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A charge is made on all overdue books. University of Illinois Library M32 Digitized by the Internet Archive in 2010 with funding from University of Illinois Urbana-Champaign http://www.archive.org/details/panamericangeolo81891desm v) ys L a Py } Gl L by a THE MeMERICAN GEOLOGIST A MONTHLY JOURNAL OF GEOLOGY ALLIED SCIENCES EDITORS AND PROPRIETORS: SAMUEL CALVIN, Jowa City, Lowa. Epwarp W. CLayeoLe, Akron, Ohio. Francis W. CRAGIN, Colorado Springs, Colo. JOUN EYERMAN, Zaston, Pa. ANDREW C. Lawson, Berkeley, Cal. PeERSIFOR FRAZER, Philadelphia, Pa. ROLLIN D. SALISBURY, JZadison, IVis. Ropert VT. Hitt, Austin, 7evas. JosEPH Bb. TyRRELL, Offaiwa, Ont. Epwarp O. ULRicu, Newport, Ay. ISRAEL C. WHITE, Morgantown, W. Va. NEWTON H. WINCHELL, AZinneapolis, Minn. VOLUME VIII. Juty tro DECEMBER, 1891. MINNEAPOLIS, MINN, THE GEOLOGICAL PUBLISHING ComPANy. 189] L. KIMBALL PRINTING CO,, PRINTERS. 1 x \ ’ () = CONTENTS. JULY NUMBER. The Greylock Synclinorium. sa T; NELSON The Fuel Resources of ( ‘olor: ado, ry) LAKES ..... aes: C Pleistocene of the Winnipeg Basin. J. B. TyRR ELL 19 On a Leaf-bearing Terrane in the Loup Fork. F. W. ERE yi RRM MMO Se CARAS eee aie mara 29 wegen peries. G. ©. BROADHEAD.....:.....-...-. ao Some Recent Graptolitic Literature. KR. R. GurLEy.... BD The Floodplain and the Moundbuilders. Stepnen D. Peer 44 Review of Recent Geological Literature.—Chemical and gealogical essays, T. STERRY ag 51.—The fossil insects of North Americ a, SAMUEL H. ScuppEr, 52 Tertiary and post-tertiary changes of the Atlantic and Pagific coasts; with a note on the mutual relations of land ele- vation and ice accumulation during the Quaternary period, Jos. Le Contr, 54.—Composition of certain Mesozoic igneous rocks of Virginia, H. D. CampBeti and W.G. Brown, 54—The Cinnabar and Bozeman coal fields of Montana, W. H. W EED, 54.—On the recognition of the angles of crystals in thin sections, A. C. LANE, 55.—Johns Hopkins University scientific expeditions, 55.— Remarks on the reptiles commonly called Dinosauria, G. Baur, 55.—Two new reptiles, H. G. SEELEY, 56.—Geology of the Barbados, A. J. JuKEs-BROWNE, 56.—A revision of the Cretaceous Echinoidea of N. A., W. B. Cuark, 56.—Tables for the determination of minerals hy their physical properties, PeERstror FRAZER, List of Recent Publications, 58. Correspondence.—Fish remains in the Lower Helderberg of New Bruns- wick, G. F. MATTHew, 62. Personal and Scientific Nera np Scientific meetings at Washington Award of Geological medals. The Wheeling deep well. Miscel- lany. AUGUST NUMBER. The Recorded Meteorites of Lowa, with Special Mention of the Last, or Winnebago County Meteorite. — [Tl- lustrated.| Jos. Torrey and KE. H. Barpour...... O65 On the Contrast in Color of the Soils of High sand Low Latitudes. W. O. Crossy. cee ee te eee eek TA The Fauna of the Lower Cambrian or Bertisaclina Dana Jos. oh OTe a a x? 1\ Contents. The Fauna with Goniatites Intumescens Beyrich. J. M. tc.) Cen res He ER es 6 Ona Peculiar Form of Metallic Tron Found in Huronian Quartzite, on the North Shore of St. Joseph Island, Lake Huron, Ontario. [Illustrated.] G. C. Torr- MAME) CR css S06 a > SS 1 ee. 105 Editorial Comment.—Tlhe Crenitie Hypothesis, 110. Revivw of Recent Geological Literature On the nickel and copper depos- its at Sudbury, Ontario, A. E. Bartow, 114.—On the sequence of strata forming the Quebec group of Logan and Billings, with re- marks on the fossil remains found therein, Henry M. Amt, 146.— Qn the lower Cambrian age of the Stockbridge limestone, J. E. Wou.r, 117.—The geology of Mouot Diablo, California, 117,--Two belts of fossiliferous black shale in the Triassic formation of Con- necticut, W. M. Davis and §. Warp Lorrr, 118.—-Pantobiblion, 118. Geology of the environs of Quebec, with map and sections, Junes Marcov, 119.-Geological survey of New Jersey, Jonn C. Sock, 120.—The Texas Permian and its Mesozoic types and fos- sils, C. A. Wirrre, 120. List or Recent Publications, 123. Correspondence.—Area and duration of Lake Agassiz, WARREN Upriam, 126.—To the members and friends of the corresponding geological chapter of the Agassiz Association, FRANKLIN Barrows, 128.— Orange Sand, LaGrange and Appomattox, E. W. HitGarp and * James M. Sarrorp, 129. Personal and Setentific Nerrs, 131. SEPTEMBER NUMBER. Preliminary Notes on the Topography and Geology of Northern Mexico and Southwest Texas. and New Mexico... [Tilustrated.], | Rose. Ti Bisiiiw occu cease iss Additional Notes on the Devonian Roeks of Buchanan County, Formic. SS... CUAIS Wie eee as ech tea ee eee 142 The Ice-sheet of Greenland. WARREN UPHAM. ........ 145 An Episode in the Paleozoic History of Pennsylvania. K. Wee CA FROME er. kn ee eRe ee ee 152 Neolithic Man in Nicaragua. J. CRAWFORD.=')- = 20) s- 160 The Post-Archean Age of the White Limestones of Sus- sex County. N. J.. A Reply toa Review. Frank L. NABONS. \c>ci5-+ Sgsgeis beb= oc 9s + - bye 166 New Observations on the Genus ‘Trinacromerum, FF. W. ORAGIN G25 oe. 20 ee 171 On the Confounding of Nassa Trivittata Sey, and Nassa Peralta (Con. Sp.) Gitperr D. Harris.......... 174 Kditorial Comment. —Diminution of natural gas, 176.—-Supposed Trenton fossil fish, 178.—Man and the Mammoth, 180. Review of Recent Literature —Congres Géologique International. Com- pte rendu de la 4me Session, 188. —Mesozoic and Cenozoic forma- tions of eastern Virginia and Maryland, N. H. Dantrox, 185,—On Contents. \ the Triassic of Massachusetts, B. K. Emerson, 155,—Glacial grooves of the southern margin of the drift, 186.—Post-pleistocene subsi- dence versus glacial dams, J. W. SPENCER, 186.—On the Geology of (Quebec and environs, Henry M. Amr, 186.—Some new species of -Crinoids and Blastoids, Pror. R. R. Row.ey and Srp. J. Hare, 186. —Advance sheets from the 17th Report of the Geological Survey of the State of Indiana, Pror. 8.8. Gorby, 186.—-Second Annual Report of the Geological Survey of Texas, 1890, E. T. DumBLE, 187. List of Recent Publications, 188. Correspondence.—The so-called sand-dunes of East Hampton, L. 1., Joun é Bryson, 188.—-Viejo range, of Nicaragua, J. CRAWFORD, 190. Personal and Scientific News.—American Association for the advance- ment of Science, Washington meeting: The Geological Society of America, the summer meeting: Miscellany, 10. OCTOBER NUMBER. Beecherella. a New Genus of Lower Helderberg Ostracoda. eid. ys WO. ULRICH. .a3(.- 5: 25 .ci te... 197 Notes on the Muir Glacier Region, Alaska, and Its Geol- Seeeeslustrated.| H. P»CUSHING!:........... 207 Pleistocene Papers at the Washington Meetings......... 230 Editorial Comment.—Vbe International Congress of Geologists, Wash- ington meeting, 245. Review of Recent Geological LiteratureVhe Comanche series of the Texas Arkansas region, Rosperr T. Hit, 259,.—Carboniferous fossils from New Foundland, Sin J. WinniAmM Dawson, 259.—Proposed system of Chronologic Cartography, on a Physiographic basis, T. .C. CHAM- BERLIN, with Ve Geological dates of origin of certain topographic forms on the Atlantic slope of the United States, Wi_Ltram M. Davis, 260.—Variations in the Cretaceous and Tertiary strata of Alabama, Danret W. Lanapon, Jn., 260.—Bulletin of the Geologi- «al Society of America, Proceedings of the Third Annual Meeting, J. J. STEVENSON, Secretary, 261.—Arkansas Geological Survey; Manganese, its uses and deposits, R. A. F. Penrose, 261. List of Recent Publications, 265. Personal and Scientific News.—The Geological Map of Europe, 266. Pres- ervation of Glacial grooving on Kelly’s Island, 266. NOVEMBER NUMBER. The Attitude of the Eastern and Central Portions of the United States During the Glacial Period. TL C. SS RI RRR oy <8, 8) i ee ee ae 267 An Outline of Mr. Mellard Reade’s Theory of the Origin of Mountain-Ranges by Sedimentary Loading and Cumulative Recurrent Expansion: In Answer to Re- Gangcrmcoms, . MELUARDIRBADE........4. 0... 275 Notes on Cambrian Faunas. G. F. Marrugw.......... 287 The Source of the Mississippi River. — [{Illustrated.| J. We BROWER... ..°- bs: Re eee 20] Evidences of a Glacial Epoch in Nicaragua. J. Craw- SEMI ME PIRI Aree Oke Scent 0h le SIP 2 Bitsy cain S) i203. 2% prs 81k Se “0S BOG Vi Contents. On Cycles of Sedimentation, J. LAWTON WILLIAMS .... 315 Editorial Comment, 324. Review of Recent Geological Literuture. On the Vertebrata from the Ter- tiary and Cretaceous Rocks of the N. W. Territory of Canada, E, D. Corr, 326.—The British Tertiary Echinoid Faunas and their affini ties, J. W. GREGORY, fetes ~The Mesozoic and Tertiary Insects of New South Wales, rk. 1 STHERIDGEH, JIR., ard A. 8, OLLIFF, 327-—On the Osteology of Pobrotherium, W. B. Scorr, 327.—T he Tudor Specimen of Eozoon, J. W. Grecory, 328.—Stones for Building and Decoratio: , Geo. P. Merrit, 328.—Annual Report Geol. Surv. of Ark., J. C. BRANNER, F. W. Srwonps and F. V. Covin1e, 329. Meehan’s Monthly, 829. List of Recent Publications, 329. Correspondence. —VThe New Zealand Glaciers, Roperr L. Jack, 329.—Mr. Cushing and the Muir Glacier, G. FRepERick Wricit, 330, Personal and Scientific News, 331.— Universality of Gold. The Calumet and Ifecla Mine. Appendix.—A Catalogue of the Paleontological publications of Joseph Leidy, Jomn EyeRMAN, 333. DECEMBER NUMBER. Jean N., Nicollet [Portrait.). Non. WiIncHELL........ 345. Genesis of Iron-Ores by Isomorphous and Pseudomorous replacement of Limestone, JAMES P. KIMBALL...... 352 Criteria of Knglacial and Subglacial Drift, WARREN UpHam 376 The W innebago Meteorite. KE. N. Karon. BRh Editorial Conunent Recent studies in Spherulitic ( ry stallization 387 Review of Recent Geological Literature. Geological and Natural [History Survey of Canada, Annual Report, Vol. tv, New Series, ALFrep R. C. Senwyn, 387—Report on a portion of the West Kootanie Dis trict, British Columbia, Geo. M. Dawson, 392.—Report on an ex ploration in the Yukon and Mackenzie basins, N. W. T., R. G. McConneE.i, 394.—Report of Exploration of the Glacial lake Agassiz in Manitoba, Warren Upnam, 394.—Report on the Min- eral Resources of the Province of Quebee, R.W. Ents, 394.—Report on the Surface Geology of Southern New Brunswick, Roserr CHAMLERS, 594,—Chemical contributions to the Geology of Canada, from the laboratory of the survey, G. CRISTIAN Horrmann, 395.— Report on the mining and mineral statistics of Canada, iH. PB. BRUMEL, 595. Division of mineral statistics and mining; annual report for 1889, E. D. INGA, 395.Annotated list of the minerals occurring in Canada, G. CrristrAn ITorrMANN, 396,—Supplement A to Geo, L, English & Co.’s Catalogue of Minerals, 396,—From Japan to Granada, JAmues Henny Craprn, 396.— Note on rock speci mens collected by W. Gowland, Esq., in Korea, T. H. Honnianp, 396,—Descriptions of a remarkable new Genus and species of brachiopod, R. P. Witrrrtenp, 397,—The Potosi, Bolivia, Silver Dis - trict, ArrtHur F. Wenpr,397,—Fossil Botany, G. Somus-Laubacn, 397.—Fossil Resins, CLARENCE Lown ‘and: Henry Boorn, 398,- Geological Excursions, 1860-1890, Epwarpd STanrorn, 398, New minerals from the Serpentine belt at Easton, Pa., Joux Eyer MAN, 398. tdet of Hecent PUubucgttons. . ..... 