictional qualities by given fixed amounts. Hence the two surfaces of demarcation which at the time zero coincided with the free surface. In general if there be n groups of particles uniformly distributed, then at the time zero m continuous columns interpenetrate and coincide throughout their extent. At the time ¢, the free surface will be repre- sented by nm consecutive surfaces of demarcation below it, each of which caps a column, the particles of which form a distinct group. This phenomenon is Prof. Brewer’s stratified subsi- dence. In the case of particles which have undergone an earlier fractionated sedimentation either in nature or in the arts, the occurrence of groups possessing the distinctive character- istics here discussed is not improbable. On the other hand when during subsidence the surfaces of demarcation follow each other in regular succession, one is tempted to look for some- thing more than an adventitious cause for the phenomenon. An orderly arrangement of groups of particles might for instance indicate successive stages of hydration. Of. § 6. In case of stratified subsidence, it is convenient to speak of the planes of demarcation as orders of surfaces, numbering them from the top downward. Seven or even ten orders are not uncommon. 124 C. Barus—Subsidence of fine Particles in Liquids. 2. With these deductions as a poit of departure, I then attempted to find relations between rates of subsidence, the viscous and capillary properties of the liquid, and its electrical behavior, under analogous conditions of concentration and of temperature. This general survey proved that the phenomenon of sedimentation is unique; that the frictional resistances en- countered by the particles are apparently different from the viscosities of the liquids in which subsidence takes place; that many of the occurrences observed are closely allied to the elec- trolytic and the capillary properties of this liquid. Finally utilizing Prof. Brewer’s stratified subsidence, which I obtained very clearly with certain kinds of tripoli, I commenced a series of more rigorously quantitative measurements showing that caet. par., rate of subsidence is primarily dependent on the tur- bidity of the mixture. In my experiments with tripoli, the observed rates of subsi- dence (em/ (sec X 10°)) in ether, alcohol, water, glycerine were 7500, 1800, 3, 0:09, respectively; but owing to the difference in character of the divers precipitates, these figures have no further signification than to emphasize the said difference in character. §§ 5,6. Let water and ether be mixed so that there shall be equal bulks of etherized water below, and aqueous ether above, and then let the dust (bole) be added. If now the mixture is violently shaken and then allowed to subside, the ether is washed clean Of particles in a few minutes whereas the sediments remain suspended in water for weeks and even months. Here however the separation and subsidence is pro- moted by the surface energy of water. On the other hand if dry tripoli be added to ether dried over CaCl,, in a test tube, and if the tube be held obliquely after shaking, subsidence is so rapid that the upward current.of ether along the upper line of the tube is almost tempestuous. The close relation of the present phenomena to electrolytic phenomena appears at once by observing that so little as a single molecule of HCl (for instance) added to 10,000 or even 50,000 molecules of H,O, produces appreciable increase of the rate of subsidence. Remembering that the arrangement is in three dimensions, and supposing the molecule HCl as large as the molecule H,O, the effect of the molecule HCl must be appreciable at a distance of at least 30 times, its own radius,* and extend much beyond this asymptotically. Quincke’s radius * The estimated diameter of HO (distance between centers of adjacent mole- cules 20 =40/10%™) I take from Kohlrausch (Wied. Ann., vi, p. 209, 1879). In how far the molecule of liquid water differs from H.O remains to be seen. In- deed the underlying cause of continuous and of discontinuous fusion and yapori- zation, and the cause of allied phenomena such as retarded solidification, ebulli- tion, etc., seems clearly to be some form of polymerization. Nevertheless the atomic theory in its present stage of development fails to suggest a satisfactory mechanism for these occurrences. $ OC. Barus—Subsidence of jine Particles in Liquids. 125 of capillary attraction, (000005, being at least 100 times the molecular radius H,O, it appears that the striking effect of the molecule HCl in accelerating subsidence, is not an abnormal occurrence, at least from a physical point of view. Other rela- tions are adduced in the Bulletin. 3. To account for these phenomena as a whole, Mr. Durham, in his second paper, proposes an hypothesis in virtue of which the scope of the action of affinity is enlarged, and suspension regarded as the lower limit of solution. This view is rapidly gaining ground; nevertheless without concise experimental ref- erence to the density and size of the solid particles and the vis- cosity of the liquid, Mr. Durham’s explanation contains no sufficient reason for the observed suspension, nor for changes of rate of subsidence. Prof. Brewer’s ingenious hypothesis of colloidal hydrates so constituted that the particles may ulti- mately swell up and float something like gelatinous silica, or even like starch grains, is more direct; and before further reasons of the cause of suspension are sought the validity of this inference must be tested. This test is feasible, I think. If the phenomenal difference of rate with which the same par- ticles subside in water and in ether is due to volume changes of the particles, then a marked difference in the density of the sediment (clay or tripoli) im water and in ether respectively, must be experimentally demonstrable. Cf. equation (1). I made these experiments with both solids, using two nearly identical density flasks, one for water and the other for ether, in the usual way. The powders were sampled and dried at 200° in an air bath for half a day, transferred to the pyenome- ters, dried and weighed when cold. They were~then left in a dessicator for 18 hours and again weighed ; and finally dried in vacuo and weighed. The results throughout were satisfactorily constant. By aid of an apparatus specially devised for the pur- pose, the two flasks were once more thoroughly exhausted (mercury air pump), and then filled with water and with ether respectively, in vacuo, over sulphuric acid. In both cases (the experiments were made consecutively), the vacuum ebullition was kept up for some time to give full assurance of the expul- sion of air, etc. The density of the ether had been previously determined by the same flasks, once for each experiment. Thus I obtained for tripoli, 1 In water, density =4,=2°672, In ether, density =4,=2°697. Again, I obtained for white bole, In water, 4"°=2°639, In ether, 4°=2°663. The manipulation being somewhat difficult, the observed 126 CC. Barus—Subsidence of fine Particles in Liquids. differences of 4,, and 4, are no larger than the many sources of error led me to anticipate, particularly in view of the fact that the two samples for ether and for water may not have been absolutely identical. The concentrated ether used was the same commercial reagent with which I obtained the sub- sidence phenomena. In consequence of the high but normal values of both J,, and 4,, I saw no need of specially purify- ing it. I add finally that after calcination, the dry tripoli lost 1-2 per cent in weight, and the dry bole about 11-4 per cent. In both eases this is probably water of constitution, the elimi- nation of which was of course not permissible. In spite of differences of chemical composition, the bole and tripoli parti- cles are about equally suspended before and after calcination, and the phenomena with ether dried over CaCl, are identical with the above. 4. These results show that the densities in the two eases (sediment in water and in ether respectively), are not essen- tially different. Moreover, the density of tripoli is so nearly that of quartz, and the density of bole so nearly that of kao- linite, as to leave the hydration hypothesis very seriously in the lurch, so far as favorable evidence is concerned. It is im- probable that the addition of water to the dry powder is ac- companied by sufficiently marked volume changes; it is cer- tain that the enormous variation of rates of subsidence actu- ally observed when the particles descend in water, in solutions, and in ether, must be referred to some general cause apart from the density of the particles and the viscosity of the liquids. 5. This premised, the explanation of sedimentation may be so made as to give emphasis to the following principle: If particles of comminuted solid are shaken up in a liquid, the distribution of parts after shaking will tend to take place in such a way that the potential energy of the system of solid particles and liquid, at every stage of subsidence, is the mini- mum compatible with the given conditions. In the case of solid particles and pure water the configuration answering this condition, is schematically, Particle, water. .... Particle, water. In the case of solid particles and ether, or of solid particles and solutions, this configuration is schematically, — Particle, particles... .. ether, ether. For the exemplification of this inference my paper contains varied experimental evidence. The principle asserts that in case of water the sediment is graded and the suspended mate- rial granular, whereas in ether the sediment is apparently ho- mogeneous, as | found; that the bulk of sediment is necessa- \ CO. Barus—Subsidence of jme Particles in Liquids. 127 rily less in water than in ether, being compact in the first in- stance and of a microscopically arched or castellated internal structure in the second instance, as I found; that the effect of a precipitant is particularly marked when the mixture is densely turbid with relatively coarse particles, as I found; that finally the phenomena of sedimentation must be of a dis- tinct and special kind, and by no means the immediate con- verse of capillary viscous transpiration. The inferences are thus based on equation (1) above, and follow at once when & and gare nearly constant. In the Bulletin, | computed the relative size (radii) of particle of tripoli subsiding in water, alcohol, ether, to be 1, 19 and 24 respectively.* It is exceedingly curious to note in case ot water, that despite the phenomenally large surface energy of the liquid, subsidence takes place in such a way that for a given mass of suspended sediment, the surfaces of separation are a maximum. On the other hand, in case of subsidence in ether, or in salt solutions, the solid particles behave much like the capillary spherules of a heavy liquid, shaken up in a lighter liquid with which it does not mix. In other words the tendency here is to reduce surfaces of separation to the least possible value, large particles growing in mass and bulk mechanically at the expense of smaller particles. Finally it is clear that the condition of stratified sedimentation is very slow subsidence of a granular precipitate. The experimental evidence adduced bears directly on the size of the particles of any precipitate. A given mass of small solid particles presupposed, the observations of the foregoing paragraph make it probable that the potential energy of the system of solid particles and liquid increases with the radius of the particle. These observations also show that the potential energy of the system of solid particles alone, decreases as the size of the particles increases, a state of things due both to the immediate action between solid particles, and probably also to the surface energy of the liquid in which suspension takes * This is the first of the hypotheses which I develop in detail in Bulletin No. 36, pp. 34, 35, 37. In are-calculation since made with more accurate values of k (water 0° to 100°, Slotte in Wied. Ann., xx, p. 262, 1883; ethyl and methyl aleohol, Graham in Phil. Mag, (4), xxiv, p. 238, 1861; ether, Landolt and Boernstein’s Tables, p. 153; glycerine estimated 7=10 ¢ em-! sec.—!), the radii of the particles in water, ethyl alcohol, methyl alcohol, ether and glycerine are found to be r=0:000009™, 0:00019°™, 0:00018°™, 0:00020¢" and 0:00005°™ re- spectively. In case of bole suspended in water at 15° and 100°, the radii were approximately < 0:000010°" and > 0:000020. § 6 points out, that whereas these dimensions may be called in question when considered absolutely, the rela- tive values of r are probably true. The fact that particles so extremely light descend at all is a result showing the almost marvelous delicacy of these experiments. In case of tripoli-water, for instance, the estimated weight of particle is only 1/101! milligrams; being in- visible microscopically it must have weighed less than 1/10!° milligram. 128 C0. Barus—Subsidence of fine Particles in Liquids. place. Under these conflicting conditions it is probable that there is a critical shell, within which the energy solid-liquid decreases less rapidly than the energy solid-solid; and beyond which shell the energy solid-liquid increases more rapidly than the energy solid-solid. This critical shell, being compatible with the conditions of minimum potential energy of the sub- siding system as a whole, is the size of the precipitated particles: for any change of the radius of a particle bounded by the eriti- cal shell, implies an expenditure of work, which under the usual conditions of precipitation is not available. 6. I have finally to endeavor to assign some value to the radius of the critical shell for the case of the above water sus- pensions. In my experiments with tripoli, rates of subsidence, #, in em (sec. X 10°), varied from w= 1-0 # = 20, according as higher orders of surfaces or turbidities of lower degree, were chosen. Taking the more usual value, « = 3, the radius of the particles subsiding was probably not less than 400 times the molecular radius of water. The bole particles under analogous conditions of suspension in H,O, were smaller, probably only 100 water radii. In Prof. Brewer’s indefinitely suspended clays the limit of comminution can not be estimated at all, except perhaps from purely optical considerations.* Whether in this extreme case colloidal hydration with concomitant volume changes is still demonstrably absent, remains to be seen. To test it, a sufficient quantity of the extremely fine material would have to be collected and dried by low temperature evaporation. Again in Bulletin No. 35 (p. 21), 1 point out at some length that “when the particles decrease (in size) from some estimable mean value indefinitely,’ liquid viscosity, being at least partially if not largely kinetic in charac- ter, can no longer be considered constant as regards time ; that therefore a particle may descend, or in other words the continuous and constant action of gravity produce an effect even when the weight of the particle is below the mean or physically measurable value of the friction encountered ; that the limits of time-variation of viscosity will increase as the radius of the circumscribed space decreases. In such a ease the particle to be stationary must weigh less than the lower limit of the variable viscosity—a quantity which may be reasonably conceived to approach zero very nearly. I carried these inferences one step further by supposing, rationally, I think, * The optical properties of light reflected from particles small in comparison with the wave length of light are discussed by Stokes (Phil. Trans., 1852, p. 530). How large a particle may be without interfering with optical clearness, I can not say. It is well to bear in mind that the suspension of corpuscles consist- ing of a small number, say ten molecules per critical shell, would bear the out- ward characteristics of solution. J.W. Gibbs—Electric Theory of Lrght. 129 that the limits within which this elementary viscosity (say) varies, will increase with the degree of molecular agitation of the liquid. On the basis of this postulate I then endeavored to explain sedimentation kinetically, both in its relations to temperature and the effect of precipitants. One point which antagonizes this hypothesis must not be lost sight of: Two or more particles sufficiently near together will tend to screen each other; and receiving impact mainly on their outer surfaces will be brought to permanent coherence so long as the conditions of pronounced molecular agitation last. This is actually observed in water suspensions at 100°, in solu- tion-suspensions, in ether suspensions, ete. In these instances there seems to be difficulty in preserving .the granular state (Bull. 36, p. 38). To pass judgment on the validity of such explanation, it is necessary to have in hand better statistics of the size of the particles relatively to the water molecule, than are now avail- able. Inasmuch as the particles in pure water are individ- ualized and granular, it is apparantly at once permissible to infer the size of the particles from the observed rates of subsi- dence. But my observations show that the said rate decreases in marked degree with the turbidity of the mixture. Hence the known formule for single particles are not rigorously applicable, though it cannot be asserted whether the cause of discrepancy is physical or mathematical in kind. It follows that special deductions must be made for the subsidence of stated groups of particles before an estimate of their mean size can fairly be obtained. Phys. Lab., U. 8. G. S., Washington, D. C. Art. XVI.—A Comparison of the Electric Theory of Light and Sir Wiliam Thomson's Theory of a Quasi-labile Ether; by J. WILLARD GIBBS. A REMARKABLE paper by Sir William Thomson, in the No- vember number of the Philosophical Magazine, has opened a new vista in the possibilities of the theory of an elastic ether. Since the general theory of elasticity gives three waves char- acterized by different directions of displacement for a single wave-plane, while the phenomena of optics show but two, the first point in accomodating any theory to observation, is to get rid (absolutely or sensibly) of the third wave. For this end, it has been common to make the ether incompressible, or, as it is sometimes expressed, to make the velocity of the third wave infinite. The velocity of the wave of compression be- comes in fact infinite as the compressibility vanishes. Of Am. Jour. Sc1.—Tuirp Serizs, VoL. XXXVII, No. 218.—Fep,, 1889. 9 4 130 J.W. Gibbs—Comparison of the Electric Theory of course it has not escaped the notice of physicists that we may also get rid of the third wave by making its velocity zero, as may be done by giving certain values to the constants which express the elastic properties of the medium, but such values have appeared impossible, as involving an unstable state of the medium. The condition of incompressibility, absolute or ap- proximate, has therefore appeared necessary.* This question of instability has now, however, been subjected to a more searching examination, with the result that the instability does not really exist ‘‘ provided we either swppose the medium to ex- tend all through boundless space, or give it a fixed containing vessel as its boundary.” This renders possible a very simple theory of light, which has been shown to give Fresnel’s laws for the intensities of reflected and refracted light and for double refraction, so far as concerns the phenomena which can be directly observed. The displacement in an aeolotropic medium is in the same plane passing through the wave-normal as was supposed by Fresnel, but its position in that plane is different, being perpendicular to the ray instead of to the wave-normal.t It is the object of this paper to compare this new theory with the electric theory of light. In the limiting cases, that is, when we regard the velocity of the missing wave in the elastic theory as zero, and in the electric theory as infinite, we shall find a remarkable correspondence between the two theo- ries, the motions of monochromatic light within isotropic or aeolotropic media of any degree of transparency or opacity, and at the boundary between two such media, being repre- sented by equations absolutely identical, except that the sym- bols which denote displacement in one theory denote force in the other, and wice versd.t In order to exhibit this corre- spondence completely and clearly, it is necessary that the fun- damental principles of the two theories should be treated with the same generality, and, so far as possible, by the same method. The immediate consequences of the new theory will therefore be deduced with the same generality and essentially by the same method which has been used with reference to the electric theory in a former volume of this Journal (vol. xxv, p. 107). * Tt was under this impression that the paper entitled ‘“‘A Comparison of the Elastic and the Electric Theories of Light with respect to the Law of Double re- fraction and the dispersion of colors,” in the June number of this Journal, was written. The conclusions of that paper, except so far as respects the dispersion of colors, will not apply to the new theory. + Sir William Thomson, loc. citat. R. T. Glazebrook, Phil. Mag., December, 1888. { In giving us a new interpretation of the equations of the electric theory, the author of the new theory has in fact enriched the mathematical theory of physics with something which may be compared to the celebrated principle of duality in geometry. Light and the Theory of a Quasi-labile Ether. 131 The elastic properties of the ether, according to the new theory, in its limiting case, may be very simply expressed by means of a vector operator, for which we shall use Maxwell’s designation. The curl of a vector is defined to be another vector so derived from the first that if wu, v, w be the rectan- gular components of the first, and w’, v’, w', those of its eurl, en OlO dv Re NC dw pL OD du QA deny es es Sa Sy ee OD é zee Gl) dy dz dz). dz da dy where 2, y, 2 are rectangular coédrdinates: With this under- standing, if the displacement of the ether is represented by the vector &, the force exerted upon any element by the sur- rounding ether will be — Becurl curl € dx dy dz, (2) where B is a scalar (the so-called rigidity of the ether) having the sanie constant value throughout all space, whether ponder- able matter is present or not. Where there is no ponderable matter, this force must be equated to the reaction of the inertia of the ether. This gives, with omission of the common factor dx dy dz, jC AG = — Beurl cul &, (3) where A denotes the density of the ether. The presence of ponderable matter disturbs the motions of the ether, and renders them too complicated for us to follow in detail. Nor is this necessary, for the quantities which occur in the equations of optics represent average values, taken over spaces large enough to smooth out the irregularities due to the ponderable particles, although very small as measured by a wave-length.* Now the general principles of harmonic mo- tiont show that to maintain in any element of volume the motion represented by t 2r1— E=H%e *, (4) % being a compiex vector constant, will require a force from outside represented by a complex linear vector function of &, that is, the three components of the force will be complex * This is in no respect different from what is always tacitly understood in the theory of sound, where the displacements, velocities, densities considered are al- ways such average values. But in the theory of light, it is desirable to have the fact clearly in mind on account of the two interpenetrating media (imponderable and ponderable), the laws of light not being in all respects the same as they would be for a single homogeneous medium. + See Lord Rayleigh’s Theory of Sound, vol i, chapters iv, v. 1382 J.W. Gibbs—Comparison of the Electric Theory of linear functions of the three components of © We shall represent this force by BYE de dy dz, (5) where ¥ represents a complex linear vector function.* If we now equate the force required to maintain the motion in any element to that exerted upon the element by the sur- rounding ether, we have the equation WE = — curl curl &, (6) which expresses the general law for the motion of monochro- matic light within any sensibly homogeneous medium, and may be regarded as implicitly including the conditions relating to the boundary of two such media, which are necessary for determining the intensities of reflected and refracted light. For let u, v, w bethe components of 6, He Ory Oop oS cs curl &, WEA Onn lueBi ee inice eS curl curl &, so that ede dv pees dw en) du dy dz? We daz’ da: dy’ in Cy! dv' Hae. dw’ POL du' ee =— — —, w= — — —_—; dy dz da die dee dy and let the interface be perpendicular to the axis of Z. It is evident that if wv’ or v’ is discontinuous at the interface, the value of w’”’ or v’ becomes in a sense infinite, 2. ¢., curl curl &, and therefore by (6) LT 6, will be infinite. Now both & and ¥ are discontinuous at the interface, but infinite values for 7E are not admissible. Therefore wu’ and v’ are continuous. Again, if « or v is discontinuous, wv’ or v’ will become infinite, and therefore wu’ or v’. ‘Therefore ~ and v are continuons. These conditions may be expressed in the most general manner by saying that the components of & and curl € parallel to the interface are continuous. This gives four complex scalar con- ditions, or in all eight scalar conditions, for the motion at the interface, which are sufficient to determine the amplitude and * Tt amounts essentially to the same thing, whether we regard the force as a linear vector function of € or of €, since these differ only by the constant factor 4r? : d : — But there are some advantages in expressing the force as a function of €, because the greater part of the force, in the most important cases, is required to overcome the inertia of the ether, and is thus more immediately connected with &. Light and the Theory of a Quasi-labile Ether. bo dag phase of the two reflected and the two refracted rays in the most general case. It is easy, however, to deduce from these four complex conditions, two others, which are interesting and . sometimes convenient. It is evident from the definitions of wand w’’ that if w, v, uv’, and v’ are continuous at the inter- face w’ and w’’ will also be continuous. Now —w” is equal to the component of WE normal to the interface. The follow- ing quantities are therefore continuous at the interface : the components parallel to the interface of G, the component normal to the interface of W&6, (7) all components of curl ©. To compare these results with those derived from the elec- trical theory, we may take the general equation of monochro- matic light on the electrical hypothesis from a paper in a former volume of this Journal. This equation, which with an unessential difference of notation may be written* —Pot § — 7Q = 479%, (8) was established by a method and considerations similar to those which have been used to establish equation (6), except that the ordinary law of electro-dynamic induction had the place of the new law of elasticity. @ is a complex vector representing the electrical displacement as a harmonic function of the time; @ is a complex linear vector operator, such that 479 § represents the electromotive force necessary to keep up the vibration §. Q is a complex scalar representing the electrostatic potential, py the vector of which the three components are dQ dQ dQ Ofte) GE GIB Pot denotes the operation by which in the theory of gravita- tion the potential is calculated from the density of matter.t When it is applied as here to a vector, the three components of the result are to be calculated separately from the three components of the operand. —p Q is therefore the electrostatic force, and —Pot % the electrodynamic force. In establishing the equation, it was not assumed that the electrical motions are solenoidal, or such as to satisfy the so-called “equation of continuity.” We may now, however, make this assumption, * See this Journal, vol. xxv, p. 114, equation (12). + The symbol —Pot is therefore equivalent to 4my—, as used by Sir William Thomson (with a happy economy of symbols) at the last meeting of British Asso- ciation to express the same law of electrodynamic induction, except that the sym- bol is here used as a vector operator. See Nature, vol. xxxviii, p. 571, sub. init. 134. JW. Gibbs—Comparison of the Electric Theory of since it is the extreme case of the electric theory which we are to compare with the extreme case of the elastic. _ It results from the definitions of cwrl and p that curl pQ=0. We may therefore eliminate Q from equation (8) by taking the eurl. This gives —curl Pot F=40 curl OF, (9) A 1 : Since curl curl and 7 Pot are inverse operators for solen- oidal vectors, we may get rid of the symbol Pot by taking the eurl again. We thus get —*=curl curl OF. (10). The conditions for the motion at the boundary between dif- ferent media are easily obtained from the following considera- tions. Pot 5 and Q are evidently continuous at the interface. Therefore the components parallel to the interface of 7Q, and by (8) of OF, will be continuous. Again, curl Pot * is con- tinuous at the interface, as appears from the consideration that curl Pot % i is the magnetic force due to the electrical motions ee. Therefore, by (9), curl 9F is continuous. The solenoidal con- dition requires that the component of * normal to the inter- face shall be continuous. The following quantities are therefore continuous at the interface : the components parallel to the interface of OF, the component normal to the interface of §%, (11) all components of curl Of these conditions, the two relating to the normal components of § and curl @% are easily shown to result from the other four conditions, as in the analogous case in the elastic theory. If we now compare in the two theories the differential equations of the motion of monochromatic lght for the in- terior of a sensibly homogeneous medium, (6) and (10), and the special conditions for the bonndary between two such media as represented by the continuity of the quantities (7) and (11), we find that these equations and conditions become identical, if By =) GAS (12) C= 0%, : (13) UL Sie (14) In other words, the displacements in either theory are subject to the same general and surface conditions as the forces re- Light and the Theory of « Quasi-labile Ether. 135 quired to maintain the vibrations in an element of volume in the other theory. To fix our ideas in regard to the signification of ¥ and @, we may consider the case of isotropic media, in which these operators reduce to ordinary algebraic quantities, simple or complex. Now the curl of any vector necessarily satisfies the solenoidal condition (the so-called ‘equation of continuity’), therefore by (6) YE and € will be solenoidal. So also will ¥ and @%§ in the electrical theory. Now for solenoidal vectors ricunle— sh + cdl 15 isa Te ake dy! de? >) so that the equations (6) and (10) reduce to wo 2 a? @ \ Pe cat ape (16) x Gna 10 5=(Getaet a) DF (17) For a simple train of waves, the displacement, in either the- ory, may be represented by a constant multiplied by gllgt+ ax + by + cz) | (18) Our equations then reduce again to gf VE=(V+V+e)6, (19) Sb=(C+0' +0’) OF. (20) Hence, A ere Ue = auras . (21) The last member of this equation, when real, evidently ex- presses the square of the velocity of light. If we set et +0 +e Tele, Se ; (22) k denoting the velocity of light 7 vacuo, we have Nakao, (23) When v’ is positive, which is the case of perfectly trans- parent bodies, the positive root of n’ is called the index of refraction of the medium. In the most general case, it would be appropriate to call n—or perhaps that root of »* of which the real part is positive—the (complex) index of refraction, although the terminology is hardly settled in this respect. A negative value of n* would represent a body from which light would be totally reflected at all angles'of incidence. No such cases have been observed. Values of n* in which the coefli- 136 J.W. Gibbs—Comparison of the Electric Theory of cient of ¢ is negative, indicate media in which light is ab- sorbed. Values in which the coefficient of ¢ is positive would represent media in which the opposite phenomenon took place.* It is no part of the object of this paper to go into the de- tails by which we may derive, so far as observable phenomena are concerned, Fresnel’s law of double refraction for transpar- ent bodies, as well as the more general law of the same char- acter which relates to aeolotropic bodies of more or less opac- ity, and which differs from Fresnel’s only in that certain quantities become complex, or Fresnel’s laws for the intensi- ties of reflected and refracted light at the boundary of trans- parent isotropic media, with the more general laws for the case of bodies acolotropic or opaque or both. The principal cases have already been discussed on the new elastic theory in the Philosophical Magazinet and a farther discussion is promised. For the electrical theory, the case of double refraction in per- fectly transparent media has been discussed quite in detail in this Journal,t and the intensities of reflected and refracted light have been abundantly deduced from the above conditions by various authors.§ So far as all these laws are concerned, the object of this paper will be attained, if it has been made clear, that the two theories, in their extreme cases, give iden- tical results. The greater or less degree of elegance, or com- pleteness, or perspicuity, with which these laws may be devel- oped by different authors, should weigh nothing m favor of either theory. The non-magnetic rotation of the plane of polarization, with the allied phenomena in aeolotropic bodies, le in a cer- tain sense outside of the above laws,as depending on minute quantities which have been neglected in this discussion. The manner in which these minute quantities affect the equations of motion on the electrical theory has been shown in a former paper,|| where these phenomena in transparent bodies are treated quite at length. For the new theory, a discussion of this subject is promised by Mr. Glazebrook. . But the magnetic rotation of the plane of polarization, with the allied phenomena when an aeolotropic body is subjected to magnetic influence, fall entirely within the scope of the above equations and surface-conditions. The characteristic of this * But ¢ might have been introduced into the equations in such a way that a positive coefficient in the value of n? would indicate absorption, and a negative coefficient the impossible case. + Sir William Thomson, loc. citat. R. T. Glazebrook, loc. citat. t Vol. xxiii, p. 262. § Lorentz, Schlémilch’s Zeitschrift, vol. xxii, pp. 1-30 and 205- 219; vol. xxiii, pp. 197-210; Fitzgerald, Phil. Trans., vol. olxxi, ps COL Ieee Thomson, Phil. Mag. (V), vol. ix, p. 284; Rayleigh, Phil. Mag. (V), vol. xii, p. 81. Glazebrook, Proc. Cambr. Phil. Soe., vol. iv, p. 155. || This Journal, vol. xxiii, p. 460. Light and the Theory of a Quasi-labile Hither. 137 case is that Y and @ are not self-conjugate.* This is what we might expect on the electric theory from the experiments of Dr. Hall, which show that the operators expressing the relation between electro-motive force and current are not in general self-conjugate in this case. In the preceding comparison, we have considered only the limiting cases of the two theories. With respect to the sense in which the limiting case is admissible, the two theories do not stand on quite the same footing. In the electric theory, or in any in which the velocity of the missing wave is very great, if we are satisfied that the compressibility is so small as to pro- duce no appreciable results, we may set it equal .to zero in our mathematical theory, even if we do not regard this as express- ing the actual facts with absolute accuracy. But the case is not so simple with an elastic theory in which the forces resist- ing certain kinds of motion vanish, so far, at least, as they are proportional to the strains. The first requisite for any sort of optical theory is that the forces shall be proportional to the displacements. This is easily obtained in general by supposing the displacements very small. But if the resistance to one kind of distortion vanishes, there will be a tendency for this kind of distortion to appear at some places in an exaggerated form, and even to an infinite degree, however small the dis- _ placements may be in other parts of the field. In the case be- fore us, if we suppose the velocity of the missing wave to be absolutely zero, there will be infinite condensations and rare- factions at a surface where ordinary waves are reflected. That is, a certain volume of ether will be condensed to a surface, and vice versd. This prevents any treatment of the extreme case, which is at once simple and satisfactory. The difficulty has been noticed by Sir William Thomson, who observes that it may be avoided if we suppose the displacements infinitely small in comparison with the wave-length of the wave of com- pression. Thisimpliesa finite velocity forthat wave. A similar difficulty would probably be found to exist (in the extreme case) with regard to the deformation of the ether by the mole- cules of ponderable matter, as the ether oscillates among them. If the statical resistance to irrotational motions is zero, it is not at all evident that the statical forces evoked by the disturbance caused by the molecules would be proportional to the motions. But this difficulty would be obviated by the same hypothesis as the first. These circumstances render the elastic theory somewhat less convenient as a working hypothesis than the electric. They do not necessarily involve any complication of the equations of optics. For it may still be possible that this velocity of the * See this Journal, vol. xxv, p. 113. HSM OW, fe eaten abe of the Electric T. heory of missing wave is so small that the quantities on which it de- pends may be set equal to zero in the equations which repre- sent the phenomena of optics. But the mental processes by which we satisfy ourselves of the validity of our results (if we do not work out the whole problem in the general case of no assumption in regard to the velocity of the missing wave) cer- tainly involve conceptions of a higher degree of difficulty on account of the circumstances mentioned. “Perhaps this ought not to affect our judgment with respect to the question of the truth of the hypothesis. Although the two theories give laws of exactly the same form for monochromatic light in the limiting case, their devi- ations from this limit are in opposite directions, so that if the phenomena of optics differed in any marked degree from what we would have in the limiting case, it would be easy to find an experimentum crucis to decide between the two theories. A little consideration will make it evident, that when the prin- cipal indices of refraction of a crystal are given, the interme- diate values for oblique wave-planes will be less if the velocity of the missing wave is small but finite, than if it is infinitesi- mal, and will be greater if the velocity of the missing wave is very great but finite than if it is infinite.* Hence, if the velocity of the missing wave is small but finite, the interme- diate values of the indices of refraction will be less than are given by Fresnel’s law, but if the velocity of the missing wave is very great but finite, the intermediate values of the indices of refraction will be ‘ereater than are given by Fres- nel’s law. But the recent experiments of Professor Hastings on the law of double refraction in Iceland spar do not encour- age us to look in this direction for the decision of the ques- tion.t In a simple train of waves in a transparent medium, the po- tential energy, on the elastic theory, may be divided into two parts, of which one is due to that general deformation of the ether which is represented by the equations of wave-motion, and the other to those deformations which are caused by the interference of the ponderable particles with the wave-motion, and to such displacements of the pondetable matter as may be caused, in some cases at least, by the motion of the ether. If we write 4 for the amplitude, 7? for the wave-length, and p forthe period, these two parts of the statical energy (esti- * This may be more clear if we consider the stationary waves formed by two trains of waves moving in opposite directions. The case then comes under the following theorem: “Tf the system undergo such a change that the potential energy of a given con- figuration is diminished, while the kinetic energy of a given motion is unaltered, the periods of the free vibrations are all increased, and conversely.” See Lord Rayleigh’s Theory of Sound, vol. i, p. 85. ¢ This Journal, vol. xxxiii, p. 60. Light and the Theory of a Quasi-labile Ether. 139 mated per unit of volume for a space including many wave- lengths) may be represented respectively by nd ie ? 