053k .d ab aan amas tae ape n tee OYS Personal and Scientific News ..2...025cecc ees Hea ool atantats Seite 104 Thee to Viol: VETL , sees civics veoh cues ee eee eee 105. ERRATUM: On pave 291, line 7, for “* Microdescies,” read Microdiscus, : Ue - AMERICAN GEOLOGIST Vou. VILLI. JULY, 1891. No. IT. THE GREYLOCK SYNCLINORIUM,* T. NELSON Datez, Newport, R. I. The topography of the NW. part of Massachusetts is marked by three main parallel mountain masses having the N. NE. trend common to the Appalachian system. The most westerly of these is the Taconic range, the crest of which divides the states of New York and Massachusetts; the most easterly, situated about ten miles east of the N. Y. lineis Hoosac Mt. traversed by the Hoosac tunnel, while the central one is Mt. Greylock, the prevailing rock of which, farther south, merges in that of the Taconic range. Mt. Greylock forms a topographical unit, measuring about 14 miles in length and averaging about 5 in width, and consists mainly of one central and two lateral subordinate ridges with the same N. NE. trend. The ‘‘saddle,” from which it derives one of its ancient names, and which is a conspicuous object all through Berkshire county, is formed by a SW. bend in the central ridge between Greylock summit proper (3505 feet above sea level) on the north and Saddle Ball (3300 ft.) on the south. These are about two miles apart, and the lowest part of the saddle is 2900 ft. above sea level. *Abstract of a report by T. Nelson Dale, Assistant Geologist U. S. G. S. to Raphael Pumpelly, Geologist in charge of the Archean Division, covering field work done by the writer in 1886-1888 assisted during a portion of the time by Wm. H. Hobbs. This abstract is published by permission of the Director of the U.S. Geol. Survey. The full report, amply illustrated, and entitled ‘‘Mt. Greylock, its areal and structural geology,’’ goes to make up, together with a monograph by Raphael Pumpelly and one by J. E. Wolff, a memoir on the Green mountains, now in course of publication by the Survey. af 2 The American Geologist. July, 1891 Situated right in the midst of the Taconic region Mt. Greylock has been often alluded to during the last seventy years in the much debated ‘Taconic Question.”’ Professors C, Dewey, E. Emmons, E. Hitchcock and J. D. Dana are the principal authorities on the geology of the mountain, The general synclinal structure of the mass and also the fact that it consists mainly of certain schists underlaid by limestone are well known. Professor Dana has also conjectured the anticlinal structure of the hollow which separates two of its ridges. The following description is based upon the new 20 ft. contour map made by the topographers of the U. 8. Geological Survey, and upon extended and laborious geological explorations, and upon the careful microscopic study of lithological specimens by Mr. J. E. Wolff. The results of modern topography, orography and petrography have been brought to bear upon the subject. Structural. The rocks are all metamorphic and of few kinds: crystalline limestones and various schists, micaceous (sericitic ) chloritic, albitic, pyritiferous, plumbaginous, calcareous. The key to the real structure of the mountain is in clearly distinguish- ing cleavage-foliation from stratification-foliation, the apparent dip and strike being generally entirely misleading excepting at con- tacts and even there sometimes.* The phenomena of cleavage and stratification as they occur on Mt. Greylock are illustrated by a number of typical cases which substantiate and illustrate the following structural principles: I. Lamination in schist or limestone may be either stratifica- tion-foliation or cleavage-foliation or both. In rare instances traces of false-bedding occur in the limestone. To establish conforma- bility the conformability of the stratification-foliations must be shown. The importance of this is manifest and it would seem too elementary a principle to be stated here were it not that at one locality where the limestone and schist are in apparently conform- able contact, their cleavage-foliations alone are conformable while the stratification-foliation of the schist is at right angles to that of the limestone owing to a fault. II. Stratification-foliation in the schist is indicated by: (a) the course of minute but visible plications; ()) the course of micro- *The more important references to the subject of cleavage occur in the writings of Sedgwick, Phillips, Darwin, Sharpe, Sorby, Tyndall, Rogers, Kyerulf, Heim, Daubrée, Jannettaz, Reusch, Bonney, Cadell and Harker. The Greylock Synclinorium.—Dale. 3 : Se = CC tc Heo os scopic plications; (c) the gen-|FFzEs22i222 F125 22 z wm re cos AL, - = eral course of the quartz lamine | Z = ~ aan ° whenever they can be clearly| 2 2 ¢ 3 ¢ . . . = Oo - ips distinguished from those which} %Z¢ £ tar me = lie in the cleavage planes. 5 s III. Cleavage-foliation may | 2 = F . a ve consist of: (a) planes produced | = 2 " Eo shores YH 499 by or coincident with the faulted limbs of the minute plications; (b) planes of fracture resem- bling joints on a very minute scale with or without faulting of the plications; (c) a cleavage approaching ‘‘slaty cleavage”’ in which the axes of all the par- ticles have assumed either the direction of the cleavage or one forminga very acute angle to it and where stratification-foliation is no longer visible. IV. A secondary cleavage resembling a minute jointing oc- curs in scattered localities. V. The degree and direction of the pitch of a fold are indi- cated by those of the axes of the minor plications on its sides. VI. The strike of the stra- tification and cleavage-foliations often differ in the same rock and | “A oT) UoK ‘ASVAVOIO OD SV [JOA SV POJVOTPUL av SdIp LOTPVOYTRAIG poarasqo ou, “GggT Jo de Mojyuop AAMAS “LOD 8 WOIMONTTONAS MOOTARUMY 01998 THALOAUVLS MIAVAOMd OF SULMOTS “TIT WA JO po Y.tou oy pur T, ‘UMdIdOH ON} ‘(do} oO} JO'NAON off | NMOGV) MOOTAMUWY WLI ‘HOLON 909 “LIN GAD YN VU SsO.108 “SSVI ‘SNVAV HLOOS 9 SIA Motuoy ety Uto1y NOTLOWS hoan aboard 42049 Wo} ” ay M ere oda snpostet athe: “O[TUL OTP} OF TOUT [ LO NNGZI-] OTVOYG [RoT}AVA PUR [eIWOZTAO FT ‘a are then regarded as indicating 8, a pitching fold. | ae VIL. Such a correspondence | hian exists between the stratification | and cleavage-foliations of the #0 great folds and those of the ad minute plications that even very | oe small specimens properly orient- ed givein many cases the key to | the structure over a large part of | the side of a great fold. * "393 —~< yrrcoou eb. *The full report will contain reproductions of photographs of slightly enlarged rock sections, and also sketches and diagrams Wineteating these principles. 4 The American Geologist. July, 1891 On these structural principles thirteen complete and six partial sections have been constructed across the Greylock mass. These show that it consists of a series of more or less open or com- pressed synclinals and anticlinals which, beginning at the north end (North Adams), increase southerly in number and altitude with the increasing width and altitude of the schist mass, and then, from a point about a mile and a half south of the summit, begin to widen out and diminish in number and hight until they finally pass into a few broad and low undulations. Mt. Greylock with its subordinate ridges is a synclinorium consisting in its broadest por- tion of ten or eleven synclinals alternating with as many anti- clinals. While the number of these minor synclinals at the surface is so considerable, in carrying the sections downwards they resolve themselves chiefly into two great synclinals with several lateral and smaller ones. The larger one forms the central crest of the mass, the smaller one east of it forms Ragged Mt., the subordinate ridge on that side. The major central synclinal is so compressed near the highest part of the mountain and its axial plane is so inclined to the east, i. e. it dips to the west, that the strata which under- lie it have on its west side a westerly dip. Further south this synclinal opens out and all the relations become more normal. On either side of these two main synclinals the subordinate folds are more or less open and have their axial planes vertical or in- clined east or west. The accompanying figure 1, shows one of the more important of these cross sections, Section G, which passes about a mile north of the top.* That which crosses about a half mile south of the top, and through the Bald Mt. spur on the south side of the ‘* Hopper,” is even more complex in its western portion. There are long undulations in the axes of these synclinals as shown in several longitudinal sections. The side or edge of this great double trough is at the extreme north end of the mass and its southern about eight miles distant. South of these main troughs is another shallower pair. The same N. §. trough struc- ture prevails also through all the subordinate lateral folds. The deepest part of the synclinorium appears to be under the saddle between the two summits, Greylock and Saddle Ball. *In order to show the current conceptions of the topography and geology of Greylock the reader is referred to Dana’s Manual of Geology, 3d edit., 1880, p. 213 where Emmons’ section of the mountain is re- produced. The Greylock Synclinorium.—Dale. 5 Traversing the folds of this canoe-like complex synclinorium is a cleavage-foliation sometimes microscopically minute, dipping almost uniformly east. This cleavage-foliation is generally dis- tinct from the ‘‘slaty cleavage” early described by Sedgwick, Sharpe, and Sorby, and reproduced experimentally by Tyndall and Jannettaz ; but consists sometimes of a minute joint-like fracturing of the laminz, but more generally of a faulting of the laminz as the result of their extreme plication—a mode of cleayage (aus- weichungs-clivage) so well described by Heim,* and recently re- produced in part by Cadell t+ by a slight modification of the exper- iments made by Alphonse Favre of Geneva in 1878.{ This fault- cleavage, when carried to its extreme, results in a form of cleavage very nearly approaching, although not identical with ‘‘slaty clea- vage.” To the unaided eye all traces of stratification-foliation are lost and even under the microscope they are so nearly lost as to be of little or no avail in determining the direction of the dip. 2 Lithological Stratigraphy. There are five more or less distinct horizons in the Greylock mass. Beginning above: The Greylock Schists: muscovite (sericite) chlorite and quartz schist, with or without biotite, albite, octahedral magnetite, tabular crystals of interleaved ilmenite and chlorite, ottrelite, microscopic rutile and tourmaline. Thickness 1200 to 2000 feet. Part of Emmons’ Pre- Cambrian or Lower Taconic No. 3, ‘‘Talcose Slate.’ Walcott’s Hudson River (Lower Silurian). The Bellows Pipe Limestone, (so named fromits occurrence at the ‘« Bellows Pipe” in the notch between Ragged Mt. and Greylock): Limestone more or less crystalline, generally micaceous or pyri- tiferous, passing into a calcareous mica schist or a feldspathic quartzite or a fine grained gneiss with plagioclase and occasional *A. Heim. Mechanismus der Gebirgs bildung, im Anschluss an die Geologische Monographie der Toedi-Windgzllen Gruppe. Basel tHenry M. Cadell. Experimental Researches on Mountain Building. Paper read before the Royal Society of Edinb., Feb. 20, 1888. Transac. Roy. Soc. Edinb. Vol. XX XV, part 7, p. 337, 357. Ab- stract in Nature, Vol. 37, p. 488, Mch. 23, 1888. Third series of experiments. tAlphonse Favre. The formation of Mountains. Nature, Vol. XIX, 1878, p. 103. 4Slaty cleavage results from the destruction of the small laminze by the breaking up of the sedimentary arrangement of the particles and changing the direction of the axes of all the particles. In this connec- tion see: Alfred Harker, The causes of Slaty Cleavage; compression vy. shearing. Geological Magazine, London, 1885, p. 15, and also by the same author; On the Successive Stages of Slaty Cleavage. Ibid, p. 266. 