4 The sum of these may be equated to the kinetic energy, giving an equation of the form mB Di NTE (24) P + po B is an absolute constant (the rigidity of the ether, previ- ously represented by the same letter), A’ and 6 will be constant (for the same medium and the same direction of the wave- normal) except so far as the type of the motion changes, ~. ¢., except so far as the manner in which the motion of the ether distributes itself between the ponderable molecules, and the degree in which these take part in the motion, may undergo a change. When the period of vibration varies, the type of mo- tion will vary more or less, and A’ and 6 will vary more or less. ‘In a manner entirely analogous,* the kzmetie energy, on the electrical theory, may be divided into two parts, of which one is due to those general fluxes which are represented by the equations of wave-motions, and the other to those irregularities in the fluxes which are caused by the presence of the ponder- able molecules, as well as to such motions of the ponderable par- ticles themselves, as may sometimes occur. These parts of the kinetic energy may be represented respectively by On adie 2 Their sum equated to the potential energy gives 222 2 2 2 zEPH | aifl’ _ Git (05) he i 4 Here F is the constant of electrodynamic induction, which is unity if we use the electromagnetic system of units, f and G (like A’ and 4) vary only so far as the type of motion varies. We have the means of forming a very exact numerical esti- mate of the ratio of the two parts into which the statical en- ergy is thus divided on the elastic theory, or the kinetic en- ergy on the electric theory. The means for this estimate is afforded by the principle that the period of a natural vibration is stationary when its type is infinitesimally altered by any constraint.+ Let us consider a case of simple wave motion, and suppose the period to be infinitesimally varied, the wave- * See this Journal, vol. xxii, p. 262. t+ See Lord Rayleigh’s Theory of Sound, vol. i, p. 84. The application of the principle is most simple in the case of stationary waves. 140 J.W. Gibbs—Comparison of the Electric Theory of length will also vary, and presumably to some extent the type of vibration. But, by the principle just stated, if the ether or the electricity could be constrained to vibrate in the original type, the variations of 7 and p would be the same as in the actual case. Therefore, in finding the differential equation be- tween Z and p, we may treat 6 and A’ in (24) and 7 and G in (25) as constant, as well as Band F. These equations may be written P 4B + bp’ = 47°A’, ae aP ZS, = 4G. Differentiating, we get sn'Bae = — Up’); ib aF d= — 7faUp*); P . or 47°B & d log oe = — bp’ dlog p’, Ps Noe ee I Galo rege P Pp p Hence, if we write V for the wave-velocity (//p), n for the index of refraction, and 4 for the wave-length 7m vacuo, we have for the ratio of the two parts into which we have divided the potential energy on the elastic theory, Wis. “ele d log V dlogn —_ a — ‘) is == 9 (26) 4 if d log p d log aA and for the ratio of the two parts into which we have divided the kinetic energy on the electrical theory, pth ee aAwirls 3 ( Moges Ni OS (27) Pp i AIO ID d log A It is interesting to see that these ratios have the same value. . This value may be expressed in another form, which is sug- gestive of some important relations. If we write U for what Lord Rayleigh has called the velocity of a group of waves,* me COS eNI Wi anoatal dliog V _ V—U loevaertnven » dog Ngee Men). (28) d log p U * See his Note on Progressive Waves, Proce. Lond. Math. Soe., vol. ix, No. 125, reprinted in his Theory of Sound, vol. ii, p. 297. Light and the Theory of a Quasi-labile Ether. 141 It appears, therefore, that in the elastic theory that part of the potential energy which depends on the deformation ex- pressed by the equations of wave-motion, bears to the whole potential energy the same ratio which the velocity of a group of waves bears to the wave-velocity. In the electrical theory, that part of the kinetic energy which depends on the motions expressed by the equations of wave-motion bears to the whole kinetic energy the same ratio. Returning to the consideration of equations (26) and (27), we observe that in transparent bodies the last member of these equations represents a quantity which is small compared with unity, at least in the visible spectrum, and diminishes rapidly as the wave-length increases. This is just what we should expect of the first member of equation (27). But when we pass to equation (26), which relates to the elastic theory, the ease is entirely different. The fact that the kinetic energy is | affected by the presence of the ponderable matter, and affected differently in different directions, shows that the motion of the ether is considerably modified. This implies a distortion, su- perposed upon the distortion represented by the equations of wave-motion, and very much greater, since the body is very fine-grained as measured by a wave-length. With any other law of elasticity, we should suppose that the energy of this superposed distortion would enormously exceed that of the regular distortion represented by the equations of wave- motion. But it is the peculiarity of this new law of elasticity that there is one kind of distortion, of which the energy is very small, and which is therefore peculiarly likely to occur. Now if we can suppose the distortion caused by the ponder- able molecules to be almost entirely of this kind, we may be able to account for the smallness of its energy. We should still expect the first member of (26) to increase with the wave- length, on account of the factor /’, instead of diminishing, as the last member of the equation shows that it does. We are obliged to suppose that b, and therefore the type of the vibra- tions, varies very rapidly with the wave-length, even in those cases which appear farthest removed from anything like selec- tive absorption. The electrical theory furnishes a relation between the re- fractive power of a body and its specific dielectric capacity, which is commonly expressed by saying that the latter is equal to the square of the index of refraction for waves of infinite length. No objection can be made.to this statement, but the great uncertainty in determining the index for waves of in- finite length by extrapolation prevents it from furnishing any very rigorous test of the theory. Yet, as the results of extra- polation in some eases agree strikingly with the specific dielec- 142 JW. Gibbs—Comparison of the Electric Theory of tric capacity, although in other cases they are quite different, the correspondence is generally regarded as corroborative, in some degree, of the theory. but the relation between refrac- tive power and dielectric capacity may be expressed in a form which will furnish a more rigorous test, as not involving ex- trapolation. We have seen on page 140 how we may determine numeri- cally the ratio of the two first terms of equation (25). We thus easily get the ratio of the first and last term, which gives Gh dlogt) zECh (29) © \Tolonhe Aa In the corresponding equation for a train of waves of the same amplitude and period 7m vacuo, 1 becomes A, F remains the same and for G we may write G’. This gives G'h* mE A*h? er = Pp 5 ‘ (3 0) Dividing, we get G@ _ dlogi F _ acer) ay G dlogi 2K d (X*) Now G’ is the dielectric elasticity of pure ether. If K is the specific dielectric capacity of the body which we are con- sidering, G’/K is the dielectric elasticity of the body and G’/2K is the potential energy of the body (per unit of volume), due to a unit of ordinary electrostatic displacement. But Gh7/4 is the potential energy in a train of waves of amplitude A. Since the average square of the displacement is 47/2, the po- tential energy of a unit displacement such as occurs in a train of waves is G/2. Now in the electrostatic experiment the dis- placement distributes itself among the molecules so as to make the energy a minimum. But in the case of light the distribu- tion of the displacement is not determined entirely by statical considerations. Hence G G' 5 = 2K? (32) (eu = K = @ and d (2) K= (Py (33) It is to be observed that if we should assume for a dispersion- formula n~=a—ba~, (34) Light and the Theory of a Quasi-labile Ether. 143 1/a, which is the square of the index of refraction for an infi- nite wave-length, would be identical with the second member of (38). fee similarity between the electrical and optical proper- ties of bodies consists in the relation between conductivity and opacity. Bodies in which electrical fluxes are attended with absorption of energy absorb likewise the energy of the motions which constitute light. This is strikingly true of the metals. But the analogy does not stop here. To fix our ideas, let us consider the case of an isotropic body and circularly po- larized light, which is geometrically the simplest case, although its analytical expression is not so simple as that of plane-po- larized light. The displacement at any point may be symbolized by the rotation of a point in a circle. The external force nec- essary to maintain the displacement § is represented by n°. In transparent bodies, for which n~ is a positive number, the force is radial and in the direction of the displacement, being principally employed in counterbalancing the dielectric elas- ticity, which tends to diminish the displacement. In a con- ductor v~ becomes complex, which indicates a component of the force in the direction of %, that is, tangential to the circle. This is only the analytical expression of the- fact above men- tioned. But there is another optical peculiarity of metals, which has caused much remark, viz: that the real part of n? (and therefore of n~*) is negative, i. e., the radial component of the force is directed towards the center. This inwardly directed force, which evidently opposes the electrodynamie in- duction of the irregular part of the motion, is small compared with the outward force which is found in transparent bodies, but increases rapidly as the period diminishes. We may say, therefore, that metals exhibit a second optical peculiarity,— that the dielectric elasticity is not prominent as in transparent bodies. This is like the electrical behavior of the metals, in which we do not observe any elastic resistance to the motion of electricity. We see, therefore, that the complex indices of metals, both in the real and the imaginary part of their in- verse squares, exhibit properties corresponding to the electri- cal behavior of the metals. The case is quite different in the elastic theory. Here the force from outside necessary to maintain in any element of volume the displacement € is represented by nS. In trans parent bodies, therefore, it is directed toward the center. In metals, there is a component in the direction of the motion &, while the radial part of the force changes its direction and is often many times greater than the opposite force in transpar- 144 J.W. Gibbs—Electric Theory of Light. ent bodies. This indicates that in metals the displacement of the ether is resisted by a strong elastic force, quite enormous compared to anything of the kind in transparent bodies, where it indeed exists, but is so small that it has been neglected by most writers, except when treating of dispersion. We can make these suppositions, but they do not correspond to any- thing which we know independently of optical experiment. It is evident that the electrical theory of light has a serious rival, in a sense in which, perhaps, one did not exist before the publication of Sir William Thomson’s paper in November last.* Nevertheless, neither surprise at the results which have been achieved, nor admiration for that happy audacity of genius, which, seeking the solution of the problem precisely where no one else would have ventured to look for it, has turned half a century of defeat into victory, should blind us to the actual state of the question. It may still be said for the electrical theory, that it is not obliged to invent hypotheses,t but only to apply the laws fur- nished by the science of electricity, and that it is difficult to account for the coincidences between the electrical and opti- cal properties of media, unless we regard the motions of light as electrical. But if the electrical character of light is conceded, the optical problem is very different from any- thing which existed in the time of Fresnel, Cauchy, and Green. The third wave, for example, is no longer something to be got- ten rid of guocunque modo, but something which we must dispose of in accordance with the laws of electricity. This would seem to rule out the possibility of a relatively small velocity for the third wave. * « Since the first publication of Cauchy’s work on the subject in 1830, and of Green’s in 1837, many attempts have been made by many workers to find a dy- namical foundation for Fresnel’s laws of reflexion and refraction of light, but all hitherto ineffectually.”’ Sir William Thomson, loc. citat. ‘“‘So far as 1 am aware, the electric theory of Maxwell is the only one satisfy- ing these conditions [of explaining at once Fresnel’s laws of double refraction in erystals and those governing the intensity of reflexion when light passes from one isotropic medium to another].” Lord Rayleigh, Phil. Mag., Septem- ber, 1888. + Electrical motions in air, since the recent experimeuts of Professor Hertz, seem to be no longer a matter of hypothesis. We can hardly suppose that the case is essentially different with the so-called vacuum. The theorem that the electrical motions of light are solenoidal, although it is convenient to assume it as a hypothesis and show that the results agree with experiment, need not oc- cupy any such fundamental position in the theory. It is in fact only another way of saying that two of the constants of electrical science have a certain ratio (infinity). It would be easy to commence without assuming this value, and to show in the course of the development of the subject that experiment requires it, not of course as an abstract proposition, but in the sense in which experiment can be said to require any values of any constants, that is, to a certain degree of approximation. J. C. Branner—Geology of Lernando de Noronha. 145 Art. X VII.—The Geology of Fernando de Noronha. Part 1; by Jon C. BRANNER. With a map, Plate V. THE island of Fernando de Noronha has never attracted much attention, owing to its small area, its want of commercial importance, and its somewhat forbidding character as a land- ing place, and partly also to its having long been used as a place of exile and punishment for criminals. Prior to the visit of the writer the geologic observations made upon the island of Fernando were very few; the only ones worthy of especial notice being those of Charles Darwin in 1832, made while on the voyage of the Beagle and published in his Geo- logical Observations in 1844, and a few observations made, along with the collection of specimens, when the Challenger touched here in 1878. , of the tables. It will be seen that the energy per candle power varies from 1°5 Watts at 0°5 C. P. to about 0°3 Watts at 16 C. P. In every case the intensity of the light, as measured by its candle power, increases more rapidly than the energy of the light. In this connection it is interesting to compare the value of the mechanical equivalent of a candle power of lamp here found by Dr. J. Thomson some twenty years ago.* is method was similar to that used in these experiments. A cell of distilled water was used instead of an alum solution, and no correction was made for the dark heat passing through. To get absolute measurements of energy he standardized his ther- mopile by means of Leslie tubes. He found the energy of one candle power of light from an oil lamp to be 2°5 Watts, and for a gas flame and a standard candle the value was very nearly the same. This is considerably larger than the greatest value that I found. 6> c. All of these determinations agree closely with those given by Rosenbusch.* The other minerals observed were sphene, magnetite and very sparingly apatite, allof which present their character usual in the phonolites. Noticeable for the sphene is its frequent occurrence in the black corrosion rims around the hornblende. A point of considerable interest with regard to the Fer- nando phonolites is the possible occurrence in them of inclu- sions of eleolite-syenite as mentioned by Prof. Rosenbusch.t+ The material in hand is not however sufficient to definitely decide this question. In a communication from Prof. Orville Derby of Rio de Janeiro, in whose hands the entire collection made by Professor Brauner formerly was and who still has charge of the greater part of it, he says that in this large amount of material only a single specimen showed any sign of such an inclusion. This was a pale gray and rather coarse grained phonolite from the Peak (No. 50) which contained a sharply defined inclusion, apparently of a typical eleolite-syen- ite about 8™ square. Of this inclusion and a portion of the surrounding phonolite one fragment was sent by Prof. Derby to Prof. Rosenbusch and another to myself. Prof. Derby has also kindly furnished me with a photograph of this specimen. If the inclusion is really an eleolite-syenite it belongs to an exceptionally porphyritic type, inasmuch as more than one-half of its small area (83) 1s occupied by a single crystal of a blue iridescent orthoclase (2x14). Both Profs. Derby and Branner agree that inclusions of this sort must be of rare occurrence in the Fernando phonolites,{ and in no way com- parable to those so abundant in the tinguaites of the Rio de Janeiro neighborhood. Prof. Derby is inclined to regard this inclusion as an early and intratelluric secretion of the phonolite magma. This view§ may derive some support from the fact * Die massigen Gesteine, 2d ed., p. 616. + Die massigen Gesteine, 2d ed., pp. 91, 628 and 821. ¢ Quart. Jour. Geol. Soc., xliii. p. 459, 1887. § Opinion expressed in a letter to the writer (cf. reference just cited and Neues Jabrbuch fiir Min., etc., 1887, II, p. 258.) ‘ 186 Wéaliams—Petrography of Fernando de Noronha. that another phonolite specimen of this collection (No. 5) does undoubtedly contain such coarse-grained secretions composed of large crystals of nepheline and sanidine. The appearance of these is however undeniably different from that of the apparent inclusion; and, in the absence of more abundant material, the writer would refrain from expressing a decided opinion. Ill. Basaltie Rocks. No. 31. Nepheline-basanite, Sao José Island.—This is a very compact black rock in which minute crystals of olivine and augite are macroscopically visible. Under the microscope these two constituents are seen to be present in abundant well- formed crystals possessing their usual characters. The ground- mass in which they are imbedded is a fine holocrystalline aggregate of augite and plagioclase microliths and magnetite grains. Some interstitial nepheline is also present, but this is of so small amount as to ally this rock to the feldspar basalts. No. 34 is a fragment of a coarsely granular inclusion or secre- tion in the last described specimen. It is composed of per- fectly fresh olivine and enstatite with hardly a trace of any other mineral, and is analogous to the so-called ‘“‘ olivine bombs,” common in many basaltic rocks but whose origin is still a mat- ter of discussion. No. 2. Nephelinite-dolerite—A dark gray, coarse grained rock collected in the N.E. part of the main island, but nowhere found im situ. Long black crystals of augite and small grains of olivine are macroscopically visible. The microscopic char- acter of this rock agrees very exactly with Rosenbusch’s de- scription of the doleritic type of nephelinite ;* and, in spite of its comparatively large amount of olivine, it is here assigned to this class on account of its close resemblance to the classic occurrences at Meiches and Lébau. The structure of this rock is holocrystalline and granular (hypidiomorph-kérnig i the sense of Rosenbuscht) like that of a plutonic mass. Its most prominent constituent is augite. whose jet black crystals are often a centimeter or more in length and impart ‘to the hand-specimen a porphyritic appear- ance. Under the microscope these crystals have a brownish red color, a decided pleochroism and a distinct zonal structure. The colors of the different rays are c and 6 reddish brown; a ereenish yellow; absorption c>b>> a. The outer zones are invariably more intensely colored (i. e. richer in ferric iron) than the inner and are hence more pleochroic. The hour-glass structure is also frequent as a form of zone growth. The ex- * Die massigen Gesteine, 2d ed., p. 791. tallbr spaslile Wiliams—Petrography of Fernando de Noronha. 187 tinction angle is very high and twinning lamellze intercalated parallel to the orthopinacoid (011) of common occurrence. To all appearances this augite is identical with that of the Kaiser- stuhl basalts which has been studied by Knop and found by him to be titaniferous.* The olivine of this rock is in some slides quite abundant ; in others Jess so. It is very fresh and of a pale yellow color. It occurs commonly in small grains, but more rarely in sharp erystals. The colorless component is for the most part nepheline in large crystals, easily recognized by negative uniaxial character, its parallel extinction, lack of cleavage and the ease with which it is attacked by acids. Its specific gravity is from 2°61 to 2°59. An unstriated feldspar, probably sanidine, is present in smal! quantity,t and also occasionally particles of a striated feld-spar. Sodalite in irregular patches is present in almost every sec- tion, its isotropic substance being penetrated in every direction by brightly polarizing needles of some zeolite which has re- sulted from its alteration. Apatite is abundant in its characteristic forms. The iron ore is octahedral—probably a titaniferous magnetite. A small amount of the peculiar copper-colored and but slightly pleo- chroic mica, so common in nepheline rocks, is also present. Nepheline-basalt is represented by three specimens in Prof. Branner’s collection. One of these (No. 45) from Morro Francez agrees almost exactly with the figure and description given by Renard of a similar rock from Rat Island{ (Lha Rapta.) Its only porphyritic constituents is olivine in sharp crystals or irregular grains. These are surrounded by a yellow border of iron hydroxide and more or less opaque iron oxide resulting from decomposition, and appear in the compact black hand specimen as rusty yellow spots. The interior of these olivines is however shown by the microscope to be quite fresh and colorless. The groundmass is a fine aggregate of idiomorphic augite crystals, octahedrons of magnetite and nepheline, without any unindividualized base. No. 72, from Ilha Rapta, differs from the last described speci- men in having the porphyritic olivines nearly devoid of the yellow border and in possessing a slightly coarser groundmass. Within the latter may also be seen occasional flakes of a brown mica and transparent octahedral crystals which are without doubt perofskite. * Zeitschrift fiir Krystallographie, x, p. 58, 1885. + Knop has shown that a barium orthoclase is present in the closely allied mnephelinite from Meiches in the Vogelsgebirge. Neues Jahrbuch fiir Min., etc., 1865, p. 687. t Bull. d. Acad. roy. de Belge (3), III, No. 4, 1882. 188 Wélliams—Petrography of Fernando de Noronha. No. 27 from a point on the south side of Fernando agrees closely i the last specimen except that it contains no perof- skite. No. 65 from Portao, at the west end of Fernando is a typ- ical limburgite. In the hand-specimen it is of a dark gray color and filled with vesicular cavities of all sizes which are either coated or completely filled with zeolites. Small rusty yellow spots indicate the position of abundant olivine crystals which are the only constituent macroscopically visible. Under the microscope well-formed olivines surrounded by a yellow border are seen imbedded in a groundmass of augite micro- liths, magnetite octahedra and a colorless glass. Thus the rock is a limburgite of the second class in the sense of Bucking, which, as we might expect from the present association, is more nearly allied to the nepheline, than to the feldspar basalts. No. 14, from Atalaia Grande, may also be classed as a lim- burgite, although from its poverty of olivine it is closely related to the augitites. The hand-specimen of this rock presents a striking contrast to the last, it being compact and black like the nepheline-basalts. Small, sharply-formed augite crystals. and a few olivines are the only components visible. Under the microscope this specimen is seen to differ greatly from all the others. The olivines are few but very fresh. The augites are distinguished by their pronounced zonal structure, their interior being of a brilliant green and pleochroic, while the outer zone is reddish gray. “Their extinction is very high. Smaller crystals of brown basaltic hornblende are also abund- ant. The groundmass consists of a brown glass somewhat devitrified with globulitic dust and occasional arborescent growth forms. This contains augite microliths, magnetite in octahedra and occasional crystals of blue hauyne. As a sec- ondary product analcite occurs, either after the hauyne or in minute cavities. No, 115, from Morro Francez, is a more typical augitite in being wholly tree from olivane, although it "approaches the nephelinites in containing nepheline, ‘mostly i in the form of porphyritie crystals. The hand- -specimen shows abundant black porphyritic crystals which are in part hornblende and in part augite. The groundmass is mostly composed of a color- less olass containing augite microliths and magnetite. ) D Go BR yi | FIGURE 1.—Right hind foot of Anchisaurus major, Marsh; front view. One-fourth natural size. In the present specimen there are only three sacral vertebre. All the dorsal vertebre preserved have their articular ends biconcave, or nearly plane. The ilium has a slender preacetabular process, thus differing from most of the other Zheropoda. The ischia are very slender, and are directed backward. For the posterior half of their length, they are closely adapted to each other. The known remains of this species indieate an animal about six or eight feet in length. Notice of New Dinosauria. 333 Morosaurus lentus, sp. nov. One of the most interesting specimens of Sawropoda in the Yale Museum pertains to a species of JMorosaurus much smaller than J. grandis, the type, and differing materially in other respects. The skull is not known, but nearly all the important parts of the skeleton are well represented, and in excellent preservation. The individual was not fully adult, and hence, the elements of the vertebrae and sacrum are, in most cases, separate, thus affording special facilities for inves- tigation. The limb bones and feet show that the fore and hind legs were much shorter than those of the other species of the genus. The vertebre, also, are shorter, more massive, and the cavities in them, smaller. All parts of the skeleton preserved are of similar density, indicating that the whole osseous struc- ture of the animal was more solid than any other of the known Sauropoda. The vertebre of the cervical and dorsal regions have their centra more depressed than in the other species of this genus, and may easily be distinguished by this feature alone. The neural arch rests directly upon the -centrum, instead of being elevated on pedestals above the articular faces. This feature is well shown in the figure below. KiG@- 2). Figure 2.—Posterior cervical vertebra of Morosaurus lentus, Marsh; front view. One-fifth natural size. The type specimen of the species here described indicates an animal about thirty feet in length. The known remains are from the Atlantosaurus beds of the Upper Jurassic, in Wyoming. 334 Notice of New Dinosauria. Morosaurus agilis, sp. nov. A. second new species, which apparently belongs to the same genus, is represented by the posterior half of the skull, the anterior cervical vertebree, and other parts of the skeleton. This animal was in direct contrast with the one last described, the skull and skeleton being especially light and delicate in structure for one of the Sawropoda. It was also much smaller in size, being the most diminutive known member of the genus, probably not more than fifteen feet in length. The figure below represents the back of the skull with the atlas attached, and the postoccipital bones in place. The axis and third cervical were also found in position. These will serve to distinguish the present species from the others of the genus, as they are proportionally much longer, and of lighter structure. Figure 3.—Skull of Morosaurus agilis, Marsh; posterior view. One-half natural size. The hind feet of the present specimen agree in general structure with those of MMorosaurus grandis, but differ in having the first digit unusually large and massive in comparison with the others. The third, fourth, and fifth, are especially slender. . This interesting specimen was found in the Upper Jurassic beds of Colorado, by Mr. M. P. Felch, whose researches have brought to light so many important remains of the Dznosauria. Ceratops horridus, sp. nov. The strange reptile described by the writer as Ceratops montanus* proves to have been only a subordinate member of, * This Journal, vol. xxxvi, p. 477, Dec., 1888. See also p. 327 of the present number. The specimen figured in vol. xxxiv, p. 324, may prove to belong to the same genus. Notice of New Dinosauria. 330 the family. Other remains received more recently indicate forms much larger, and more grotesque in appearance. They also afford considerable information in regard to the structure of these animals, showing them to be true Stegosauria, but with the skull and dermal armor strangely modified and specialized just before the group became extinct. The vertebre, and the bones of the limbs and of the feet, are so much like the corresponding parts of the typical Stegosaurus from the Jurassic, that it would be difficult to separate the two when in fragmentary condition, as are most of those from the later formation. The latter forms, however, are of larger size, and nearly all the bones have a peculiar rugosity, much less marked in the Jurassic species. In the form here described, this feature is very conspicuous, and marks almost every known part of the skeleton. In the type specimen of the present species, the posterior horn-cores are much larger than these appendages in any other known animal, living or extinct. One of them measures at the base, no less than twenty-seven inches, and about sixteen inches around, half way to the summit. Its total height was about two feet. In general form, these horn-cores resemble those of Ceratops montanus, but the anterior margin is more compressed, showing indications of a ridge. The top of the skull, in the region of the horn-cores, is thick and massive, and strongly rugose. This skull as a whole must have had at least fifty times the weight of the skull of the largest Sawropoda known, and this fact will give some idea of the appearance of this reptile when alive. As previously stated, the posterior pair of horn-cores of this family are hollow at the base, and in form and surface mark- ings are precisely like those of the Bovidw. The resemblance is so close that, when detached from the skull, they cannot be distinguished by any anatomical character. This accurate repetition, in later and still existing forms, of the highly special- ized weapons of an extinct group of another class is a fact of much interest. The present specimen is from the Laramie formation of Wyoming, but fragmentary remains, which may be referred provisionally to the same species, have been found in Colorado. Hadrosaurus breviceps, sp. nov. An interesting specimen in the Yale University Museum, from Montana, indicates a large Dinosaur, apparently belonging to the genus Hadrosaurus, and hitherto unknown. It is the dentary portion of the right maxillary, and is so characteristic, that it is here briefly described and figured. Its main features are well shown in figures 4 and 5 below. 336 Notice of New Dinosauria. The teeth are very numerous, and form a tessellated surface, as in Hadrosaurus Foulki, Leidy, but they are more elongate, and the outer enamelled faces ard less distinctly rhomboid in form. The grooves, also, in which the inner surfaces of the fangs were inserted, are less regular, than in that species. Figure 4.—Right maxillary of Hadrosawrus breviceps, Marsh; outside view. FIGURE 5.—The same jaw; showing worn surface of teeth. Both figures are one-fourth natural size. The present specimen is from the Laramie formation of Montana. Hadrosaurus paucidens, sp. nov. In strong contrast with the species above described is another from the same region and same formation. The best preserved specimen that now represents it is a left maxillary, nearly complete. With this was found some other portions of the skull, but the maxillary affords the best distinctive char- acters. All, however, indicate a skull of extreme lightness and delicacy of build for one of the Ornithopoda. The max- illary is especially slender, and the anterior and posterior ex- tremities are pointed. The middle of the bone is more mas- sive, but yet very light for this portion of the skull. The teeth are of the general type of those in this genus, but are comparatively few in number, and only one row appears to have been in service. The maxillary preserved is about ten inches in length, and three inches high near the center. The row of teeth in use contains about thirty. The remains on which the present species is based were found in 1888, in the Laramie formation of Montana, by Mr. J. B. Hatcher, of the United States Geological Survey. New Haven, Conn., March 25, 1889. PUBLICATIONS OF THE TONS HOPKINS “UNIVERSITY. I. American Journal of Mathematics. S. Newcoms, Editor, and T. Crate, Associate Editor. Quarterly. 4to. Volume XI in progress. $5 per volume. II. American Chemical Journal.—I. Remsen, Editor. 8 Nos. yearly. 8vo. Volume XI in progress. $4 per volume. Ill. American Journal of Philology.—B. L. GILDERSLEEVE, Editor. Quar- terly. S8vo. Volume IX in progress. $3 per volume. IV. Studies from the Biological Laboratory.—lIncluding the Chesapeake Zodlogical Laboratory. 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Drawings of fossils and shells made, and museum work done by Dr. OTTO MEYER, 54 Kast 7th Street, New York. AMERICAN JOURNAL OF SCIENCE. FOUNDED BY PROFESSOR SILLIMAN IN 1818. Devoted to Chemistry, Physics, Geology, Physical Geography, Mineralogy, Natural History, Astronomy, and Meteorology. EDITORS: JAMES D. DANA and Hpwarp S. DANA. Associate Editors: J. P. Cooks, JR., GrorcrE L. GoopaLe, and JoHN TROW- BRIDGE, of Cambridge, H. A. Newton and A. E. VEeRRILL, of Yale, and G. F. BARKER, of the University of Pennsylvania, Philadelphia. Two volumes of 480 pages each, published annually in MONTHLY NUMBERS, This Journal ended its first series of 50 volumes as a quarterly in 1845, and its second series of 50 volumes as a two-monthly in 1870. The monthly series com- menced in 1871. 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Cross... 261 XXX.—Eyvents in North American Cretaceous History illus- trated in the Arkansas-Texas Division of the South- western Region of the United States; by R. T. Hitt._-. 282 XXXIL—A General Method for determining the Secondary Chromatic Aberration for a double Telescope Objective, with a description of a Telescope sensibly free from this defect; ‘by, C.:S.-FLASTINGS| {S28 et (5 Se eee 291 XXXII.—The distribution of Phosphorus in the Ludington Mine, Iron Mountain, Michigan; by D. H. Brownz. With Plates: VITI-XTT) = 22 ee XXXTIL—Paleohatteria Credner, and the Proganosauria ; by Gay Bare. sole Ns NS ls os ee ee 310 XXXIV.—Appendix: Comparison of the Principal Forms of the Dinosauria of Europe and America; by O. C. IVDAR Sia 2 2 Se Se he Sie Ee .- 323 XXXV.—New American Dinosauria; by O. C. Marsu.-__ 332 SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Presence of a new Metal in Nickel and Cobalt, KRuss and ScHMIDT, 313.—Atomic Mass of Tin, Bongartz and CLASSEN: Studies from the Laboratory of Physiological Chemistry, R. H. CHITTENDEN, 314.— Divergence of Electromotive force from Thermo-chemical data, H. F, HER- ROUN: Behavior of Metals to Light, Kunpt, 315.— Hertz’s experiments on Hlectro- magnetic Waves, FItzGERALD and F. T. TRouToN: Electrified Steam, HELMHOLTZ: Viscosity of gases at high temperatures and a new Pyrometric method, BARUS, ~ 316. Geology and Natural History.—Brachiospongide; On a Group of Silurian Sponges, C. H. BrecuER, 316.—Waverly Group of Ohio, C. L. HERRICK, 317.—Sacca- mina Hriana, J W. Dawson: Ueber eine durch die Haufigkeit Hippuritenarti- ger Chamiden ausgezeichnete Fauna der oberturonen Kreide yon Texas, F.. ROEMER, 318.—Shall we teach Geology? A. WINCHELL: The Descending Water-current in Plants and its Physiological Significance, J. WIESNER, 319.— Certain Coloring Matters in Fungi, W. Zopr: Bacterial Forms found m Normal Stomachs, J. E. ABELOUS, 320.—Mr. Morong’s Journey in South America, 321. —Botanic Garden at Buitenzorg, Java, Dr. TRruB: Structure of the “Crown” of the Root, Lion Fiot, 322. — Obituary.—U. P. JAMES, 322. Chas. D. Walcott, U. S. Geological Survey. ae aS Bvo.. xxxvi. MAY, 1889. THE AMHRICAN JOURNAL OF SCIENCE. : EDITORS 4 ' JAMES D. anv EDWARD 8. DANA. 4 ASSOCIATE EDITORS | | i Prorzssors JOSIAH P. COOKE, GEORGE L. GOODALE laa ann JOHN TROWBRIDGE, or Camprinez. | || Proressors H. A. NEWTON axp A. E. VERRILL, or * a New Haven, & Proressor GEORGE F. BARKER, or Pswapetruta. q THIRD SERIES. a VOL. XXXVII—[WHOLE NUMBER, CXXXVIL] 1 No: 221 = MAY. 1889: NEW HAVEN, CONN.: J. D. & E. 8. DANA. 1889. TUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET. ~ fi ve —— 3 Published monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- " seribers of countries in the Postal Union. Remittances should be made either by : ve money orders, registered letters, or bank checks. \ MINERALS. A few recent additions to our stock: Beryllonite, 400 specimens, 25c. to $3.50. For description of this new and interesting species see this Journal for January. Topaz from Japan. Just received direct from Japan, 800 specimens, including many clear and highly modified crystals, some 2% inches in diameter. Prices very low, 50c. to $5.00. Blue Barite from a new locality in Colorado. Over 300 fine specimens. The crystals are of a beautiful blue color. They are not surpassed by those of any other locality. 15c. to $6.00. Descloizite from a new locality in’ New Mexico. Superb sta- lactites of rich velvety druses of crystals of the most brilliant shades of red, yellow and brown. 25c. to $3.50. Large and magnificent Museum specimens, $5.00 to $50.00. Vanadinite in barrel-shaped, elongated crystals, grouped like pyromorphite from Ems. Small and good specimens only 10c. to 50c. Most interesting to the erystalloer apher. Sphalerite, Calamine, Marcasite, Galenite, etc., from Missouri in choice specimens. Nearly a ton of fine Copper Minerals just shipped by Mr. English, who is now collecting in Arizona. Particulars later. The above are but a few of the many additions recently made to our stock, which we believe is unquestionably the finest and most complete in the U.S. We have been adding largely to our stock of minerals for blowpipe analysis. We aim to supply the very best material ob- tainable. Send for list. ‘ College professors are especially urged to give us a trial order. Illustrative collections of all kinds in stock and to order. Cor- respondence solicited. Monthly Catalogue free to any address. GEO. L. ENGLISH & CO., Dealers in Minerals, 1512 Chestnut Street, - - Philadelphia, Pa. he ® oe he ee i Et Cie ie _ _ = > —_—oee ef “2 Ee eee te ae % 7 ’ 2 oMid 4 mt /, f fey Wi PU THE AMERICAN JOURNAL OF SCIENCE [THIRD SERIES.] Art. XXX VI.—The Electrical Resistance of Stressed Glass; by CARL BARUS. THE thermal relations of the resistance of glass, originally studied by Buff,* have more recently been made the subject of research in memoirs by Beetz,t Foussereau,{ Perry,$ Thos. Gray,| and others. Warburg’s{ experiments, however, throw new light on the inquiry, by showing that the apparent polar- ization evoked by the passage of current, is due to a layer of non-conducting silica depositing at the anode. If this be con- tinually dissolved by an electrode of sodium amalgam, the apparent polarization is so far removed that an almost constant current may be kept up indefinitely. If the film be not removed, conduction soon ceases and the glass behaves like a condenser of measurable capacity. The effect of temperature on the conductivity of glass has thus been mapped out with considerable detail, and it will be superfluous to add new data in the following paper. I pur- pose therefore to confine myself narrowly to the effects of * Buff: Lieb. Ann., xc, p. 257, 1854. + Beetz: Pogg. Ann., Jubelband, p. 23, 1874. t{ Foussereau: Journ. de phys., II, xi, p. 254, 1883. § Perry: Proc. Roy. Soc., xxiii, p. 468, 1875. || T. Gray: Proc. Roy. Soc., xxxiv, p. 199, 1883. §] Warburg: Wied. Ann., xxi, p. 622, 1884; ib., xxxv, p. 455, 1888. Am. Jour. Sct.—THIRD SERIES, Vou. XXXVII, No. 221.—May, 1889. “ 340 C. Barus— Resistance of Stressed Glass. stress* on electrolyzing glass, kept as nearly as practicable at different constant temperatures between 100° and 360°. 2. The apparatus with which most of my definite experi- ments were madet+ are shown in figures 1 and 2, and are differ- ential in kind. The resistances across equal parts of the walls of two nearly identical glass tubes, respectively stressed and Figure 1.—Apparatus Figure 2.—Apparatus for 200°. for 100°. unstressed, are compared. These tubes are shown at abc¥ and E-khf. The ends proper are bent hook-shaped ; and those of the glass tube to be operated on, fastened by aid of screws and cement, between slabs of wood A and &. A is fixed; B pro- vided with a hook, P, from which a scale pan may be hung; * Reference may here be made to J. and P. Curie (C. R., xci, pp. 294, 383; xcii, p. 350, 1881; xciii, p. 1137, 1881), and to Hankel (Wied. Ann., p. 640, 1881), who show that in certain hemihedral crystals longitudinal compression is aecom- panied by the manifestation of electromotive force. Curie’s very recent work is summarized in the Beiblatter, xii, p. 857 to 867, 1888. + The earlier experiments were made with single tubes alternately stressed and unstressed, inserted in a simple galvanic circuit. In such a case, however, fluc- tuations of temperature often obscured the effect to be observed, beyond recogni- tion. Cf. § 7. C. Barus—Resistance of Stressed Glass. 341 or with a lever arrangement for twisting. In the experiments made the load was gradually increased as far as 20 kg., but the tubes were strong enough (theoretically) to sustain about three times this weight. The remainder of the figure shows the devices for heating and for passing the currents. Figure 1 is adapted for high boiling points (aniline, etc.), figure 2 for steam. An apparatus similar to figure 1 was used for mer- — eury. In figure 1, @ is the ebullition liquid, heated by a Gibb’s ring burner #/ surrounding the wide glass tube dd. A narrower glass tube gg, closed below with a perforated cork’ through which pass the experimental tubes abc and ekh, is partially filled with sodium amalgam. This is practically one terminal of the battery, the wire connecting at p. The other terminal, after passing through the respective coils of a differ- ential galvanometer, connects at m and f with the sodium amalgam contained in the experimental tubes abc and ekh. The notation in figure 2 is the same as that in figure 1. The two forms of apparatus are essentially identical, except that in figure 2 it is expedient to pass steam through dd, the vapor entering at S and leaving the apparatus at S’. For reasons stated below, $5, it is desirable that the menisci of the amalgam contained in abc’ and ekhf, figure 1, be visible above the level of the upper cork of the tube dd. The amalgam in g9, figure 1, should be submerged below the level of G. Inas- much as sodium amalgam is only necessary at the anode, ordinary mercury may be used at cathodal parts; and these may therefore be exposed to hot air or steam without annoy- ances. To summarize: current arriving at m and 7 passes into the sodium amalgam core of the tubes, abc and ekh, thence across the walls of the hot parts of these tubes into the mer- cury surrounding them, and finally via p back to the battery. Regarding other apparatus, ef. § 7. 3. I commenced work with torsion experiments of which I may indicate something here. A battery of 10 Grove cells was used and the aniline at G, figure 1, kept both below and at the temperature of ebullition. The deflection of each coil alone being 16-4, it was found that the differential action (nearly zero) could not be modified by twisting more than ‘02™. Hence the specific electrical effect of twisting can not be greater than about ‘1 per cent. The resistances encountered in these cases were about 200,000 ohms. Profiting by this preliminary experience however I was ultimately able to de- tect and measure the effect of torsion on electrolytic conduc- tivity, using a different and more sensitive method to be indi- cated below, $7. 4. In case of traction, the data decisively indicated an increase of conductivity proportional to the pull. But this 342 C. Barus—Resistance of Stressed Glass. result is necessarily complex in kind, and must be carefully scrutinized before its true signification can be stated. I will therefore give my experiments in chronological order, the first series being made at 185° (aniline), the second at 100° (steam), the third series finally at 360° (mercury). One remark may be made at the outset: inasmuch as the electrical effect of traction is persistant with the traction, and is an increment of conductivity, it can not be due to tempera- ture. or the extension of an elastic solid like glass* produces temporary cooling, § 8. 5. The resistance across the walls of the experimental tube at 190° was about 100,000 ohms. In ease of intense ebullition, the temperature is not fully constant. It is therefore desirable to use the apparatus, figure 1, just below the boiling point of aniline, and to bring the plane of the ring burner slightly below the plane of the ebullition liquid G. Parts of the ap- paratus which are not to be heated are screened with asbestos. In this way a nearly stationary distribution of temperature is reached. Under these circumstances, when a weight of 18 kg. is alter- nately placed on the scale pan and removed from it b mechanism, thus subjecting the tube to periodic pulls of the force given, a definite and persistent oscillation of the galvano- meter needle ensues synchronously with the period of stress. The amount of this oscillation was found to be equivalent to a resistance-decrement of 1500 ohms for the stressed tube. In other words the effect of the pull of 18 kg. is a diminution of the resistance of the stressed tube amounting to about 1:4 per cent. These experiments were repeated many times with prac- tically the same results, e. g. P= 2kg., resistance reduced .4 per cent. ee WG lge, BG Aaa GO P=20ke, <« Ca AAs lace data in which the oscillation of the needle was made the basis of comparison. They betray a somewhat wide margin of error, because glass at 190° is exceedingly sensitive even to trifling changes of temperature. Nevertheless the data are sufficient for the present purposes ; and work of a more precise character with high temperature vapor baths seemed to me to be superfluous. By using a more sensitive galvanometer such measurements can be repeated at 100° with facility and much greater precision. 6. The result obtained is clearly a superimposed effect, being due in part to the elastic change of dimensions during stretch- ing, and in part to the direct action of stress in promoting * Cf. Sir William Thomson’s collected papers, vol. i, p. 308. C. Barus—Resistance of Stressed Glass. 343 molecular break-up. It is therefore necessary to estimate the value of the former influence. The radii of the tube being p,='26™ and p,=:19™, the sec- tion is about g="1™. Supposing the tenacity of glass to be 65x10° dynes per square centimeter, this tube should bear 65 kg. Tubes are rarely free from imperfections, such as result from insufficient annealing, and it is moreover difficult to apply traction in an experiment like the present, without some flexural or other strain across the section (tendency to be crushed between the slabs, A, B, at the supports for instance). Hence I found it practically difficult to strain these tubes with more than a pull of about 25 ke., without producing rupture. But from all this it appears clearly that the longitudinal ex- tension produced by 18 kg. is much de/ow the maximum for the given dimensions and mean strength of tube. If the tenacity of glass be 65 10° and Young’s modulus 5°5 X10", the values given by J. D. Everett,* then the maxi- mum longitudinal extension is (0012. Again since Poisson’s ratio for glass is nearly 4, it follows that the corresponding radial contraction is about ‘00038. Finally the resistance /? of a hollow-cylinder, of length 7, radii p, and p,, and specific resistance s, to conduction across the walls of the tube is (J/ being the modulus of Brigg’s 1 8 8 Snr 7 10S Pil P= "8865, log p,/p,.- - Q). To evaluate the resistance effect of elastic change of dimen- sions, /? is to be regarded as a function of /, p, and p,. In view of the symmetrical occurrence of the last two variables, and if the simplifying relation 400,/0,=40p,/ 0,=01/0, nearly, it follows that 0'/R=(dR’/dl)ol/R+ (dR’'/ dp,)do,/R+(dR’/dp,) 0, /f¢’=—0l/1, where the accent has reference to elastic change. Nevertheless radial contraction enters in case of an apparatus of the form figure 1, in which decrease of bore during traction lengthens the column of mercury contained. If A be the length of this column before stretching, its length during stretching is A(1+209, /o,),=A14+(1/2)00/). Hence in consequence of elongation of the mercury column, d/?”/?=—(A/2/)0l/1, nearly, where / is the length of the hot part of the column. Hence the elastic discrepancy is (OR oR R=“ (14 Aneyt. |. (2). In none of my apparatus did 2 exceed 2°5 7. Moreover 2 is always one shank of a U-tube. Therefore 003 may be as- sumed as a decidedly superior limit of the numeric of equa- tion (2). * Hverett: Units and Phys. Constants, p. 56. These data are reduced from Rankine’s ‘‘ Rules and Tables,” p. 895. logarithms); /?= 344 C. Barus—Resistance of Stressed Glass. Hence in an extremely unfavorable case, the resistance effect due to elastic change of dimension (—‘30 per cent) is only about + of the observed effect of traction (—1°4 per cent) pro- duced by a pull much below the tenacity of glass, the said pull (18 kg.) being certainly not more than 4 the maximum load. Hence these effects are very different, and it follows. that the decrement actually observed is principally due to decreased molecular stability superinduced by stress. In equa- tion (1), s is therefore the variable which chiefly responds to the action of stress. To obviate the troublesome occurrence of df” / R, the column of mercury in most of my experiments was made so long as to extend far above the zone of conduction of the stretched glass tube (see figure 1). In the apparatus for steam, figure 2, the menisci of the column are advantageously raised quite above the cork. In such a case 0R’’/R=0, and the elastic discrepancy is simply — 07/1. In one respect this reasoning is deficient. It does not take into account the changes of elastic behavior of glass due to the heating to 190°. Tabulated constants for this large interval are not available.* Hence special cathetometric measurements must be made. At 190° this is difficult, and for these and the other reasons given above, §5, it is expedient to refer to the complete set of measurements at 100°. $6. 6. At 100° the results can be made more accurate than the above chiefly for two reasons. In the first place the tempera- ture is easily obtained absolutely constant ; in the second elas- tic changes of dimensions can be directly measured with facility. In Table I, I have given the results obtained with the appara-. tus, figure 2. The method of measuring these large resistances (glass at 100°) is necessarily chosen more delicate than above. I used a high resistance Thomson’s galvanometer read off by Hallock’s short range telescope, and adjusted for differential work. The needle being practically ballistic in kind, the maximum deflections (swing) obtainable by alternately adding and removing the loads P, were used for comparison (method of multiplication). I then determined the amount of oscilla- tion produced by inserting known resistances into one or the other coil of the differential galvanometer. Knowing the resistance of each tube (mean values) from special and pre- liminary measurements, I was able to deduce the percentage variation of the resistances of glass across the lines of stress. Table I contains four series of these experiments, i. e. two sets of results for each pair of tubes. 2, the observed electri- cal resistance per tube was found to be about 7,500,000 ohms * Kohlrausch and F. E. Loomis (this Journ., II, 1, p. 350, 1870), give low tem- perature data for metals. C. Barus—Resistance of Stressed Glass. 345 per tube, of which the external and internal diameters were 20,='53"20,='388™ respectively. The table gives the oscilla- tions for the divers loads P; the corresponding absolute de- crement 0 of Ff, and the relative value of this decrements in terms of &. The amount of variation here given for glass is somewhat smaller than was found at 200° above. In the last case, how- ever, the data are less accurate, and definite statements can not be made. In Table I the values for the 2d apparatus are smaller than for the first, a cireumstance obviously depending on the tubes chosen, but which I will also leave without further comment. TABLE I.—Resistance of stretched glass at 100°. Maximum Tubes. LEM are oR 103 x OR/R. Method. g. cm. ohms. Differential Galvanometer. T and IT 6 1:05 — 21000 —2°8 10 1°63 —33000 —4:4 15 2°20 —44000 —5'8 19 2°90 —58000 —T% T and I 6 “87 —17000 —2°2 10 1°50 — 29000 —3°8 15 217 — 42000 —54 19 2°91 — 56000 —7:3 Iii and IV) 6 29 — 6000 — 9 10 14 —15000 —2°2 15 1:05 — 21000 —31 Ili and IV} 6 33 — 7000 —1:0 10 “16 — 15000 —2°3 15 USI — 22000 —3°3 IV 5 GD ONaeiailiipnetec i ue —12 Bridge. 10 Mee SSS masala peers LE —2°8 This table proves conclusively, that within the given limits of variation, the resistance decrement experienced by glass is proportional to the applied stress. For the given conditions (20,=538°"20,="40) it isas high as 380/10° per kilo stress, and is not below 210/10° per kilo stress. Since the section g=*10™ nearly, it follows that the mean relative variation of resistance due to stretching is about 30/10° per gram load, per square centimeter of section. Mr. H. Tomlinson* who investigated the effect of stretching metals, finds that for steel, iron and brass the total variations are only about 1/15 as large as this, and of the opposite sign. $11. 7. When the temperature is sufficiently constant, for instance in the case of a steam bath, experiments may be made with a single tube. Let a bridge adjustment be so arranged that * H. Tomlinson: Proc. Roy. Soc., xxv, p. 451, 1876; id, xxvi, p. 401, 1877. 346 C. Barus—Resistance of Stressed Glass. a/b=r/R, where 7 is a known rheostatic resistance, and R the resistance of the tube, the current in the galvanometer being nearly zero. Then if 07/7 produce the same maximum oscillation of the needle as 0R/R, it follows that d7/r=d R/R. An accurate chart or table of d7/r considered as a function of the oscillation is therefore first to be constructed, by aid of the rheostat. This being in hand, the value of dR/R correspond- ing to any oscillation produced by alternately adding and_re- moving the load on the tube, is given at once. This method may be made very accurate, and I was able to obtain not only traction effects, but torsion effects as indicated by the following data. Here vis approximately 53000 ohms, /? approximately 5900000 ohms. In ease of torsion, / denotes the load acting during the alternate twisting and untwisting. TABLE II.—Resistance of stressed glass at 100°. Preliminary. 10° x dr/r |Oscillation. Torsion. Traction. P | Oscillation.|103 x bR/R P | Oscillation.| 10° x dR/R cm. kg. cm. ke, cm. “16 *35 5 709 —1°'3 0 “22 —'5 1:89 °89 10 1:27 —2°8 5 29 — ‘6 BSUt 1°63 16 1°86 —4'1 | 10 28 — 6 The traction data 0/f are numerically larger than in Table I, and hence lend greater favor to the views just expressed. The torsion data d/?/f are of the same sign as the traction data. ance. In other words torsion increases the electrolytic resist- They are of smaller magnitude than traction data and are independent of the load which the tube sustains, so far as I could follow them. TABLE I1.—Longitudinal extension of the tubes, Table ist. Temperature. | Load. L 6L/L °C, ke. em 107° x 16° 2 10-53 0 6 77:53 0 10 17-54 130 15 17°55 260 100° 2 17°58 0 Coefficient of expansion “000008 6 77-58 0 10 77°60 260 15 77:60 260 100° 2 TT57 0 19 77-59 260 100° 2 T1757 0 19 77°60 390 8. To interpret the above data, special measurements of ex- tension are necessary. These are given in Table I]. They were C. Barus— Resistance of Stressed Glass. 347 made cathetometrically, and are not intended to give more than a safe estimate of the elastic effect in question. The glass tube to be examined was surrounded conaxially by a second wide tube of glass, through which steam at 100° con- tinually circulated. Measurements were also made at 16°. L is the length between fiducial marks. Utilizing these values to obtain a superior limit of the elastic discrepancy in Table I, it appears that 0///<:0004 and do/o< 0001, these data being the largest obtained for the largest load, 18 kg. Hence by equation (2), —d2’/2<2°5 x :0004= 0010. In other words the elastic discrepancy is numerically much less than ‘1 per cent of #, whereas the corresponding mean value for the traction effect in Table I (apparatus with tubes I and II, low menisci) is *75 per cent. Again for raised menisci (Tables I and II, tubes III and 1V),—0/2’/R=01/l=-0004. In this case the corresponding mean value of the traction effect is numerically greater than ‘50 per cent. In both instances it may be safely inferred that error introduced by elastic change of dimensions is at most about 1/10 of the decrement of resist- ance actually observed as the effect of stretching. 9. I will make a final consideration here, relative to temper- ature. . The thermal effect of traction is negative, its influence on / must therefore be a resistance increment, i. e. opposite in sign to the effect observed. Nevertheless, it is desirable to obtain some estimate of its value, which will probably be found too small for direct measurement. Since P=20 kg. and OL/L< 0004", the total energy elastically potentialized per linear centimeter during stretching is PdL/Z<10000 ergs. Henee, even if all this energy were converted into heat, the increase of temperature resulting in case of the given tubes (section -10™, density <3, sp. heat <2) would be about 10*/240x10*; i. e. less than -005°. This datum is too small to produce serious error even in consideration of the phenomenal sensitiveness of hot glass to temperature variations. Estimat- ing that the resistance of glass decreases several per cent (5 to 20) per degree, between 100° and 200°, the thermal discrep- ancy can not be greater, numerically, than the elastic dis- crepancy. 10. I have now to communicate the data obtained at 360°. This case possesses some points of special interest, because the differential apparatus is itself a battery, the action of which enters in a complex manner. The electrolytes here are the hot glass tubes containing amalgam and surrounded by mercury. The actual apparatus was a simplified form of figure 1. Figure 3 presents a clearer diagram of parts, in which @ and 6 are the hot glass tubes in question, #’ the battery and D the differen- tial galvanometer. The electrical currents due to # are indi- 348 C. Barus—Resistance of Stressed Glass. cated by the znszde arrows; but these currents are considerably reénforced by the action of the element sodium amalgam /hot glass / mercury, as shown by the arrows crossing the tubes @ and 6.. The electromotive force of this element is easily found by reversing the action of # In an actual experiment I meas- ured NaHg/hot glass / Hg=1:4 volts, a datum somewhat affected by polarization and depending for its value on the strength of the amalgam and the purity of the mercury. Besides this large electromotive force there is another of smaller value, due to the fact that the tubes @ and 6 with appurtenances, represent two elements switched against each other. ‘The currents are indicated by the owts¢de arrows in the diagram, and they are necessarily so cireumstanced as not to flow through the galvanometer @ differentially. Their occur- rence is therefore a serious and annoying disturbance, such that. measurements at 360° can not, without unreasonable painstak- ing, be made with the same accuracy as measurements at 100°. I measured the electromotive force in question, as about ‘2 volt; but it is necessarily variable even as to sign, containing as it does the polarization inconstaney of both elements. Figure 3.—Apparatus for 360°. Since the resistance of glass near 360° is enormously low relative to its value at ordinary temperatures (in some practical cases the apparatus showed less than 10V0 ohms), the extran- eous electromotive force /# can be withdrawn altogether. The present measurements of the electrical effect of traction are therefore made with the NaHg / hot glass / Hg element in the apparatus, figure 8. Notation being as above 20, = ‘63, 20,=40™. The small resistance at the boiling point is not available ; owing to the formation of bubbles at the surface of contact between mercury and glass the resistance is too variable even for approximate measuremeut. Hence I observed at a lower temperature, encountering somewhat larger resistances P. C. Barus—Resistance of Stressed Glass. 349 Even under favorable conditions these data are only quali- tatively satisfactory. They are important, however, because they indicate that at 300°, the diminution of resistance due to traction is not larger in numeric value than at 100°; and since this would be the case if the decrements 0 observed were due to elastic change of dimensions, I have here in hand addi- tional evidence against this assumption. TABLE II1.— Resistance of stretched glass at 360°. Apparatus. iP ae R oR 10?xdR/R kg. em ohms ohms it 6 50 13000 —30 —2 10 50 eee —30 —2 15 “70 el —50 at 19 70 Meee —50 4 Til 6 1:00 17000 —15 —1 10 1°40 | Meares —22 =] 15 2°00 Nee —31 —2 The present experiments are attended with much annoyance. As the load increases, the tube is apt to break in such a way as to spill the hot mereury; and with all reasonable care several tubes are usually sacrificed before a full series of obser- vations can be obtained. 11. The above paragraphs summarized, prove that a solid electrolyte like glass is a better conductor of electricity (i. e. manifests smaller specific resistance), when in a state of strain (traction, torsion), than when free from strain. Inasmuch as the necessary concomitant of conduction in this case is molecu- lar decomposition* and recombination, stress of the given kind | must promote such decomposition. The rate at which molec- ular reconstruction occurs per unit of volume increases nearly proportionally to the intensity of stress; and it may in case of traction carried as far as the limit of rupture of glass amount to an increment of one per cent. In case of torsion the effect. is not much larger than about 1/10 of this ; and the increased break-up due to torsion is therefore studied with greater diffi- culty. The influence of temperature in changing the value of the electrolytic effect of stress is not marked. So far as ob- served the same pull per unit section does not increase the conductivity of glass more at 850° than at 100°, if indeed it increases it as much. * Tt is best to avoid the term dissociation here. The term molecular recon- struction is used in preference. 350 CO. Barus—Resistance of Stressed Glass. Again the traction effect in case of electrolytic conduction, being a decrement of resistance, is of the opposite sign of the traction effect in cases of metallic conduction* (increment of resistance). The former is also of decidedly greater magnitude. If, therefore, conduction in metals is essentially the same phe- nomenont as in electrolytes, then the soft metallic state must be singularly well adapted to promote molecular reconstruction. This fine adaptation of structure is destroyed by strains of dilatation, by heat, by alloying,t ete. In the data given, the electrical traction-coefficient, as well as the electrical tempera- ture-coeflicient (resistance), are similar in sign and in relative magnitude, both in metals and in electrolytes. They are posi- tive in metals and small, negative in electrolytes and large. This is additional evidence in favor of a volume effect dis- cussed at some length elsewhere. 12. The chief result of the present paper is the emphasis thrown on the fact that, independently of the passage of cur- rent, such a solid as glass must be conceived as undergoing spontaneous molecular reconstruction at all temperatures. For if the reconstruction in question were superinduced by the electric field, then the current passing would vary at a power higher than the first of electromotive force; whereas it may be taken for granted that currents of the intensity of those discussed above, pass through glass in accordance with Ohm’s law.§ Recently J. J. Thomson| among many results of his development of the Lagrangian function, investigated an ex- pression for the number of times, 7, the electric field is dis- charged at any point, in case of conduction through either metals or electrolytes. If A be the specific conductivity, A the specific inductive capacity of the medium, then n=27fA/ K; where is a coefficient the value of which is less than unity and depends on the relative time of destruction and existence of the electric field. Accepting provisional values for # and FX, Thomson computes a table of values for the superior limit of n, in cases both of metals and of electrolytes. From this table it appears that » for mercury for instance, is less than 8x10". Similar values for the limit of m in case of glass at the above temperatures of observation, 100°, 200°, 360°, may be deduced. In round number the specific resistances of glass at the temperatures stated were, in ohms, 10°, 10°, and 5X 10%, * Mousson: Neue Schweizer, Zeitschr., xiv, p. 33, 1855; H. Tomlinson: Proc. Roy. Soc, xxv, p. 451, 1876; id., xxvi, p. 401, 1877. + J. J. Thomson: Applications of Dynamics to Physics and Chemistry, p. 296; Macmillan, 1888. This Journal, xxxvi, p. 427, 1888. § Fitzgerald and Trouton (Rep. Br. Assoc., 1886, p. 312) show that electrolytes obey Ohm’s law accurately. || J. J. Thomson: 1. ¢., p. 299. W. H. Weed—Formation of Siticeous Sinter. 351 respectively. From this it follows nearly, that for glass at 100°, n=8 X10"; at 200°, n=8xXx10°; at 360° 2—16x 10". Thus it is fair to conclude that at temperatures quite as low as 100° the spontaneous chemical action, i. e. the continuous re- arrangement of the molecules of glass is a pronounced occur- rence. The given value of the frequency of discharge of field, n, may be further expressed in terms of the number of molecules m, which break up per unit of volume, per unit of time, when the number of molecules g per unit of surface, whose disinte- gration just discharges the field, and the mean distance, x, over which they are urged by the field during the interval between break-up and recombination, are known. For n=ma/q; or m=n (q/a). Here w is a very small quantity, not exceeding the centimeter numeric of the mean free path of the molecule of a gas; whereas g isa very large quantity. Hence m is larger than the given value of n, even if the above superior limits be 100 times the true value of 7. These approximate statistics are the nearest exact statement for the phenomenon of molecular break-up, which I can ad- duce; but they suffice for the present purposes. They show that even when glass is practically an insulator, the number of active molecules m, considered absolutely is very large; and that m need by no means be negligibly small even in com- parison with the total number of molecules per unit of volume. The above paragraphs prove that the rate at which molecu- lar break-up takes place is appreciably greater when glass is under stress than when it is not. It is improbable that the system will pass from one state of molecular equilibrium to another, instantaneously. Hence, since even in case of very high resistance, such as that of glass at 100°, the number of unstable molecules per unit of volume must still be conceived to be very large, it follows that the species of molecular break- up in question may be looked upon as a fruitful cause of viscous deformation.* Phys. Lab. U.S. G. S., Washington, D. C. Art. XXX VII.—On the Formation of Siliceous Sinter by the Vegetation of Thermal Springs; by WALTER HARVEY WEED, of the U.S. Geological Survey.t It is a well known fact that hot spring waters often contain considerable silica in solution, particularly those issuing from volcanic rocks, with which boiling springs are so frequently as- * This Journal, xxxvi, pp. 178, 179, 183, 202, 208, 1888. Phil. Mag., V, xxvi, pp. 397, 398, 1888. + Published by permission of the Director of the Survey. 352 W. H. Weed—Formation of Siliceous Sinter. sociated. Such waters, upon reaching the surface, deposit a portion of their burden of silica, as siliceous sinter, forming the white platforms, cones, and mounds which are a character- istic feature of the three geyser regions of the world. This . material covers many square miles in the hot spring region of the Yellowstone National Park, occurring in beds of con- siderable thickness, which are of much geological interest, not only as chemical deposits but because they also afford evidence of the age of the hydrothermal forces which have played so important a part in the later history of the region and to which it owes its popular name of ‘ Wonderland.” Although the formation of siliceous sinter has been noticed by many observers in connection with geyser and hot spring waters in Iceland and elsewhere, it is found that the causes ad- vanced to account for the precipitation of the silica from the hot waters and its deposition as sinter do not offer a satisfac- tory explanation of the origin of many of the deposits of this material found about the hot springs of the Yellowstone. Such deposits are largely, sometimes wholly, due to a separa- tion of silica by the vital growth of the algous vegetation of the hot spring waters. The present article is extracted from a paper in the Ninth Annual Report of the Director of the Survey, in which the work of this vegetable life of thermal waters is fully described. The conditions governing the stability of a solution of silica are but imperfectly known, especially for such complex solu- tions as those of the Yellowstone hot springs, however the causes producing a separation of silica from these natural waters can be grouped under the following heads: Relief of pressure. Cooling. Chemical reaction. Evaporation. Plant life. The first four tend to produce a supersaturated solution of silica, and thus to cause its separation. So far as known the oniy waters in the Yellowstone Park in which cooling or relief of pressure are operative causes are those of the Norris Geyser Basin. If a highly heated underground water dis- solves more silica from the lavas, whose fissures it traverses, than it can retain in permanent solution at the ordinary atmos- pheric pressure and temperature, it becomes supersaturated and deposits silica upon reaching the surface of the ground. The exact amount of silica which can be held in solution by the alkaline waters of the Yellowstone and similar hot springs is not known. The waters most highly charged with silica are those of the Norris Geyser Basin. That of the Opal Spring W. H. Weed—Formation of Siliceous Sinter. 353 carries 0°7620 gms. of silica to the kilogram of water, and issues with a temperature of 199° F., one degree above the theoretical boiling point of pure water at this altitude. This water is perfectly clear and without sediment, and remains so upon cooling to 35° F. and after standing several days. Yet about the spring, sinter is deposited under such conditions that evaporation can have but little effect, though it is also deposited elsewhere through evaporation. It is possible that in this water as in that of the Coral Spring, the influence of the silica already deposited causes a separation from water that would not other- wise deposit silica. Sinter deposition beneath the surface of the water is ex- tremely rare among the hot springs of the Park and has never been observed at either the Upper or Lower Geyser Basins. The waters of the Coral Spring, Norris Basin, containing 0°6070 grams of silica to the kilogram of water, is opalescent from silica in suspension or “pseudo solution,’ but does not de- posit silica after standing several years in the laboratory, and as in other siliceous waters cooling does not affect the silica, which only separates out after freezing (crystallization). Yet the water deposits silica freely upon the sides and bottom of the spring. The constitution of this water, its peculiar opa- lescence and the situation of the spring lead to the belief that the saturation of the solution is due to chemical reaction be- tween an alkaline spring water and acid vapor. This accords with the theory of Damour regarding the deposition of silica by the waters of the Iceland hot springs.* Moreover, in such waters there is often a neutralization of the alkaline solution by descending acid waters, made acid by oxidation ; this is the way in which LeConte and Rising explain the de- position of the gelatinous silica of Sulphur Bank, Cal.+ That the carbon dioxide of the atmosphere has any effect in producing sinter deposition{ is disproven by the occurrence of free CO, in these waters. Evaporation, partial or complete, certainly produces a depo- sition of silica from the siliceous waters of the Park, both acid and alkaline. It is, according to Bunsen, the only cause pro- ducing the deposition of sinter by the geyser waters of Ice- land. Though evaporation is certainly an efficient agent, par- ticularly in the dry air of the Park, producing some of the most beautiful and striking forms of sinter known, yet the deposits of the Yellowstone (excepting those of Norris Basin) are but partly due to this cause, and as already stated, are chiefly formed by a separation of silica by the vegetable life of the hot water. * Phil. Mag., xxx, 1847, p. 405. ¢ This Journal, ITI, vol. xxiv, p. 33. t Roscoe and Schorlemmer, Treatise on Chem., vol. i, p 571. 354 W. H. Weed—Formation of Siliceous Sinter. Alge sinter.—This action of plant life consists in the abstrac- tion of silica from the hot spring waters, by the vital processes of the algous vegetation, and in its deposition as a stiff gelat- inous substance, occurring in a great variety of forms. This material, seemingly an inorganic deposit of gelatinous silica, con- sists of the siliceous filaments of various species of alge, and their slimy envelope. Upon the death of the alge this jelly loses part of its water, becoming cheesy in consistency and gradually hardening, and with a further separation of silica owing to the action of the decaying vegetable matter upon the water, it becomes a hard stony mass of sinter. If, however, a mass of the algous jelly be removed from the water and dried in the sun, it becomes a very light, pinkish material, containing about 94 per cent of silica, three to four per cent of water and one to two per cent cf organic matter, with a little alumina—showing it to have the composition of a very pure siliceous sinter. That vegetable life can exist in highly heated waters is well known to botanists. In the Yellowstone springs the maximum temperature at which vegetable life has been found is 185° F., only 13 degrees below the boiling point at this altitude, and algous growths are very common in the alkaline waters of the Geyser Basins—forming a brilliant and beautiful feature of the springs and their deposits. With rare exceptions the yellow and salmon tints of the geyser pools and the reds, orange, greens and browns of the hot springs are produced by algous vegetation. The clearest case of sinter formation by algous life is that shown by a species of Leptothrix, forming thick masses of jelly, often assuming columnar, and vase-shaped forms, in the areas overflowed by the Black Sand, and Emerald Springs, at the Upper Geyser Basin. Here we have the conditions most favorable for the development of this form, viz: a constant volume and temperature of the overflow, and a gently sloping surface. Undersuch circumstances the overflow area is first car- peted with a membranous algous sheet, the color depending upon the temperature. From this flooring warty excres- cences grow upward into pillar-like forms of soft jelly, until, reaching the surface of the water, their upward growth ceases, and a lateral development results in the formation of a cap, or “ileus” upon each pillar. These caps uniting, together with the growth of new, and the thickening of older pillars, fill up the channel and dam back the water, forming a little basin. Such growths thus form a series of terraced pools, in which the aleve thrive or die according to the supply and temperature of the water. In such basins one ean see all gradations from the slender spikes of soft jelly to the hard firm sinter into which W. H. Weed—Formation of Siliceous Sinter. 355 they pass. The larger columnar and vase-shaped forms result from a concurrent life and death of the vegetation, the inner layers dying and decaying as the outer coating of living algze increases. This results in the formation of a hardened bony core, whose innumerable thin layers correspond to successive membranes of alge. A pillar several inches in diameter con- sists of such a bony skeleton surrounded by a thin coating of ereen or red jelly. When by reason of changing conditions the algze die, a different species of cooler habitat coats the sur- face with a fuzzy nap and adds its quota of silica, to which is added a further coating of silica by the action of the decom- posing vegetation. The granular coating of silica thus formed rounds off and obscures the original outlines of the pillar, now a hard and solid mass of sinter. This conversion of soft algous jelly into stony material is going on in all the cooler pools, where the algous growth has itself dammed back the water, and diverted the supply. Where the basins are filled with algous forms whose tops uniting form a more or less continu- ous roof, supported by innumerable little pillars, the dull gray- ish surface of the sinter, shows no indication of the nature and origin of the sinter beneath, and may serve in turn as the floor of a new basin, and new growth. Such is the origin of the sinter deposits of Specimen Lake, the Emerald Spring, north of the Grand Geyser, and numerous other parts of the Upper and Lower Geyser Basins. Similar to this in its origin and nature is the sinter, resulting from the growth of thick cushions of algous jelly, abundant during the past sea- son in the area overflowed by the waters of the Beauty, Soli- tary and other springs, a sinter forming the greater part of the mound of the Solitary. Another form of sinter, quite different from those mentioned, but also formed by algous vegetation, is common in all the gey- ser basins. It consists of fibrous layers, 4, to $ inch thick, each layer resembling a thick and short white fur, and formed by the growth of a cedar-red (Calothrix gypsophila), or an olive green (MMastigonema thermale) alga—each formed of, and encrusted with, silica. A bright red alga, Leptothrix ochracea, occurring in hot streams at 110° F. to 130° F., forms thatch-like layers of fibrous sinter, resembling interlacing straw. This sinter is very abun- dant about the Excelsior Geyser, and together with the variety last mentioned forms nearly the whole of the sinter platform of the Midway Geysers. A section of this plateau, exposed in the walls of the great pit of Excelsior, is twelve feet thick and shows 24 strata, each one composed of many layers of one variety of sinter. In this thickness of twelve feet, ten feet are formed of Am. Jour. Sci.—Tuirp Series, VoL. XXXVII, No. 221.—May, 1889. 23 356 W. H. Weed—Formation of Siliceous Sinter. sinter produced by algee, a striking illustration of the proportion of algous sinter of such deposits, while the remaining two feet consist principally of the cemented fragments of the same: varieties of sinter. This preponderance of algous sinter in the deposits of all the geyser basins (save the Norris basin), is due to the greater rapidity with which it is formed. Rate of formation.—Excepting the deposits formed by the highly charged waters of the Norris Basin, which deposit silica very rapidly, the hot spring and geyser waters deposit silica very slowly, by causes other than vegetable life. The beaded deposits which characterize the vents of the geysers, and to which the name geysertte is most properly applied, are formed entirely by evaporation. It is of course difficult to make any estimate of the average rate at which such deposits are formed about the older geysers. Quite recently, however, the development of a quiet “dawg,” a non-boiling spring, into a geyser named the Liberty has afforded an excellent opportu- nity for the study of the rate of formation of this class of sin- ters. A careful examination shows that an average thickness of #, of an inch has been formed in the eighteen months’ activ- ity of this vent. The laminated sinters about many of the springs are less rapidly formed. At the Model Geyser, under very favorable conditions for the formation of sinter by evapo- ration, i.e. alternate wetting and drying of the surface, a deposit formed over a name written upon the surface of the sinter nine years ago, and known to be authentic, is but ;4, of an. inch thick, while more recent names are glazed with a coating of silica of extreme thinness. The salmon-colored floor of a channel near the Castle geyser is liberally inscribed with names. of visitors, and although marring the beauty of the deposit they furnish a record of the rate at which the sinter forms at this place. In this case, moreover, the salmon-pink color is due to: the presence of a fuzz of algee, so that a coating of ;4, to sy of an inch a year, is not due wholly to evaporation. The fibrous sinter forming the floor of the channels of Old Faithful is composed of layers, whose average thickness is 5 of an inch, separated by lines of dense glassy silica. Each layer probably represents a summer’s growth, and the annual thick- ness formed at this place can scarcely exceed ;', of an inch. The algous jellies, however, grow very rapidly—a thickness of four to five inches forming in several months under very favorable conditions, and a thickness of 14 inches in 24 months by actual experiment. Such jellies, deprived of the necessary supply of water, soon harden, and a crust forms on their sur- face by evaporation so that a considerable thickness of this form of sinter may be produced in a comparatively short time: by this agency. W. H. Weed—Formation of Siliceous Sinter. B57 Moss sinter.