6 The American Geologist. July, 1894 grains of microcline, zircon. The more common minerals are graphite, pyrite, albite, microscopic rutile and -tourmaline; rarely galena and zine blende. Thickness 600-700 feet. This horizon was entirely overlooked by Emmons, as his section happened to cross the mountain where this upper limestone is covered with drift. It belongs in his Lower Taconic No, 3, and in Walcott’s Hudson River as do the Greylock Schists. The Berkshire Schists (so named from their prevalence through- out Berkshire county): In character like the Greylock schists, but more frequently calcareous especially towards the underlying limestone. Thickness 1000 to 2000 feet. Also forming a part of Emmons’ Pre-Cambrian or Lower Taconic No. 3, ‘‘Talcose Slate,” and Mather’s, Hall’s, and Walcott’s Hudson River (Lower Silurian). Considerable allowance should be made for thickening in consequence of plications in the estimates of the thickness of both the Berkshire schists and the Greylock schists. The Stockbridge Limestone. Limestone crystalline, in places a dolomite, quartzose or micaceous, more rarely feldspathic. Very rarely fosiliferous. Galena and zinc blende rare. Irregular masses of iron ore (limonite) associated sometimes with manganese ore (pysolusite) and with siderite, occasionally replaced to a small extent by quartzite. Thickness 1200 to 1400 feet. Emmons’ Pre-Cambrian Lower Taconic No. 2, (Stockbridge Limestone), Dana’s Lower Silurian, Walcott’s Trenton Calciferous and Chazy (Lower Silurian). From Mr. Foerste’s and Mr. Wolff’s re- cent discoveries in Vermont some of the lower part of this horizon may be Cambrian. * The Vermont Formation. Quartzite, cropping out in the Grey- lock area only once (See Section G.) but possibly underlying the entire mass. Thickness 870 feet. Emmons’ Pre-Cambrian, Lower Taconic, I. Granular quartz, Dana’s Cambrian, Walcott’s, in part Lower Cambrian, ‘‘Olenellus.”’ It should be noted that the maximum thickness estimated does not exceed the thickness usually attributed to the Lower Silurian in the Appalachian region. Areal Geology. The geological map of Greylock and the ad- jacent masses presents a great body of the schists of the horizon of the Berkshire schists almost surrounded by the underlying *J. Elliot Wolff, on the Lower Cambrian Age of the Stockbridge lime- stone, Bulletin of the Geological Society of America, Vol II, 1891. The Fuel Resources of Colorado.—Lakes. 7 Stockbridge limestone. The Berkshire schists send out tongues into the Stockbridge limestone area. There are also re-entering angles of limestone in the schist area corresponding to anticlinals. There are isolated schist areas which are more or less open syn- clinals and isolated limestone areas which are compressed anticlinals forced up through the overlying schists or truncated by erosions. Their relations are repeated between the upper limestone (Bellows Pipe limestone) and the Greylock schist. Relations of Geology to Topography. The physically and chem- ically more resistant schists form the more elevated portions and the steeper slopes, while the broad valleys and gentle undulations about the mountain generally correspond to limestone areas. The upper limestone and calcareous schist constitute the benches of agricultural land high up on the sides of the mountain and ‘the notch ” so early settled ; and to the presence of this rock also, together with a northerly pitch, is due the deep incision in the central crest between Saddle Ball and Round Rocks. The N.-S. part of the Hopper cut was occasioned by the trend and up- turned edges of the calcareous belt. A minor anticlinal occurs on the west side of this part of the Hopper. The deep E.—W. incisions on both sides of the mountain are the results of erosion crossing the strike, while the great spurs on the west side are portions of the original mass left by this erosion. The saddle be- tween Greylock summit and Saddle Ball is due to the central synclinal of the mass, and the saddle seen in the mass from Mt. Equinox on the N.N.W. is due to the great trough in the cen- tral synclinal. The center of this trough is the deepest part of the entire synclinorium. Newport, f. I., April 22, 1891. THE FUEL RESOURCES OF COLORADO. By A. Lakgs, Golden, Col. RECENT DEVELOPMENT OF THE COAL FIELDS. Up to the past five or six years the comparatively small areas of coal discovered and developed within the reach of railroads, were confined to the narrow eastern and northeastern border of our mountains, and were monopolized by two or three companies, or leagued with two or three railroads. The markets were local also. Now, far greater and more important fields, with larger seams and 8 The American Geologist. July, 1891 superior quality of coal have been discovered and partially devel- oped on the western slope of the Colorado range. There are now twenty companies at work where before there were but one or two, and these not merely on the old fields, but on the new. From a once local trade we have now come to supply many neighboring States as far east as the Missouri river. From nothing asa coal State, Colorado has leaped into the front ranks. EASTERN COAL AND THAT OF COLORADO COMPARED. It has been by no means easy to convince eastern men either of the quality of Colorado coal, or of the area of its fields as com- pared with similar data of eastern states. They have long thought of our coals as ‘‘lignites,” little better than peat, owing to the fact that they were so dubbed by Hayden in his report of 1873. This was true enough of the northern field about Boulder, but wholly unjust to the great bulk of our coal fields, which produce true bituminous coal—the same in quality and character as that of Pennsylvania. We have coals that not only produce good coke, equal, some of it to that of Connellsville, but even anthracite, limited in quantity, similar to that of the eastern states. This fact is emphasized by the leading coal expert and geologist of the eastern states, Dr. J. S. Newberry, of the Columbia School of Mines of New York, who says of our Colorado fields west of the range : ‘Here we see sometimes eight to ten different seams in one section, reaching a united thickness of forty to fifty feet, of a quality which will compare with any known in the world. Owing to peculiar conditions this coal forms several varieties, each of which has its special uses. Here is anthracite, as hard and bright as any mined in eastern Pennsylvania; semi-bituminous coals, similar to those of Blossburg and Cresson, but more compact and pleasanter to work, transport and use; bituminous coal, yielding a coke as good as that of Connellsville, and open-burning furnace coals similar to the famous Briar Hill coal, of Ohio, and of equal value. These coals are of unusual purity, sometimes containing 3 per cent. and rarely more than 5 per cent. of ash, with little sul- phur or phosphorus. ” Our fields belong geologically to the Cretaceous, but what old age and pressure have done for the eastern coals, has been accom- plished for ours by the heat of volcanic eruptions attendant upon mountain upheaval. The Fuel Resources of Colorado.—Lakes. 9 DISCOVERY OF THE COAL FIELDS. A glance at Mr. R. C. Hill’s map in ‘ Hall’s History of Color- ado,” gives some idea of the great area occupied by our coal fields, and their distribution in the state. And since formerly only that marked ‘‘ The Northern Colorado Field’’ was known and worked, it will appear how largely the knowledge of our coal re- sources has increased within the past few years. This north- ern field developed at Marshall, Erie, Louisville and Golden was formerly the main supply of Denver and the mountain towns. Later the southern portion of the field was developed and worked from time to time at Franceville, near Colorado Springs. Excel- lent coal, too, was opened on the small isolated field near Canon City. But the most important discovery was made some years later in the Raton field, where the coal was found to be not only bituminous, but also capable of making very fair coke, a com- modity long desired by the smelters, who up to this time had to rely upon Pennsylvania. Later, a mine was opened at Crested Butte, across the range, which produced a first-class coke, equal to that of Connellsville. Since this epoch of coke discovery, large areas of coking coal have been discovered in various parts of the state. In the same area a small field of excellent anthracite was dis- covered, covering a few hundred acres. Thus, in a very short time, our reputation as a so-called ‘‘lignite” bearing state had been raised to that of a first-class bituminous, coke and even an- thracite producing region. THE GRAND RIVER COAL FIELDS. The contest for a path to Utah between the Midland and the Rio Grande railways led to the discovery and development of still another new field, along the banks of the Roaring Fork and Grand river, even richer than the rest, in the varieties and great thick- ness and number of seams of bituminous, domestic, coking, and anthracite coals. The coking coals were developed by the Marion mines, near Cardiff, and the coke found to be as good as Connells- ville. The great, thick and numerous seams of bituminous and domestic coal were, and still are being developed all along the great Hogback, from Glenwood to Meeker, a distance of forty miles. Thus began the development of the great Grand River field, which for area, variety and excellence of its coal is the most important field of the future in Colorado. As yet its out- 10 The American Geologist. July, 1891 skirts only have been touched, and there is a vast area for future enterprise, whilst north and beyond it is yet another large and un- touched field known as the Yampa. The coal of this Grand River field has a further importance from its close proximity to the greatest iron deposits so far discovered in Colorado, such as those of the Iron King, at White Pine, about thirty miles from Gunnison City, and the Cumberland iron mine, in Pitkin county, also within fair distance of this great coal field. SOUTHWESTERN OR LA PLATA FIELD, Meanwhile in southwestern Colorado the Rio Grande railway had entered and discovered another large field, covering thousands of square miles, and extending from Colorado into New Mexico and Arizona, known as the La Plata field. Here is an immense amount of coal in bodies from seventy feet down to five feet in thickness ; yet over this great area the development is restricted to four or five small mines, one at Monero, another at Florida, and three or four about Durango, doing a very local trade. This small development is due to the possession of much of the field by the Ute Indians, and to the fact that but one railroad pene- trates the region. The coal is bituminous, and over certain areas makes fine coke. Besides these large fields, there are several smaller isolated ones, such as one in North Park, with thick seams of lignitic coal, an- other in South Park, for some years developed by the Union Pacific, and another undeveloped field on ‘‘ Tongue Mesa,” near Montrose. NORTHERN COLORADO COAL FIELD. This field extends north from Boulder into the Laramie plains of Wyoming, and south to Colorado Springs. Its approximate eastern boundary is a line drawn north and south some forty miles east of the mountains. This field has long been developed in Boulder county by the Marshall, Erie and Louisville mines, also by mines at Golden and Ralston. Marshall is one of the oldest mines in the state, having been worked for at least twenty years. By a series of faults, accompanied by erosion, the coal has locally been brought near to the surface at a gentle dip of 5 degrees. The principal seam is six to eight feet thick. The coal is a good, pure, high-class lignitic coal, not coking, but well adapted to all purposes where extraordinary heat is not required. A large area has been worked out, a good deal burnt out by spontaneous com- The Fuel Resources of Colorado.—Laukes. 