—Siliceous sinters formed by algous vegetation are common at all the geyser basins of the Yellowstone Park, but so far as known the only places where mosses produce de- posits of siliceous sinter are the Terrace Springs and the springs issuing from the slopes west of the Upper Geyser Basin. At the latter place the hot waters of the Hillside Springs, flow- ing down the steep slopes have deposited their carbonate of lime, and lost much of their silica, by the growth of those brilliant masses of red jelly, which can be seen when several miles dis- tant, coloring the slopes with their brilliant tints. Near the foot of the slope, the water now cooled down to 80° F-, fills a series of terraced basins suggesting those of the Mammoth Hot Spring, but covered with a bright green mossy growth. These basins are formed of a porous, buff-colored sinter composed of the stony forms of the moss covering its surface, which has been deter- mined by Prof. Chas. R. Barnes, of the University of Wiscon- sin as Hypnum aduncum Hedw., var. gracilescens Br. and Sch. Specimens obtained by the writer show the green and living moss passing into the hard siliceous sinter—without break or mterruption. Chemical analysis shows this sinter to have the composition of a typical geyserite; it is undoubtedly formed by the action of the moss—as the composition of the water shows that no silica would be deposited under ordinary circumstances. In physical character, the sinters resulting from algous vege- tation differ from those formed by evaporation or other inor- ganic causes by their greater lightness and opacity. They are often soft and easily crushed, and sometimes soil the fingers ; their structure is readily distinguished from that of other forms of sinter. Chemical analyses by J. Edward Whitfield of three varieties of siliceous sinter from the Upper Geyser Basin are given below. The first 1s a geyserite—a beaded deposit formed by the spray of the Splendid Geyser; the second an algous sinter from the Solitary Spring, the third the sinter formed by the Hypnum from the waters of the Asta Spring. Geyserite. Algee Sinter. Moss Sinter. SOs ene Owen 81°95 93°88 89-72 FeO SOE OE ON a 6-49 1°73 1-02 DIY ce a sg tr. a ee NO (heen 2°56 0-28 aR IGG) ae ed et tan 0°65 0-23 une CxO 0:56 0-25 2-01 MeOn a obits 0°15 0°07 t1 SO rns tha Me 0-16 tee en (OVgia An ames ea hal tr. 0-18 cea EIR Gy eee epee 7°50 3°37 734 358 W. H. Weed—Formation of Siliceous Sinter. The numerous analyses of sinters, made in the Survey Lab- oratory, show that those formed by mosses and algous vegeta- tion are generally purer than the true geyserite, the latter con- taining more or less clay, resulting from particles in suspension in the geyser waters. The algous sinter does not differ in com- position from the opal sinters produced by the waters of the Coral and other springs at the Norris Basin, nor from the purer geyserites formed by evaporation. Siliceous Sinter from New Zealand. Through the courtesy of Prof. F. W. Clarke I have been enabled to examine a small collection of New Zealand “ geyser- ites” and to compare them with the Yellowstone sinters. The specimens are mainly from the hot springs of Rotorua (or Ohinemutu), where the waters, long used by the Maori for cooking and bathing, are now utilized for a government sanita- rium. The collection embraces a number of varieties of sinters: true geyserites, formed by the evaporation of spattered drops of water; incrustation sinters, resembling a crushed handful of hay converted into silica; opal sinter and hot spring sandstones. Besides these varieties there are two specimens whose struc- ture indicates that the algous vegetation of the New Zealand waters produces siliceous sinter. These specimens are, however, quite unlike; the first resembles the sinter resulting from the growth of membranous sheets of red or green algee, a form of vegetation resembling certain species of sea-weeds. Such algous sheets occur in hot waters all over the globe, and are described as “sheets of a slimy confervoid growth” * in the Rotorua wa- ters. The sinter is creamy pink, showing a wavy, very thinly laminated structure, with occasional vesicular blisters lined with red and green patches, presumably the remains of alge. It so very closely resembles sinters, whose algons origin is known, that a similar origin seems probable. An analysis of this specimen is given in the table following. The second specimen is quite different in structure, consist- ing of several layers of fibrous silica, the fibers all perpendic- ular, and resembling a very fine, short and thick white fur. This sinter is exactly like the algous sinter forming the floor of the channels of the Old Faithful geyser and making one-half of the section of 12 feet of sinter exposed in the walls of the Excelsior, and there seems no reason for doubting that it has been formed in the same way. The following analyses of New Zealand sinters have been made by Mr. J. Edward Whitfield, of the Survey Laboratory. * Skey, Trans. N. Z. Inst., vol. x, p. 433. W. Upham—Marine Shells in the Boston Till. 359 Algous Pulverulent Geyserite. sinter? deposit. SL Oe EG ees el 90°28 92°47 74°63 NOS Sanne Samm 3°00 2°54 15°59 (EO). ee I ty 0°44 0°79 1°00 JN ox Oasys a ie lla trace 0°15 trace ING Ope te ory srr a Sale blips 0°30 ROMO 0k Tae ani want 1-02 omition 422 cae eee 6°24 3°99 7°43 Motalty: Renn ie 99°96 99°94 99°97 The first is typical geyserite, undoubtedly an evaporation de- posit; the second is the laminated sinter already alluded to. The third is a pure white pulverulent deposit resembling a block of diatomaceous earth, but composed of impalpable par- ticles of glass. Its composition corresponds to that of rhyolite (the rock from which the Rotorua waters also issue) with the alkalies leached out and replaced by water. Summary. The study of the origin of the deposits of siliceous sinter found in the Yellowstone proves that they are largely formed by the vegetation of the hot spring waters. Waters too poor in silica to form sinter deposits by any other cause may be ac- companied by beds of siliceous sinter formed by plant life. The extent and thickness of these deposits establishes the importance of this form of life as a geological agent. Washington, D. C., Jan. 20, 1889. Art. XXXVIII.—WMarine Shells and Fragments of Shells in the Tilt near Boston; by WARREN UPHAM. [Read before the Boston Society of Natural History, Dec. 19, 1888.] THE fossils here described, occurring in drift deposits near Boston, and belonging wholly to species that are still living in Massachusetts bay, have been previously noticed by several ob- servers, who have regarded them as evidence of a marine submergence within the Pleistocene or Quaternary period. Instead of this, my observations made during the past summer and autumn show that these fossils were transported from the bed of the sea on the north by the ice-sheet in the same man- ner as the materials of the drift, including its bowlders and rock fragments, large and small, have been carried various dis- tances from north to south, being often deposited at higher elevations than the localities from which they were brought. 360 W. Upham—Marine Shells and Fragments These glacially transported shells and fragments of shells can- not therefore be regarded as proof of the former presence of the sea at the height where they are found. So long ago as during the Revolutionary war a fort was built on the top of Telegraph hill, in Hull, near the extremity of the peninsula of Nantasket, and a well was dug inside the fort, of which the commander, Gen. Benjamin Lincoln, wrote as fol- lows.* “There is a large fort on the E. Hill, in which there is a well sunk 90 feet, which commonly contains 80 odd feet of water. In digging the well the workmen found many shells, smooth stones, and different stratas of sand and clay, similar to those on the beach adjoining to the hill. These shells and appearances were discovered from near the top of the ground to the bottom of the well.” Again, nearly forty years ago, Dr. William Stimpson col- lected fragments of shells, representing fourteen species, from the cliffs of drift which form the east and west sides of Win- throp Head, or, as it is more commonly called, Great Head on the Point Shirley peninsula of Winthrop, then a part of Chelsea.t This peninsula has two lenticular hills or drumlins of till, namely, Great Head which rises about 100 feet above the sea, and another, a third of a mile farther south, which may be more properly called the Point Shirley hill, about 60 feet high. It seems clear, from Stimpson’s description of the sec- tions where his shells were obtained, that they belonged to the higher one of these hills, which at the present time is being undermined by the sea. The southern hill, nearer to Point Shirley, is not sufficiently high to agree with his description, and moreover its eroded eastern cliff is separated from the ocean by a low tract of beach gravel and sand 20 to 40 rods wide, so that probably within the present century it has not . presented any freshly exposed section. Stimpson also reports that at some little distance from the place where he discovered these fossils, the digging of a well encountered shells in the drift at a depth of 50 feet below the level of high tide. Seventy years ago it was recorded that fragments of clam shells had been found 40 feet below the surface at Jamaica Plain, and at the depth of 107 feet in dig- ging the well at Fort Strong, which was built in 1814 on Noddle’s island, now East Boston.{ About twenty years ago, in digging a well in Fort Warren, on George’s island, shells * Geographical Gazetteer of the Towns in the Commonwealth of Massachusetts, 1785, p. 56. (Only a small part of this work was published.) + Proceedings of the Boston Society of Natural History, vol. iv, p. 9, January 15, 1851. t Outlines of the Mineralogy and Geology of Boston and its vicinity, with a geological map. By J. Freeman Dana, M.D., and Samuel L. Dana, M.D., 1818. 96. Pp. of Shells in the Tull near Boston. 361 were found 100 feet below the surface and about 40 feet below the sea level.* An article published last summer by Mr. W. W. Dodge,t describing the section of the sea-cliff of Great Head, Winthrop, and noting its fossil shell fragments, specially directed my attention to this subject. An examination of Great Head and of the lower drumlin at Point Shirley convinced me, as before stated, that the former was the locality of Dr. Stimpson’s earlier and widely known observations. Mr. Dodge also in- formed me of the occurrence of similar shell fragments in ‘Grover’s cliff on the northeast shore of Winthrop, nearly one and a half miles north of Great Head. My observations have included these drift sections and others in Winthrop, Revere, Chelsea, and thence southwest and south around Boston harbor, on several of the islands in the harbor, on the peninsula of Hull and Nantasket, and in Hingham, Cohasset, and Scituate. In only a small proportion of the whole number of sections examined were glacially transported shells and fragments of shells observed, these being found in Grover’s cliff and Great Head, Winthrop, on Long island, Moon, Peddock’s and Nut islands, in Quincy Great hill, in the drumlin forming the north shore of Hull close northwest of Telegraph hill, and in Sagamore Head, which rises from the Nantasket beach. All the other sections seen failed to yield any trace of organic remains, excepting that scanty fragments of lignite were found along an extent of two or three feet in the modified drift forming the base of the drumlin of Third cliff in Scituate by Prof. Crosby and Mr. Bouvé, who accom- panied me in an excursion there. Without doubt, however, such transported shell fragments will be found in many other drumlins on islands in the harbor and on its eastern and southern shores, where they should be looked for in any deep section of the till, as in digging wells and in cliffs undermined by the sea. The area where shells and fragments of shells are known to occur in the till has an extent of ten or eleven miles from northwest to southeast, reaching from East Boston and Grover’s cliff to Sagamore Head, with a width of three or four miles, if not more, its eastern limit, which is the open ocean, being at a distance of four and a half miles east-northeast and eleven miles east-southeast of Boston. The fossiliferous sections are all in lenticular hills of till, like the drumlins of Great Britain, which name is now adopted for them. These hills have a very fine . * Reported by Mr. W.-H. Niles in the Proceedings B.S. N. H., vol. xii, 1869, pp. 244 and 364. In commenting on this discovery, Mr. T. T. Bouvé read a letter from a gentleman in Hull, noting similar facts known to him in his own vicinity. (p. 364.) + This Journal, III, vol. xxxvi, p. 56, July, 1888. 362 W. Upham—Marine Shells and Fragments development upon most of the country in the neighborhood of Boston, rising with smooth, ovally rounded contour to heights from 50 to 200 feet, and have been the subject of several papers before this Society. s Approximate elevations of the drumlins in which fossils have been found are as follows: Grover’s cliff, 60 feet above the sea; Great Head, 100 feet; Eagle hill, East Boston, 120 feet; nor th end of Long island, 5 feet ; George? s island, 60 feet ; Moon island, 100 feet ; nor th end of Peddock’s island, 70 feet ; Nut island, 40 feet; Quincy Great hill, 100 feet ; on the north shore of Hull, 80 feet ; Telegraph hill, 125 feet: and Sagamore Head, 65 feet. The cliffs eroded by the sea on most of these drumlins extend from 10 or 15 feet above mean tide sea level upward very steeply or often in part ver- tically to near their tops. Excepting Great Head, which contains modified drift near its base, to be presently described, these sections consist wholly of till or bowlder-clay, the direct deposit of the ice-sheet, un- modified by the transporting and assorting action of water. Weathering has changed the small ingredient of iron in this deposit from the protoxide combinations which it still retains in the lower part of the till to the hydrous sesquioxide in its upper part for a depth of commonly fifteen or twenty feet from the surface, thereby giving to the latter a yellowish color in contrast with the darker gray or bluish color of the former. Both portions are very compact and hard till, an intimate un- stratified commingling of bowlders, gravel, sand, and clay, and seem by these characters, and by their abundant striated bowl- ders and smaller fragments of stone, to be distinetly the ground moraine of the ice-sheet. The southeast and east- southeast trends of the longer axes of the drumlins in this vicinity, coinciding at least approximately with the direction of striation of the bed- rock, further indicate that these oval hills of till were accumu- lated beneath the ice-sheet, this form being that which would op- pose the least resistance to the glacial current passing over them. Though the till is destitute of stratification, its materials, coarse and fine, from boulders often several feet and occasionally ten feet or more in diameter to the finest rock-fiour, being indis- criminately mixed in the same mass, it yet generally shows an obscure lamination in parallelism with the surface, having thus. in the drumlins an inclination like that of their slopes. This structure is best displayed after some exposure of the section to the action of the weather. Itseems to be an imperfect cleavage * By Prof. N. S. Shaler, Proceedings B. S. N. H., vol. xiii, pp. 198-203; by Prof. C. H. Hitchcock, vol. xix, pp.63-67 ; and by the present writer, vol. xx, pp- 220-234. Also, see Geology of New Hampshire, vol. iii, pp. 285-309; ‘The Distribution and Origin of Drumlins,” by W. M. Davis, in this Journal, III, vol. xxviii, pp. 407-416, Dec. 1884; and Jllustrations of the Earth’s Surface: Glaciers, by Professors Shaler and Davis, Plate xxiv. of Shells in the Tull near Boston. 363 resulting from the enormous pressure of the overlying ice, and also indicates that the accumulation of the drumlins took place by gradual addition of till over their surface. Only a thin layer of englacial till, with its numerous large bowlders, con- tained within the ice-sheet and allowed to fall loosely from it during its final melting, is observable upon these drumlins, its probable thickness in this vicinity being not usually more than one or two feet. Plentiful fragments of shells, up to one or two inches in length and rarely of larger size, are imbedded, like the small fragments of rock, in the dark lower portion of the till. They were found most abundant in Grover’s cliff, Great Head, Ped- dock’s island, and the northern cliff of Hull, one or several shell fragments being usually seen on each square yard of the exposed surface, so that hundreds may be gathered in an hour. In all the localities a single species, the round clam or quohog, Venus mercenaria L., makes up probably ninety-nine per cent. of the specimens found ; but no entire valve of this shell was obtained among the thousands of its fragments. The spe- cies next in numbers is Cyclocardia borealis Conrad, which, like the foregoing, is thicker and stronger than most species and therefore better fitted to resist the grinding action of the ice. The smaller size of the latter has enabled some of its specimens to escape almost unbroken and with only slight abrasion of its margin. In no instance, however, have the two valves of this or any other species been found united. Some of the fragments show little wearing or none, their broken edges being sharp and the markings of their surface perfectly preserved ; but the majority are considerably worn, and pieces perforated by burrows, like the dead shells cast up on a beach, are frequently found. No glacial striation has been detected on any of these shell fragments, and indeed it is rarely observ- able on pieces of stone of so small size. The cliff at the northeast end of Peddock’s island, though not showing more of the large fragments than the other locali- ties specially mentioned for their abundance, yet far surpasses these in its multitude of very small fragments and even minute particles of shells, from a quarter and an eighth of an inch in length down to the least speck visible to the eye. In one place, by no means exceptional, near the base of this cliff, the number of these particles and specks of shells, ground up in the process of formation and deposition of the till, averaged not less than forty to each square foot of the section. This locality, too, is the only one where the shell fragments were observed in the yellowish upper part of the till nearer to the original surface than a depth of ten or fifteen feet. Here small fragments of shells, an inch or less in length, were found in considerable 364 W. Upham—Marine Shells and Fragments numbers to a height only one or two feet below the sod forming the surface of the hill and brink of the cliff. The highest were in a soft and crumbling condition, and those found thence downward in the yellow till showed a gradation to the hard and strong character of the shell fragments in the dark blue till. These observations indicate that the transported and bro- ken fossils were probably originally as plentiful in the upper as in the lower part of this drumlin, and perhaps likewise of all the others, but that they have been mostly dissolved out of the upper part by infiltrating water. Great Head is a typical drumlin, the eastern third of which has been eroded by the sea, forming a cliff about 100 feet high. This consists of ordinary till, yellowish above and dark bluish below, from its top to within 20 or 15 feet above mean tide, where its base, exposed a few years ago during the construction of a railroad, was observed by Mr. Dodge to be a somewhat arched bed of “loose, clean, rather fine gravel filled with small fragments of shells. Venus mercenaria and Cardium TLslan- dicum (2) were the only shells identifiable with any reasonable degree of certainty among the fragments.” This was seen to be overlain by till, which exhibited traces of an imperfect strati- fication close to their line of separation but above is entirely unstratified. The till contains fragments of shells up to a height of about 80 feet. A similar structure of the drumlins of Third and Fourth cliffs on the east shore of Scituate, each of which includes extensive anticlinal beds of modified drift, overlain by a thick covering of till, and in Fourth cliff also seen to be underlain by till and interbedded with it, promises to contribute much to our knowledge of the mode of deposition of these remarkable drift hills, as I shall hope to show in a future paper. Following the nomenclature and arrangement of the cata- logue of the marine invertebrate animals of the southern coast of New England and adjacent waters, by Verrill, Smith, and Harger,* the species represented by these fragments of shells in the drumlins near Boston are noted in the following table. Those marked by asterisks in the first column have been c¢ol- lected in Grover’s cliff, the most northern section yielding these fossils. In the second column are those found in Great Head, mostly by Dr. Stimpson, to whose list Mr. Dodge has added, somewhat doubtfully, three species. An hour’s search there by Mr. Q. E. Dickerman and myself was rewarded by frag- ments of Venus mercenaria, abundant; M/ya arenaria and Cyclocardia borealis, frequent; Astarte wndata, rare; and a * United States Fish Commission, Report of 1871-72. This work and Gould’s Invertebrata of Massachusetts give notes of the geographic range of our species, living and fossil, and of the situations and depths at which they occur. of Shells in the Till near Boston. 365 columella, perhaps of Chrysodomus decemcostatus. In the third column are the species found in the cliff of Moon island ; in the fourth column, those obtained from the well at Fort Warren; in the fifth, those of Peddock’s island; and in the sixth, those of the northern cliff in Hull. At the other locali- ties only Venus mercenaria was found in the limited time available for search. List of Species in the Till near Boston. i) w i nr fer) Species. 1 BalanMuUsMcrenatus., Bruce UieLe ene Meee eee sl ae ae Chrysodomus decemcostatus, Say ..------..---------- aI Thierry berbel PACGL eprint poe perp ee ene n= Ay ae Wrosalpinxi cinerea; Stimpy Ss Orsi appa Ne aay aS) Seas ILIA) INGRORY MACKIE eee ene hh a ae * Lacuna neritoidea, Gould (?)-------- Poel ND aye A pS Saxicayalarctica Weshayes sue jue Ou nt Vue ON Wee < Mayakanenariagliimne Silas scans i bee ek eae kya HinsatellaeAin et Camm arya Vie Pill ema reps yay ayes sn eee ia Mactraisolidissima, Chemnitz 222 2.02 Sans asta WGN maveroe ine Ibo) oe en i x VAP ESPHITCtIOSasySOWelDiyis (2) ee apse ns sete eee ea Carcdiumylislandicum, Tinne (2) 2 se C@yclocardiagoorealisn( Comma dessa) s yee pe ene a pain 2 A\ ayer waco enrl (Croyulel es ee Ae a el se Astarte castanea, Say Woyapohoiss GGlMMbeL Ibvavanes 2 os ee Modiolaimodiolusyiurtones see ens sansa ees eee Rectenlislandicusy| Chemnitz = 092 sey yates edu Uagn ea BH Ostrea Virginiana, Lister Cliona sulphurea, Verrill kX RK * xX * RX KR KK KX *% Ke * * % * All these species, which remain from the marine fauna that existed before the formation of the last ice-sheet upon this area, excepting one whose determination is doubtful, are found living at the present time in the adjoining waters of Massa- chusetts bay. Stimpson wrote of his collection: “ With the exception of Venus mercenaria, I have obtained all of them in a living state by dredging within a mile of the locality where they are now found fossil.” Nor are any noteworthy differ- ences observable between these fossils and the living shells, excepting that the Venus mercenaria belongs, like most of the fossils of this species in Sankoty Head, Nantucket, to the very massive and strongly sculptured form, probably not to be re- garded as a distinct variety, which still survives in the waters of Nantucket.* Four species in this list attain their southern limit at Cape Cod: and one, Tapes fluctuosa, is not reported south of Nova Scotia and the Fishing Banks. The remaining sixteen have a * This Journal, III, vol. x, 1875, pp. 369, 371. 366 W. Upham—Marine Shells and Fragments range beyond Cape Cod. In northward range, five extend only to the Gulf of St. Lawrence; and three of these, namely, Urosalpinx cinerea, Venus mercenaria, and Ostrea Virginiana, occur only in isolated colonies north of Massachusetts bay. Another, Astarte castanea, has its northern limits on the coast of Nova Scotia and at Sable island; while the burrowing sponge, Cliona sulphurea, is not reported beyond Portland. Fourteen are more boreal, of which four continue to Labrador, and ten to the Arctic ocean. The great abundance of the round clam, Venus mercenaria, which is now scarce in Massachusetts bay but plentiful south of Cape Cod, indicates that the sea here during part of the epoch just preceding the last glaciation was warmer than at the present time.* Similarly, the colonies of this and associated southern species, scattered here and there northward to the Bay of Chaleurs, are evidence that since this last glacial epoch the sea has been again warmer than now along this coast, per- mitting these species to advance so far to the north. The in- termingling of characteristic southern and northern forms in this assemblage of fossils from the till seems to be readily accounted for by the gradual refrigeration of climate which culminated in the formation of the ice-sheet. Before that time the round clam or quohog and other shells of chiefly southern range were doubtless succeeded by a wholly boreal and arctic marine fauna. In the Pleistocene beds containing fossil shells on Gardiner’s islandt and at Sankoty Head,t which are refer- able to the same epoch with these near Boston, namely, the interglacial epoch preceding the latest glaciation, the round clam occurs in abundance; but it has not been discovered fossil north of the sections here described, which indeed are the most northern yet found in northeastern America holding fossils of interglacial age. It has not been found in the plentiful fauna of the marine beds of modified drift deposited in southern Maine during the departure of the last ice-sheet, nor in the scantily fossiliferous continuation of these beds southward to Portsmouth, Gloucester, and Cambridge. Nearly all the species of our list inhabit the shore or shallow water, from low tide to the depth of a few fathoms, though * From the same evidence and the occurrence of other species elsewhere in the Pleistocene deposits of the eastern United States north of their present range, Desor announced in 1847 to the Geological Society of France (Bulletin, vol. v, p. 91) and in 1852 in this Journal, (II, vol. xiv, pp. 52, 53) that a warmer climate then prevailed throughout this whole district. + Sanderson Smith in Annals of the Lyceum of Natural History of New York, vol. viii, 1867, pp. 149-151; F J. H. Merrill in Annals of the New York Academy of Sciences, vol. ili, 1886, p. 354, with sections on Plate xxvii. t Desor and Cabot in Quarterly Journal of the Geological Society, London, vol. v, 1849, pp. 340-344, partly quoted by Packard in Memoirs B. 8. N. H., vol. i, pp. 252-3; Verrill and Scudder in this Journal, III, vol. x, 1875, pp. 364-375. of Shells in the Till near Boston. 367 some of these also range downward to considerable depths. Three, of which two are doubtfully determined, are probably restricted to comparatively deep water; but even these are often cast ashore in severe storms. Considering the outlines of our eastern coast and the direction of the motion of the ice-sheet, it seems probable that these fossils were living along the shore and in the shallow edge of the sea on the area be- tween the mouths of the Charles and Saugus rivers. In that interglacial epoch the drumlins of this district had not been accumulated, and the greater part of Chelsea, Revere, and Winthrop, formed of these and other deposits of glacial and modified drift, may then have been sea of similar depth with the present harbor of Boston or the part of Massachusetts bay between Winthrop and Nahant. From this tract the south- easterly moving ice-sheet, plowing up the marine beds and their inclosed shells, with those then tenanting the sea, carried them forward to form a portion of the till of the drumlins. That the sea-bottom from which these shells were derived had been shallow is evident from the predominance of the round clam, which, according to Professor Verrill, is seldom found in any abundance below five fathoms. Glacially transported shells and fragments of shells have been previously observed in till at Brooklyn, N. Y., where E. Desor and W. C. Redfield gathered fragments of the round and long clams, oyster, and other species, ‘imbedded in a reddish loam intermixed with pebbles and bowlders, many of which are distinctly scratched ;’* and in till, or at least de- posits of clay enclosing numerous stones and bowlders, on the lower part of the St. Lawrence river, from the vicinity of Quebec northeastward more than a hundred miles, chiefly on the southeastern shore, to opposite the mouth of the Saguenay.t But the descriptions of these beds containing shells and bowl- ders on the St. Lawrence indicates that they were mostly, if not altogether, deposited by water with floating ice during the recession of the ice-sheet, while these marine shells lived where they are now found, being thus comparable with the fossilifer- ous, bowlder-bearing brick-clay of Paisley, Scotland.t In the modified drift forming Cape Cod, derived from the melting ice-sheet in which it had been contained, I collected ten years ago fragments representing sixteen species of shells, all now living, eight of which appear also in the foregoing list.§ * Bulletin de la Société Géologique de France, second series, vol. v, 1847, pp. 89, 90; Quart. Journ. Geol. Soc., vol. v, p. 343; Am. Jour. Sci., I, vol. xiv, 1852, 51 i + J. W. Dawson’s Notes on the Post-pliocene Geology of Canada, 1872, pp. 7, 45, and 50-53. ¢ T. F. Jamieson in Quart. Journ. Geol. Soc., vol. xxi, 1865, pp. 175-177. § American Naturalist, vol. xiii, 1879, p. 560. 368 W. Upham—Marine Shells and Fragments Looking over the various lists of Pleistocene fossils found on Gardiner’s island and in Sankoty Head under the drift of the last ice-sheet, in these drumlins of till near Boston, and in the modified drift of the glacial recession thence northward to Maine, New Brunswick, and the valley of the St. Lawrence, we cannot fail to be surprised that all these are still living in the adjoining ocean to-day. So recent was the glacial period* that none of them has become extinct, nor, with very rare ex- ceptions, undergone any noteworthy change in form or size. But the vicissitudes to which they were exposed during the last of our two principal glacial epochs, when the ice-sheets east of the Alleghenies advanced farther than in the earlier glaciation, were doubtless well adapted to cause both extinctions and mod- ifications of species. How vast then must be the duration of the time occupied in the evolution of the complex faunas and floras of our globe, and in the formation of all the fossiliferous groups of rocks since the dawn of terrestrial life ! In various parts of Great britain such transported Pleisto- cene shells are found in the till, both in its low and smooth tractst and in its hilly and knolly terminal moraines traced by Professor Lewis, as well as in the associated kames.{ Some of these fossiliferous glacial deposits occur in Ireland, northern Wales and northwestern England at heights 1,100 to 1,350 feet above the sea, and have been generally considered as proof of marine submergence to that depth. Instead of this, Lewis has shown§ that the shells and fragments of shells found there were brought by the currents of the confluent ice-sheet which flowed southward from Scotland and northern Ireland, passing over the bottom of the Irish sea, there plowing up its marine deposits and shells, and carrying them upward as glacial drift to these elevations, so that they afford no testimony of the for- mer subsidence of the land. This removes one of the most perplexing questions that glacialists have encountered ; for no- where else in the British Isles is there proof of any such sub- mergence during or since the glacial period, the maximum known being 510 feet near Airdrie in Lanarkshire, Scotland.| At the same time the submergence on the southern coast of England was only from 10 to 60 feet,4] while no traces of raised * Compare Proceedings B. 8. N. H., vol. xxiii, 1887, p. 446. + Geikie’s Great Ice Age, second ed., pp. 164-185, and 337-340. t Quart. Journ. Geol. Soc., vol. xxx, 1874, pp. 27-42; xxxiv, 1878, pp. 383-397; xxxvi, 1880, pp. 351-5; xxxvii, 1881, pp. 351-369; and xliii, 1887, pp. 73-120; also, Geological Magazine, II, vol. i, 1874, pp. 193-197. § Report of the British Association for Ady. of Sci., Birmingham, 1886, pp. 632-635; Am. Naturalist, vol. xx, pp. 919-925, Nov., 1886; this Journal, III, vol. xxxii, pp. 433-438, Dec., 1886. Also, see the American Geologist, vol. ii, pp. 371-379, Dec., 1888. || Quart. Journ. Geol. Soc., vol. vi, 1850, pp. 386-8; xxi, 1865, pp. 219-221. § Quart. Journ. Geol. Soc., xxxiv, 1878, pp. 454-7; xxxix, 1883, p. 54. Geol. Mag., II, vol. ii, 1875, p. 229; II, vi, 1879, pp. 166-172. of Shells in the Till near Boston. 369 beaches or of Pleistocene marine formations above the present sea level are found in the Shetland and Orkney islands.* The occurrence of transported marine fossils in the till near Boston shows that during the epoch preceding the latest glacia- tion the North American coast in this latitude was not higher than now in relation to the sea; for in that case no marine de- posits and shells would have existed here to be eroded by the southeasterly moving ice-sheet and incorporated in its drift ac- cumulations. Conversely, we know that the land then was not appreciably lower than now, in other words, that there was no considerable submergence of the border of our present land area; for this would have led to the intermingling of such broken sea-shells with the glacial drift farther inland, where no trace of themisfound. So it appears that the relative levels of land and sea here were closely the same before the last glacial epoch as at the present time. The chief element of my interest in this subject has been a hope that its bearing thus on the oscillations of land and sea during the Quaternary period would contribute to the solution of the question whether the northward ascent of the beaches of the glacial Lake Agassiz, assigned to me for investigation in the United States Geological Survey, is to be explained mainly by northward attraction of the water of that lake in gravitation toward the ice-sheet, or mainly by a depression of the earth’s crust beneath the vast weight of the ice and its re- elevation when the weight was removed. In this study of our Atlantic coast, I have therefore sought to connect these obser- vations near Boston with the allied evidence supplied by other Pleistocene marine fossils both south and north of our latitude. Some of the conclusions to which this correlation seems to lead I will endeavor to state briefly. As before noted, itis only toward the south that we find Pleistocene fossiliferous beds antedating the last epoch of glaciation, when an ice-sheet covered all New England. They occur in Sankoty Head and on Gardiner’s island at elevations respectively about 80 and 15 feet above the sea, and in numer- ous localities on Long Island from the sea level up to eleva- tions of about 200 feet. But at least the higher of these beds appear to have been “upheaved by the lateral pressure of the ice-sheet and thrown into a series of marked folds at right angles to the line of glacial advance,” as shown by Merrill ;+ and he finds that this uplifting and folding is also very distinctly seen in the strata underlying the glacial drift on Gardiner’s island, so that the fossiliferous layer there, though raised little above the sea level, is probably higher than its original position. * Quart. Journ. Geol. Soc., xxxv, 1879, p. 810; xxxvi, 1880, p. 663. + Annals of the New York Academy of Natural Sciences, vol. iii, 1886, pp. 341-364, with sections and map. 370 W. Upham—Marine Shells and Fragments To such glacial thrust and uplifting I would attribute likewise the tilted condition of the beds forming the base of Sankoty Head and the elevation of the included lay ers of shells. More than this, | believe that the same cause will account for the elevation and folding of the wonderful section of steeply in- clined Miocene strata which underlie the terminal moraine in Gay Head.* It may well be true, therefore, so far as paleonto- logic evidence can inform us, that this part of our coast, ex- tending south to the farthest limit reached by the continental ice-sheet, held approximately the same relation to the sea level in preglacial and interglacial time as now.t During the final melting of the ice-sheet, however, the land was higher, or, as I would prefer to say, the sea was lower than now, as is shown by channels of drainage, which extend southward from the terminal moraines across the bordering plains of modified drift of Long Island, Martha’s Vineyard, Nantucket, and Cape Cod, continuing beneath our present sea level.t Nor have we any proof in marine beds overlying the glacial drift that the sea there has stood higher than now at any time since the glacial eriod. ; Near Boston and northeast to Cape Ann the coast seems to have been submerged to a slight depth, probably not exceed- ing 10 to 25 feet, when the ice-sheet retreated from this area.§ In New Hampshire this submergence amounted to 75 feet or more, and the fossils in the marine beds overlying the glacial drift, being partly of arctic and partly of temperate range, show that the severe climate of the glacial period was gradually changed until the ocean became as warm as now before it sank to its present level.| After this the ocean within recent times has held even a somewhat lower level than at present, and seems to be now very slowly rising upon this shore and in- deed along the entire coast from New Jersey to the Gulf of St. Lawrence, as is shown by submerged stumps of trees in * Hitchcock’s Geology of Massachusetts, 1841; Lyell’s Travels in North Amer- ica in 1841-2, vol. 1, pp. 203-6. + The fossils in South Marshfield and Duxbury, Mass., which I once referred to the Pleistocene (Am. Naturalist, vol. xiii, p 557), extend back to the Miocene in the Southern States, and seem more probably to be of similar age with the beds of Gay Head (Hitchcock’s Geology of Mass., 1833, pp. 199-201; do, 1841, pp. 91, 427). ¢ This Journal, ITI, vol. xiii, 1877, pp. 142-146, and 215; vol. xviii, 1879, pp. 89, and 198-205. Am. Naturalist, vol. xiii, 1879, p. 553. § Evidenced by layers of shells of the common or long clam, mussel, oyster, and other species at Lechmere Point in Cambridge (Outlines of the Mineralogy and Geology of Boston, before cited, p. 96), and by fossils discovered by Profes- sor Shaler at Gloucester, Mass. (Proceedings B.S. N. H., vol. xi, 1868, pp. 27-30). In the same notice with the former of these localities, the authors men- tion a stratum of clam shells, observed on the side of a hill in Cambridge at the distance of a half mile from the Charles river, which seems from its description to be probably an aboriginal kitchen-midden. || Geology of New Hampshire, vol. iii, pp. 165-7. of Shells in the Till near Boston. 371 many localities, rooted in the ground where they grew, and by tracts of marsh and peat-swamps covered by the sea.* During part of the time of lower level of the sea, its temperature was apparently warmer, as indicated by the range of Venus mer- cenaria with other southern species northward to the Gulf of St. Lawrence, though now it is wanting along most of the shore of Maine, the Bay of Fundy, and Nova Scotia. Proceeding from Boston toward the north and northwest, the elevation of fossiliferous marine beds lying on the glacial drift increases to about 225 feet in Maine, about 520 feet in the St. Lawrence valley at Montreal, and 440 feet at a dis- tance of 130 miles west-southwest of Montreal; but eastward along the St. Lawrence it decreases to 375 feet opposite the Saguenay, and does not exceed 200 feet in the basin of the Bay of Chaleurs, while these marine deposits are wanting in Nova Scotia and Cape Breton island.t The changed condition in the relative heights of land and sea at the time of the recession of the ice-sheet thus caused the land to be submerged in in- creasing amount northwestward from a line drawn through Nova Scotia, Boston, and New York. This condition, due probably in part to depression of the land and in part to up- lifting of the sea level by gravitation, seems to have been caused by the ice-sheet, which had its greatest thickness, esti- mated by Dana to be not less than two miles, on the highlands between the St. Lawrence and Hudson bay, where its influ- ence to produce such changes of level would be greatest. The submergence seems to have been more than can be wholly at- tributed to gravitation of the sea toward the ice-sheet ;+ but it is much less than would be expected for agreement with the views advanced by Jamieson§ and Shaler,| that the ice-sheet must depress the earth’s crust to a vertical extent approximately measured by a thickness of rock equal to the ice in weight. * Outlines of the Min. and Geol. of Boston, p. 95; Memoirs B. 8. N. H., vol. i, p. 324; Quart. Journ. Geol. Soc., vol. xvii, 1861, pp. 381-8; Geol. of N. H., vol. iii, p. 173; J. W. Dawson’s Acadian Geology, third ed., 1878, pp. 28-32, and Supplement of do., pp. 13-17. + A. S. Packard, jr., in Memoirs B. 8. N. H., vol. i, pp. 231-262." J. W. Daw- son in Notes on the Post-pliocene Geology of Canada; and Am. Jour. Sci., ITI, vol. xxv, 1883, pp. 200-202. C. H. Hitchcock in Proc., Amer. Assoc. for Adv. of Sci., Portland, 1873, vol. xxii, pp. 169-175; Geol. of N. H., vol. iii, pp. 279-282; and Geol. Mag., II, vol. vi, 1879, pp. 248-250. R. Chalmers in Transactions of the Royal Society of Canada, sec. iv, 1886, pp. 139-145. + Sixth Annual Report U.S. Geol. Survey, 1885, pp. 291-300. § Quart. Journ. Geol. Soc., vol. xxi, 1865, p. 178. Geol. Mag., II, vol. ix, Sept. and Oct., 1882; and III, vol. iv, Aug., 1887. Also, see Fisher’s Physics of the Earth’s Crust, and Geol. Mag., II, ix, p. 526. || Proceedings B. S. N. H., vol. xii, 1868, pp. 128-136; and xxiii, 1884, pp. 36-44, Memoirs B.S. N. H., vol. i, 1874, pp. 320-340. Am. Jour. Sci., III, vol. xxiii, 1887, pp. 210-221. Lowell Lectures, Nov. and Dec., 1888. Am. Jour. Sci.—THIrD SERIES, VOL. XXXVII, No. 221.—May, 1889. 24 372 Clarke and Catlett—Nickel Ore from Canada. Besides the testimony of marine fossils, one further obser- vation contributes greatly to our knowledge of the relation of land and sea on the south side of Massachusetts bay while this area was enveloped by the continential glacier. On the shore of a peninsula in Cohasset Little Harbor, fifteen miles south- east of Boston, pot-holes similar to those of water-falls on rivers are found in two localities, reaching from sea level to a_ height of fifteen feet. The contour of their vicinity precludes the possibility of referring their origin to any stream since the close of the glacial period ; and they must doubtless be attrib- uted to the action of a water-fall plunging down hundreds of feet through a moulin of the ice sheet.* To Mr. Bouvé, long the president of this Society, belongs the honor of first observ- ing these pot-holes and appreciating their significance. It was under his guidanee that my visit to them was made ; and it is with his permission that I speak of them here, previous to the detailed description which he will later present before the Society. Such water-wearing of the bed-rock could not take place beneath the sea level, so that they prove that here during a part, probably the later part, of the time when this area was covered by the ice-sheet, the land stood at least as high as now, not being depressed under its vast weight. Art. XXXIX.—A Platiniferous Nickel Ore from Canada ; by F. W. CLARKE and CHARLES CATLETT. DURING the autumn of 1888 we received, through two dif- ferent channels, samples of nickel ores taken from the mines of the Canadian Copper Co. at Sudbury, Ont. From one source we obtained two masses of sulphides, to be examined for nickel and copper; from the other source came similar sul- phides, together with a_series of soil and gravel-like material, seven samples in all. In the latter case an examination for platinum was requested, and in five of the samples it was found, the gravel above mentioned yielding 74°85 oz. of met- als of the platinum group to the ton of 2000 ibs. At the out- set of the investigation we were decidedly incredulous as to the existence of platinum in such ores; but the discovery of sper- rylite by Mr. Wells in material from the same mines gave our work a wholesome stimulus, and the assays were carefully ear- ried through. The sulphide ores submitted to us from Sudbury were all of similar character. They consisted of mixed masses, in which a gray readily tarnishing substance was predominant, with * Compare Quart, Journ. Geol. Soc., vol. xxx, 1874, pp. 750-771. i ito uy Clarke and Catlett—Nickel Ore from Canada. 878 some chalcopyrite, possibly some pyrite, and a very little quartz. Two samples were examined in mass; one gave 31°41 per cent of nickel with a little copper, the other gave 85°39 per cent of nickel and 5:20 of copper. The nickel mineral itself proved to be a sulphide of nickel and iron, and as ores of that composition are not common, it was thought desirable to examine the substance further. As above stated, the nickel mineral is the predominating constituent of the masses submitted for examination. It is steel-gray, massive, and exceedingly alterable in the air, and its specific gravity, determined by pycnometer, is 4541. An analysis of carefully selected material gave the following re- sults : TING Tee Era ee PSC 41°96 I pee ee aie ein a TA dh 15°57 SKC) Mera a sea aN 1°02 CSTs Sine hs 62 oy Ae Vi SO EIA 40°80 99°97 Neither cobalt nor arsenic could be detected. The foregoing figures work out sharply into the ratio R:8::4:553 and approximately into the formula Ni,FeS,. If we deduct silica, together with the copper reckoned as admixed chalcopyrite, and recalculate the remainder of the analysis to one hundred per cent we have the following figures: As found. Cale. as NisFeS;. Nf epee eas etal LA 43°18 44°6 IEA aes PLE appa al aM 15°47 14°4 SS AY) ce Ra pe es 41°35 41°0 100°00 100:0 In short, the mineral has the composition Ni,S,, with about one-fourth of the nickel replaced by iron. The only known species with which this agrees is Laspeyres’s polydymite, of which the Sudbury mineral is evidently a ferriferous variety. What relations it may bear toward beyrichite, pyrrhotite, etc., is as yet a matter of considerable uncertainty. Probably in most cases the niccoliferous constituent of pyrrhotite is mill- erite, but other sulphides, like the polydymite, may perhaps occur also. The polydymite which was selected for the above analysis came from the mass in which, in average, 35°39 Ni and 5-20 Cu had previously been found. The mass weighed several kil- ograms, and was remarkably free from quartz. The same mass, with two smaller pieces resembling it, were also examined 374 C.D. Walcott—Position of the Olenellus Fauna. for platinum, by the following method: One assay ton of the finely ground ore was treated with nitric acid until all or prac- tically all of the sulphides had been dissolved. The dried residue was then assayed in the usual manner; except that, to facilitate cupellation, a little pure silver was introduced into the lead button. From the final bead the silver was dissolved out by sulphuric acid, leavin'g the platinum in a finely divided gray powder. The latter dissolved easily in aqua regia, and gave all the reactions needful to identify it thoroughly. The results were as follows, “A” representing the large mass in which the polydymite was determined. A, 2°55 oz. Pt to the ton, or 0°0087 per cent, B, 1°8 & (5 "0060 6¢ i We <3 6 "024 66 That the metal weighed was nearly all platinum is certain ; but it may have contained small amounts of other metals of the same group. The material separated was not sufficient to warrant a search for the rarer associates of platinum. Probably the platinum exists in the ore as sperrylite, although this point was not proved. The amount of platinum in the mass most thoroughly examined would require, to form sperrylite only about 0-007 per cent of arsenic, which is too small a quantity for detection by ordinary analysis. That platinum should exist in appreciable quantities in an ore of such character is some- thing quite extraordinary. Whether it could be profitably ex- tracted is an open question. Washington, Feb. 2, 1889. Art. XL.—Stratigraphic Position of the Olenellus Fauna in North America and Europe; by CuHAs. D. WAucortt, of the U. 8. Geological Survey.* In reviewing the history of American opinion on the succes- sion of the Cambrian faunas, we find that the first systematic arrangement of the terranes containing them was made by Sir William Logan, on the basis of the paleontological determina- tions of Mr. E. Billings. Ina table published on page 46 of the report of the Geological Survey of Newfoundland for 1864, the order of succession of the Lower members of the series is : 3. Upper Potspam. 2. Lowzr Potspam. 1. St. Jonn’s Group. * Read before the Philosophical Society of Washington, March 16, 1889. C. D. Walcott—Position of the Olenellus Fauna. 375 In commenting on the table the author (Logan) said: “ It thus appears that the lower portion of the series is complete in Newfoundland, and the upper in New York and Central Canada. Divisions 3, 4 and 5 have not yet been recognized in the Hast- ern continental region. The St. John’s group, 1, is represented at St. John, New Brunswick by 3,000 feet of black slates and sandstones, whose fauna, described by Mr. Hartt, was correctly referred by him to Etagé C of Barrande’s Primordial zone. It there reposes on older schistose rocks, as yet unstudied, but by Messrs. Hartt and Matthew designated as Cambrian. “The slates of St. John, New Brunswick, Newfoundland, and the Paradoxides beds of Braintree, Massachusetts, also probably belong to the same horizon. “ The Lower Potsdam, 2, is represented by several hundred feet of limestones and sandstones on the Straits of Belle Isle, and on White Bay, Newfoundland, and by the slates of St. Albans and Georgia, Vermont. “The Upper Potsdam, 3, is that of Wisconsin and Min- nesota, represented in the typical Potsdam of New York, which is overlaid by the Lower Calciferous, 4, while the Upper Calciferous, 5, is only recognized in the Northern peninsula of Newfoundland.’’* This order of succession was accepted and adopted by Amer- ican geologists while no stratigraphic evidence appeared that negatived it. It was not questioned until the work of the Swedish geologists showed that Olenellus Kjerulfi occurred beneath the Paradoxides zone in Sweden; then it became probable that the American Olenellus fauna was of a similar age and hence older than the Paradoxides fauna. Mr. S. W. Ford adopted the classification of Billings and Logan, and argued from the embryonic phases of growth of ~ Olenellus asaphoides that the species showed a genetic relation to Paradoxides and succeeded it in time—a view in which I concurred at a later datet Mr. Ford held that Olenellus Kjerulfi was a true Paradoxides, allied to P. Olandicust and, on the report of Mr. Matthew§ that he had found the species in America, decided that it, O. Ajerulfi, belonged to the Me- nevian fauna. Mr. G. F. Matthew has studied the Paradoxides fauna of America with more thoroughness than any other paleontologist and he has concluded from the paleontological evidence that it preceded the Olenellus fauna.| In the introduction of the * Bull. U. S. Geol. Survey, No. 30, p. 64, par. 141. + Bull. U.S. Geol. Survey, No. 30, 1886, p. 166. ¢ This Journal, ITI, vol. xxxii, 1886, pp. 473-476. § This Journal, III, vol. xxxi, 1886, p. 472. || Canadian Record Sci., vol. iii, 1888, pp. 71-81. 3876 =. D. Walcott—Position of the Olenellus Fauna. Second Contribution to the Studies on the Cambrian faunas of North America,* there was given a description of the typical geologic sections of the Cambrian System, and the order of succession of the faunas contained in their strata as then known. A diagramt was introduced to show the correlation of the sec- tions and the order of successions of the three sub-faunas into which the Cambrian fauna was divided. The first and oldest was the Lower Cambrian or Paradoxides fauna; the second, the Middle Cambrian or Olenellus fauna, and the third, the Upper Cambrian or Dicellocephalus fauna. Each fauna was designated by the most characteristic genus of trilobite con- tained in it. It was stated{ that “the conditions that de- veloped the Middle Cambrian (or Olenellus) fauna appeared to have been largely peculiar to the American Continent ;” also that (119) ‘ there does not appear to be an equivalent fauna in the Cambrian System of Europe, either in Bohemia, the Sean- dinavian area, or in Wales. The nearest approach to it is on the Island of Sardinia.” At the time the introduction was written (1885) there was no satisfactory evidence that “ Paradoxides Kjerulfi,” of the lowest Cambrian strata of Sweden, was not a true Paradoxides ; nor that it was an Olenellus, similar in type to Olenellus asa- phoides of the American “ Middle Cambrian.” Brogger’s ex- cellent paper on the Age of the Olenellus Zone in North America had not appeared; nor had the beautiful memoir of Holm’s on Olenellus Kjerulfi.| The latter proved conclusively that the genus occurs in the lowest fossiliferous bed of Sweden, beneath the horizon of the genus Paradoxides. Still more re- | cently F. Schmidt has published an account of the finding of Olenellus in Estoria, in the Cambrian blue clay, and he states that he must coneur with Brégger in his view that the Olenellus fauna is beneath, and older than, the Paradoxides fauna.4 From the evidenee given by Brégger, Holm and Schmidt, there appeared to be no doubt that the Olenellus zone in Eu rope was beneath the Paradoxides zone. In America it had been regarded by Billings, Logan, Ford, Matthew, Walcott, and Winchell** as above the Paradoxides and subjacent to the Dicellocephalus zone. Brogger analyzed the evidence upon which this view was based and concluded that, in the face of the direct stratigraphic proof of the position of the Olenellus * Bull. U. S. Geol. Survey, No. 30, 1886, + Loe. cit., p. 44. ete. cit., p. 57, par. 120. S Aftryek ur Geol. Foren Stockholm, Férhandl., vol. viii, Hatt. 3, 1886. j Thid., vol. ix, Haft. 7. 1887. q rer: Acad. Imp. Sci. St. Petersburg, VII, vol. xxxvi, No. 2. Uber eine Neuentdeckte Untercambrische Fauna in Estland, 1888, pp. 1-27, pl. i-ii. ** As reporter of American opinion, Cong. Geol. International 4 me. Session Londres; Res. Rep. Sous. Com. Americans, 1888, jews C. D. Walcott— Position of the Olenellus Fauna. 377 zone in Sweden, the American geologists and paleontologists had mistaken the order of succession. It was stated in 1886* that the only locality known in Amer- ica where the two faunas (Paradoxides and Olenellus) occur in the same geographic area is about Conception Bay, Newfound- land. The evidence given by Logan of the order of succession was unsatisfactory, but it was all that was available and I con- tinued to use the scheme given by him in 1865. Even after reading Brogger’s paper I did not feel warranted in changing the table without stronger evidence than that there given. Compar. ing the two faunas zoologically, it appeared to me that in time the Olenellus fauna should follow the Paradoxides fauna. In May, 1888,+ I reprinted Logan’s scheme, stating that the table was tentative and expressive of my present knowledge and opinion, requesting that all who use it should decide individ- ually upon the value of its correlations. Such was the condition of our knowledge in the spring of 1888, when I began an investigation to determine, if possible, the actual stratigraphic succession of the Cambrian faunas of North America. I first re-examined the section of Cambrian strata in Eastern New York, as some evidence was known to me there of the presence of the Paradoxides fauna. One of the results of this study was the discovery of entire specimens of Olenellus asaphoides that showed it to be generically identical with Olenellus Kjerulfi of Sweden, and Olenellus Mickwitzet of the East Baltic region of Russia, as described by Schmidt. Also that the genus Mesonacis, based on Olenellus Vermontana, included Olenellus asphoides, O. Kyerulfi, and O. Mickwitzi, in having a similar type of pygidium. Knowing that O. (J/eson- acis) Vermontana was associated in the same stratum of rock with O. Thompsoni, and that the same type occurred beneath the Paradoxides zone in Sweden, Norway and Russia, I fully believed that the stratigraphic position of the faunas would be found to be the same in America as in Europe I also found at the base of the great Berlin sandstone in Rens- selaer County, N. Y., several species of fossils that appear to be more closely allied to the species occurring in the Para- doxides fauna than to any known elsewhere in the Olenellus fauna, notably, Linnarssonia Taconica, Agnostus desideratus, n. sp., Agnostus like A. pisiformis, Macrodiscus connexaus and Lacanthoides Eatoni, n. sp. These species occur in the upper portion of the shales that in their middle and lower parts con- tain only the Olenellus fauna * Bull. U.S. Geol. Survey, No. 30, 1886, pp. 49-50, par. 97. Distributed in January, 1887. + This Journal, III, vol. xxxy, 1888, p. 399. 378 C.D. Walcott—Position of the Olenellus Fauna. I next proceeded to Newfoundland, where there appeared to be a prospect of settling the question for America, by discoy- ering the two faunas in the same stratigraphic section. The first section examined was that beneath Topsail] Head, Conception Bay. It was found to be as described by Mr. Alexander Murray.* The limestone at the base is separated from the ‘ Huronian” rocks by a fault line. Over the lime- stone a hundred feet or more of greenish shale completes the section. In the limestone I found Odolella Atlantica, Kutorgina Labradorica, Scenella reticulata Billings, Hyolithellus micans Billings, Hyolithellus micans, var. rugosa, Hyolithes princeps Billings, 7. ompar Ford, Microdiscus speciosus Ford, Miecro- discus, sp. undet., Olenellus Bréggeri, n. sp., Avalonia Man- uelensis, n. gen., n. sp., Solenopleura bombifrons Matthew, Agraulos WS.) strenuus Billings, Agraulos (S.), n. sp. In the superjacent green shales a few fragments of a trilobite were observed that indicated, by a portion of the glabella and eyelobe, a large species of Paradoxides. The evidence here obtained being somewhat inconclusive, the section at Brigus Head, on the west side of Conception Bay, was next examined and found to be essentially the same as that at Topsail Head, with the addition of a greater thickness of green and red shales above the limestone, and a sandy deposit beneath the limestone which rested unconformably against the ‘‘Huronian.”” The limestone series is divided into three bands. In the lowest, a specimen of Hyolithes impar was found similar to that in the limestone at Topsail Head, associated with fragments of a species of Olenellus (O. Bréggeri), Microdiscus — and Ptychoparia (?) In the second bed of limestone frag- ments of trilobites were seen ; and in the upper bed Olenellus Broggert and Agraulos strenuus, were observed, the latter in great abundance. No fossils were discovered in the superja- cent slates. There remained but one section, known to me, where the Cambrian rocks rested on the ‘“ Huronian” gneiss and the stratigraphic succession ot the beds continued unbroken up to the unquestioned Paradoxides horizon. This was on Manuel’s Brook, one-and-a-half miles west of Topsail Head. A coarse conglomerate rests directly and unconformably upon a syenitic eneiss. Along the line of the brook the conglomerate is con- formably subjacent to a belt of greenish shale which is suc- ceeded by a band of red shale subjacent to a thin stratum of limestone, which is followed by greenish shales, and these in turn by black shales carrying an abundant Paradoxides fauna. This section being conformable, a careful search was made for * Rept. Geol. Survey, Newfoundland, 1868, Reprint of 1881, p. 154. C. D. Walcott— Position of the Olenellus Fauna. 879 fossils in the beds just above the conglomerate. They were first found about 1,500 feet north of the brook, in a railway cut, in some irregular masses of impure arenaceous limestone resting on the conglomerate, and subsequently in red and green shales resting on the conglomerate. In the reddish argillaceous shale a large fine species of Olenellus was found that may be referred to the sub-genus Mesonacis. It is allied to O. (JZ) asaphoides, and I propose to call it Olenellus (Mesonacis) Broggert.* Associated with O. (AZ) Bréggeri, in the red and green shales and in an impure siliceous limestone, are the following species: Obolella Atlantica, n. sp., Hyolithellus micans Billings, Hypolithellus ?, n. sp., Hyolithes princeps Billings, H. «mpar Ford, 1. quadricostatus 8. and Foerste, and one new species of Hypolithes, Gasteropod, n. gen., n.sp., Scenella reticulata Billings, Stenotheca rugosa, var. acuta-costa, n. var., Stenotheca rugosa, var., erecta, n. var., Stenotheca rugosa, var. levis., nu. var., Steno- theca rugosa, var. paupera Billings, Platyceras primevum Billings, Microdiscus Helena, n. sp., UZ. speciosus Ford, Micro- discus sp. 4, Olenellus Bréggert Walcott, Avalonia Manuel- ensis, n. gen., n. sp., Ptychoparia Morrisi, n. sp., Agrautlos (S.) strenwus Billings, Agraulos (S.) strenuus, var. nasutus, n. var., Agraulos, n. sp., Solenopleura bombifrons Matthew, Soleno- pleura, XQ. sp. This fauna is essentially the same as that of the limestones of the Topsail Head and Brigus sections, and proves conclu- sively that the Olenellus fauna is subjacent to the Paradoxides fauna. Mr. Murray in his report for 1868, placed on lithologic evi- dence the Topsail Head limestone above the conglomerate of Manuel’s Brook, and the limestone of Brigus Head heneath the conglomerate, in the generalized section published in the report for 1870.+ Mr. Matthew, in studying the collections sent to him by the Geological Survey of Newfoundland, placed the fossils of the Topsail Head and Brigus limestones beneath the Paradoxides horizon on Manuel’s Brook,t thus following the stratigraphic arrangement of Mr. Murray. Subsequently he changed his views and placed the Topsail Head and Brigus faunas in the Paradoxides zone of the Manuel’s Brook section.§ The stratigraphic section on Manuel’s Brook, as measured by me in Angust, 1888, is as follows: | : * The specific name is given in recognition of the excellent work of Brégger on the Cambrian faunas of Sweden, and of the work of the Swedish geologists in first clearly proving the true order of succession of the Cambrian faunas in Hurope, and suggesting that the same order of succession probably prevailed in America. + Report Geol. Survey, Newfoundland, 1870, Reprint of 1881, p. 238. { Canadian Record Sci., vol. ii, 1886, p. 256, § Canadian Record Sci., vol. iii, 1888, p. 74. 380 0. D. Walcott—Position of the Olenellus Fauna. Manuel’s Brook Section. 1. Coarse conglomerate, in massive layers. The material next to the gneiss varies in size, from bowlders of quartz and gneiss six feet in diameter, down to small pebbles, and in the upper beds from pebbles to fine sand._----- 35 Strike, N. 80° E. (Magnetic) ; Dip. 12° to 13° N. 2. Irregular beds of calcareous sandstone, siliceous limestone and greenish-colored argillaceous shale, covering the irreg- ular upper surface of the conglomerate ..-_-_---------- 0-25 Fossils :— Obolella Atlantica, Hyolithellus micans Bill- ings, Hyolithellus?, n. sp., Hyolithes princeps Billings, Hyolithes impar Ford, Hyolithes quadricostatus, 8. and F. and two undescribed species, Gasteropod, n. gen., n. sp., Scenella reticulata Billings, Stenotheca rugosa, var. acuta- costa, n. var., Stenotheca rugosa, var. erecta, n. var., Steno- theca rugosa, var. levis, n. var., Stenotheca rugosa, var. paupera Billings, Platyceras primevum Billings, Micro- discus Helena, vu. sp., Microdiscus speciosus Ford, Micro- discus, sp.?, Olenellus Bréggeri Walcott, Avalonia Man- uelensis, n. gen., n. sp., Ptychoparia Morrisi, n. sp., Agrau- los (S.) strenuus Billings, Agraulos (S.) strenwus, var. nasutus, n. var., Solenopleura bombifrons Matthew, Solen- opleura, n. sp. 3. Greenish argillaceous shale, conformably subjacent to 2.. 40 4, Reddish-colored argillaceous shale _-_.._..------------- + 5, Calcareous sandstone, with pinkish limestone in irregular TIN AS SOS elie 8 Ae eh AO UE ERS Baer oP te OPE pes Eas 5 2 6. Green argillaceous shale with thin layers of hard, dark, ferruginous sandstone, interbedded at several horizons_--.. 270 Strike, N. 80° E.; Dip. 12° N. Fossils :—Near the base the head of an Olenellus was found, also fragments of an Agraulos or Ptychoparia. At 218 feet from the base a layer of pinkish limestone con- tained the head of an Agraulos, like A. strenuus, and many fragments of trilobites. Fifty-two feet higher up quite an abundant fauna was found, and the following Species were collected: Lingulella sp.'a, Acrothele Mat- thewt Hartt (sp.), Agnostus sp. a, Agnostus sp. d, Par- adoxides Hickst Salter, Conocoryphe Matthewi Hartt (sp.), Liostracus sp. a. 7. Dark argillaceous shales with thin layers of limestone and Sandstone, at, various horizons 445) saee ts ate eee 295 Fossils :—Zone a. From 10 to 20 feet feet from the base the following species were collected: Lingulella sp. a, Linnarssonia misera Billings, Acrothele Matthewt Hartt (sp.), Zyolithes sp. a, Agnostus, 3 sp., a, b, c, Microdiscus punctatus Salter, Paradoxides Hickst, Conocoryphe (C) Matthewi Hartt (sp.), Conocoryphe elegans Hartt (sp.), Agraulos socialis Billings, Liostracus tener Hartt (sp.). C. D. Walcott—Position of the Olenellus Fauna. 381 Zone b.—Forty-five feet higher up the fauna is much larger and includes: Linnarssonia misera Billings (sp.), Lingulella sp. a, Orthis sp. ?, Stenotheca sp. ?, Agnostus punctuosus Angelin, Agnostus, 5 sp., 5, e, f, g, h, Micro- discus punctatus Salter, Paradoxides Davidis Salter, Par- adoxwides Hicksi Salter, Paradoxides sp. ?, Anopolenus venustus Billings, Conocoryphe elegans, Ctenocephalus Mat- thewi Hartt (sp. ap Erinnys venulosa Salter, Ptychoparia Fobbi Hartt, P. variolaris Salter, Holocephatina in flata Hicks, A graulos socialis Billings. From 235 to 250 feet from the base a belt occurs in which a small species of Aristozoa occurs in large num- bers, associated with Zingulella sp. a, Agnostus sp.? and the heads of a small Ptychoparia ?, sp. undet. 8. Alternating bands of dark shale and dark, compact sand- stone that carry a small species of Orthis in large numbers, 400 The section is here cut off by the shore of Conception Bay.* On the islands in the bay the Upper Cambrian horizon is well developed. In the lower arenaceous shales at Lance Cove, on Great Bell Island, I found Lophyton sp. ?, Cruziana semi- plicata Billings, Arthraria antiquata Billings, Olenus sp. undet. and, at a higher horizon, near the center of the island, Lingulepis afimis Billings, and Lingula? Murrayz Billings, with fragments of Cruziana. In the sandstone at the summit of Little Belle Island, twenty feet above a band of sandstone earrying Lingula? Billingsiana Whiteaves and an elongate, narrow species of Lingulella, a long slender Hyolithes? and a broad species of Hyolithes occur. In the dark argillaceous shales beneath, LZ. ? Billingsiana occurs in great numbers. The conglomerate (No. 1, of the section) was traced, just north of the outcrop of the gneiss, for a mile to the west of Manuel’s Brook and the shales and limestone of 2 were seen in a number of sections, resting directly upon it: On the brook the stratigraphic succession is unbroken up to the summit of 8, and the strata are conformable and undisturbed with the ex- ception of the dip of 12° to the north. The Manuel’s Brook section is the only one known to me on the North American Continent where the typical Olenellus and Paradoxides faunas occur in an unbroken stratigraphic section. The Olenellus fauna is well developed and typical, and the same is true of the Paradoxides fauna.t * 1 hope to prepare a paper on the Paradoxides zone of the Cambrian, and will then give the distribution of the fauna in the Manuel’s Brook section more in de- tail, and add descriptive notes on the genera and species. + In Newfoundland my work was made much easier by the assistance given by Rey. M. Harvey, of St. Johns, Father Morris, of Villa Nova Orphanage, and a 382. C. D. Walcott—Position of the Olenellus Fauna. The relative position of the Middle and Lower Cambrian faunas is now changed in the American scheme of classifica- tion;* the Paradoxides zone being removed to the Middle, and the Olenellus zone to the Lower division. The three divi- sions—Lower, Middle, and Upper—are useful in classification, as they indicate both physical and faunal changes during the deposition of the sediments forming the American, Swedish, and English sections. In the Appalachian and Rocky Mountain areas of the United States, the genus Paradoxides is unknown, and most of the typical fossils of the zone are unrepresented ; but in the great Cambrian section of Eastern New York it is indicated by Agnostus desideratus, n. sp., Agnostus of the type of A. pisiformis, Microdiscus connexus, Linnarssonia Taconica and Zacanthoides Hatoni. The third and fourth species may prove to be identical with Jicrodiscus punctatus and Linnarssonia sagittarius from the Paradoxides zone of Newfoundland. In Nevada a peculiar fauna that is recognized by the trilobitic genera Olenoides, Zacanthoides and Asaphicus, occurs midway between the Olenellus and Dicellocephalus or Upper Cambrian faunas. Brégger has noted that the genus Agnostus is first characteristic of the Paradoxides zone, and by it he has correlated certain horizons in Nevada witn those of Sweden. This will undoubtedly hold good in many instances, and be of value when taken in connection with other genera.t The following table exhibits the order of stratigraphic suc- cession of the three subdivisions and sub-faunas of the Cam- brian System as known in America to-day. As previously stated the three divisions of Lower, Middle and Upper Cambrian are recognized in America and Europe. The names of the subdivisions of these three primary divisions of the period in America are the names of the typical terranes that are respectively included in each of the primary divisions. Thus under the term Prospect, of the Lower Cambrian, are included the strata of the Olenellus zone in Nevada, Utah, and the Rocky Mountain region north into British America. The typical section is that crossing Prospect Mountain in the Eureka district, Nevada. In this section the sedimentation and fauna are essentially the same as in the Rocky Mountain area. letter telling of localities from Mr. J. P. Howley. The geological map of the Avalon Peninsula, by Mr. Howley, was of great service. In the six weeks’ search for the Olenellus fauna about Conception Bay, Mrs. Walcott was my con- stant companion and efficient assistant, and shared with me the pleasure given by the finding of the fauna on Manuel’s Brook. *In all my previous papers with the exception of the note in ‘“‘ Nature,” Octo- ber, 1888, the term Middle Cambrian is to be changed to Lower Cambrian and Lower Cambrian to Middle Cambrian. +Om alderen af Olenelluszonen; Nordamerika. Aftryck ur Geol. Forenin- gens; Stockholm Férhandl., No. 101, vol. viii, H. 3, 1886. M C. D. Walcott—Position of the Olenellus Fauna. 383 SILURIAN (ORDOVICIAN). Lower portion of the Calciferous sandrock of Lower Calciferous_| New York and Canada: Lower Magnesian limestone of Wisconsin, Missouri, ete. Rotsdamy sso. 4-22 Potsdam sandstone of New York, Canada, Wis- consin, Texas, Wyoming; Gallatin limestone of Montana and portion of Pogonip limestone KG ee Sears of Nevada; Knox shales of Tennessee; Coosa shales of Georgia and Alabama; the Alabama section may extend down into the Middle Cam- Montonsees eames brian. Tonto calcareous shales of Arizona. Shales and sandstones of Great and Little Bell and Kelley’s Islands, Conception Bay, New- IBelMTslep ees foundland. UPppPrER CAMBRIAN, CAMBRIAN. Sta Ohne ceeeen Shales and slates of Braintree, Massachusetts; St. John, New Brunswick apd the Avalon eles sa Peninsula of Newfoundland. Central portions of the New York and Nevada Cambrian sec- PAtvalongieyn seen tions. MIDDLE CAMBRIAN. o ler} s j=) B ier] (a>) (a>) 7 lesores Georgia shales and ‘‘Granular Quartz” of Ver- | Sea lett mont, Canada, New York and Massachusetts. Limestones, etc., of L’Anse au Loup, Labrador; northwest coast and Peninsula of Avalon, Newfoundland; lower part of Cambrian sec- tion of Eureka and Highland Range, Nevada; Upper arenaceous shales of Big Cottonwood Cation, Cambrian section of Utah. Terra Nova .._--- Prospect Sap) ees ce LOWER CAMBRIAN ALGONKIAN. The topmost division, Lower Calciferous, includes the passage beds between the Cambrian and subjacent Lower Silurian (or Ordovician) systems. In northeastern New York the line between the two systems is very distinct, but in central New York and Nevada there is no stratigraphic break between them. Passage beds must necessarily exist in some localities; in the table these are recognized by the Lower Calciferous, as in Wisconsin that horizon contains a fauna more intimately related to the Cambrian than to the superjacent second fauna. The names Potsdam, Acadian and Georgian might be used in the second column to replace Upper, Lower and Middle Cambrian. The objection, for instance, that the typical Aca- dian fauna is not present in the great Rocky mountain area, and that there is a Middle Cambrian zone which is recognized there, ieads me to drop the denotive names in the second column and use the more universally applicable terms Upper, Middle and Lower Cambrian. 384. C. D. Walcott— Position of the Olenellus Fauna. Stratigraphic Position of the Olenellus Zone. Determined by our present information the Olenellus fauna is at the base of the Cambrian. Beneath the Olenellus zone the strata are to be referred to some of the pre-Cambrian groups. As already mentioned the Olenellus zone of the Atlantic basin occurs in sediments resting on the Archean and close to the base of the strata referred to the Paleozoic group. In Vermont the Winooski marble series shows over seven hundred feet of limestone beneath the Olenellus zone that have not as yet yielded any characteristic fossils.* Murray and Howley state that in Newfoundland several thousand feet of sandstone occur, on the shores of Trinity Bay and vicinity, beneath the horizon of the Manuel’s Brook conglomerate. They do not report fossils, which leaves in doubt the horizon to which this sandstone series should be referred. The great series of siliceous rocks of the Wasatch section, Utah,t+ show 11,000 feet of strata conformably subjacent to the Olenellus zone; and all through the uplifts of Cambrian rocks in Utah and Nevada a considerable thickness of strata is known to occur in a similar position. In western Nevada the sandstone and siliceous shales of the Wasatch and similar sections are represented by more or less calcareous strata, and it is there that we may hope to find a pre-Olenellus fauna. _ At present I draw the basal line of the Cambrian in Utah and Nevada, at the bottom of the band of arenaceous shale carrying the Olenellus fauna. This refers the quartzites and siliceous shales of the Wasatch and similar sections, including that of the Eureka district and that of the Highland range of Nevada, to the Algonkian Period. The section laid bare in the Grand Cafion of the Colorado, beneath the great unconformity at the base of the known Cambrian, shows 12,000 feet of unaltered sandstone, shales and limestone that, I think, were deposited in pre-Cambrian time and should be referred to the Keweenawan Group.{ This presents one of the best opportunities known to me for the discovery of a pre-Olenellus fauna. The entire section is unbroken, and the sandstones, shales and limestones are much like those of the Silurian section of New York. In a bed of dark argillaceous shale, 3,550 feet from the summit of the section, | found a small Patelloid or Discinoid shell, a fragment of what appears to be the pleural lobe of a seoment of a trilo- bite, and in a layer of bituminous limestone, an obscure, small * Bull. U. S. Geol. Survey, No. 30, p. 15, par. 13, Nos. 1, 2 and 3 of the section. + Loe. cit., p. 38, par. 74. ¢ This Journal, ILI, vol. xxxii, 1886, p. 153, foot-note. 0. D. Walcott—Position of the Olenellus Fauna. 385 Hyolithes. In layers of limestone, still lower in the section, an obscure Stromatoporoid form occurs in abundance.* A similar series of rocks occur, unconformably beneath the Cambrian, in Llano County, Texas. Fossils have not been reported from them.t The Geographic Distribution of the Olenellus Fauna. I have endeavored to show that on the American continent the Olenellus fauna occurs in sediments deposited on the margins of a continental area that, in later Cambrian time, was depressed beneath the sea and largely covered by sediments of Upper Cambrian age.t My studies in Newfoundland, during the past summer, lead me to think that there the Olenellus zone was also a shore deposit about an Archean land area that was probably not depressed deeply, if at all, at any one time, beneath the sea in any part of Cambrian time. The Olenellus zone of Norway, Sweden, Russia (Lapland and Esthonia) occurs on the margins of an old Archean continent, and the Olenellus zone of England and probably of Scotland and the Island of Sardinia is on the western side of the Euro- pean area. In other words, the Olenellus fauna, as far as known to-day, lived on the western side of a pre-Cambrian continental area, outlined by the present continent of Europe; also on the eastern and western sides of a continental area that extended, on the east, from Labrador southwest along the Atlantic coast line, and also on a line now occupied by the valleys of the St. Lawrence, Lake Champlain and the Hudson River, and probably the central line of the Appalachians to Alabama; and on the west by the eastern ranges of the Rocky Mountains, from Arizona far into British America. The correlations in the following table follow the New- foundland section. In New York the Paradoxides zone has not been recognized, unless we consider the representative species, Linnarssonia Taconica, Agnostus desideratus, Agnos- tus, of the type of A. pisiformis, Microdiscus connexus, and Laconthoides Eatoni, as indicating it. This I am at present inclined to do. In Newfoundland the genus Olenus is represented, but in New York, Nevada, Wisconsin, etc., the genus Dicellocephalus is taken as the representative genus of the Upper Cambrian. In the southern Appalachian area, Tennessee, Alabama, etc., the Upper Cambrian fauna is wel] developed, and the Middle is indicated by Olenoides Curticei, n. sp., Ptychoparia ante quata Salter, Agnostus, 2 sp. * This Journal, III, vol. xxvi, 1883, pp. 437-442. + This Journal, III, vol. xxviii, 1884, pp. 431-433. t This Journal, II], vol. xxxii, 1886, pp 154-157. 386 C. D. Walcott—Position of the Olenellus Fauna. Table showing the order of succession of the Cambrian faunas in typical areas in America.” ‘i E Upper Mis- Newround Masgechu New York. | Tennessee. SO ns siselppi Val- ‘ ey. A i , oe < Dicello- Dicello- Dicello- ;| Ss | Olenus Palliat pa | aoa Unknown. | cephalus | Present. cephalus | cephalus 3) =) ; zones. zones. zones. 2 ie) al | RR | wl 4 e Indicated | Repre- Ao = Biel paradox |lParadoxl by other | Same as | sented by Pen asmansetleides coneatl occas than in Nevada|other genera) Unknown. eel) Se) j ‘| Paradox- and Utah.| than Para- a es) ides. | doxides, } Ss | es Z & = | Olenellus | Olenellus | Olenellus Olenellu =e | § fe) g zones. Zones. zones. | Pistsenor zones. Unknown: 4 a | S) | The details of this table will be described in a future paper. The succession of the Cambrian faunas in Europe is the same as on the Atlantic basin side of North America, as shown in the following table: Table showing the order of succession of the Cambrian faunas in Europe, where the Olenellus zone has been recognized. The local sections are given in Dr. Lapworth’s paper.* CAMBRIAN SYSTEM. Scandinavia. Russia. Britain. Sardinia. | Upper Cambrian | Dictyonema | Dictyonema. | Dictyonema emOTs and | and im Olenus zones. |Olenus zones. ‘Olenus zones.| . Middle Cambrian | Paradoxides | Unknown. | Paradoxides | or zones. Zoues. i Paradoxides zones Lower Cambrian Types of the or Olenellus Olenellus Olenellus Olenellus Olenellus zones, zoues. zones. zones. fauna, but not Olenellus. * Nature, vol. xxxix, 1888, p. 213. C. D. Walcott—Position of the Olenellus Fauna. 