11 bustion, and an unknown amount presumably left. The develop- ment is sometimes impeded by the faults which cut off the contin- uity of a seam. The following is an analysis of Marshall coal : Per Cent. We AUT. 2+ co no etek dS Sera it SSO pay aree te a 10.73 WORDEN HIVE oo oie oe 0 SG BEE SIE EID ce tea en ee 44,11 SE ore eC HMAC E INES Rep ENEE Sirs 2) 2 re clser tava tol oravatelevstelete, siekels aia ttele gversiev a'sicle’ gva's 38.38 UNL stand olny ice etn SCD Seco EE IO On Bes cai Oa eet ole 6.11 The area of the Colorado portion of the northern field is esti- mated by Hills at 6,800 square miles, the accessible portion at 405 square miles, and the available coal at 2,568,600,000 tons. From Franceville, for about thirty miles south, there are no de- velopments until we reach Canon City, on the south bank of the Arkansas river where is a small isolated field, twelve miles long by two miles broad, carrying a seam four to five feet wide of non- coking bituminous coal, which has long been a favorite fuel from its high calorific power and general purity. The gentle dip of the strata admits extensive development. There are three or more companies developing this small field at present. THE SOUTHWESTERN FIELD. From the Arkansas river to the Huerfano river, a distance of fifty miles, another barren space, and then we meet the northern extremity of the great Raton plateau and Raton coal fields. Some of this coal has been burnt, or changed into natural, but worthless coke by volcanic dykes with which the region abounds. As a whole, however, it represents an enormous amount of bituminous, domestic and coking coal. The cause.of this change from a lig- nitic to a bituminous and coking character may be found in the great volcanic manifestations of this area. The following analysis of Al Moro coal gives: Per Cent. VEUIET? «c.205.0°S) Sey ashen Ot ROMO CE ceca econ 6 ie Anes en 0.54 WELSH Ey TRG FTES RE SE a) ig Spe le a 30.29 Fixed carbon... 54.43 AMSTEL 3 po cS SETS Se RSE aes en See ae 14.74 MPRCh uch Meee tae trong ET oy c ia: sed co Satoh rere RR eT erte Ob ecdsis ee seas de tie 100.00 Hills estimates the available area of this field in Colorado at 473 square miles, and the available coal at 4,490,200,000 tons. In former years there were but two companies working in this great field, now there are a dozen. From the fields of the eastern slope we turn to those on the 12 The American Geologist. July, 1891 west slope of our mountains. We cross the Sangre de Cristo range, the broad San Luis park and the Conejos range, seeing no coal for over 100 miles. From the Conejos range we look down on a region of endless plateaus, representing the La Plata coal fields. Over this large area there is, as we have stated, but half a dozen small mines. One body of coal on the Animas river, be- low Durango, is seventy feet thick, caused by the running together of several seams. It is developed at the Carbonero and La Plata mines. The great body is traceable for several miles along the ‘« hog-backs”’ by a valley caused by the washing out of the softer coal. The individual seams composing this mammoth body can be worked individually to advantage, but worked collectively the result would be a high per cent. of ash from the admixture of shale ‘‘partings.’’ Close to the town of Durango a seam five feet thick, of excellent quality, is worked by the San Juan and Porter mines. The coal of all these seams makes very good coke, but the market of it is at present local. The drawbacks to this coal field are its distance from the main central market, the presence of only one line of railroad, and the proximity of the Ute reservation. When some of these obstacles are removed there is a good future for the region. An analysis of the smaller seams is : Per Cent. Water woe co eased co Sn cuecdio cm 0 'b:0 ib. 2 Rae ee Cn ee ee ee 0.63 Volatile*matter. ook agi cia i> rele io eidlotale eee ee EE eee 54.78 STs sia ens ine choise le SielaieapreG nie eyor's.s ofe,'s Oldie o1e:5.5 Shae e ae eee ee 4.22 "Dota iors sce ers ee oie 5 lee 6 o,0 0 on ee teow, uk ROG et oe oe 100.00 Hills estimates the Colorado portion of this field 1,250 square miles, the available portion at 300 square miles, the available coal at 3,387,200,000 tons. FIELDS OF NORTHWESTERN COLORADO, From Ouray we go northeast to Crested Butte. Here is a small portion of the Grand River field isolated by a circle of volcanic mountains, forming the Elk range. The heat from these volcanic The Fuel Resources of Colorado.—Lakes. 13 sources has altered the coal into several varieties. We have bitu- minous, coking, semi-anthracite and true anthracite, the alteration being more or less great, according to distance from volcanic heat. The anthracite portion is limited to an area of about 500 acres ; the seam is six feet thick and yields an anthracite as hard and lustrous as that of Pennsylvania. Its analysis is: Per Cent. RE ren eR SORES BR oe cy ca ccare Heal aretasloue bole tansae s so sins waeoete cde © fc se Otho HOY 2s Third Magnesian limestone......... DA OREO ron Oo AOR S50 “Tiedt! Siisnd@ Stans & 4 eet Ie Iga Senco HON. Hounphneviaonesian limestone... .....,.sccneceeveenne S00) 0¢5 This series of magnesian limestones is known in Missouri by its numbers; the ‘ First”’ is rarely found in central-southern Missouri, excepting on the most elevated points, but it is better developed in the counties bordering the Missouri river, occurring as a gray or buff or drab limestone, sometimes odlitic as near Horifie in Jef- ferson county, or abounding in Cythere sublevis, as at Pacific, in Franklin county. The First, or Saccharoidal sandstone reaches its greatest thickness near Augusta, St. Charles county, where it is 135 feet thick. ‘A corresponding thickness was recorded in the boring at the Insane Asylum, St. Louis. Its upper part is white and pure silica, its lower part often colored brown. It is the equivalent of the St. Peter’s sandstone. The only evidence of organic remains found in it isa large Orthoceras, about 8 inches in diameter. This sandstone is valuable as a material for glass-making, and the glass-works at Crystal City, in Jefferson county, are located at a favorable outcrop. The Second Magnesian limestone is well ex- posed at Jefferson City, and includes all the strata in sight at that city; The lower beds are thick and cellular, the small cells filled with a white powder, or else empty. Above these there is a good deal of chert occurring mostly in a concretionary form, together with some shale, and earthy drab-colored magnesian limestone beds, locally called ‘‘cotton rock.’’ Buta small per cent. of this 3 34 The American Geologist. July, 1891 is suitable for building. Fossils are not abundant. Those found area Lingula (like L. prima Hall) an Ophileta, and Pleurotomaria, At the base of the hill at Hermann, a trilobite (probably Cono- cephalites), an Orthis, &c., were obtained. The Second sandstone occupies the tops of the hills in Madison, Washington, Reynolds, and some other counties, and is apparently replaced by certain chert beds in those counties. This sandstone is coarser than the First sandstone, and is often slightly colored with iron, and is often a firm, solid rock, useful for building pur- poses. The Third Magnesian limestone occupies the base of nearly all the hills of southern Missouri, sometimes reaching to the hill tops. It occurs chiefly in thick beds of coarse, gray dolo- mites, or finer textured flesh-colored layers, the latter sometimes as much as 20 feet thick between the bedding planes. The coarse gray dolomites often disintegate and weather into rough surfaces, and at the lead mines decompose into dolomitic sand. The Third sandstone was recognized by Prof. Swallow, on the Osage and Niaugua rivers, in Camden and Dallas counties. A part of this series may be referred to Prof. Dana’s Canadian period. The First Magnesian limestone lying below the Trenton group, may be Lower Silurian, and some have considered it to be of the age of the Chazy; in the absence of fossils it is not easy to assign it to its proper place. The series below, including to the base of Second sandstone, and probably part of the Third Mag- nesian limestone, may be considered of equal age with the Calcif- erous of the New York system. The Lower part of the Third Magnesian limestone may probably be of the age of the Potsdam, and the other strata below seem certainly to be of Potsdam age. The Second Magnesian limestone and the other series below to the Archzean seem to correspond with the description and position of beds referred to the Upper Cambrian by Mr. C. D. Walcott. So, whatever may be the true geological position of this series of rocks, they belong to different periods of geologic time. I there- fore, for this reason and from the similarity of the composition of the rocks, think best to place them in one series, and call that great series ‘THE OZARK SERIES ” Distributed as follows: First Magnesian limestone. First or Saccharoidal sandstone—St. Peter’s sandstone. Second Magnesian limestone. Some Recent Greaptolitic Literature.— Gurley. 35 Second sandstone. Third Magnesian limestone. Third sandstone. Fourth Magnesian limestone. The term Magnesian has been applied to rocks of other ages, and, for that reason, has not been welltaken. The term Ozark, is peculiarly well adapted, for it includes rocks that are not only found amid the Ozarks, but are there better developed. In south-eastern Missouri certain members of the lower part of the series are wanting, and the Third Magnesian limestone is not well separated from a lower limestone which may be the equiva- lent of the Fourth. The lowest rock near Mine La Motte is a sandstone which, near Fredericktown rests directly upon granite. There are also occasional exposures of a variegated red, purple, buff and drab marble whose position is above the sandstone. Above the marble beds are gritstones and magnesian limestones and dolomites which are the lead-bearing rocks of Madison and St. Francois counties. These lower limestones contain Lingulella lamborni of Meek at several places. If that fossil is of Potsdam age, then these lower limestones and sandstones are of Potsdam age. The marble beds have occasionally furnished beautiful polished slabs of marble. Nearly 35 years ago Mr. Henry Cobb, of St. Louis, had a quarry of it opened near Ironton, in Iron county, and attempted to bring it into notice. He termed it ‘‘ Ozark” marble, and in deference to him I will still use the name. The series in Iron, Madison, and St. Francois counties is as follows: OZARK SERIES. Second sandstone — on hill-tops with chert.......... 125 feet Third Magnesian limestone with chert and quartz... 225 ‘“ crmsvoneang Wingnla D6GS... . << actos saitcs a cere vaccces 50 Ozark Marble beds... .. 00. ..0 «3. COOL DOU De COOIOE 25 Lower sandstone and conglomerate.................. 90 The above series rests on Archzean porphyries and granite. University Columbia, Mo., April, 1891. SOME RECENT GRAPTOLITIC LITERATURE. By R. R. Guruey, U. S. National Museum. Besides several minor papers* the graptolitic literature of 1890 com- *De Rouville, Prof. P. G. Note sur le presencé du Pleurodictyum problematicum dans le Devonien de Cabriéres et sur.un nouvel horizon de Graptolites dans le Silurién de Cabriéres; Bull. Geol. Soe. France, XVIII, pp. 196-97 (Notes dis- covery of an Arénig fauna). ; Dodge, W. W. Some Silurian Graptolites from Northern Maine; Am. Jour. Sci., L, pp. 153-55 (Notes occurence of the Norman’s Kill fauna in Penobscot County). Nicholson, H. Oliphant. Notes on the discovery of Trigonograptus ensiformis, Hall (sp.) and of a variety of Sa head V-fractus Salter in the Skiddaw Bee Geol. Mag. VII, pp. 340-44 (Describes J). V-fractus var. volucer, var. nov.). 