387 The Olenellus Fauna. A summary of the Cambrian fauna is given in the Introduc- tion to Bull. 30, U. S. Geol. Survey, in which the Olenellus fauna is credited with 43 genera, 107 species and 2 varieties. In this summary 3 genera and 19 species are included that are not found in association with the genus Olenellus or typical species of the fauna. They were found beneath the Potsdam horizon and above the Georgia or Olenellus horizon, and are now referred to the Middle Cambrian. They are: Proto- spongia fenestrata Salter, Hocystites ?? longidactylus W alcott, Leperditia Argenta Walcott, Agnostus interstrictus White, Olenoides Nevadensis Meek (sp.), O. quadriceps Hall and Whitfield (sp.), O. Wasatchensts Hall and Whittield (sp.), O. spinosus Walcott, O. typicalis Walcott, Ptychoparia Housensis Walcott, P. Kingi Meek (sp.), P. Prochensis Walcott, P. ? Prospectensis Waleott, P. quadrans Hall and Whitfield (sp.), P. subcoronata Hall and Whitfield (sp.), Bathyuriscus How- elli Walcott, B. productus Hall and Whitfield (sp.), and Asa- phiscus Wheelert Meek. Ptychoparia Piochensis occurs 100 feet above the Olenellus zone proper, in the Highland Range section,* but as it also occurs 1137 feet higher up in the same section, it is now referred to the Middle Cambrian fauna and not to the Olenellus fauna. From the Olenellus zone of eastern New York, I subse- quently described :¢ Lingulella Granvillensis, Linnarssonia Taconica, Orthis Salemensis, Hyolithellus micans, var. rugosa, Modiolopsis ?? prisca, Leperditia dermatoides, Aristozoa rotundatu, Muicrodiscus convexus, Olenoides Fordi, Soleno- pleura ?? tumida, Ptychoparia Fitchi and P.? clavata, and recent collections have added Agnostus desideratus, n. sp., Agnostus of the type of A. pisiformis, and Zacanthoides Eatoni n. sp. All of these occur in association with Olenellus, although Linnarssonia Taconica, Agnostus desideratus, Agnostus type of A. pisiformis. Microdiscus connexus, Zacanthoides Eaton, n. sp., are types of the Paradoxides fauna. Professor N. 8. Shaler discovered an area of fossiliferous Lower Cambrian rocks in Bristol County, Massachusetts, from which he has described, in association with Mr. A. F. Foerste, the following species :{ Obolella crassa Hall (var.), Obolella ?, Fordilla Troyensis Barrande?, Lamellibranch?, Scenella reti- culata Billings, Stenotheca rugosa, var. paupera, S. rugosa, var. abrupta, S. recurvirostra (n. sp.), Platyceras primevum * Bull. U. S. Geol. Survey, No. 30, 1886, pp. 33, 34. + This Journal, III, vol. xxxiv, pp. 188-198, 1887. t Bull. Mus. Comp. Zodlogy, vol. xvi, No. 2, 1888. Am. Jour. Sc1.—TuHirD SerRigs, Vor. XXXVII, No. 221.—May, 1889, 25 888 C.D. Walcott— Position of the Olenellus Fauna. Billings, Pleurotomaria (Raphistoma) Attleborensis (n. sp.), Hyolithes quadricostatus (n. sp.), H. communis, var. Hmmonsi Ford, 7. Americanus Billings, H. princeps Billings, (7. Bil- lingst Walcott ?, Hyolithellus micans Billings, Salterella eur- vatus (n. sp.), Paradoxides ? Walcotti, nu. sp., Ptychoparia mucronatus (n. sp.), P. Attleborensis (n. sp.). Of these, two genera—Pleurotomaria and Paradoxides—have not before been found in a strongly marked Olenellus zone fauna; and eight of the species and two varieties were unknown in 1886. It is doubtful if the genus Paradoxides occurs in this lower Olenellus zone fauna. /. Walcottc is founded on a small head that appears to be generically identical with similarly sized heads of Olenellus asaphoides that are associated with a similar fauna at Troy, N. Y. In Newfoundland I have found 14 genera and 23 species and 5 varieties in the Olenellus zone, as follows: Odolella At- lantica, n. sp., Kutorgina Labradorica, Hyolithellus micans Billings, //. micans, var. rugosa Walcott, Hyolithellus ?, n. sp., Hyolithes princeps Billings, H. impar Ford, H. quadricostatus S. and F., 7., 2 n.sp., Pteropod ?, n. gen., n. sp., Scenella reti- culata Billings, Stenotheca rugosa, var. acuta-costa Walcott, Stenotheca rugosa, var. erecta Walcott, Stenotheca rugosa, var. levis Walcott, Stenotheca rugosa, var. paupera Billings, Pla- tyceras primevum Billings, Microdiscus Helena, nu. sp., DL. spectosus Ford, Microdiscus sp.?, Olenellus Briéggeri Walcott, Avalonia Manuelensis, n. sp., Ptychoparia Morrisi, n. sp., Agraulos (S.) strenuwus Billings, A. (S.) strenuus var. nasutus, n. var., Agraulos n. sp., Solenopleura bombifrons Matthew, Solenopleura, n. sp. Of these, 2 genera, 14 species and 4 varie- ties were not previously known in the fauna. A list of all the genera and species now known to me from — America, gives a total of 55 genera, 127 species and 9 varieties, as follows : Spongice. Crinoidea. Leptomitus Zitteli, Walcott. Kocystites ? sp. ? Girvanella ? sp. ? Trails, burrows and tracks. Protospongia sp. ? Planolites incipiens, Billings. Hydrozoa sp. ? congregatus, Billings. Phyllograptus? simplex, Emmons. annularius, n. sp. Climacograptus?? Emmonsi, Walcott. | Helminthoidichnites marinus, Em- Corals. mons. Protopharetra, sp. ? Scolithus linearis, Haldeman. Spirocyathus A tlanticus, Billings. Cruziana sp. ? Coscinocyathus Billingsi, Walcott. Brachiopoda. Archeocyathus profundus, Billings. Lingulella ceelata, Hall (sp.) “~ -— ~ —~(A) rarum, Ford. Ella, H. and W. * ~ — —~ (A) Rensselaericum, Ford. Granvillensis, Walcott. Dwighti, n. sp. Linnarssonia Taconica, Walcott. Ethmophyllum Whitneyi, Meek. Kutorgina cingulata, Billings. Meeki, n. sp. Labradorica, Billings. ho Brachiopoda. Kutorgina pannula, White (sp.) C. D. Walcott— Position of the Olenelius Fauna. 389 Crustacea. Leperditia (I) dermatoides, Walcott. sp. ? Prospectensis, Walcott. Iphidea bella, Billings. Acrotreta gemma, Billings. Acrothele subsidua, White. Obolella Atlantica, n. sp. chromatica, Billings. Circe, Billings. crassa, Hall (sp.) gemma, Billings. * ~ —— nitida, Ford. Orthis Highlandensis, Walcott. Salemensis, Walcott. Orthisina festinata, Billings. orientalis, Whitfield. ? transversa, Walcott. ? (sp. undetermined.) 2 sp. ? Camerella? antiquata, Billings. ? sp. ? Lamellibranchiata. Fordilla Troyensis, Barrande. Modiolopsis (??) prisca, Walcott. Gasteropoda. =Helenia bella, n. gen., n. sp. —Stenotheca ? elongata, Walcott. ~ curvirostra, 8. and F. ~? rugosa, Hall. (sp.) var. abrupta, S. and F. var. acuta-costa, n. var. var. erecta, n. var. var. levis, n. var. var. paupera, Billings. Scenella conula, Walcott. ~reticulata, Billings. y ~ - —— retusa, Ford. ~? yarians, Walcott. Platyceras primevum, Billings. Pleurotomaria (Raphistoma) A ttlebor- ensis, Shaler and F. Pteropoda. Hyolithes Americanus, Billings. Billingsi, Walcott. minunis, Billings. y ~~ ~~ var. Emmonsi, Ford. > — ~ — —~impar, Ford. princeps, Billings. quadricostatus, S. and F. sp. (undetermined.) similis, n. sp. terranovicus, n. sp. Hyolithellus micans, Billings. var. rugosa, Walcott, Coleoloides typicalis, n. gen., n. sp. Salterella pulchella, Billings. rugosa, Billings. curvatus, Shaler and F. Aristozoa rotundata, Walcott. y ~ +» ~ ~ Troyensis, Ford. sp.? Protocaris Marshi, Walcott. Trilobita. » Agnostus nobilis, Ford. desideratus, n. sp. sp. Microdiscus bella-marginatus, S.and F. connexus, Walcott. lobatus, Hall. ~ —- ~ ~~ —Meeki, Ford. Parkeri, Walcott. speciosus, Ford. sp. ? Olenellus (Mesonacis) Vermontana, Hall (sp.) (M.) asaphoides, Em. (sp.) Gilberti, Meek. Iddingsi, Walcott. Thompsoni, Hall. (M.) Broggeri, n. sp. Paradoxides? Walcotti, Shaler and F. Olenoides Fordi, Walcott. ? Marcoui, Whitfield. (sp.) Zacanthoides Hatoni, n. sp. levis, Walcott. Bathynotus holopyga, Hall. Avalonia Maniuelensis, n. gen., n. sp. Conocoryphe trilineata, Emmons. (sp.) Ptychoparia Adamsi, Billings. Attleborensis, S and F. (?) Fitchi, Walcott. misera, Billings. sub-coronata, H. and W. Teucer, Billings. (sp.) Vulcanus, Billings. (sp.) 2 sp. ? Agraulos strenuus, Billings. var. nasutus, n. var. Crepicephalus Augusta, Walcott. Liliana, Walcott. Oryctocephalus primus, Walcott. Anomocare parvum, Walcott. Protypus Hitchcocki, Whitfield. (sp.) (?) clavata, Walcott. senectus, Billings. (sp.) var. parvulus, Billings. Selenopleura bombifrons, Matthew. y ~— — —~ nana, Ford. (2?) taumida, Walcott. Harveyi, n. sp. Howleyi, n. sp. 390 ©. D. Waleott—Position of the Olenellus Fauna. Resumé of Fauna. Genera. Species. Varieties. SPON Sie ee eae 2) ee 3 2718 ) Ey droz0a ee =e eee nes a soe 2 0 Coral Seas Ne eae ae 2 Te 5 9 0 Grin ord ays: S ee me a ts 1 1 0 Trails, burrows and tracks ___-.- 4 6 0 Brachiopodayerer sneer Selo 27 ? ) amellhibranchiatay 22. 225.2) 223. 2 2 0 Gasteropodagerescs. emee is selen 5 10 5 GeO OG A tare re. sic teen lence + 15 2 Wrustacearre an 300) (2 {ene 3 5 0 Privo bray eriee: fe es a 16 46 2 Total wees so ale Via ss 55 127 9 The Olenellus Fauna in Europe. Until the memoir of Holm’s on Qlenellus Kjerulfi* ap- eared, American paleontologists were unwilling to admit that the genus Olenellus was represented in Europe. The figures and descriptions given by Linnarsson and Brogger were unsat- isfactory, and they did not care to change the scheme of classi- fication proposed by Logan without very positive evidence. Personally I avoided referring to the debated question while engaged in its study in America and while waiting for fuller data from Europe. I felt the force of Brégger’s argument, but preferred to wait for stronger proof before accepting or rejecting the European view. To the American fauna I will add the European forms that are at present known to me: Scandanavia.—Holm statest that according to Linnarsson and Brégger, the fauna of the Olenellus zone in Scandanavia consists of : Olenellus Hgerulfi Linnars., Hllipsocephalus Nor- denskioldi, Avrionellus primevus Brogger, Hyolithes sp. undet., Metoptoma sp., Lingulella ? Nathorsti Linnars., Obolus sp., Discina ? sp. From the Eophyton sandstone beneath the Olenellus Kjer- ulfi zone Linnarsson described{ Bythrotrephis sp., Medusites radiata Linnars., Medusites Lindstrom: Linnars., Mick- witzia Monolifera Linnars., Hyolithes levigatus Linnars., Arenicolities spiralis Torell, Frena tenella Linnars., Cru- ziana dispar Linnars., Scotolithus mirabilis Linnars., Hophy- * Aftryck vr. Geol. Foren. Stockholm, Forhandl., vol. ix, haft 7, 1887. + Aftryck vr. Geol. Foren. Stockholm, Forhandl., vol. ix, haft 7, p. 22, 1887. + Geog. och Pal. Iakttag. Hophytonsandstenen i vestergotland Kongl. Svenska Vet. Akad. Handl., vol. ix, No. 7, 1871. C. D. Walcott—Position of the Olenellus Fauna. 391 ton Linneanum Torell, E. Torelli Linnars. These last three species are probably based on inorganic markings. Russia.—The Olenellus zone in Estland, Russia, has, aecord- ing to Schmidt, the following genera and species: Olenellus Mickwitzi Schmidt, Scenella discinoides Schmidt, Scenella ? tuberculata Schmidt, Mickwitzia monilifera Linnars- son (sp.), Obolella? sp., Discina? sp., Volborthella tenuis Schmidt, Platysolenites antiquissimus Kichwald (sp.), Medusites Lindstromé Linnarsson, /)-ena tenella Linnarsson, Cruziana, Primitiu ? (sp.).* Britain.—The Olenellus fauna was first described in Britain by Professor Charles Lapworth.t At the Cumley quarries, Little Caradoc, Shropshire, he obtained Olenellus , Hyolithellus, Kutorgina, Scenella, Ptychoparia and Obolella, from calcareous sandstone, in the Cumley sandstone. The stratigraphic posi- tion of the sandstone in relation to the Paradoxides zone was not known until the fauna proved that it belonged to the Lower Cambrian. In the more complete section of the Cam- brian, at St. David’s, S. Wales; the purple, green and red sand- stones and slates of the Caerfai group of Hicks occupy the stratigraphic position of the Olenellus zone in Newfoundland, as do the somewhat similar beds near Llanberis and Bangor, in North Wales. As yet the few fossils found—Lingulella pro- meva, Discina? Caerfaiensis, Leperditia ? Cambrensis,—from St. David’s, and Hyolites sp., and Conocoryphe viola, from North Wales, do not prove the presence of the Olenellus zone, although I shall include them in the Lower Cambrian fauna. Spain.—The only species recorded from the Spanish penin- sula that can be classed with the Olenellus fauna is Athmo- phyllum Marianus Roemer. On the Island of Sardinia a large Cambrian fauna has been discovered that includes the genera Archeeocyathus, Coscino- eyathus, Obolella, Kutorgina, Olenopsis, Metadoxides, etc., ete. _ Until more complete data are published on the geological sec- tion and the range of the species. it is not safe to assign any of the species to the Olenellus zone. Excluding the Sardinia fauna and admitting the genera and species except where evident duplication exists, the pre- Paradoxides-Olenellus-zone faunas of Europe may now be credited with twenty-five genera and thirty-eight species. Of these twelve genera and all the species have not been recog- nized in America. Adding the European fauna to the Ameri- can we have Genera 67; | Species 165; _— Varieties 9. ZALOCHCIE Palos + Nature, vol. xxxix, pp. 212, 213, 1888. Advanced sheets dated Oct. 25, 1888. 392 E.'S. Hokden—Larthquakes in California. To this number there will yet be added many of the genera and species from Sardinia, and probably a considerable number from Britain and Seandanavia. In the second part of this paper the stratigraphical and zoological relations of the Lower and Middle Cambrian faunas will be discussed. [To be continued. ] Art. XLI.—Larthquakes in California, (1888); by Epwarp 8. HoupEn. In 1887 I compiled a list of earthquakes which had been recorded in Californiay ete., from 1769 to the end of 1887. This was printed by the Regents of the University of California in a pamphlet of 78 pages and widely distributed. The data there given have been discussed in two papers subsequently written. The first is a note on Earthquake Intensity in San Francisco (1808-1888) printed in this Journal for June, 1888 ; and the second has the title Earthquakes in California, Wash- ington, and Oregon (1769-1888) and has been communicated to the California Academy of Sciences. These three publica- tions contain all the data which I have been able to collect, and I believe that no deductions of especial value can be drawn from the data except those which are there given. These statistics could, of course, be tabulated in several different ways, but it is my opinion, from trials, that no important results not already given would follow. The examination of past records has naturally led to the consideration of the best manner of making future ones. The object of such records is to bring to light all the general facts as to distribution of earthquake shocks, as to topographic areas, as to time, as to average intensity, ete., and also to enable a study to be made of particular shocks,—as to velocity of transit, area of the disturbed region, intensity, ete. In order to study © any of these questions with profit it is necessary to have some kind of a measure of the intensity of each earthquake shock. The most satisfactory instruments which I have seen for this purpose are those invented by Professor Ewing, F.R.S. These are devised on sound mechanical principles and are well con- structed by the Cambridge Scientific Company. It is necessary at the Lick Observatory to keep a register of all earthquake shocks in order to be able to control the positions of the astronomical instruments. Accordingly I ordered a set of Professor Ewing’s instruments for the Observatory, which were delivered in 1887. ‘They are described with woodeuts in Volume I of the Publications of the Observatory, (page 81), E. S. Holden— Earthquakes in California. 393 and in the Hand Book of the Observatory, (page 54). The complete set of instruments will give for each shock the time of its beginning, and that of every tremor; the amplitude of the vibration in the east and west, the north and south, the up and down directions at every instant. Such a complete set of instruments requires continual attention and is far too delicate and troublesome in adjustment for general use. The Duplex Seismometer of Professor Ewing seems, however, to be well suited for general purposes. It gives with considerable accu- racy, the magnitude of the earthquake force in any two directions as east and west and north and south. The vertical component is not registered, and the time of occurrence must be taken from a watch. Copies of this instrument can be had from the California Electrical Works (85 Market street, San Francisco), for $15. It therefore seems to be a suitable pattern for use in California, and elsewhere, since it combines compar- ative accuracy, with cheapness. A complete set of Professor Ewing's instruments, is provided as I have said, at the Lick Observatory. The duplex seismometers multiply four times ; while the vertical component is multiplied 1,8, times, the horizontal component 3,8, times in the complete instrument. Another complete set, exactly similar, belongs to the Univer- sity of California, at Berkeley, and is installed at the Student’s Observatory there, under charge of Professor Soulé. This Observatory also has a Gray-Milne seismometer, complete. Copies of the duplex seismometer are set up also at the following stations : (1.) San Francisco, near Cliff House, residence of Hon. A. Sutro. (2.) San Francisco, 917 Pine street, residence of Hon. J. R. Jarboe. (3.) Chabot Observatory, Oakland, in charge of Mr. Burck- halter. (4.) Private Observatory of Mr. Blinn in East Oakland. (5.) Kono Tayee, Clear Lake, residence of Capt. R. S. Floyd. (6.) Observatory of University of the Pacific, San José, in charge of Professor Higbie. (7.) Students’ Observatory, Berkeley, in charge of Professor Soulé, (8.) One will be shortly installed at Smith Creek Hotel, at the foot of Mt. Hamilton. (9.) Office of State Weather Bureau, Carson, Nevada, in charge of Charles Freund, Esq. Copies of this instrument are also in possession of Warner and Swasey of Cleveland, and of Capt. C. E. Dutton, of the U. S. Geological Survey for experiments. I believe that one will be shortly mounted at the Blue Hill Observatory, near 394 LE. S. Holden—LKarthquakes in California. Boston, Massachusetts. The Lick Observatory also possesses a seismometer invented by Professor Milne and kindly presented by him, which is designed to serve for general purposes. We have not thoroughly tested this as yet. It is simple in construe- tion, and inexpensive. A description of it may be found in Trans. Seis. Soc. of Japan, vol. xii. The instruments above named which are in California have been visited and adjusted by Mr. Keeler of the Observatory (who is in charge of our earthquake instruments), and the owners of these instruments have kindly reported the oceur- rence of shocks, and have often sent blue prints or tracings of the records made. The reports of Mr Jarboe, Mr. Blinn, and Mr. Burekhalter have been especially full, as will be seen from what follows. Wm. Irelan, Esq., Dr. J. B. Trembley of Oak- land, and U. 8. Surveyor General Irish of Nevada, have kindly taken the pains to send accounts of all shocks. I have also copied from such newspapers as fell under my eye all data respecting California earthquakes. These are given in what follows, together with the results obtained from the various instruments. To make this record complete the reports of the U. 8. Light House Board, of the U. 8. Geological Survey, and the annual records of earthquakes given by Professor Rockwood in this Journal should be consulted. As these are available to all, I have not reprinted any data from them. It is intended in future years to continue such records as the present one. The extremely local character of some of these shocks is noteworthy. EARTHQUAKES IN CALIFORNIA, 1888. 1888, January 7, 10:25 Pp. M.—S. F. (II): Berkeley (1V),— at Berkeley a loud explosion.—Professor Kellogg. January 13, at night.—Berkeley, a slight shock (N.E.-S.W.) recorded on duplex seismometer (1? II? ILI ?).—Professor Soule. January 16, 11:39 Pp. M.—S. F.: single, short, sharp shock ([V).—E. 8S. H. (1 have no other report of this, and it must therefore be regarded as doubtful.) January 17, 10:10 p. m@.—S. F.—E. E. Barnard. Oakland, from N.E. to 8. W. (III? LV #).—Professor Edwards. January 26, ’—Healdsburg, 10 see. duration, 8. F. Chronicle, Jan. 28. (Total eclipse of the moon on January 28.) January 29, 10:35 Pp. M.—Carson, Nevada, a slight shock (IV to V) Grass Valley, Cal.: the same shock (II).—G@rass Valley Tidings, Feb 3. January 80, 4:15 A. M.—S. F. [not reported in newspapers].— el@aidle E. S. Holden—EHarthquakes in California. 395 February 18, 2:50 a. M—Fort Bragg: three severe shocks, (V 2); the first at 2:50, the other at intervals of one or two minutes. Mendocino: three shocks; the first at 2:55, the others at intervals of three or four minutes.—(S. F. Bulletin, February 18.) % February ¢ about 4 A. M&a—Menlo Park: sleepers waked (V or VI).—J. T. Doyle, Esq. February 29, 2:51 p. m—S8. F.: on Montgomery street, peo- ple alarmed (V); Pine and Mason streets, more severe, (VI); Washington and Mason streets, (VI). Two waves on duplex seismometer (917 Pine street.). The motion of the earth was a—N. 68° W. to 8S. 68° E. b—S. 56° E. to N. 56° W. The shock 4 was most severe. Berkeley: not felt, not registered.—Oakland: (II.)—Bel- mont: not felt—San Rafael: (IV or V) 2:48 Pp. M., E. to W.— Santa Rosa: 2:55 Pp. M., violent; people ran out of houses, (VI).—Petaluma: 2:55 Pp. M., walls cracked (VII) sound of an explosion heard. The severest for many years.— Healdsburg : 2:44 Pp. M., light N. to S.—Martinez: 2:45 P. M., two shocks one minute apart (VI).—S. F. Alta, Chronicle, Bulletin, Feb. 29th and Mar. 1. March 7, 7:54 A. M.—Pasadena: 7:58 A. M., (VI); from N.W. to S.E., duration three seconds.—Los Angeles: a little after 8 A. M. (VI)? “severest for 18 years; no damage to buildings,” no very heavy articles overturned (VI). [Note: on 1888, Sept. 5th, a shock (VI) was felt at Los Angeles, E. 8. H.]—San Diego: scarcely felt (II). (Pasadena Dadly Star, also 8. F. Alta, Chronicle, Mar. 4, 8). March 28, 1:41 a. M—S. F.: slight shock, but sufficient to awaken a sleeper (V). Direction of shock nearly N. and &., on duplex seismometer, 917 Pine street. Professor Davidson says duration # second, and shock from W. to E.—S. F. Bulletin, Mar. 29. April 9, 7:50 A. Mi—Riverside: slight shock (IV) N.E. and S.W. (8S. F. Bulletin, April 9, Chronicle, April 10.) April 12, about 5:15 A. M.—Riverside: the shock sufficient to waken sleepers (VI) with loud noises accompanying. Col- ton, 5:30 A.M. (S. F. Chronicle, April 138.) April 28, [8:45 Pp. m.|—On the Lick Observatory seismo- graph an earthquake record was found April 29. From the trace of this shock the following data are taken. The dimen- sions given below are to be divided by 3°3 for the Horizontal and by 1°6 for the Vertical components, to get the actual earth movements. The times are given in seconds after a zero epoch arbitrarily assumed. The pen which marks the W. and E. components registered a line ;; of a millimeter wide throughout. There appear to be widenings of this line as 396 EF. 8. Holden—EKarthquakes in California. early as fifteen seconds before the zero second adopted, but the amplitude of E. and W. tremors is never more than 5 of a millimeter during the whole shock and the time of their beginning cannot be fixed. I presume we have here a case where the normal vibrations were strictly, in an E. and W. plane. The transverse vibrations which arrived later are there- fore N. and 8. and of their full size in the diagram. We may then dismiss all further consideration of the E. and W. wave. It had scarcely a measurable amplitude. At 0 seconds the N. and S. tremors begin to show; the whole record of the vertical component is lost till 17 seconds. At 8 sec. the earth moved S. of the neutral line 1™™ 5 66 N. 66 1 6 ce Ss. ce 71 9 eS S. ss 1 10 t ING oe 1 114 iy Ss. oh 1 13. 66 N. 66 1 15 c S. «“ 8 16 ‘ N. ss 4 18 6¢ S. (74 4 19 (79 N. (74 4 and small tremors with a double amplitude of about $™™ (on the trace) continue till 66 seconds. The vertical component as recorded by the machine is given below : At 18 see. the earth moved above the neutral line 1™™ 19 below 1 4 214 ‘ above ‘ 4 23 ss below i 1 and tremors of not more than 3™ continue on the trace till about 56 seconds. We may assume for a basis of computation : Number of waves in 10 seconds =4, Period, about 2°5 seconds =T, Amplitude magnified, 1™™, a=0°3"", 27a Velocity of projection =V= a a 0°75, 2 ‘ Ni Intensity = Pian 490) which corresponds to about I on the Rossi-Forel scale. The period of these waves is very slow. April 28, 8:48 p. M.—Reno (Nevada), a smart shock: three waves in 8 sec., followed by a general trembling for 10 see. E. S§. Holden— Earthquakes in California. 397 The time of the third and severest shock was 8 h. 48 m. 38 s. p.M. Direction 8. to N. (letter from U.S. Surveyor General Trish). Two other observers say W. to E.—Grass Valley : felt in the Idaho mine below the 1600 ft. level, Alta, May 2d. Very heavy, lasting 5 sec., from HE. to W. (Chronicle, April 30). —Grass Valley: the Orleans mine was flooded. The shock was at 8:45 Pp. M. and very heavy (VII). It was preceded by a loud noise. The duration was about 5 sec., and the wave was E. to W. Clocks stopped, plastering fell, and also tops of chimneys.—Nevada City: walls of courthouse cracked (VIII). —At Marysville, Downieville, Truckee, Colfax and Sacramento the shock was very strong (G. V. Tzdings, April 80, May 2).— Nevada City: two severe shocks at 8:48 Pp. M. preceded by a deep rumbling sound. Direction N.—Dutch Flat; 8:46 pP. ., severe from 8S. to N. People were badly frightened.—Stock- ton: four shocks at 8:40, from N. to S.—Dixon, 8:45 Pp. M.— Biggs: heavy shock “lasting 75 (?) seconds” [seven to five ? E. 8. H.], at 8:45 (VII) plastering cracked, ete.—Santa Rosa: slight shock at 8:45, N. and S. (I11).—Truckee: 8:47, duration two seconds, (S. F. Axaminer, April 29).—Oroville: 8:45 P. M. Short, quick shock.—S. F.: barely perceptible in third story of 917 Pine street. No record on duplex seismometer in basement (I). April 30, about 4 a4. Mi—Grass Valley: Tidings, April 30. —Downieville: 3:40 a. M. two light shocks (IV), (8. F. Bud- letin, April 30). May 4, 1:55 p.m.—S. F., 917 Pine street, decided shock, not registered on duplex seismometer, J. R. J.—S. F., slight shock (II) of a few seconds duration, (Bulletin, May 4). May 6,9 h. 42 m. 22s. p. uw. (E.S. H.).—Lick Observatory : sudden shock (III) E. S. H., preceded by a rumbling noise (PorcHER.) (Registered on duplex seismometer). Suly 11, at night.—Susanville: slight shock (IV %), S. F. Bulletin, July 18. August 14, 9:57 a. M—S. F., 917 Pine st. Intensity (II) on R. F. scale. The duplex seismometer gives a looped trace on the plate (magnified four times) 7™™ N.N.E. to S.S.W. (direc- tion of first shock), 4™™ at right angles to this. The motion of the earth was therefore 8.8.W. to N.N.E.—Lick Observa- tory: direction on the plate N.N.E., of the earth S.S.W. The trace is a wavy line (magnified four times) 8™™ long. N.N.E. and S.S.W. with six waves 1™ high at right angles to this. Probably the shock was nearly vertical here. September 10, 1:53 a. w.—S. F., 917 Pine street: slight shock (II) not registered on duplex seismometer, J. R. J.—Oakland: slight shock, C. Burckhalter. Three shocks at 1:50 a. M. in quick succession, attended by noise; windows did not rattle 398 E. S. Holden— Earthquakes in California. (III?), Dr. Trembley. It waked sleepers in Oakland (V 4), E. Booth.—Berkeley ; slight. September 15 ¢—Lick Observatory: the seismograph started at 6:15 A. M., but as the record was not like that of a shock, Mr. Keeler (in charge of the instrument) supposes the tremor which started the instrument to have been due to a high wind. September 17, 3:51 A. M.—Lick Observatory: The seismo- graph gives the following records (magnified 1:6 times for the vertical, 3°3 times for the horizontal components). At 3 seconds after an assumed zero second, the vertical component began its trace with a wave of period about 14 seconds. The amplitude (on the trace) is hard to estimate but is probably not less than 5™™ for the first semi-wave, then about 1™™ for a full wave, and after this mere tremors until about 40 seconds. The N. and 8. component (magnified) was as follows: At 4°3 seconds the earth moved S. of the neutral line 5™™ 57 66 N. 66 2 5-9 “ on to «“ A 671 “ N. «“ a4 6-4 « S. “ 14 6°9 sf N. és 1 15 «“ S. “ ee 8-9 & N. “ 13 and tremors occasionally as large as ?"™ continued until about 40 seconds. The EK. and W. component (magnified) was as follows: At 43 seconds there was strong movement of the earth west of about 38™™; this was followed by a wave of period about 1 second double amplitude 2™™; and this again by another of period # second double amplitude 1™™. After this tremors continue for about 380 seconds. The strata of which Mt. Hamilton is composed le at a high angle to the horizon and the direction of the stratification is nearer N. and 8. than E.and W. The earthquake instruments are at the very summit of the mountain. This may account for the fact that (at least for the shocks so far observed) the vertical component is relatively large, and that the N. and 8. component (in the general direction of the stratification) is usually far larger than the HE. and W. component. The record of this shock on the duplex seismometer is very interesting, but it gives no information additional to the above. We may then assume as a basis of computation for this shock : Number of waves in 10 seconds =6 or 7, say 63. Period, T, of the representative wave =0°5 sec. Amplitude of the representative wave (magnified) =2°5™™. Gi— O58 me : EF. S. Holden—Earthquakes in California. 399 27a =10°0. Ae Velocity of projection = : V Intensity = = 126. This corresponds approximately to V-VI on the Rossi-Forel seale, according to the table in this Journal, June, 1888, p. 429, which was derived from Japanese shocks. Chabot Observatory: the time of the shock is 3 h. 50 m. plus or minus ove-quarter of a minute (W. Irelan, Esq.). It is registered on the duplex seismometer plate as follows. The first motion (of the pen, magnified four times) is 2™™ to the W., then follow several small tremors towards the 8.E. The mo- tion of the earth is of course in the reverse directions.—Lick Observatory, 3:51 a. M.: severe shock, lasting several seconds. Strong vertical component (VI to VII) observed by E. 8. H. Also on L. O. seismometer.—Gilroy, sharp shock: Santa Cruz, heavy, (S. F. Call, Sept. 18).—S. F., 917 Pine street: very slight, no record on seismometer, J. R. J. September 238, about 11:30 aA. m.—S. F., 917 Pine street: very slight shock, J. R. J. October 3, 12:52 P. MM—San Miguel, 8. L. O. Co.: light shock, 2 sec. duration, N. to 8. (III). Another at same place at 1:02 Pp. M., quite severe, N. to S., 4 sec. duration, no damage done (VI), 8. F. Chronicle, Oct. 4. October 4, P. MM—Paso Robles: slight shock.—8S. F. Peport, October 5. October 4,11 P.M.—San Diego.—S. F. Bulletin, October 5. October 5, 4h. 41m. 30s.+10s. A. M—Chabot Observatory : the shock was sufficient to waken a sound sleeper (VI). On the duplex seismometer plate the trace begins with a tremu- lous motion toward the W., followed by two sharp jerks to the S. The motion of the earth is contrary to the motion of the plate. October 23%—Lick Observatory: During Mr. Keeler’s ab- sence the earthquake instruments were in charge of Mr. Hill. On October 23, at 6 Pp. M., I noticed that the earthquake instru- ments were in their usual state. I also noted at 9 P. M., October 24, that a shock had occurred previously. The clock dial of the earthquake clock is divided to 12 hours (instead of to 24 hours as it should have been), and there is an ambiguity of 12 hours in the time of the shock, which is either October 28, 11h. 42m. P. M., or October 24, 11h. 42m. a. M— The shock was sufficient to start the clock of the Ewing seismograph, but the plate did not move. The duplex seismometer plate shows a tremulous wave in the direction N.E. and 8.W. 400 LS. Holden—Karthquakes in California. October 24, 2:50 A. M.—East Oakland: (V) Mr. Blinn’s Observatory. The duplex seismometer plate shows a trace from 8. to N. in general direction. The first trace on the plate is that of a single wave about 2m. in amplitude (magnified four times) followed by small tremors.—Chabot Observatory : the plate of the duplex seismometer shows the first wave strongly towards the N.E. The trace of this wave (magnified four times) is a straight line 6" long. This is followed by two waves of the earth as it regained its original position. The motion of the earth is contrary to that of the pen on the plate. October 25, in the night.—Mr. Blinn’s Observatory. The duplex seismometer gives a tremor, and the general direction of the trace on the plate is 8S.E. to N.W. November 4, 3:36 A. M.—Lick Observatory (VI).—E. 8S. H. Mr. Barnard gives the time as 8h. 374m., plus or minus 4 m. The duplex seismometer gives a very complex knot of curves ending by a trace on the plate towards the S.W. The trace on the Milne seismometer (in cellar of the Meridian Circle House) cannot be interpreted, as the instrument had just been set up and probably was not adjusted properly. November 18, 2:28 Pp. M.—S. F., 917 Pine street : two shocks north and south (VII) registered on seismometer. Another light shock at 5:38 p. m.—J. R. J.—San Rafael: 2:30 P. ., N. and 8.—Oakland: 2:29 Pp. M.; one chimney fell (VII ?).— Berkeley : 2:28 P. M.; duration 7 sec.; a third shock at 5:35 p.M. (S. F. Hxaminer, Nov. 19.) Lick Observatory: not felt, not registered.—Chabot Obser- vatory: 2h. 27m. 58s., very sharp shock; 3:30, slight; 5h. 37m. 20s., sharper than the second shock. The duration was 83sec. The trace on the duplex seismometer is a very com- plicated circular knot of 5 to 6™™ diameter (magnified four times) with a looped excursion of the pen toward the east 6™™ from the center of the knot, and another straight one from the center to the W.S.W , also of 6™. All three shocks are on this single plate—In Oakland no real damage was done. Two or three chimneys were overthrown and panes of glass were broken (VI, or VII ?).—East Oakland: 2:29 p. m., N. to S., duration 2 sec.; 3:45 P. M., very ight; 5:36 p. u., E. to W., duration 2 sec.—(S. F. Bulletin, Nov. 19).—Napa: 2:36 P. M., duration 10 see.—S. F. Chronicle, Nov. 19.—Haywards, San Leandro, Niles: not felt—Mr. Burekhalter.—Clear Lake: not felt—Capt. R. S. Floyd. It is also reported by Capt. Edmundson of the ship “ Drum- lanrig,” that he found soundings of 35 fathoms, 35 miles 8. W. of the Farallones where no shoal is now known to exist. This point will be determined by the proper authorities. It is E. S§. Holden— Earthquakes in California. 401 supposed by some that the shock of Nov. 18 may have pro- duced this shoal which is not down on the charts. East Oakland: Mr. Blinn’s Observatory. The first shock was severe (VI) lasting about two seconds. The time was very approximately 2h. 27m. 57s. (Blinn). Mr. Irelan gives 2h. 27m. 54s. Trees and hedges were seen to move. A few light articles were overthrown, pictures were displaced, a clock was stopped, (its pendulum was in the plane N.E. and 8.W.); 5 chimneys were thrown down on 23d avenue ; a noise was: heard after the first shock. The second shock was (II) at 3:48 Pp. M. The duplex seismometer trace is a loop about 1™™ in diameter. The third shock was (III) at 5h. 38m. 45s. Pp. mM. The trace on the duplex seismometer begins in an ellipse 2™™ E. and W., 1=" N. and S., and then there is a confused record of tremb- ling 3™ N.W.and S.E. by 13™™ at right angles to this. December 11, 3:29 p. m.—Lick Observatory: the shock was sudden and ([V) in intensity. Time by watch 3h. 28m. 59s. ; by earthquake clock 3h. 294m.—J. E. K. A humming’ noise was heard after the shocks. There were two such at an interval of 2 sec. The time of the last was 3h. 28m. 58s. plus or minus 3 sec.—E. E. B. Intensity (V), time 3:28.8.—E. S. H. The duplex seismometer gives a record (magnified) begin- ning with a sharp straight trace to the N.W. 3™™ long, then a straight trace to the N.E. 1#™™ long, then a straight trace to the N.W. nearly 2™™ long, and at the end of this the pen has recorded a confused tremor in a space about 1™™" square. The record of the Ewing seismograph is as follows: (The adjustment of the marking pen for seconds has been changed so that there are 95 beats of the pen to 1 min. of time.) There are very slight vertzcal tremors for the first three beats ; they then vanish completely. Their period is from + to 4 of a second of time; their double amplitude is not above 3, of a millimeter. The cast and west vibrations last only for two beats though the faintest perceptible tremor lasts until the twentieth beat after the beginning... Their greatest double amplitude is not above 4a millimeter, and their period appears to be about $a second. The north and south vibrations are well marked. From the zero beat (beginning) until 14 beats there are marked tremors. . From 14 beats to 4? beats vibrations having a double amplitude of about one-half a millimeter, and a period of about 4 to + of a second time. At the end of the 6th beat the marked tremors cease and a very faint tremor continues to the end of the 20th beat, and possibly to the end of the 33d beat. Asa basis of computation we may assume from the record of the north and south component : 402 W. Hallockh—Chemical Action between Solids. Double amplitude magnified 3°3 times =0°5™™. Os 0:08@™, T =0'3 seconds. 27a We 0 [=—-=36. T a This corresponds to about II on the R.-F. scale according to the paper frequently cited above. The intensity was, however, IV or higher. Art. XLII.—Chemical Action between Solids ;* by WILLIAM HALLOCK. In a note on a new method of forming alloys published some time ago,t I suggested some additional experiments which I intended to make, and I now give the results thus far obtained. Unfortunately other work prevents my continuing the investi- gation at present. Inasmuch as the method and principlet seemed well estab- lished where metals were used to produce alloys, an attempt was made to include some chemical reactions in the list. The most natural cases were the freezing mixtures where solid reagents are used. In order to surely have both constituents in a decidedly solid state the experiments were performed in a vessel cooled to a temperature of minus 10° or 12°C., care being always taken to leave the reagents in the vessel long enough for them to assume a temperature decidedly below zero Centigrade. Under these conditions a erystal of rock salt (NaCl) and a piece of clean dry ice were gently brought in contact, lying side by side on a watch glass. Of course the result was a solution of salt, but old as this experiment may be, it appears here in a new connection, as an example of the union of two solids below the melting point of either, but above that of the product. The piece of ice was frozen to the glass and during the operation the crystal was drawn several millimeters across the glass, doubtless by capillarity, as the solution ran out at the bottom of the surface of contact as fast as it formed, the attraction being sufficient to move a crystal several grams in weight. Similar experiments were performed with sodium and potas- * This paper was read in part before the Phil. Soc. of Washington, D. C., October 13th, 1888. + W. Hallock, Zeitschr. f. Phys. Chem., ii, 6, 1888. Science, xi, 265, 1888. t O. Lehmann Wiedemann Ann., xxiv, p. 5, 1885, suggested the theoretical possibility of producing an alloy in this way. I had overlooked his paper until recently. Mr. Lehmann, however, evidently did not consider it possible to fulfill the necessary conditions and did not try the experiment. W. Hallock—Chemical Action between Solids. 403 - sium nitrate, potassium, calcium and ammonium chloride and sodium and potassium hydrate, with a similar result in all cases. These are all well known results, but wherein do they differ from the new method of forming alloys? This question sug- gests another. Are the metals combining to form an alloy in the new way a freezing mixture? A thorough investigation of this question would require more complicated experiments tban I had time to perform. One test, however, is very simple, that with potassium and sodium. Into a small porcelain crucible weighing 15 grams and containing about an equal weight of petroleum were placed ‘pieces of the two metals, about 3 grams of each. One junction of a thermo-element was forced into the piece of potassium and gave its temperature accurately. After the whole had assumed the room temperature, clean faces of the two metals were brought in contact, the liquefaction began and the temperature immediately fell. It required about two hours to complete the liquefaction and about one and a half hours to attain the minimum of temperature. No precautions were taken to prevent the calorimeter taking up heat from its surroundings, and no doubt it absorbed considerable in the long time, and yet the maximum fall in temperature amounted to 2°4° ©., very large considering the small weight of the reagents compared with the calorimeter. Thus it appears that sodium and potassium are, under such circumstances, a ‘‘ freezing mix- -ture,’ and analogy at least would lead one to believe that other alloys also absorb heat in their formation; but future experiment must decide the point. In the cool vessel above described a piece of sodium or potassium was placed upon a piece of dry ice, almost instantl the reaction commenced and proceeded vigorously. It is, however, scarcely safe to consider this a case of chemical action between solids, because the reaction is probably as follows: the vapor from the ice attacks the metal forming the hydrate which unites with other ice forming a solution, which is then further acted upon by the metal, and in the whole process heat is generated sufficient to raise the temperature of the reagents very considerably. Perhaps in. the other freezing mixtures, ice and salt, etc., it is the vapor of the water or ice which initiates the reaction. In view of these and other considerations, the idea is evident that perhaps many substances have a slight vapor tension at temperatures considerably below their melting points, and are surrounded by a thin atmosphere of their own vapor over their clean surfaces, and it is only necessary to bring two such atmo- spheres to interpenetration in order to initiate the reaction which Am. Jour. Sci1.—Tuirp Series, Vor, XXXVII, No. 221.—May, 1889. 26 404 W. Hallock—Chemical Action between Solids. will then continue, provided the produet (liquid or gas) escapes easily and does not clog the operation. In very many cases substances are found to give off a vapor below their melting point, and it is natural to suppose that there is a film of that vapor over the surface of the body, as there is a layer of satu- rated air over water. The mechanical theory of the composition of matter lends plausibility to the above suggestion. If these considerations are correct they foretell the regelation of sub- stances like camphor, and ice, without any pressure whatever. That loose pieces of camphor will become welded together by simple contact is well known. The operation appears to me thus: In an irregular mass of camphor in an atmosphere of eamphor vapor, there is a constant interchange of state for the molecules at the surfaces of the solid, molecules previ- ously solid are getting too far off and becoming gas, and molecules previously gas are beating upon the solid and staying there, thus the state of equilibrium is when, as a whole, there are as many molecules which fly off and become gas as fly on and become solid. On a projecting point of the solid the chances are in favor of more flying off than on, in a reéntrant angle the reverse is true. Theoretically, then, the piece ought ulti- mately to become a sphere, not only by the rounding down of the corners, but by the building up of the flat or reéntrant sides. ‘That the corners do round off all know. If this is all true we only need to bring the two pieces together and con- sider them as one and the crack between them as a reéntrant . angle, and the union is brought about as above indicated. If in the above the word liquid be substituted for vapor or gas, the explanation will apply to the regelation of ice in water at 0° C. We may go even further and predict a uniting without act- ual contact and this prediction has been experimentally demon- strated in the case of ice and water. A large rough block of ice (about 15 lbs.) was sawed nearly in two, the slit washed out and all the fine pieces removed. In this way it was possible to hold two plane surfaces of ice parallel and near each other (1 to 2==) without danger of actual contact. Into the outer edge of the saw-cut a cotton wick was pressed, thus isolating the space between the faces from the outside and preventing any currents from circulating through the crack. The whole block was then placed in water at zero and enclosed in non-conducting cases and left for 25 to 30 hours. This experiment was tried three times and each time a freezing across the space had taken place. The whole space was not filled, but in numerous places notably along just inside the wicking and up from the bottom of the cut. No doubt the regelation would have gone further if the experiment could have been continued longer. The melting of W. Hallock—Chemical Action between Solids. 405 the whole block puts an end to each experiment. As these ex- periments were performed in summer there is scarcely a possi- bility that the ice was colder than 0° C. Tnasmueh as there seems to be an increasing inclination to regard solutions and alloys as chemical compounds it seems justified to speak of the action according to the alloy law as chemical. On the other hand there are some cases which at first appear as chemical action between solids which upon ‘closer investigation can be explained on a simpler assumption. For example, Mr. W. Spring* in a recent paper on this sub- ject cites three particular cases as being chemical action be- tween solids, the union of copper and sulphur, the reaction between copper and mercuric chloride, and between potassium nitrate and sodium acetate. The formation of the sulphide of copper, and other sulphides, was accomplished by Mr. Spring by compression of the ele- ments. But it is not even necessary that the sulphur and copper be in contact. I have made the sulphide at ordinary temperatures with the two an inch apart and a wad of cotton in the tube between them. It is simply the vapor of sulphur which attacks the copper. That sulphur gives off a perceptible vapor at ordinary temperatures, especially in vacuo, is a fact any one can easily demonstrate. The case of the copper and mer- curic chloride is precisely the same. The vapor of the chloride will go through a whole tube past cotton wads and attack the copper (or color potassic iodide). Hence we can scarcely assert that these reactions are between solid bodies. The reaction between potassium nitrate and sodium acetate is equally uncon- vincing. Mr. Spring expected an interchange of bases and acids and left the mixture of the dry fine powders four months in a desiccator to give time for the exchange. On removing them from the desiccator a deliquescence was noticeable and he _ therefore concludes that the interchange had taken place, since the original salts do not easily deliquesce; but the product of the reaction (potassium acetate) does. It appears to me thus: the moment the powders were brought to the air, the water vapor enters the operation and we have, potassium nitrate, water vapor, and sodium acetate, and the result of their mutual in- teraction is a solution of potassium acetate and sodium nitrate. In fact if the dry powdered salts are stirred together, in a very few moments deliquescence begins, showing that whatever the reaction it goes on at once, and is a matter of moments and not of months. Thus even this experiment in its present form does not convince us that a chemical exchange took place before the water vapor entered the reaction.+ * W. Spring, Zeitschr. fiir phys. Chemie, ii, p. 536, 1888. + See note on p. 406. 406 Scientific Intelligence. The question of chemical action between solids is by no means new but is being constantly extended. I may say I be- lieve chemical action may take place wherever, the product or products are liquid or gaseous even though the reagents are solid, with perhaps the added condition that one or both the reagents be soluble in the liquid produced. If this be true my new method of forming alloys is but a special case of the above general principle.* Phys. Lab. U. 8. Geological Survey, Washington, D. C. SCIENTIFIC INTELLIGENCE. If CHEMISTRY AND PHYSICS. 1. Onthe Spectrum of Magnesium.—LiveEine and Dewar have studied the spectrum of magnesium produced by the are dis- charge. Most of the lines produced by the spark discharge are observed in an electric arc formed between electrodes of magne- sium. The greater number of lines seen in the arc discharge, how- ever, may be due not to lowness of temperature but to the greater mass of incandescent matter and to a wider range of temperature at different portions of the discharge, recombinations occurring at its edge. The electric discharge itself may also give rise to vibrations distinct from those due to heat. The seven bands in the green are due to the oxide, as they are produced only in the presence of oxygen or of its compounds. Ifa piece of burned magnesium wire be heated in the oxyhydrogen flame, the spectrum of magnesium is produced, the metallic lines appearing if the hydrogen is in excess. The triple line near M, which is pro- duced when magnesium is burned, is found to be produced in the arc between magnesium electrodes and in many other cases when oxygen is present, but not in an atmosphere of nitrogen or hydro- gen; hence it is due to the oxide. Vacuum tubes are found to be very untrustworthy for the ultra-violet spectra as the water- spectrum and lines of nitrogen are nearly always present and the spectra sometimes vary unaccountably. The authors describe in their paper a pump in which rubber connections and free contact of mercury with air, are both avoided.—Proc. Roy. Soc., xliv, 241; J. Chem. Soc., lvi, 89, February, 1889. (Chega; 15, 2. On a Lecture Haperiment for showing Raoult’s Molecular depression of the Freezing Point.—Crmician has described an apparatus for showing, as a lecture experiment, Raoult’s law of the lowering of the freezing point. Miscellaneous Intelligence. 421 E. D. Cope: Pliocene Vertebrate Fauna of Western North America.—North American Proboscidia. A. Hatt, Jr., The mass of Saturn. TrA ReMSEN: Nature and composition of double halides.—Rate of reduction of nitro-compounds.—Connection between taste and chemical composition. T. C. MENDENHALL: Recent researches in atmospheric electricity. A. A. MICHELSON: Measurement by light waves. A. A. MicHELSON and EK. W. Morisey: Feasibility of the establishment of a light-wave as the ultimate standard of length. S. C. CHANDLER: The general laws pertaining to stellar variation. C. H. F. Peters: Review of the trivial names in Piazzi’s star catalogue. J. S. NEWBERRY: Cretaceous flora of North America. CLEVELAND ABBE: Terrestrial magnetism. Romyn Hircucock: Spectrum photography in the ultra-violet. W. K. Brooks: North American Pelagidee.-—Development of Crustacea. C. D. Watcorr: The plane of demarcation between the Cambrian and _pre- Cambrian rocks. D. P. Topp: Report of the American Eclipse Expedition to Japan, 1887. 4, Proceedings of the U. S. National Museum. Vol. X, 1887. Published under the direction of the Smithsonian Institution. 772 pp. 8vo, with 39 plates.—This volume is made up of orig- inal contributions to Zoédlogy and Botany, partly paleontological, and mostly describing new species. The chief contributors are R. Ridgway, L. Stejneger, J. B. Smith, R. Rathbun, J. McNeill, T. H. Bean, C. H. Bollmann, C. H. Gilbert, E. D. Cope, D.S8. Jordan, G. N. Lawrence, L. Lesquereux, T. Gill, C. H. Eigen- mann, F. W. True, R. E. Call, E. Linton, C. H. Townsend, O. P. Hay, and E. G. Hughes. It contains also an account of an Ar- kansas meteorite, by 8. F. Kunz, with a plate. 5. Heamination of Water for sanitary and technical pur- poses, by Dr. H. Lerruan and Wm. Bream. 106 pp.12mo. 1889. Philadelphia (Blakiston, Son & Co.).—This little volume gives the chemical methods for testing mineral and other waters es- pecially with reference to those ingredients that have a sanitary bearing, and also other facts and information on the subject. The Geological Record for 1880-1884 inclusive. A list of publications on Geol- ogy, Mineralogy and Paleontology published during those years, together with certain references omitted from previous volumes; edited by Wm. TOPLEY, F.R.S., F.G.S., and CHARLES Davies SHERBORN, F.G.S. Vol. 1. Stratigraphical and Descriptive Geology. 544 pp. 8vo. London, 1888 (Taylor & Francis).—A work of great value to students in Geology, although only a catalogue. The six preceding volumes covered the years 1874 to 1879 inclusive, and were by Mr. W. Whitaker, excepting that for 1878, which was by Whitaker and W. H. Dalton. Price of each, 16s., excepting for that for 1874, 15s. Bulletin from the Laboratories of Natural History of the State University of Iowa, lowa City, Lowa, vol. i, No. 1, contains valuable geological papers by Prof. S. Calvin; on the Saprophytic Fungi of Eastern lowa by T. H. McBride; and on the Mollusks of eastern Iowa by B. Shimek, besides other papers. University Studies, published by the University of Nebraska, at Lincoln. This quarterly publication, No. 2 of. which was published in October, 1888, contains, besides literary and linguistic papers, a memoir on the conversion of some of the homologues of benzol-phenol into primary and secondary amines, by Rachel Lloyd. Preliminary Report of the Dakota School of Mines upon the Geology of the Black Hills. 171 pp. 8vo. Rapid City, 1888. A Bibliography of Indian Geology: compiled by R. D. Oldham, Deputy Super- intendent Geol. Survey of India. 145 pp. roy. 8vo. Calcutta, 1888. 499 Miscellaneous Intelligence. _ OBITUARY. Miss AnnrE E. Law was born in Carlisle, England. She was the eldest of three children of John Law, whose brother was governor of the Island of Malta. Her father with his family emigrated to Tennessee about the year 1851, settling near Marys- ville, where her parents and brother are buried. She remained at various points in eastern Tennessee until about 1874, when she moved to Hollister, California, and thence to Watsonville, where she remained with her sister, Mrs. Andrews, in impaired health, until Jan. 12th, 1889, when she passed away, endeared to all with whom she came in contact. Her rare intellect, combined with her wonderful musical talent, made her the center of a large and cultivated society, while as a writer she occupied a high position, her poems being remarkable for their pathos and sweet- ness. While Miss Law will be long and widely missed by those acquainted with her socially, there is a much larger circle who will ever honor her name as that of one of the most devoted conchologists we have ever known. She described no species and wrote no articles on the subject, but she contributed none the less to the advancement of science by collecting material for the publications of others. She was a most generous correspond- ent, distributing lavishly the many novelties she collected in the mountains of Tennessee and North Carolina. She first drew attention to the richness of those localities which have since proved almost a new fauna in land mollusks, collecting eleven Species and one genus new to science. As an instance of her enthusiism, the writer may mention that when he ur gently begged her to obtain for him the living animal which had formed the shell of the so-called Vitrina latissima in order to verify its generic position, she undertook a perilous wagon journey of several weeks over mountain roads, camping out at nights; she reached Black Bald Mountain, and found numerous specimens, which enabled the writer from its external and anatomical char- acters to describe the remarkable genus. W. G. B. Dr. Heryricu von DEcHEN, the eminent geologist of Germany, died at Bonn on February 15, having nearly reached his 90th birthday. Professor GiusEPPE Mrnreuini, of the University of Pisa, and Senator of the kingdom, the author of works and memoirs on zoology and geology, died on the 29th of January, 1889, at the age of 78. THEODOR KsERvULF, one of the best and. most active of Nor- wegian geologists, died on the 26th of October, 1888. Joun Ericsson, physicist and mechanician, and one of the most remarkable men of the century, died in New York, on the 8th of March. He was born in Wermland, Sweden, on the 31st of July, 1803. ‘ae PUBLICATIONS OF DEE I@ENS: HOPKINS UNIVERSITY. I. American Journal of Mathematics. S. Newcomp, Kditor, and T. Crate, Associate Editor. Quarterly. 4to. Volume XI in progress. $5 per volume. ; II. American Chemical Jourual.—I. Remsen, Editor. 8 Nos. yearly. 8vo. Volume XI in progress. $4 per volume. Ill. American Journal of Philology.—B. L. GILDERSLEEVE, Hditor. Quar- terly. 8vo. Volume IX in progress. $3 per volume. IV. Studies from the Biological Laboratory.—Including the Chesapeake Zodlogical Laboratory. H. N. Martin, Editor, and W. K. Brooks, Asso- ciate Editor. 8vo. Volume IV in progress. $5 per volume. V. Studies in Historical and Political Science.—H. B. ApDams, Editor. Monthly. Svo. Volume VII in progress. $3 per volume. VI. 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Address the PROPRIETORS, J. D. and HE. S. DANA, New Haven, Conn. CONTENTS. Arr. XX XVI.—The Electrical Resistance of Stressed Glass; by, Cann, Barts? Ae you... +2 2s eg XXXVII—Formation of Siliceous Sinter by the Vegetation of Thermal Springs; by Warrer Harvey WeeEp..-. 351 XXVIIL—Marine Shells and Fragments of Shells in the Till near Boston; by Warren Urnam.__..-_.- 2.22) 359 XXXIX.—A Platiniferous Nickel Ore from Canada; by F. W..:Cruarknland, CHartEs CaTuET?T 2 227 3 372 a XL.—Stratigraphice Position of the Olenellus Fauna in North i America and Europe; by Cuas. D. Waucorr ---.--- 374 | XLI—Earthquakes in California; by Epwarp 8. Hotppn_ 392 | XLII.—Chemical Action between Solids; by Wm. Hattock 402 SCIENTIFIC INTELLIGENCE. Chemistry and Physics.—Spectrum of Magnesium, Livetne and DEwAR: Lecture Experiment for showing Raoult’s Molecular depression of the Freezing Point, CimiciAn, 406.—Chydrazaine or Protoxide of Ammonia, Maumens, 407.—New Stannic Acid, Sprine: Ethyl Fluoride, Morssan, 408.—Chemical Lecture Notes, P, T. AUSTEN: Elementary Text- Book of Chemistry, W.G. Mixrer: Rays of -Electric Force, Hertz: Rotation of plane of polarization of light by the dis- charge of a Leyden jar, O. Longs, 409.—Limit to Interference when Light is radiated from moving Molecules, EBERT, RAYLEIGH: Selective Reflection by Metals, REUBENS, 410. Geology and Mineralogy.—Recent Discoveries in the Carboniferous Flora and Fauna of Rhode Island, A. S. PACKARD: Annual Report of the Geological Sur- vey of Arkansas for 1888, J. C. BRANNER, 411.—Cretaceous and Tertiary Geol- ogy of the Sergipe-Alagéas basin of Brazil, J. C. BRANNER: Tertiary Volcanoes of the Western Isles of Scotland, J. W. Jupp, 412.—Nummaulites up the Indus valley at a height of 19,000 feet, T. D. LaFoucwe: Sand-drift rock-sculpture, R. D. OLDHAM: Catalogue of Fossil Cephalopoda in the British Museum, A. H. Foorp: Nature and Origin of Deposits of Phosphate of Lime, R. A. F. PEn- ROSE, JR., 413.—Fulgurites of Mt. Viso, F. Rutuey: Scheelite from Idaho, W. P. BLAKE: Hiulfstabellen zur mikroskopischen Mineralbestimmung in Gesteinen zusammengestellt von H. RosSENBUSCH: Les Minéraux des Roches par Livy and Lacroix, 414. Botany.—Contributions to American Botany, XVI, SERENO WATSON, 415.—Key to the System of Victorian Plants, F. von MuUnLLER, 416.—Revision of North American Umbelliferee, J. M. CoutterR and J. N. Rose: Flora Italiana, OARUEL: Diagnoses plantarum novarum asiaticarum, C. J. MaximMowicz: Orchids of the Cape Peninsula, H. BoLus, 417.—Handbook of the Amaryllidez, J. G. BAKER: Synoptical List of North American Species of Ceanothus, W. TRELEASE and ©. C. Parry, 418.—Multiplication of Bryophyllum calycinum, B. W. Barron: Hnumeratio Plantarum Guatemalensium imprimis a 4H. DeTuerckheim, J. D. Smite: Journal of André Michaux: Annals of Botany: Herbarium of the late Rev. Dr. Joseph Blake: Outlines of Lessons in Botany, J. H. NEWELL, 419. Miscellaneous Scientific Intelligence.—Deep-sea depression in the Pacifie near Ton- gatabu: Dredging Stations in North American Waters, 8S. SmirH: National Academy of Sciences, 420.—Proceedings of the U.S. National Museum: Exami- nation of Water for sanitary and technical purposes, H. LEFFMAN and W. BEAM, 421. Obituary—ANNIE HE. Law: HINRICH VON DECHEN: GIUSEPPE MENEGHINI: THEODOR KJERULF: JOHN ERICSSON, 422. “ Chas. D. Walcott, PA TS Rote eg 0. ee a S. Geological Survey- fai Aas : 3 vor. XMxXVIL 2 7 JUNE, 1889. Established by BENJAMIN SILLIMAN in 1818. ~ THE AMERICAN JOURNAL OF SCIENCE, EDITORS JAMES D. anp EDWARD 8. DANA. ASSOCIATE EDITORS ormssors JOSIAH P. COOKE, GEORGE L. GOODALE _ any JOHN TROWBRIDGE, or Camprines. Prorzssors H. A. NEWTON xp A. E. VERRILL, ov New Haven, Proresson GEORGE F. BARKER, or PHILADELPHIA. THIRD SERIES. VOL. XXXVII._[WHOLE NUMBER, CXXXVIL] No. 222.—JUNE, 1889. WITH PLATE XIV. NEW HAVEN, CONN.: J. D. & E. 8. DANA. : 1889. 4 = \as2 fe TUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET. “shed monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- of countries in the Postal Union. Remittances should be made either by jers, registered letters, or bank checks. “tt R rae UR ee Nat x“ Pp at.y 8 oe ' z / ‘ By . . po < = wd? 2 ; + > “iy 8 } Fs t t ; MINERAL Eabhig Wicjamh hate tihng le ns ad i - he wie u > Catalogue Issued Monthly. Free to any Address. Vanadates. _ We can supply a high grade concentrate of Mineral Vanadates, in large quantities. Correspondence solicited. COPPER MINERALS FROM ARIZONA, Azurites, both from the Clifton District and from the Copper Queen Mine, Bisbee, famous for yielding the finest specimens known, now in stock. Fine specimens, 75c. to $2; larger specimens, $2.50 to $35. Malachites, in as fine specimens as have ever been offered for sale. Surfaces covered with tufts of superb crystals, $1 to $5. Velvety specimens, 50c. to $5. Malachite and Azurite on the same specimen, 75c. to $10. Chrysocolla, in exceedingly pretty botryoidal specimens, 25c. to $2. Chaleanthite, or native “Blue Vitriol,’ in very remarkable fibrous specimens of a rich translucent, deep blue color. Some specimens show the Chalcopyrite partially decomposed, with veins of the Blue Vitriol extending through it. 10c. to $2. ne8 Cuprite, a few specimens showing good crystals, 35c. to $1. Besides the above we mention :— . Beryllonite, Sperrylite, Japanese Topaz, Blue Barite, Harmotome from N. Y. Island, Descloizite and Vanadinite from New Mexico, Tiemannite, Diadochite, Nemalite, Breithauptite, Adamite, Domeykite, Phillipsite, Allemontite. Satisfaction guaranteed. GEO. L. ENGLISH & CO., Dealers in Minerals, dj 1512 Chestnut Street, - - Philadelphia, Pa. — THE AMERICAN JOURNAL OF SCIENCE [THIRD SERIES.] Arr. XLIIL—TZopographic Development of the Triassic For- mation of the Connecticut Valley; by Wittiam Morris Davis. [ Published, as far as relates to work done for the;U. 8. Geological Survey, with the permission of the Director. ] ContTENTs :—Itinerary of Harvard Summer School of Geology— Faults in the Meriden region—Cross-section of the District— Means of detecting the unfaulted sequence of Triassic beds— Mechanism of monoclinal faulting—Topographic development of the- Triassic belt—lInitial constructional stages represented by the faulted blocks of Southern 1daho—Mountain ranges of the Great Basin equivalent to a later Jurassic Stage—The whole region base-leveled in late Cretaceous time—The present valleys worn in the Cretaceous base-level plain after its eleva- tion—Polygenetic topography—The origin of the Connecticut river outlet via Middletown—The Connecticut river was orig- inally consequent on the monoclinal faulting, and still persists near the course then taken, but has entered a second cycle of life as a result of the elevation of the lowland that was pro- duced in its first cycle. SINCE presenting two years ago a suggestion to account for the mechanical origin of the faulted Triassic monocline* I have visited the region about Meriden with the Harvard Summer School of Geology during its sessions of 1887 and 1888. An itinerary of the excursions made by the school in ' * This Journal, xxxii, 1886, 342-352; Proc. Amer. Assoc., xxxv, 1886, 224-227; Seventh Ann. Report U.S. Geol. Survey, 1886, just issued. Am, Jour. Scl.—THIRD SERIES, VOL. XXXVII, No. 222.—JuneE, 1889. 2 424. W. M. Davis—Topographic Development of the deciphering the structure of the district together with maps and sections to illustrate the facts of observation and a detailed consideration of the arguments leading to certain conclusions is now in press in the Bulletin of the Museum of Comparative Zodlogy at Cambridge. The structural problems of the region afford excellent opportunity for practical instruction in geology. A brief summary of the results reached is presented here. The small black square in figure 1 indicates the position of the Meriden district in central Connecticut and in the southern part of the New England Triassic area. Figure 2 is the same Ihe bo district on a larger scale. The main trap sheet, whose mono- clinal ridges dominate the relief of the region, is shaded with oblique lines; the subordinate ridges formed on the anterior and posterior trap sheets are indicated by lines on either side of the main ridges. The chief faults of the region are drawn in broken lines, and their general southwest trend is clearly seen. The several enclosed spaces numbered 1 to 5 mark the areas represented on maps of still larger scale in the Bulletin above referred to. The “mountains” formed by the main trap sheet are, beginning on the southeast : Higby (or Besick) Mountain, Chauncy Peak and Lamentation Mountain, the Hanging Hills group northwest of Meriden (consisting of Cat-hole Peaks, Notch Mountain and West Peak), Short Moun- tain, High Rock and Shuttle Meadow Mountain, and Bradley’s Mountain, before coming to Cook’s Gap, a pass followed by the New York and New England railroad westward from New Britain. The evidence seems to me very strong that the faults separating all these blocks were produced after the trap sheets had taken their place in the stratified series, all the sheets here shown being extrusive surface flows, poured out during the accumulation of the aqueous strata. ane Triassic Formation of the Connecticut Valley. 425 A cross-section of the district from northwest to southeast, on the scale of figure 2, is given in figure 3; but its construc- tion is not very accurate as to the values of dip and dislocation. The heave of the faults is on the southeast in every case, with the single exception of the fault between High Rock and Short Mountain, where the heave is on the other side; this departure from the prevailing rule of dislocation being indi- cated by a corresponding departure from the prevailing rule of topography. In passing northward across a fault of the ordinary kind, the repeated portion of a ridge is found in what Percival called “advancing order,” that is, farther west than before; but here the repeated ridge is found in “receding order,’ and hence the fault is known to have a reverse throw. The distinct topographic effect of the faults is illustrated in two figures. The first (fig. 4.) is a view southwestward through a gap in the anterior trap ridge, on the line of the fault that GENERAL CROSS SECTION. 4. NORTH END oF EASTERN RIDGE. ii, FAULT SOUTH END of WESTERN RIDGE, i a GAP rafter Mea ol el tere, 5 runs from New Britain through Shuttle meadow reservoir. The heaved side of the fault is on the left (southeast), where the back of the ridge is shaded by an apple orchard and its outcrop bluff is clothed with hemlocks: the thrown side is on the right, where the trap sheet lies lower, but rises westward to another ridge like the first ; an old pasture field on its back, and a bold cliff facing the broad Southington valley beyond. This cliff runs two or three miles north, but shortly turns around the southern end of the ridge where it is terminated by the oblique fault; the other ridge falls away to the left of the view as it approaches the fault, but continues southward till it is again broken by another fault, and the topographic dislocation is repeated. The second view (fig. 5.) is of larger range: it is taken from a hill about a mile east of Berlin, looking south to two masses 426 W. WM. Davis—Topographic Development of the of the main trap sheet. Lamentation Mountain is on the right with the slightly detached Chauncy Peak rising a little over its farther end ; and Higby (Besick) Mountain rises on the left. The strong fault that passes a little east of Meriden separates 5. HIGBY ann LAMENTATION MOUNTAINS. these two mountains, while the greater fault which runs west of Meriden cuts off the north end of Lamentation. The view of these mountains is highly suggestive. The extension of the faults to the northeast and southwest of the trap ridges is seldom traceable very far. Southwest of the anterior trap ridge, the country is generally soon covered with drift ; but occasionally certain beds of conglomerate serve to indicate the course of a fault, as is the case with the great fault between the Hanging Hills and Lamentation Mountain, which may be followed two miles southwest of Meriden. To the northeast, the occurrence of a second posterior ridge in certain localities may in time serve to unravel the fault lines, as it has already for the fault between Chauncy Peak and Higby Mountain, which is thus traced about three miles to the north- east of the gap that it produces in the main sheet. All these localities are given in detail in the itinerary of the summer school, as above. The systematic arrangement of the faults in this district, already mentioned in earlier papers, is thus confirmed. When this is once perceived, it is evident that the normal sequence of the Triassic beds can be found only by crossing the monocline obliquely to the northeast, always keeping within the limits of a single fault-block. This seems to me to be the key to the structure of the region. The remainder of this paper is occupied with considerations not discussed in the Bulletin. The mechanism suggested to account for the production of — a monocline with its system of faults thus arranged has been in the mind of other writers. Some fourteen years ago, Mr. G. K. Gilbert conceived its essential features, and gave a brief account of it in his description of the Great Basin Ranges.* He made the theoretical suggestion “that in the case of the Appalachians, the primary phenomena are superficial ; and in that of the Basin Ranges they are deep-seated, the superticial being secondary; that such a force as has crowded together the strata of the Appalachians—whatever may have been its * Wheeler’s Surveys west of the 100th Meridian, iii, 1875, 62. Triassic Formation of the Connecticut Valley. 427 source—has acted in the Ranges on some portion of the earth’s crust beneath the immediate surface; and the upper strata, by continually adapting themselves, under gravity, to the inequal- ities of the lower, have assumed the forms we see. Sucha hypothesis, assigning to subterranean determination the position and direction of lines of uplift in the Range system, and leaving the character of the superficial phenomena to depend on the character and condition of the superficial materials, accords well with many of the observed facts, and especially with the persistence of ridges where structures are changed.”’ The essential peculiarities of the method for the production of a faulted monocline is here clearly stated, although no oppor- tunity is noted for independent verification of the suggestion, such as appears in Connecticut in the correspondence between the course of the faults and the trend of the underlying schists. In my previous paper concerning the origin of the faulted monocline, no special consideration was given to the cause of the discordance between the course of the faults and the strike of the beds in the Meriden region, which now appears as so strong a structural characteristic. [t may be suggested that this is the result of a force of compression acting on the whole mass of crystalline and overlying rocks in a direction oblique to the strike of the schists, whose structure determines the course of the faults. The schists trending northeast and the compression being exerted from west to east so that movement of any point in the schists must take place in an east and west vertical plane, a result such as that which here obtains might be produced. A consequence of this would appear in the much greater uplift given to the southwestern than to the northeastern part of any block thus obliquely tilted ; but the unworn surface of any block would slope eastward, in the direction of the dip of its beds. When deeply eroded, the older members of the series of tilted beds would be revealed in the southwestern part of the block; while the newer still remain in the northeastern part, as we find them. The topographic development of the Meriden region and indeed of the valley as a whole, may be briefly sketched. Its early structural topography, such as would have resulted from its dislocation without erosion, finds modern illustration in the tilted lava blocks of Southern Idaho, as described by Russell. This writer, from whose vivid descriptions we derive so clear a picture of our western countr y, says that the whole of the Great Basin—the “immense region lying between the Sierra Nevada and the Rocky Mountain systems has been broken by a multitude of fractures, having an approximately north and south trend, that divide the region into long, narrow, oro- 428 W. M. Davis—Topographic Development of the graphic blocks. These have been tilted so as to form small but extremely rugged mountain ranges, often from fifty to a hundred miles in length, with a width of but a few miles.”— The fractures by which the blocks are separated “are of a comparatively recent date, and present bold scarps, that are frequently but slightly scarred by erosion, while the most recent examples of all were unquestionably formed within the past few years, and are yet unclothed by vegetation.” .. . ‘‘ The exhibition of fault-scarps, tilted blocks, and sunken areas, to be seen at the southern end of the Warner Lakes, is the most interesting of its kind that it has ever been our privilege to examine. In this narrow zone, the orographic blocks of dark volcanic rock are literally tossed about like the cakes of ice in an ice-floe; their upturned edges forming bold palisades that render the region all but impassable.” . . . “These fault- scarps rise in sheer precipices that overshadow the Warner Lakes throughout their entire extent. Toward the northern end of the valley the ) great fault-scarp forming its eastern wall sends off a number of branches, at quite regular intervals, with a general northwest trend. The blocks thus separated pass under the lake beds that floor the valley, and appear again on its western border, where they form cliffs of considerable height.” ... “It is between the high walls enclosmg the southern portion of the valley that the greatest confusion of the minor blocks is to be seen. Many of these fragments measure a mile or so on their edges and are tilted in various directions, leaving narrow rugged valleys between their up- turned margins. The diverse tilting and the numerous fault- scarps that rise without system into naked precipices combine to make this a region of the roughest and wildest description.” (Fourth Ann. Report U. 8. G. 8., 448, 445, 446.) It is apparent from these extracts and from others that could be quoted that while southern Oregon has a more complicated structure than that of the Connecticut Trias, it nevertheless serves admirably as a picture of the early stages of the latter, when its faults were still growing: except in the matter of diverse displacement and in the amount of erosion suffered, the description of these long narrow blocks might apply to those of the Connecticut valley. The blocks in Idaho have been dislocated so rapidly and so recently that they preserve their constructional topography with insignificant alteration, and in this they are the best examples of any region yet described. Nowhere else can we find so good an illustration of a mountain system in its infancy —almost in its birth. A similar constructional topography probably once existed in Connecticut ; but it has long since disappeared. The upper surface of the Triassic region being Triassic Formation of the Connecticut Valley. 429 of shales or sandstones, instead of hard sheets of lava, presuma- bly allowed erosion to follow displacement rapidly, but it seems highly probable that the topography of the region was for a considerable time closely consequent on the deformations that closed the period of deposition and ushered in the long eycle of erosion that has since then endured with little inter- ruption. As time went ov and the forces of deformation slackened, the forces of erosion made better headway in reducing the region to a water-sculptured topography ; we find existing illustration of this stage of the history of central Connecticut, in the present form of the central ranges of the Great Basin. The following description is also condensed from accounts by Russell. : The central ranges of the Great Basin are structurally com- posed ot long narrow blocks of bedded, aqueous and igneous rocks separated by faults and tilted into monoclinal attitudes ; but the simple original structural form that they may once have had is now no longer immediately apparent; the oro- graphic blocks here have been long enough exposed to denuda- tion to reduce them to a water-sculptured form, in which the slopes are trenched by numerous ravines, and the ridges are notched by passes which break the crest-line into peaks, and everywhere develop topographic detail dependent on the un- equal hardness of the bedded components of the mass. Much of the detritus taken from the upper portions is now lodged in the depressions between the adjacent ranges. Variety of form has thus been gained, and a marked feature of this variety is that it all tends to the better collection and discharge of the rain that falls upon the ranges. The topographic variety is now near its fullest development, and with further denudation it must lose strength; the ravines will consume more of the mass, the passes will be lowered and the peaks will be attacked and reduced from all sides. The original structural form will be then even less distinct than now, and a continually closer approach will be made to the ultimate featureless base-level lowland, to which all land forms are in time reduced, if no disturbance, such as elevation, interrupt the normal simple progress of their geographic evolution. Some mountainous variety of form must in a similar manner have obtained for a time im central Connecticut and Massa- chusetts, when the strongly faulted monoclinal blocks were laterally furrowed by ravines and notched by passes. This may be provisionally called the Jurassic stage of the evolution of our district. But even mountainous ridges are not perma- nent. Given time enough, and the faulted ridges of Connecti- cut must be reduced to a low base-level plain. I believe that 430 W. M. Davis—Topographic Development of the time enough has already been allowed, and that the strong Jurassic topography was really worn out somewhere in Creta- ceous time, when all this part of the country was reduced to a nearly featureless plain, a “ peneplain,’ as I would call it, at a low level; a plain that was broadly uplifted in early Tertiary time—or thereabouts—and thus thrown into another cycle of destructive development, and whose elevated remnants are now to be recognized in the crystalline uplands on either side of the present Triassic valley of Connecticut and Massachusetts (Emerson), and in the crest-line summits of the main trap ridges. The general equality of upland altitude on very diverse structures is the essential argument for the base-leveling of the region; but it is not intended to discuss this in detail at present. The post-cretaceous elevation that lifted the ancient lowlands was greater in the interior than near the coast, and our present valleys are deeply sunk and broadly opened in it. An extension of the same ancient lowland, now similarly ele- vated and dissected, is to be found in northern New Jersey. Standing on a commanding point of view, such as the fine drumlin a mile or more southeast of Meriden, whence the main trap ridges may be seen for many miles north and south, one must in imagination refill the low ground with the shales, sandstones and conglomerates that have been worn away, and thus raise the surface up to the level of the main trap ridges, or even a little higher, in order to perceive the form attained by the land in the late stage of the degradation of the dislo- cated Triassic blocks, when all this region stood lower. It was only after the close of this first eycle of degradation and after the elevation of the country to something like its actual altitude at a later date that the beginning of the present or second cycle of valley-making was reached. Some unmeasured part of the Tertiary and later time has been allowed for this part of the work. In the crystalline rocks, the valleys are narrow and steep sided, as is so finely shown in the expressive topographic map-sheets of western Massachusetts ; but in the Triassic area, where the sandstones are relatively soft, the valleys have been widened out into broad lowlands, only the thicker trap-sheets retaining still some indication of their former altitude. The latest touches have been given to their form by glacial action, both destructive and constructive, as well as by river deposits in the valley bottoms and by estuary deposits in the coastal districts. Except in terrace and gorge cutting, post-glacial erosion is insignificant. If this sketch be correct, we may conclude that the present topography is not an immediate product of erosion on the Jurassic deformations of the Triassic beds ; it is an uncompleted advance in a second eycle of development, with recent complications by glacial ac- Triassic Formation of the Connecticut Valley. 