36 The American Geologist. July, 1891 prises four papers of some length, an abstract of which is attempted in the following pages. As will be seen all are the work of foreign authors. Ueber das alter d. Sogen Graptolithen-Gesteins mit besonderer Be- riicksichtigung der in denselben enthaltenen Graptolithen; by Otto Jdkel. Ztschr. d. deutsche geol. Ges., XLI, pp. 653-716 ; Berlin 1890.. The Gestein, the author tells us, belongs unquestionably to the Upper Silurian. The only question is as to its exact horizon within that sys- tem. After reviewing the opinions of previous workers he expresses his belief that the Graptolithen-Gestein finds its equivalent in various horizons of the Wenlock Shale. The Graptolites of the formation are next considered. At the outset (p. 660) the author mentions Barrande’s division of the Graptolites into the one-rowed and two-rowed. He further tells us that all true Grapto- lites are still classified in accordance with this scheme. This state- ment does not indicate a profound acquaintance with the later grapto- litie researches and especially with that masterly series of memoirs which has made Professor Lapworth’s name to the present generation of graptolithologists what those of Hall, Barrande and Geinitz were to the preceding. Indeed we have hardly met with another recent paper on this group from which the name of Lapworth is so conspicuously ab- sent. Correlated with this peculiarity is the slight esteem in which the author holds the sicula, which might not inaptly be termed the organ of Lapworth, so closely is it associated in the mind of the graptolitholo- gist with his researches. In short, throughout the whole memoir the subject is treated from the standpoint of Nicholson’s Monograph of the British Graptolitide, a work which represented the high water-mark of the science at the time of its publication (1872) but which, we are sure, its own author would not recommend to Herr Jikel as a modern text- book on Graptolithology, so great has been the progress of our knowl- edge during the last eighteen years. Returning to the text we find that, apparently misled by the fact that Monograptus, Geinitz, has obtained currency to the exclusion of Mono- prion, Barrande, in defiance of, and not in accordance with, the rule of priority, Herr Jikel tells us that: ‘*The generic name Monograptus previously employed by Geinitz has been used by the later authors in place of Monoprion of Barrande and in the same sense as the latter.”’* We regret to find ourselves as little able to agree with Herr Jiakel’s views as to the conditions of life of the Graptolites as we were to admit the correctness of the statements quoted. He discusses at some length the subject mentioned and concludes that the true Graptolites must have been fixed. His reasons for this divergence from what we take to be the consensus of two generations of observers is his inability to under- *M. Barrande described Diprion and Monoprion in 1850. In 1852 Dr. Geinitz, remarking that Diprionwas preoccupied, employed Professor M’Coy’s term Diplo- graptus in its place. In this connection he said that Monoprion. must be changed to Monograptus for harmony (Finklang). Later the powerful influence of Prof. Lapworth has secured its retention. He gives his reasons for favoring it instead of Barrande’s name (which he admits has priority) in his memoir on the Scottzh Monograptid (Geol. Mag., 1876, III. pp. 310-11). It is probable that Lomatoceras (Brown, 1835-7, Leth. Geogn. I, pp. 55-6), should supercede them all. Some Recent Graptolitie Literature. — Gurley. 37 stand in what way the heavy polypary could have been moved. Wave action being excluded ( ‘‘the Graptolites were deep-sea dwellers” ) flota- tion could only be secured, he argues, through swimming movements of the zcoids or by the possession of a hydrostatic apparatus. The possi- bility of movement by the former means is regarded as very improbable in view of the independence of the cells, their opening upon one side only, and the form of the stem on the other side. No less improbable, he thinks, is the assumption of a hydrostatic apparatus. It is asserted that such could only have been the central disk. Herr Jikel rejects the possibility of such a view of its function as the cells would necessarily have been directed downwards, a condition which, he tells us, has never been observed in the analogously constructed living colonies. On the other hand, by assuming these organisms to have been fixed we can, he thinks, form a ‘‘simple and natural picture ” of the genus Dicty- onema with the“ cell-less net” imbedded inthe mud and the cell-bearing branches projecting with the cells directed upward. Possibly this may possess the merit of simplicity, but the fact is that the ‘‘cell-less net” has no existence. If Herr Jikel will consult Brégger’s memoir? he will find that the branches in Dictyonema are thecaphorous along their whole length; although they may apparently lack thece in any portion from unfavorably directed pressure. The central disk is also by Herr Jikel regarded as mud-imbedded. The sicula receives little notice. It indeed furnishes opportunity to ‘quote Professor Nicholson’s Monograph again to the effect that the radicle ( sicula ) was present certainly in some and probably in all cases. We are then told that ‘‘when this probably shall have been actually made credible through numerous and not as heretofore by ‘some cases,’ I would ask whether this organ may not be regarded as the foundation of the stem and have served for preliminary imbedding until, the lateral spreading of the ‘cell-less root’ or a broad disk moored it securely.” Considering the overwhelming mass of evidence showing the sicula to be the embryonic stage, so to speak, of the graptolite, it is only neces- sary to remark that in some genera the sicula is so imbedded in the substance of the polypary that it could not have been stuck in anything. For his next theory the support of Prof. Hall’s authority (under date of 1865) is invoked. This time it is a revival of the view that the Monograptide are fragments of compound forms; another defunct hypothesis which,natural enough for the date at which Prof. Hall wrote, lacks the slightest trace of support from Jater investigations. We arrive now at the proposed subdivision of the genus Monograptus. We are here reminded very strongly of the methods of securing a change of dynasty in vogue in some of the South Sea Islands. When a king becomes aged he is told by his son that he in his turn wishes to mount the throne. The old monarch acquiesces and a funeral procession is formed which escorts him to his grave. Some such custom seems about to be introduced into our midst. With regard to Herr Jikel’s proposition to divide the genus Monograptws we have nothing to say. It is not the »Brogger, W. C., 1882, Die silur Etagen 2 & 3, im Kristianiagebiet. 38 The American Geologist. July, 1892 division, but Herr Jiikel’s mode of dividing that excites our apprehen- sion. Instead of the customary gemmation we are introduced to a pro- cess of nomenclatural fission which we confess is new to us. Its chief characteristic seems to consist in the entire disappearance of the original genus. We cannot but pronounce it a most flagrant violation of the rules of nomenclature. The genus Pristiograptus (one of the two unnatural offspring which have thus devoured their parent) is characterized by an axis straight or bowed outward, a free mouth opening formed at the expense of the bey- elled upper lip; thecal processes when present are found upon the under lip. In Pomatograptus (gen. n.) on the contrary the axis is straight or curved inward, the mouth opening small under the over arching upper thecal lip. Herr Jiikel closes his remarks upon classification by the following italicised paragraph : “This highly interesting case (the above ‘ parallel’) with many others shows that the one-rowed and more-rowed Graptolites are not systematic- ally separable but are to be classified phylogenetically and naturally from a higher point of view.” The description of Retiolites which is perhaps the least faulty portion of Herr Jikel’s article terminates the section devoted to Graptolites. At the outset Herr Térnquist! feels compelled to except to the author’s statement. Hesays: Little if anything is added to our knowledge of the generic structure beyond the points elucidated by the Swedish paleontologists during the previous decade. We need only mention the author’s proposition to classify Retiolites geinitzianus along with Pristo- graptus (Monograptus). Herr Jikel tells us (p. 666) that after acquainting himself with spe- cial literature of the Graptolithen-Gestein he found it impossible to in- form himself with regard to the ‘‘almost numberless” species on record. While knowing little of the Monograptidae we detect some signs which tend to make us suspicious of the new genera. Herr Jaikel believes that a classifica- tion based (principally at least) upon the characters of the mouth opening could be applied with advantage to all graptolites, including ‘the two and more: rowed.” (p. 666.) Again; “All the various types of Monograptids find parallel forms as well among the two-rowed as among the compound forms.’ Rather unfortunately we think, he continues; ‘A very remarkable example is furnished by Monograptus testis, Barr. which with its aberrant peculiarities possesses its corresponding parallel form in Didymograptus bimucronatus Nich., and Didymo- graptus quadrimucronatus Hall” (p. 665).. Further reading (p. 676) shows this ‘parallel’ to consist in the possession by M. testis of two spines on the under lip. This peculiarity the author regards as worthy of generic distinction. Proyision- ally it is left under Pristiograptus but he remarks thatif the remaining graptolites should be classified along the lines he lays down this should form the type ofa new genus. We confess to having little sympathy with such genera. ,Térnquist, Sv. L., 1890, Undersékningar 6fy. Siljansomradets Grapt., p. 7. “The very first lines relating to that genus [Retiolites]. ‘Although the general structure of Retiolites geinitzianus had already been quite correctly recognized and very aptly figured by Barrande and Siiss, it seems to me’ ete., seems rather incomprehensible, since it is known that Barrande and Siiss entertained entirely different conceptions of the structure of that genus and how sharply the former protested against the latter’s interpretation of its rhabdosoma. ‘The author seems to have taken no cognizance of what has been written in recent times on this: matter, for example, in as important a work as Tullberg’s ‘Skanes Graptoliter.’ ” Some fecent Graptolitic Literature.— Gurley. 39 This we can well understand as the literature is quite large. Such ac- quaintance is however, no less a sine qua non for successful specialistic work in the graptolitic field than in other departments of science. The following new species are described: Pristiograptus frequens, Pomatograptus pseudoprion, and P. micropoma. Die Graptolithen d. k. mineralog. Museum in Dresden, by Dr. H. B. Geinitz. Mitth. k. min. geol. uw prehistor. Musewm in Dresden, IX Cassel, 1890. After many years spent in varied paleontological researches, Dr. Geinitz has once more turned his attention to the Graptolites. The present work is, he tells us, of the nature of a revision in the light of modern investigations of the material which formed the basis for his valuable Monograph of 1852. The Nereograpti are omitted in the present work. Those forms with an unsegmented canal as N. cambrensis, Murch., Dr. Geinitz still con- siders nearly related to the living Pennatulines (Virgularia juncoides, Blainy. and Funiculina cylindrica Blainy.) Those with a segmented canal are regarded as allied to the living Nereis and Phyllodoce, while a large number of the forms are (as shown by Nathorst and others) to be considered tracks, etc., of worms. We notice that the author includes Rastrites (also Jikel’s new genera Pristiograpltus and Pomatograptus ) under Monograptus. Concerning the propriety of this arrangement we have no opinion to offer as our experience with the family Monograptide is practically nil and we only note the author’s synonymy as it accords with his original views and differs from the consensus of present writers. More important, it seems to us, is the refusion of such genera as Climacograptus and Dimorphograptus with Diplograptus which thus again tends to include a series of forms whose only similarity is the possession in common of a double row of hydrothece. Dimorphograptus seems, (so far as we can judge from the studies of others ), to be a true transition from the Diplograptide to the Monograptide. It is of the greatest importance in showing us the futility of classifications based solely on the possession by some part of the polypary of a single or a double row of cells. Before the discovery of the forms included in this genus the Dichograptidz were looked upon as the ancestors of the Monograptide and were even considered monograptids solely because the hydrothecze occur only on one side of the common canaj. The modern improvements in classification form the corollary to recent researches upon the life history of the graptolites, and are in large part based upon the relation of the sicula to the remainder of the polypary. Relative to Climacograpus we must, while entertaining the highest re- spect for Dr. Geinitz dissent almost in toto from the following passage: “ Little regard is here taken of the scalariforms of various Grapotolites (origi- nating through compression of the horny flexible polyp-stem) which Hall has united into the genus Climacograptus since its possession by safely determinable species is little assured.” The genus Climacograptus is by no means (as one would infer from the Geinitz, H.B. Die Versteinerungen der Grauwackenform. in Siichsen, etc., Abth. 1, Die Graptolithen; Leipzig, 1852. 