481 tion and slight changes of level. Like mountains of repeated growth, this topography may be called “polygenetic.” The present form of the region.is modeled with reference to at least two base-levels. Just as southern Idaho and central Nevada furnish illustra- tion of the initial and somewhat advanced topographic forms assumed in the development of our Connecticut district, so there will doubtless be found somewhere on the earth, regions of similar structure, presenting actual illustrations of its later stages, when its stronger forms were subdued and finally worn down to the featureless surface or peneplain of its old age. Thus the evolution of the region will be better understood. By this process of comparison,* we may not only restore in some measure the past history of our region, but may as well look into its possible future. When later elevation raises our eastern continental slope to still greater altitude and exposes the mass of the land to still deeper attack by erosive forces, it may happen that the base-level will take such a position as to allow the discovery of the ridges of fundamental crystal- lines between the fault lines at the base of the Triassic trough ; and this stage has its forerunner in a district of northern China (Shantung), described by Richthofen.t The structure of the district is summarized as consisting of crystalline schists of steep dip, unconformably overlain by Cambrian sediments; this compound mass is broken by a system of sub-parallel faults running east or southeast, with upthrow on the southern side, and with a tilting of the faulted blocks by which the uncomformable cover of Cambrian sediments dips southward toward the faults. |The deformation is ancient, and subsequent denudation has exposed the fundamental ecrystallines in long narrow ridges, which by their superior hardness have become water sheds (whether they have always been so or not does not appear, as the successive cycles of river history from the first to the present are not deciphered), while the Cambrian sedi- ments remain in narrow monoclinal strips between every ridge and the next fault to the south. The bottom of our Connec- ticut trough may some day be. worn into similar ridges and valleys. * During the preparation of this paper, I have had pleasure in meeting evidence of the value of the method here outlined in an essay by Dr. V. Hilber of Graz, Austria In discussing the origin of cross-valleys, he suggests an inductive illustration of their development, as follows: ‘* Auch eine Methode welche in der vergleichende Hrdkunde noch kaum Anwendung gefunden hat, welche aber auch fiir andre Fragen derselben beriicksichtigenswert erscheint .... ist das Auf- suchen derjenigen Oberflachenformen, welche als Entwickelungsstadien der vol- lendeten Erscheinung betrachtet werden kénnen.”’ Die Bildung der Durchgangs- thaler, Pet. Mitth , xxxv, 1889, 15. + China, II, 239, Fig. 56. See also Philippson, Studien tiber Wasserscheiden, 119. . 432. W. WM. Davis—Topographic Development of the There is a peculiarity of the drainage of the Triassie belt that perhaps finds explanation through considerations such as the above. The Connecticut river from where it receives the Passumpsic between northern New Hampshire and Vermont, follows a line of ancient slates that lead it southward with direct course to the Triassic formation in northern Massachu- setts; 1t crosses this State with tolerably direct southern course and continues in much the same line across Connecticut as far as Hartford ; but there it turns to the southeast, and at Middle- town it leaves the soft Triassic rocks and enters the hard crystallines, which it follows through a deep and rather steep- sided valley to the Sound at Saybrook. This departure from the low escape now open to the river along the line of easy grades that is followed by the Consolidated railroad from Hartford to New Haven, calls for some special explanation. It is evidently an example of the same kind as those described by Jukes in his famous paper, “‘ On the mode of formation of some of the river valleys in the south of Ireland.” But it remains to be seen why the Connecticut should turn from the Triassic belt of soft sandstones which here might lead it to the sea, and why if so turning it should take a course to the south- east rather than to the southwest. Let it be admitted for the moment that the present course of the river is in the main inherited from the course that it had at the end of the development of the Cretaceous lowland ; and that the course that it had during this early cycle of development was consequent upon the original dislocations of the Triassic surface. It is natural enough that the initial drainage of a faulted area should be consequent ; we have excellent illustrations of immediately consequent drainage in the lava block country of southern Idaho, already referred to. Now if we can independently determine the probable direction of consequent drainage immediately after the time of dislocation in the lower Connecticut valley, and if this correspond to the present course of the Connecticut where it turns from the Triassic to the Crystalline rocks, the explanation offered may be at least deemed worthy of further examination. The simplest method of determining the direction of the initial consequent drainage of the dislocated Triassic surface involves a reconstruction of the primitive form that the surface would have had if its dislocation had not been accompanied by erosion; the “structural surface” of la Noé and Margerie. This may be done most easily by developing the surface of the great lava flow that we now call the main trap sheet; restor- ing its lost portions by extending it upwards into the air along the plane of its dip, and stripping it bare where still covered ; but limiting every part of the reconstructed surface by the Triassic Formation of the Connecticut Valley. 488 fault planes that bound the several blocks. The original surface of the uppermost bed of sandstone would have been essentially parallel to this surface of the trap sheet, but a few thousand feet higher. Percival long ago called attention to the great curve of the main trap sheet from the Hanging Hills to Mount Holyoke in Massachusetts. The restored surface of the sheet, although somewhat interrupted by faults, forms a great half-boat, with the keel along the line joining the ends of the curve and the western side of the boat following the main trap ridge. ‘The boat may be enlarged by extending the sheet southeast from the Hanging Hills through Lamentation, Higby (Besick), Paug and Toket Mountains to the eastern margin of the Triassic formation north of Branford. In this portion of the curve, the faults are much stronger than farther north ; but viewed in a large way, the whole sheet from Toket to Holyoke may be regarded as a somewhat broken half-boat, in the attitude already described, with the bow at Belchertown, Massachusetts, and the stern abowe Branford, Connecticut. Berore the Ore ceous base-leveling was completed, the western side of the half-boat reached much higher into the air than the crests of the main ridges reach now. The upper surface of the Triassic formation would have had a form similar to this, if not eroded. A drainage-system established upon it must have found outlet not to the west or south, where the side and the stern of the boat prevented discharge, but to the east, where the boat was open, and the location of the discharge would be somewhere about the lowest point of the keel. In other words, the chief stream of the region, during the early development of the dislocated country, would have run out to the east, some distance north of the point where the main sheet now reaches the crystalline rocks on the eastern margin of the formation. This corresponds with the general course of the Connecticut closely enough to give some degree of acceptance to the explanation ; and the lower Connecticut may therefore be tentatively classified as an originally consequent stream, which has lived far through one cycle of life, and has now in obedience to the general eleva- tion of its drainage area, entered a second cycle in which it is well advanced, still persisting more or less closely in the course chosen in its first cycle. Thus explained, it may be called in this portion of its valley a revived river of originally consequent course. It is not intended to imply that the dislocated Triassic region ever had a purely “structural surface ;’ but only to indicate that the summation of all the movements of deformation, which would produce such a surface, sufficed to throw the drainage of the region into the area of least elevation. 434 W. F. Hillebrand—Analyses of three The objection to the explanation does not seem to me to be in its inherent improbability, for I believe that every step in the process may find its homologue in the present stage of other regions of similar structure but less age. The objection lies rather in a difficulty not yet named ; namely in the oceur- rence of a strong fault or series of faults, by which the eastern margin of the formation is determined, and whose upthrow is on the east. The drainage from the centripetal slopes of the Triassic half-boat must have surmounted this barrier in order to flow to Saybrook, and in doing so may have formed a large lake in the bottom of the boat, to be drained later on when the outlet was deepened. Whether suppositions so transcendental as these shall be approved remains to be seen. Cambridge, Mass., February, 1889. Art. XLIV.—Analyses of three Descloizites from new Localities; by W. F. HILLEBRAND. [Read before the Colorado Scientific Society, Mar. 4th, 1889.] 1. Mayflower Mine, Bald Mountain Mining District, Beaver- head County, Montana. THroucH Messrs. W. H. Beck and George E. Lemon of Washington, D. C., was received about a year ago for exam- ination a large lump of friable, uncrystallized material, having a dull yellow to pale orange color, and consisting chiefly of a vanadate, but carrying a large percentage of gangue. Two samples as pure as could be selected from different parts of the lump were analyzed with the following results : Molecular ratios. If, 106, Mean. - ——_—— —— BoOwetas 56-02 55-24 55-93 2508 } CuO an 1°16 113 1-15 0145 b TIO) Go oe 0-70 0-70 0°70 -oog7 f 4718 VE VANO), Lie LESS 15-91 15-94 -1968 VEO Mma een 20-80 20-80 1140 J As:Os_... 0°39 sae 0°32 “0014 $1173 1:00 PrOVowel 0:27 te 0:27 0019 | EEO) le 4-36 437 oy) Vk | 2-07 SiGua oe 0-20 0-16 0-18 CNG). ae 0-10 Be 0-10 MgO ____- 0:06 Dane 0:06 99-82 From I 27-62 per cent of gangue insoluble in cold dilute nitric acid has been deducted, and from II 22:20 per cent; manganese was present in the gangue in small quantity, appar- ently as pyrolusite, but it was not dissolved by the acid. The insoluble portion was found also to retain very small quantities Descloizites from new Localities. 435 of lead and zine, which were estimated and included in the analysis as probably belonging to the vanadate. The water had to be estimated indirectly by deducting from the total amount of water afforded by the dried mixture of vanadate and gangue that belonging to the latter alone, which was found as follows. The mixture, dried at 100° C., was dissolved in cold dilute nitric acid, and the insoluble matter collected in a Gooch erucible was dried at the same temperature and then ignited. The loss on ignition gave the water in the gangue, there being no ferrous iron in the latter to influence the result. The traces of Si0,, CaO and MgO may be neglected as proba- bly derived from she gangue. The water, it will be noticed, is double that required by descloizite, R(OH)VO,, but in view of the liability to error inherent in the method of water estimation employed this is not deemed sufficient cause for separating the mineral from descloizite, although the close agreement of the two water determinations, made as they were on samples containing different proportions of gangue, would indicate the correctness of the formula 2[R, (OH)VO, (eee O. Other specimens have since been received from the above named persons in which the earthy vanadate was associated sometimes with compact cerussite and galena in process of alteration. A dull reddish substance which constituted a part or even the whole of some lumps contained, besides silica, iron and some antimony in an oxidized condition, but carried little or no vanadium. Professor F. A. Genth has already called attention* to the occurrence of vanadinite and probably of descloizite in the Bald Mountain mine, Beaverhead County, Montana. His specimens, however, showed the supposed descloizite as a pale brownish crystalline coating on yellow ferruginous quartz, whereas the present mineral shows no evidence of crystalline structure. 2. Commercial Mine, Georgetown, Grant County, New Mexico. This is one of the most interesting occurrences of descloizite known, because of the extreme brilliancy of coloring of the inineral. The ore bodies in the Commercial mine, as well as in the adjoming MacGregor and Naiad Queen mines, occur in limestone immediately under an overlying slate, and appear to narrow in depth where certain eruptive dikes cut through the lime, as Mr. MacIntosh, foreman of the Commercial mine, in- formed me. The absence of the superintendents of the several mines and the very brief visit I was forced to make prevented obtaining more certain and detailed information. * Proc, Am. Phil. Soc., xxiv, 38, 1887. 436 W. F. Hillebrand—Analyses of three In places where the rock is most fractured and crushed the descloizite appears in greatest quantity and finest condition as an incrustation on quar 2, often covering large surfaces, and in color varying from yellow through all shades of orange-red to deep reddish brown, the last named colors predominating. The black color so frequent in descloizite from Lake Valley, New Mexico, caused by a superficial coating or admixture of pyro- lusite, is so far as my observation extended, wanting, hence specimens from Georgetown are likely to be much sought after for their showy appearance. A specimen in one of the banks at Silver City, New Mexico, taken from one of the Georgetown mines, resembled a stalactite in form. It was probably fully three feet in height by six to eight inches or more in diameter, and was deep reddish brown in color. The incrustations are for the greater part distinctly crystal- line and are generally made up of aggregates of more or less globular forms of a size ranging from microscopic to a diameter of one or two millimeters. Each of these is composed of a great number of apparently flat crystals, intergrown, and pro- jecting sufficiently from the surface to give brilliant reflections when observed under the lens, and to the naked eye a frosted appearance where the globular growths are largest. The richest reddish brown color is always coincident with this development in size. The globular character changes fre- quently to acicular. In such cases the incrustation seems to have originally formed on bunches of radiating acicular, almost colorless, vanadinite, which frequently appears thus coating the quartz and running under the descloizite incrustations. Some- times the vanadinite has entirely disappeared, and then there may be a hollow through the center of the descloizite needle. The occurrence of vanadate of lead in the MacGregor mine at Georgetown has been noticed by Professor Genth (1. ¢., p. 38). The specific gravity of the mineral was not determined; the hardness is about 3°5; the color of the powder is orange- yellow. An analysis gave the following results after deduct- ing 11:91 per cent of insoluble matter, almost entirely quartz. Molecular ratios. See Se SSS PbO ___. 56°01 2512 ) COMO S555) 05 0132 ; : a Ua ye Pra ' 4843 4788 412 WN) See Ue 2189 | Vic Once 20°44 1119 AsoO5.2. 0:94 "0041 + +1178 °1162 1:00 POs eb sint0-26 0018 J JELOe Asse | Bek “3 Gees 1361 eally ON 0:04 “0011 SO} 52551) WADI CaO-ae 0°04 MgO _. 0:03 Descloizites from new Localities. 437 The third column of molecular ratios gives those values after allowing for admixed vanadinite calculated on the basis of the chlorine found. A further correction has probably to be made for an admixed soluble hydrous (zine %) silicate, which might make the ratio approximate more closely to 4:1: 1. 8. Lucky Cuss Mine, Tombstone, Cochise County, Arizona. Mr. W. F. Staunton, Superintendent of the Tombstone Mining and Milling Co., and Mr. Frank C. Earle, assayer at Tombstone, kindly placed at my disposal for examination specimens of a vanadium mineral the identity of which had not been estab- lished. It was found in the Lucky Cuss mine as an incrusta- tion, sometimes half an inch thick, on quartz, showing more or less botryoidal surfaces of an indefinable dull greenish color. On a. fractured surface the color is brown; the luster is resinous; the structure granular, only occasionally diverging fibrous; the hardness 3°53; the specific gravity of sample analyzed, containing a little impurity, 5°88 at 19° C.; color of powder lemon-yellow. Analysis gave the following results after deducting 0°67 per cent of insoluble matter. Molecular ratios. ue RS PbO ___. 57-00 ‘2556 | “ : 2 | pl ‘ ID ee) Re NEE IBN EE Van) Joa OG) ‘0517 J Won. eee ee Oe PASE @ ena ee eill() “0048 - °1145 “1115 1:00 AO 2 Op ILe) 0013 150), 228 DG) *1389 pokey °1389 1:25 Clg snes 0:07 “0020 SOs, een COP) (ORK) a SLO MgO... 0:04 KOR sae 0310 Na.O meses 0°17 OOS Zn bee “ORS 98:99 The low total is probably owing to a loss of zinc during analysis. Calcite was present as an impurity, and as the OO, just suffices for the CaO and MgO these are rejected in con- sidering the composition of the vanadate. The figures in the third column of molecular ratios are found by allowing for probably admixed vanadinite calculated from the chlorine found. In another specimen a qualitative test for chlorine indicated a greater admixture of vanadinite. As in the case of the descloizite from Georgetown, New Mexico, previously described, a further allowance has perhaps to be made for a soluble hydrous silicate. There can be no doubt that the general formula for the vanadate is that of descloizite. 438 W. & Hillebrand—Analyses of three Descloizites. In almost every respect this mineral resembles, so far as the published descriptions allow of judging, the descloizite of Penfield,* the cupro-descloizite of Rammelsberg,t+ and the ramirite of de Leon,t perhaps also the tritochorite of Frenzel,§ to the similarity of which with his variety of descloizite Pen- field draws attention in his paper. Professor Genth’s surmise (I. ¢., p. 389) of the specific identity of all these substances seems highly probable. Characteristic for the present variety is the greater replacement of the lead-zine vanadate—true deseloizite—by the isomorphous lead-copper vanadate, and the lessened tendency toward a fibrous stracture, which in the other varieties described seems to be a decidedly pronounced feature. Possibly this last characteristic of the Tombstone mineral, if it be not accidental in view of the few specimens (three) examined, is a condition of the first. According to Rammelsberg,| the lead-copper vanadate cor- responding to the lead-zine vanadate (descloizite) is mottramite or psittacinite, though it seems not improbable that it may be the chileite of Dana’s Mineralogy, Domeyko’s analyses,4 which led Kenngott to ascribe the above name to the Chilian mineral, show a deficiency of 2°5 and 2°8 per cent, which may very well be V,O,. At all events, a recalculation of his analyses based on this assumption leads to a proportion for PbO-+Cu0: V,O,: H,O of nearly 4:1:1. In view of the well defined character of all these highly cupriferous varieties of descloizite it would be well to designate them once for all by some distinctive name. Tritochorite would have precedence if the substance to which that name has been given is really identical with the others, but Ram- melsberg’s cupro-descloizite is more appropriate as indicating at once the relationship to descloizite, and I would suggest that it be henceforth used for all cupriferous descloizites show- ing the physical characteristics of the mineral above described. Norr.—Since the foregoing was written there has appeared in the Bull. Soc. Franc. Min., Feb., 1889, p. 38, a paper by F. Pisani, in which he gives another analysis of the Mexican cupro-descloizite and discusses briefly the relations of various vanadates. The essential identity of all the above enumerated cupriferous lead- zine vanadates, with the addition of another—schaftnerite—con- cerning which I have been unable to find any further reference in mineralogical literature, is therein upheld, and the suggestion of Penfield’s regarding the possible identity of tritochorite and * This Journal, III, xxvi, 361, 1883. + Monatsb. Berl. Acad., 1883, 1215. + La Ramirita, nueva espéce mineral, Mexico, 1885. § Tschermak’s Min. and Petr. Mitth., iti, 506, 1880; iv, 97, 1881. || Chemische Natur der Mineralien, p. 32. 4{| Ann. d. Mines, IV, xiv, 150, 1848; Phil. Mag., III, xxxiv, 395, 1849. J. E. Whatfield—New Meteorite from Mexico. 489 cupro-descloizite is confirmed by Frenzel himself, who is quoted as writing to Professor DesCloizeaux that he had not thought it necessary to consider as an essential constituent the two per cent of water which he had found in tritochorite. Laboratory of the U. S. Geological Survey, Washington, D. C., Feb. 9, 1889. Art. XLV.—A new Meteorite from Mexico; by J. EDWARD WHITFIELD. WHILE in Mexico during the summer of 1888, Prof. H. A. Ward, of Ward and Howell, Rochester, N. Y., obtained an un- described mass of metoric iron weighing 33:0 kilos. The meteorite was found ona peak of the Sierra de San Francisco, called La Bella Roca, in front of Santiago Papas- quiaro in the state of Durango. The date of its discovery and the name of the finder are unknown. The two greatest dimensions of the mass are 24:13 x 34:92™: an idea of the shape and general appearance may be had from the accompanying cut which shows what is supposed to be the front and back of the meteorite, at least during the latter part of its flight. Am. Jour. Sct.—Tuirp SERIES, Von. XXXVII, No, 222.—Junz, 1889. 28 440) J. EF. Whitfield—New Meteorite from Mexico. The composition of the metallic portion does not differ materially from that of other meteorite irons as the following analysis will show. |My eat ts A, he ee ee 2 91°48 IND Se Ser ae 3 ee 7:92 Clouse aan So ee ee 0°22 TP Rint 2 2 0°21 tage ahs 1 a URL IL O22 0-21 Cae ge, 5S ee gee 0°06 100°10 A feature of the meteorite is the presence of large, deep pittings on one side; these are a little greater in diameter just below than immediately at the surface and each one has a little substance left at the bottom, which evidently is the re- mains of what originally filled the cavities. I sueceeded in breaking from the bottom of one pitting material sufficient to determine its nature. It proved to be troilite as the analysis will show. NiS 2:13, FeS 85:27, Fe 9°37. The exposed surface of the troilite was greatly decomposed ; this portion gave by analysis the following figures. NiS 2:07, FeS 37:51, Fe,O, 37°80, Moisture =19°85. This decomposition gives grounds for the idea that the deep pittings were formed by the removal of troilite nodules, partly while the mass was hot and partly by the subsequent weather- ing. There are nodules of troilite throughout the entire mass of the meteorite but none are removed, so as to form pittings, on any other part of the surface but the side which is supposed to. have been the front. The mass is deeply furrowed, as may be seen to some extent in the figure, and all the furrows tend away from the side containing the pittings. Slices of the meteorite, when etched, show rather coarse Widmanstittian figures and also dark diagonal bands of troi- lite. From the locality in which this meteorite was found it is but proper that it should be called ** La Bella Roca.” T am indebted to Messrs. Ward and Howell for the material for examination and the privilege of description. Chemical Laboratory, U. S. Geol. Survey, Washington, D. C., March 3d, 1889. E. S. Dana—Petrography of the Sandwich Islands. 441 Art. XLVI.— Contributions to the Petrography of the Sand- wich Islands; by EDWARD 8. Dana. With Plate XIV. THE rock specimens, the results of whose study are detailed in the following pages, were in part collected by Professor James D. Dana on his trip to the Sandwich Islands in August, 1887, and the remainder by the Rev. E. P. Baker of Hilo in 1888. The first series includes about thirty specimens from Kilauea, a third of them from the projectile deposits on its borders; several from other points in Hawaii; about a dozen specimens from the island of Maui, chiefly from the extinct crater of Haleakala; and finally an equal number from different points on the island of Oahu. The special localities are mentioned beyond. The second series of specimens are all from Hawaii, and chiefly from Mokuaweoweo, the summit crater of Mauna Loa. There are also a few specimens from Makaopuhi and Nanawale on Hawaii, points which belong to the Kilauea region. For our-present knowledge of Hawaiian lavas we are in- debted in the first place to the general descriptions of J. D. Dana in the Geology of the Exploring Expedition (1849), and W. T. Brigham in his Notes* on the Voleanoes of the Hawaiian Islands (1868); also C. E. Dutton (1884) and others. On the other hand, on the petrographical side, there have been published the microscopic study of basaltic glass of Hawaii, especially Pele’s Hair, by Krukenbergt in 1877; a paper by Cohen¢ devoted chiefly to the glassy basaltic lavas of Hawaii; brief descriptions of isolated specimens of nepheline basalts beliewed to have come from Oahu by Wichmann§ and by Rosenbusch ;| finally a recent memoir by Silvestri] describing a series of ancient and modern lavas from Kilauea collected by Prof. Tacchini in 1883. 1. Lavas of Mauna Loa and its summit crater, Mokuaweoweo. For the collection of lava specimens from the summit crater of Mauna Loa, the writer is indebted, as is stated above, to the Rey. E. P. Baker.** The collection is a large one and evidently * Mem. Boston Soc. Nat. Hist., vol. i, pt. 3. + Mikrographie der Glasbasalte von Hawaii, petrographische Untersuchung von C. F. W. Krukenberg, Titbingen, 1877. ¢ Jahrb. Min., vol. ii, 23, 1880. § Janrb. Min., 172, 1875. || Mass. Gesteine, 510, 1877. §| Bull. Com. Geol. d'Italia, xix, 128-143, 168-196, 1888. ** Mr. Baker's extended trip over Hawaii, which included, besides an explora- tion of the summit crater, a visit to the sources of several of the great lava streams, was undertaken in order to make the collections of rocks and gather facts with regard to the eruptions, and some extracts from his notes are published in this volume at p. 52. The results have proved to be of very great interest. 442 EF. S. Dana—Petrography of the Sandwich Islands. represents well the characteristic types of rocks. It numbers, exclusive of the ‘‘ pumice” and scoria upwards of seventy speci- mens; of these about fifty have been subjected to microscopic study. In regard to the geographical distribution of the rocks with reference to their relative age but little can be said. A considerable part (Nos. 90-109) are from the talus within the southern crater of Mokuaweoweo against the neck between ' it and the central pit. (See the map in vol. xxxvi, plate II). A number of others (78-89) are from the eastern side of the central pit; and in the case of scattering specimens, the spe- cial source is mentioned more minutely beyond, when interest seems to attach to it. In general it may be said that all the specimens in hand from Mauna Loa belong to the same class of basaltic lavas, although they vary widely: in color from dark gray to light gray or dull brick-red ; in structure from compact to highly cellular or vesicular; from those of uniform grain to those which are prominently porphyritic with chrysolite or feldspar; and in composition from the very highly chrysolitic kinds to the feldspathic or augitic forms with little or no chrysolite. Speci- mens of pumice-like scoria are largely represented in the col- lection. The specimens may be divided pretty sharply into two groups, besides which there are several other types more or less distinct from these. Clinkstonelike basalt.—The first of these doubtless includes the rock which former observers have spoken of as resembling phonolite. Macroscopically it has a uniform fine-grained texture, for the most part free from vesicles and apparently compact, though often found on closer examination to be minutely porous. The color varies from a dark bluish gray to light gray, and to dull brick-red or brown, the grayish kinds being the most common. The specific gravity varies from 2°82 to 3:00.* Many of these specimens, as taken from the talus between the central and southern craters, are in the form of thin slabs and their resemblance to clinkstone in the hand specimen, though not going beyond external aspect, is sufii- ciently close to explain their having been so named. As regards composition the rocks of this type are most strongly marked by the fact that the chrysolite, which is so common in large grains in the other specimens to be described, is absent or only sparingly present. The microscopic characters of this group of fine-grained compact rocks are also such as readily to distinguish them from the other forms. In general they consist of augite and plagio- * Some of the separate determinations on fragments freed from air by boiling are :3°00, 2°94, 3-00, 2°87, 2°82, 3:00, 2°82. ° ES. Dana—Petrography of the Sandwich Islands. 443 clase, and titanic, or magnetic iron or both, prominent, but with little or no chrysolite. Their most interesting feature is the form taken by the augite, which is only exceptionally devel- oped as an idiomorphie constituent, but on the other hand is not simply a formless substance filling the spaces between the feldspar. It is uniformly, though with varying degrees of distinctness, grouped in radiating forms, fan-shaped or feather- like, of great variety and beauty. This structure is eminently characteristic of this group of rocks. It is shown best in a fine-grained purplish colored speci- men (No. 97, G.=2°82). Thisis seen under the hand glass to be minutely porous though not properly vesicular, with minute slender red crystals (augite) projecting into the cavities. An occasional grain of chrysolite can be detected in the mass and cleavage sections of feldspar are also seen. Under the microscope it is made up of lath-shaped feldspar individuals and the beautiful groupings of augites, these set out in relief by the fine grains Feather-forms of augite; a(x 35), b (x 35), c( x 50) from Mokuaweoweo, d(x 170) from Kilauea. of iron ore surrounding them. In the simplest cases the augite is bunched together in long parallel groups slightly diverging at the extremities; generally these branch off at various points into feather-like or dendritic forms, of such variety as to be 444 Ff. §. Dana—Petrography of the Sandwich Islands. beyond description. Groups of these forms radiating from a center are common.* The accompanying figure, 1, shows several of the more complex of these forms (a, > from this specimen) and gives a fair representation of this remarkable structure. Figure 2 gives the appearance of the entire field of the microscope, showing forms like the frost crystals occasionally seen on a stone pavement; this figure is simplified by the omission of some of the less defined parts. Some of the simpler rosettes are made up of both feldspar and augite alike radiating from a common center; and fre- quently the extremities of the feather ends are feldspar indi- viduals. Figure 3 gives a detailed drawing of part of one of Detailed drawing showing the feather-like grouping of augite and feldspar. Magnified 100 times. Feather-augite in basalt from Mokuaweoweo. Magnified 60 times. the groups. It would seem that the feldspar was as usual first separated, and the augite as it crystallized out into these den- dritic forms drew the feldspar needles into position with it. The two minerals are sometimes so intricately involved with each other that it requires close examination to separate them. In polarized light the distinction comes out more sharply. _ * Mr. H. Hensoldt of New York has called the writer’s attention to an augitic lava from Tahiti in which the pinkish, pleochroic augite is present in radiating groups of acicular crystals, often having a nucleus of chrysolite. The section is one of very exceptional beauty and interest, although the arrangement of the augite is hardly to be compared with that here described, since the individual crystals are sharp and geometrically grouped—after the manner of the tourmaline in luxullianite—which is in marked contrast to the feather forms of the Mauna Loa augite. E. S. Dana—Petrography of the Sandwich Islands. 445 Occasionally the feldspar is present in larger forms; and more interesting to note is an occasional augite crystal (fig. 1, 4) that evidently belongs to an earlier generation, and shows the distinct cleavage, and more or less also the crystalline outline of the species. The alteration to which this specimen, with others like it, has been subjected, and to which the red or purple color of the rock in the mass is due, has stained the iron red and reddened also the augite, although only exceptionally to such an extent as to make it opaque. The alteration spoken of may be simple weathering, although the occasional brick-red color rather suggests the action of hot water or steam; the feldspar remains perfectly clear and unchanged. From the specimen described, which may be taken as the type, we pass to the coarser grained kinds on the one hand and to the very fine-grained on the other; both of these still retain- ing, however, the same general characters. A highly cellular specimen (74) with large vesicles, from the northwest brink of the crater, departs in general aspect most widely from the type ; but, while relatively coarse-grained, it exhibits the same group- ing though somewhat more rigid and geometrical, and shows even more clearly the mutual relations of the feldspar and augite. In the finer grained varieties (as 78) the augite sometimes pre- dominates so largely that the whole becomes like a confused carpet pattern of interlacing arabesque forms, though here, when an individual form can be traced out, it has great beauty and. perfection, branching and re-branching like some delicate forms of vegetation. Figure 1, ¢ is an attempt to illustrate one of these forms, but it lacks the delicacy of the original. These forms consist almost exclusively of augite with very little feld- spar. In another specimen of similar character a partial fluidal structure was noticed in the arrangement of the feldspar. When the iron grains are only sparingly present and there has been no conspicuous alteration, the rock is of a light uniform gray, but the presence of iron in large amount makes it nearly black and obscures this structure; and when it and the augite are highly altered, the rock is a bright brick-red and in a section appears as a collection of nearly opaque red rosettes, the feldspar, however, still remaining clear. Glass is present occasionally, but usually in insignificant amounts, and for the most part it is nearly or quite absent. This feather-form of augite, which has been described, is not entirely confined to the clinkstone-like varieties of lava although eminently character- istic of them. It was occasionally noted more or less distinctly, in some other forms, especially the vesicular kinds to be men- tioned later (p. 450) where it is seen in the minute second- generation augite which formed in the last process of consoli- dation. All the facts observed serve to connect its formation with rapid cooling. 446 HE. S. Dana—Petrography of the Sandwich Islands. Chrysolitic basalt—The second group of rocks makes a very marked contrast with those just described. These are of coarse grain, often open-cellular, and very highly chryso- y : "4 fon } matali A a ee Pee ee ae ‘ +--+ mire \ 1. | 15; ! ena 2 ~ t, Nor es as i { | | I pe a EUS. ' —— Chrysolite in part with orientated titanic iron; a—f( x 55-60), from crystalline- basalts of Mokuaweoweo. g ( x 75) from basaltic glass, Mokuaweoweo; h (x 60) from Nanawale; (x60) Kilauea; /(x100) crystal enclosing glass, Kilauea; m (x60), forked form, Maui: 2 (x60) portions of crystal enveloped by augite- and clusters of magnetite grains, Maui. Oe E. §. Dana—Petrography of the Sandwich Islands. 447 litic; on this account the specific gravity is much higher, it varying from 3:00 to 3:°20.* In many cases they have suf- fered some alteration which has given them a dull waxy sur- face, while the large grains of chrysolite are frequently iridescent and sometimes have an almost metallic luster. The color varies with the amount of iron oxidation from light gray to dull red- dish gray or brown. The mineral constituents present are those of normal basalt; and most prominent among these is the chryso- lite; in some specimens it must make up nearly half the mass of the rock ; and in one ease (102) probably more, this particular specimen haying the unusual specific gravity of 8:20. The chry- solite was evidently early separated from the magma, and the changes of condition through which the lavas have passed is well shown in the irregularly corroded or occasional broken form of many of the crystals and grains. Even when there is a distinct crystalline outline, it is not a rare thing to find the erystal broken and the parts slightly separated. This is shown in the accom- panying figures 4, ato, f Some of the corroded forms take very fantastic shapes. A novel and common feature of this chryso- lite is the occurrence of very slender acicular forms. The length is often considerable, even when viewed macroscopically, in one case 2 to 3™™, but in breadth they are often hardly more than a line, (note fig. 4, @.) This chrysolite shows the partial alteration alluded to in a broad rim of brown iron oxide; we can pass in the same slide from a crystal still preserving its transparency throughout, to those where only a string of chryso- lite grains mark the position of the original individual, and from these to the cases where a narrow brown line of iron oxide alone is left; in a few cases (as 94) the chrysolite is stained bright red, showing that there has been oxidation of the iron without hydration. The orientation of these peculiar rod-like forms, which are distinctly visible on a polished surface of the rock, is a matter of some interest. The fact that, in such a form as that of fig. 4, b, and others like it, the plane of the optic axes is transverse to the longitudinal direction and the bisectrix normal to the surface presented, shows that they are elongated in the direction of the vertical axis, the narrow dimension being that of the macrodiagonal. This chrysolite has often an unusually deep green color possibly connected with the partial alteration, and then shows distinct pleochroism with the absorption least in the direction of the vertical axis. It often shows spherical inclusions of a pale brown glass, sometimes arranged in parallel lines. * Some of the separate determinations gave: 3°09, 3°18, 3:09, 3:04, 3°00, 3°20, 3°00. 448 F&F. §. Dana—Petrography of the Sandwich Islands. The plagioclase feldspar is present in the ordinary forms, and shows no unusual features. The augite forms irregular grains crowded among the feldspars. Occasionally augite in larger more distinctly crystallized forms appears, evidently belonging to an earlier generation. This earlier augite shows the tendency, often observed, to cluster about the chrysolite grains. The titanic iron is not as a rule abundant, and for the most part appears in long slender rods often parallel among themselves over a limited area, and sometimes orientated by the chrysolite. In two or three of the specimens of this class the augite shows a tendency to assume the radiating form but this is the excep- tion. Apatite is probably present in some sections, but only in small amount, and in most cases it was not detected. Glass is almost entirely absent from these rocks. The occasional fractured character of the chrysolite has been spoken of; one specimen (90) shows this in an extreme degree, the chrysolite being separated here into many angular frag- ments for the most part showing no crystalline outline. The feldspar and augite individuals have also suffered in the same way and the ground mass has a curiously mottled microcrys- talline structure suggestive of some porphyry. This specimen stands comparatively alone, although two or three others are of somewhat similar character. Lavas with minute crystals of feldspar and augite in their cavities.— Allied to this second class of rocks just described, are a number of specimens which are interesting because of their re- markable crystalline structure. One of these (82) is a light gray rock with only occasional vesicles. It is, however, throughout open and porous with minute cavities into which project thin tabular crystals of feldspar seen distinctly with a strong hand- glass. MSR AB a nt aang Fy Sa, a8 tity ya4* ‘ a Ohi er Ane Qan, rt | aa ers (27 ' aan sae 5 6 A\n hp, vy | - a LY an a ™ a Yau iy Ba Nay, tecseng. gent aw spit 7 anim eks Cr it 1 ; aR aminhh aL Ve F p A P ie es eA Ae @ Md Lapa atte Se z 3 f } A Biba gitmmnn med Leia. 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