40 The American Geologist. July, 1891 above ), founded upon, limited to, or in any specific way characterized by or connected with scalariform impressions. These impressions are com- mon to many genera but these genera do not for that reason become synonyms for Climacograptus as defined by its author. The charac- ter by which Climacograptus is principally distinguished is the depres- sion of the hydrothecal mouths below the surface of the polypary. Passing rapidly over that portion of the memoir which deals with synonymy we are glad to see Stephanograptus, ( Geinitz, 1866), noticed as having clear priority over both Canograptus (Hall, 1868), and Heli- cograptus ( Nich., 1868), as its just claims have heretofore been ignored. Like the other genera mentioned it was founded upon s. gracilis, Hall Graptolithus. We regret that Dicellograptus Hopk., has not fared better than Clima- cograptus. The definition given of Didymograptus is ‘‘ From a mostly short stalk (the sicula), extend in two opposite directions, sometimes nearer, sometimes farther from each other, Monograptus-like branches.” Under it is justly included (and the author includes) the two genera © Didymograptus and Dicellograptus which are universally, and we believe most justly, regarded as belonging to two exceedingly distinct families. But the definition seems to us entirely too comprehensive. Amid the wreck of genera we are glad to recognize our old friends Phyllograptus and Retiolites and to meet again on the excellent plates which accompany this work the assemblage of forms which has become classic through the labors of the two pioneers of graptolithology, Geinitz and Barrande. Undersékningar ofver Siljansomradets Graptoliter by Sv. Leonh. Torn- quist. (Lunds Univ. Arsskrift tom. 26.) . Previous writings are first passed in review. From forty species in 1881 the number has been increased by a score. The order of the strata is as follows: MEMBER. STRATUM. Leptzna limestone ? Leptzna limestone ? *True retiolites slate. *Transition stratum. Rastrites slate *Various zones of Rastrites slate. Kling Jimestone Kling limestone. { Red Trinucleus slate. } Grey limestone. | Black Trinucleus slate. | Masur limestone. Retiolites slate Trinucleus member * Bryozoa limestone. Chasmops limestone Cystid limestone. | *Flag limestone. { *Upper grey Orthoceras limestone. | Upper red Orthoceras limestone. Orthoceras limestone { Lower grey Orthoceras limestone. | Lower red Orthoceras limestone. | *Phyllograptus slate and green limestone, er oe, Obolus gravel limestone. Obolus Timestone Obolus conglomerate. *Have yielded graptolites. EE Some Recent Graptolitic Literature.— Gurley. 41 The Rastrites slate is undoubtedly capable of subdivisions but the data are defective. A provisional arrangement of zones is proposed. The author is disposed to question the received opinion that the graptolites are closely related to the Hydrozoa as difficult to reconcile with the structure of Retiolites as set forth by himself and Tull- berg. Relative to the structure of that genus ( R. geinitzianus ) the views of the author are in complete accord with those of Mr. Holm given above. The relation of the last named species to Stomatograptus tornquisti, Tullberg is shown and the identity of Tullberg’s species with Retiolites grandis Siiss, is established by comparison with specimens from Siiss’s type locality. Retiolites obesus Lapworth he thinks should probably form the type of a new genus when better material is obtained. Passing rapidly over descriptions of species which possess little inter- est except for specialists we note the suggestion of Herr Toérnquist that the genus Didymograptus be made the type of a new family, the Didy- mograptide. It differs from the compound dichograptids in having the sicula divided by a distinct wall from the two branches while in the dichograptids the sicula merges without distinct boundary into the thecaphorous hydrosoma. In Didymograptws moreover the branches are given off at different levels reminding one of the alternation of theca-formation in the diprionidian graptolites. Further on ( under Phyllograptus densus, Térnq.) we find that the theca in Phyllagraptus are inserted at the same level in whorls of fours. The structure in this genus is that of four monoprionidion polyparies soldered back to back. No distinct virgule were observed. The author thinks some specimens show a sicula with the point thrust up into the proximal thecal cycle, but adds that this requires confirmation. Besides the above outline which contains the gist of such parts of Herr Ténquist’s paper as are calculated to interest the general reader, this excellent essay abounds in descriptions which well sustain the character of the Swedish graptolites writings for accuracy of specific definition and painstaking morphological study. The new species are: Clonogruptus robustus, Tetragraptus curvatus, Didymograptus grucilis, D. decens, Climacograptus intenexus, Diplo- graptus bellulus. In addition to these many previously described forms are figured and their synonymy considered. Gotlands Graptoliter, by Gerhard Holm; Bihang till K. Sv. Vet. AK. Handl., 1890, XVI, Afd. IV, No.7, ,2 pls. Also Reprint, Stockholm, 1890, This excellent paper contains the results of the author’s studies of the graptolitic material from Gotland added to the State Museum, since the publication of Linnarsson’s paper of the same name eleven years ago. * Linnarsson knew of but three species of Graptolites occurring in Got- land. ‘Tullberg and Lindstrom subsequently increased the number to five. Mr. Holm has added three more so that the list now stands as follows: 1Linnarsson G. Ofv. K. Vet. AK. Forh., 1879, No. 5, pp. 3-12. 42 The American Geologist. July, 1892 Dictyonema cervicorne (sp. n.) Monograptus subconicus, Térnq. Dictyonema abnorme (sp. n.) Monograptus dubius, Siiss. Monograptus priodon Bronn. Monograptus sp. Monograptus priodon var. flemingii, Retiolites geinitzianus, Barr. Salter. Retiolites nassa (sp. np.) Following in the track of Dames’ and Brégger’s researches the author discusses the structure of the genus Dictyonema. Particularly apt seems to us his views regarding the heterogeneous nature of the species usually referred here. For example we find in this genus a species (D. flabelliforme ) which is undoubtedly siculate, associated with species most of which are probably, and some of which are certainly not so. As he remarks the (for graptolites) unprecedented vertical range of the genus furnishes additional reasons for suspecting some of the generic references. We may, however, note that the siculate and non-siculate types occur at one and the same horizon. But a generic division cannot, as Mr. Holm says, be satisfactorily established until the species are more thoroughly known especially in the proximal portion. Under the description of D. cervicorne we are introduced to one of the most beautiful elucidations of graptolite structure that we have ever seen. The author imbedded a specimen in Canada balsam face down upon a slide, and then removed the limestone matrix by solu- tion with acid. Part of the wall of the funnel-shaped polypary was thus obtained in full relief with the parts in their normal relations. The thece are seen to form one vertical row and to terminate in a long hay-fork like spine. Situated alternately on the two sides of these spines (and thus forming two vertical rows) are peculiar cup- shaped bodies, (‘‘ by-thece”) which are compared by the author to bird’s-nests. They are divided from the thece by a wall. It could not be ascertained whether any connection existed between these by-thece and the adjacent thece, or whether the former communicated with the common canal. He suggests that they may be gonangia. It is owing to this arrangement of the thecz in one vertical row along the inner face, and of the by-thecz in two vertical rows along the lateral faces of the branch that when looked at from the side the branches appear serrate on account of the thece and when looked at from without the thece are invisible being hidden by the branch, which latter presents a zig-zagged appearance owing to the alternately projecting by-thece on either side. The connecting cross-filaments are shown to be flattencd from above downward. They are bow-shaped with the convexity o1it- ward andpossess a pitted surface and outwardly projecting branches. They correspond in number to the thece beween each pair of which they project. : Not less beautiful than the foregoing demonstration is that of the structure of the polypary in Retiolites geinitzianus and Stomatograptus tornquisti.* In the former species we see two virgule (the one straight and the other zig-zag) occupying the central line of opposite faces of the *Although many of these points have been previously noted, this description is worthy of mention as itis almost the first based upon thoroughly satisfactory material. Some Recent Graptolitic Literature.— Gurley. 43 square-prismoid polypary. From each convex angle of the zig-zag and from a corresponding level of the straight virgula, there extends out- ward in the reticulated wall of the polypary, a chitinous bar ( ‘‘ parietal ledge”). In the ventral ( outer ) wallof the polypary the parietal ledges are connected by a horizontal ‘‘ mouth-ledge.” Tracing the parietal ledges back toward the central line of the polypary they are seen to be deflected upward in the vertical and inward in the horizontal plane so that they sink below the surface, i. e., into the interior of the polypary. Near the point of deflection they are connected by a bar which traverses the interior of the polypary ( ‘‘inner cross ledge’). On the trapezoidal frame formed by the mouth-ledge, inner cross ledge and two parietal ledges is strung a fine chitinous network which is an inward extension of the exterior network serving to divide adjacent thecz. The external network is stretched over the whole surface of the polpary being attached on the ventral surfaces, to the mouth-ledges and on the lateral surfaces to the parietal ledges as far as the point where those ledges become de- flected below the surface. At this point the attachment to the ledges ceases and the network is stretched across the median line to the sim- ilar angle of the opposite parietal ledge. From all this it follows that three canals extend the length of the polypary in the median line. The central of these is the common canal which is bounded on either side by the inner cross ledges and front and back by the two virgulas. Be- tween this canal and the network (stretched across from angle to angle as described above ) lie two canals, one in front of and one behind the common canal. It is thus easy to see what diverse appearances may be presented by one and the same polypary under different degrees and directions of pressure. Preserved in relief neither virgula is visible; the external network with the parietal ledges extending toward but stopping short of the center being all that can be seen, while if subjected to compression, the zig-zag, or the straight virgula (or with greater pressure, both the zig-zag and the straight virgula) becomes visible. The specimen which has furnished this description fails to show an outer envelope or inner dividing walls, but the author cites several authorities to prove the existence of these structures. In a general way the structure of Stomatograptus tornquisti resembles that of R. geinitzianus. The epidermic coating of the network is, how- ever, coarser and the virgulas and ledges finer than in the latter species, and the plane of the thecal mouths is oblique to the long axis of the polypary so that in profile the latter appears serrate. In a well preserved specimen of S. tornquisti Mr. Holm detected an epidermic layer external, and an endermic layer internal tothe network. The outer and inner are smooth and without gaps, the middle alone being cribriform. Our author believes (but was not able to demonstrate ) that interiorly the inter-thecal partition planes are attached to the inner cross ledges. He further believes (in opposition to Tullberg’s opinion), that the thecz were not delimited interiorly by a porous membrane from the common canal but that the communication between the two was un- restricted. The remainder of this admirable article is devoted to a criticism of Jiikel’s essay which has been noticed above. 4 The American Geologist. . July, 1891 THE FLOOD-PLAIN AND THE MOUND BUILDERS. By STEPHEN D. PEET, Ph. D., Mendon, Ill. One of the most interesting problems which the geologist and the archeologist in their combined capacity may undertake to solve is that presented by the flood-plain. The flood-plain is, to be sure, altogether a natural creation while the mound-builders’ works are artificial. Yet the two are so related that they may well be studied together. Both arecomparatively modern, the ap- pearance of the flood-plain and the erection of the earth-works having been subsequent to the glacial epoch, but both preceded the historic period. | Great changes have indeed occurred in them since the historic times, but they are in opposite directions, as the flood-plain seems to be more plainly visible and is fast becoming a regular formation, the last of the sedimentary layers, while the earth-works are fast disappearing and are only advancing in their decay and desolation. The enquiry which we desire to make has regard to the time which has probably elapsed since the erection of the earth-works as indicated by the growth of the flood-plain. The first enquiry will be about the so-called elephant effigy which we referred to in one of our former papers. This effigy is on the flood-plain, one of the very few which have been discoy- ered on this plain. The question which we ask is, was it an ele- phant which was thus built in effigy on a plain which is now oc- casionally covered with water s as to be cotemporaneous with the ancestors of the Hunter Indians? The effigy of the elephant seems to have met the same fate in Wisconsin which the rotunda mound has in Ohio. The flood has come up occasionally and washed his feet and his proboscis until his: form is obscured be- yond recognition. The clover was to be seen growing on the form when we last saw it, the water of recent freshets having drowned out all the clover vegetation in the swale where he lay, but for the life of us we could not tell whether the effigy was of an elephant, a bear or some other huge animal... ,We, however, con- cluded that the effigy must have been comparatively recent for the flood-plain must have been constantly covered with water not a very long time ago; that is, as we reckon time in the history of extinct animals. Our opinion is that the Cherokees built their burial-mounds on the flood-plain of the Scioto in Ohio about the same time that the Winnebagoes built a bear or buffalo effigy on Flood-plain and the Mound Builders. — Peet. 45 the flood-plain near Wyalusing, in Wisconsin, and that neither of them were very ancient. This, however, cannot be said of the village enclosures of Ohio nor of the pyramids of the south, for these mounds seem to be now far beyond the reach of floods, and hence older. Still we have this significent fact that there are in the Daven- port Academy some elephant pipes and a tablet with some figures which resemble elephants. Davenport is near the mouth of the DesMoines, not very far from the great Meredosia slough and a little south of Muscatine lake. Now these are all surrounded and full of the late floods and can perhaps be called the last part, or the lowest part, of the flood-plain. No mounds are found on this low ground. But it is claimed that the mound from which the tablet was taken is on the low ground, which might be considered the river bench, only eight feet above high water. Now shall we take this as evidence? The members of the academy maintain that the elephant pipes are genuine. Shall we put the mounds on the river bench back so far as to allow the elephant or the mastodon to have been present, or shall we bring the mastodon up to the time when the river bench was eighf feet above the water and when the elephant effigy was frequently submerged? Let us see where this will lead us in reference to the other mound builders and their antiquity. The hunter-tribes of which we are now speaking are the very last of the prehistoric mound builders; there were other tribes which preceded them by many years, per- haps by centuries. We grant the point about the mastodon for the sake of the argument. Then it makes the mound builder to precede the appearance of flood-plain and the disappearance of the mastodon. We now turn to the mounds of the flood-plains as compared with those on the bluffs. Here we quote from the geological report of Minnesota. Mr. Wm. Colvill says, ‘‘ The Assiniboines, the Omahas, the Iowas and the Siouxs successively dwelt along the river in this county (Goodhue). All the mounds on the edge of the high bluffs are different from those of the terraces and those on the terraces different from those on the river-bench. All the mounds on the river-bench were said by the Sioux to belong to the Assiniboines. The dwellings were constructed by digging pits and placing posts or supports inside and covering the whole with brush and earth. Incase of death within the dwelling 46 The American Geologist. July, 1891 was completely filled with earth, thus burying the house and all. All these mounds show the hearth as a burned clay bottom with charcoal and ashes. The terrace-mounds were built when the flood-plain was covered with water and when the lake reached the base of the bluffs. The mounds on the bluffs were generally loose piles of stones having circular openings or hollow cones high enough for a man to stand erect. They may have been look- outs or war towers. The Iowas and the Omahas came here after the expulsion of the Assiniboines. They had villages at Lake Pepin. There are mounds at Lake City which are said to have been built by the Omahas. There are game drives. The Oma- has were driven out of the state by Red Wing and by Wabasha. There are large mounds at Belle Creek in the shape of effigies on an isolated knob, one in the shape of a turtle.” The writer has discovered the same succession of mounds in Wisconsin and other places. Here the latest were nearest the water, those earlier were on the terrace above and the earliest of all on the top of the bluffs: These were effigies. |The mound builders proper were in the country when the flood-plains were too wet to admit of access. But the Indians came and encamped on these flood-plains, leaving shells and hearths andpdebris near the water after the water had subsided. A succession of mound builders filling up the gaps and making the terraces the places where they built their mounds. Here, then, we have the same story as before; some of the mounds were built since the flood-pJain was dry, or comparatively so, these being cotemporaneous with the later Indians, and some of them built when the water was over the terraces and near the bluffs, evidently built by the earlier mound builders. Let us go down the river farther and look at another class of works. We find a flood-plain but it seems old, and the works on it even older than the plain itself. We can imagine how the hunter kept out of the way of the flood and yet built his burial-mounds on the bluffs adjoining the swamps and lakes. But what shall we say about the agriculturist who built his pyramid on the flood- plain itself? Here is the Cahokia mound; it is 100 feet high, has a terrace 300 feet wide, and fifty deep. It is attended by sixty or seventy other mounds similar in shape and size. These mounds are all on the great American bottom; that bottom is a flood-plain; it is a flood-plain which is now rarely overflowed. The Flood-plain and the Mound Builders. — Peet. 47 writer had the privilege of visiting this mound in company with Hon. Wm. Collins who spent his youth at Collinsville near this mound. He informed me that, in the year 1840, this American bottom was overflowed and that steamboats floated over it in res- cuing cattle and men, and landed their cargoes at the foot of the bluff three miles from the group of mounds. There has been no overflow for fifty years and the land is now as dry as the prairie. It is covered with fine farms and the mounds are covered with farm-houses and barns, and outhouses, many of them being large enough to accommodate all these and give room for the kitchen garden besides on the summit. Now the point which we make is this: if the hunter mound-builder built his burial mounds before the time of the disappearance of the elephant or mastodon, and the agriculturist built his pyramid upon the flood-plain as a place for an agricultural settlement, how long ago was the mound builder living and filling the scene with his activities? These pyramids were perhaps built while the bottoms were subject to overflow. Perhaps it would be called a city of the mound-builders, but it was a city which in some respects resembled the palafittes or lake villages of Switzerland, ‘‘a lake dwelling” on dry land a part of the time, and a palafitte in an overflowed district the other part. The bottom lands extend for eighty miles north and south and are in places some eight and ten miles wide, and are covered with a number of mound-builders’ villages similar to the one de- scribed....The same fact is also perceptible in the pyramids at Seltzertown and in Bolivar county, Miss. The drainage of the flood-plain has occurred since the pyramids were built. The pyramids are really older than the flood-plain, The height of the platforms and of the levees or long walls is sig- nificant here. In looking over the works we learned that the terraces were all at least twenty feet above the level of the ground. The majority were three times that hight—or were so originally, for many of them have been graded down to make foundations for the farm-houses. Now take a vast plain covered with large farms and villages scattered over it and not a flood that has cov- ered it since 1840 and then put water over it twenty feet with the inhabitants crowded on the summits of their pyramids or crowded on the terraces looking down on the wide spread flood, and you have a picture of the two ages, the historic and the prehistoric, and the contrasts between the two. As to the Buffalo having 48 The American Geologist. July, 1891 been prevalent at this time, we leave that to conjecture and to tradition. Gen, Claiborne in his history of Mississippi says that the tradi- tion was common among the Choctaws that a race of giants formerly existed at the south and that they used herds of mam- moths as beasts of burden. These herds devoured everything and broke down the forests. The last animal of the kind had his home on the Tombigbee. The Great Spirit struck him several times with the lightning. But he presented his head to the bolt and it glanced off. Annoyed by this, he fled to the Mississippi and with one mighty leap cleared the stream and fled to the west. Here we have a tradition of the buffalo which formerly roamed as far south as Florida. We now return to the flood plain in southern Ohio. Here the villages were attended with covered ways and canoe landings, etc. and these covered ways, all of them, end at the edge of the terraces but the water has gone, and the land is high and dry.... This occurs so often that it ceases to surprise us. We find it at Piketon, at Hopeton, at High Bank, at Newark, at Marietta and in fact at every place where there is a covered way... .The hight of the terrace above the water varies with localities but it is about equal to the hight of the platforms at Cahokia and ranges from thirty to forty feet. The following are some of the figures given by Squier and Davis....At Piketon the graded way ends at a point half a mile from the river, and there are between it and the river two terraces each twenty feet high. The evidences are, how- ever, that the river ‘‘once flowed at the foot of the graded way.” At Marietta the grade runs from the upper terrace to a lower one 680 feet long and 150 wide; the hight on which the same enclos- ure is found is from 40 to 60 feet above the bottom land, and the bottom land is from 35 to 40 feet above the water of the river. The graded way ends at a distance of several hundred feet from the water’s edge though ‘‘it is supposed that when they were built the water flowed at the edge of the terrace.’ At Hopeton the covered way formed of parallel walls runs from the village en- closure to the river about half a mile, and is one hundred and fifty feet wide. The walls terminate at the edge of a terrace, ‘‘at the foot of which it is evident the river once ran, but between which and the present bed of the stream a broad and fertile bottom now intervenes.’”’....At Seal township the square and circle are upon Flood-plain and the Mound Builders—Peet. 49 the terrace, but the circle is partially obliterated by the wash of the river which formerly flowed near, but is now ata ‘long dis- tance;” the ancient bed is distinctly seen at the foot of the ter- race.’ The cedar bank works are, on a steep precipitous bank, just above the river, at a hight of about eighty feet, but the wall on the river side has been entirely obliterated, showing that much time had-elapsed since the works were deserted. At High Bank the works are seventy-five feet above the river but they extend half a mile south. . .The works at this point have been washed and obliterated by the river, though its bed is now a long distance from the works. A series of works on Paint creek show the same changes. One village was then almost obliterated by the river but the river is now overa mile away. At Newark there is a graded way which formerly ran out to the water’s edge but it ends on dry ground, while the covered way on the other side of the village which formerly reached the water now terminates on a wide bottom and the water is at a long distance away. The same is true of the walls at Portsmouth, These formerly extended to the river from the works on the upper terrace across both ter- races, and were seven miles in length. They were so arranged as to give the idea of ferries connecting the sacrificial place with the sun symbol in one direction and the square enclosure in the other direction—three groups, two ferries and 24 miles of wall. The walls at Portsmouth have been encroached upon by the Scioto, which has changed its channel and turned toward the wall and now flows where the wall once stood. The works near Dayton were formerly on the same level where now a neat modern village stands. The great Miami however has so overflowed its banks since these works were deserted, that the circle which was farthest away, near the edge of the bluffs, has been washed away and parts of it are not to be seen. The modern village lies entirely between this circle and the river, but the modern village is never flooded. These facts are significant. The rivers might have sudden freshets and so change their channels and make great havoc with the earth works, but where the land has become so dry and high that white men place their farms, build their houses and erect their villages on it, we may judge that much time has passed. We cannot look upon the earth-works as so recent as some would make them. 32 50 The American Geologist. July, 1891 As to the beginning of the mound-builder period we will give a few facts. In-the last number of the Popular Science Monthly Mr. J. F. James has given us a diagram of the old ice dam and of the lake Ohio which was caused by the glacier which is sup- posed to have crossed the channel of the river here. Now there may be a difference of opinion about this lake and the dam, and yet there is a significance to the map. It is a miap of the territory of the village mound builders, the most interesting class of mound builders which we have. Of course this does not prove much in reference to their age, and yet the limits of their territory and of the so-called lake are the same. Here we place the reign of the mound builders. If the paleolithic people preceded the forma- tion of the lake, or were cotemporary with it, the neolithic cop- per-using mound builders were subsequent to it. If the Indians of the hunter class were subsequent to the appearance of the bot- tom lands while the flood plains had become what they are, the village mound builders preceded them by many years. In this way we read dates into our Archeological records. We have the limits marked by geological changes. : The close of the mound building period. Dr. Thomas has investi- gated a mound in the Scioto valley which was swept by the floods. _...This mound is near a series of earth works which are called the Baum works situated on the lower land in the vicinity of Chilicothe, Ohio. The argument is that as this mound was so near the village enclosure, and as it contained some peculiar chambers which resemble the rotundas of the Cherokees, the vil- lage mound builders were Cherokees, a comparatively modern people. This, however, is the very point which we doubt. The evidence is that Ohio was overrun by a succession of races or tribes and that the early race of sun-worshippers who built walled villages and graded ways and dance circles, and sacred enclosures for burials, never placed their mounds on the flood-plain, but al- ways on the upper terraces ; but the Cherokees having been a later race would naturally place their works as did all late tribes on or near the flood-plains. The growth of the flood-plain in this locality seems to have been at the expense of the terrace on which the majority of the village mound builders placed their enclosures, and so the de- struction of the terrace may be regarded as a measure of the time which has elapsed since the villages were deserted. We find the —— oe Review of Recent Geological Literature. 51 works of the mound builders sometimes associated with the flood- plain, but the association was more ancient than the proximity of the village was to the water which formerly covered the plain. Formerly the waters flowed peacefully at the foot of the terrace on which the villages were built and the covered ways ran eagerly to meet them. Between these covered ways we imagine the peo- ple to have frequently passed, all of the time relying on the earth- wall to protect them from every lurking foe. We imagine also that the canoe navigators frequently landed on the grades or in- clines and drew up their canoes, quite secure in their feeling that the friendly stream would not make an onslaught and carry them away. But by and by, for some reason, this very water which was so full and strong began its uncertain, unstable course. It re- tired from the foot of the terrace, it shrunk away from the vil- lages, it began to flow in the narrow channel, but it was constantly rising and overflowing its old flood-plain, and then the havoc be- gan. The river not only deserted the villages but it turned against them and began to even undermine the defenses, and the walls were soon opened and wide gaps appeared in the enclosures. The villagers, however, had gone before this occurred, for there seems to have been no repairing of the breaches and the water was allowed to do as it would. In two remarkable cases it so happened, however, that after the villages on the terraces were deserted, and after the flood-plain was sufficiently dry for a later tribe to build its earth-work or its rotunda, then the earth-work appeared which Dr._ Thomas calls the Cherokee monument. This is our argument; the village of the sun-worshipper on the terrace, and the rotunda or tomb or whatever it is on the flood-plain, were not really the work of the same people, but that the havoc of the flood against the terrace and the drainage of the same plain all took place since the ‘lost race” made its appearance and took its departure. REVIEW OF RECENT GEOLOGICAL LITERATURE. Chemical and Geological Essays. By TnHomMAs SterRyY Hunt. Third edition, with a new preface. pp. XLVI and 489, 8vo, 1891. Scientific Publishing Co., New York. Thechapter: of this book are as follows: 52 The American Geologist. July, 1893 Theory of igneous rocks and volcanoes (1858); On some points in chem- ical geology (1859); The chemistry of meta morphic rocks (1863); The chemistry of the primeval earth (1867); The origin of mountains (1861); The probable seat of voleanic action (1869); On some points in dynami- cal geology (1858); On limestones, dolomites and gypsums (1858-66); The chemistry of natural waters; On petroleum, asphalt, pyroschists and coal; On granites and granitic vein-stones (1871-72); The origin of matalliferous deposits: The geognosy of the Appalachians and the origin of crystalline rocks; The geology of the Alps; History of the names Cambrian and Silurian in geology; Theory of chemical changes and equivalent volumes (1853); The constitution and equivalent volume of mineral species (1853-63); Thoughts on solution and the chemical process (1854); On the objects and method of mineralogy (1867); Theory of types in chemistry (1848-1861). The volume is dedicated to James Hall. Such topics, covering nearly the whole field of chemical geology, are discussed in Dr. Hunt’s well-known style—a style which for breadth of learning and comprehensive scope, no less than for its penetrating, ap- prehension of the occult relations of chemical and dynamic forces, has caused his writings to be held among our highest speculative au- thorities on these subjects. The geological literature of the latter half of the nineteenth century will always bear a profound impress derived from the labors of Dr. Hunt. The Fossil Insects of North America, with notes on some European species. By SAMUEL H.ScuppeEr. Vol. I. The Pretertiary Insects, pp. x, 455, with 35 plates. Vol. Il. The Tertiary Insects, pp. 734, with map of the Tertiary lake basin at Florissant, Colorado, and 28 plates. (New York: Macmillan & Co. 1890.) axe Ba oles alesgata ee nD pe Thus we see that the massive Hamilton sandstone of Perry Co., 800 feet in thickness, has in Huntingdon Co. dwindled down to two comparatively insignificant sheets of 50 and 75 feet thick re- spectively and separated by 225 feet of shale. The same type of structure is shown in Northumberland and ad- joining counties as we find from Prof. White’s report (G, p. 77, etc.) He says in speaking of the country east of the eastern branch of the Susquehana : ‘The type of the Hamilton series is remarkably similar to the cor- responding beds in western New York both in lithology and in the ac- companying fossils.” Again he writes: ‘*The middle type of the Hamilton comes in after passing south from the Northumberland synclinal and may be found on both sides of the Selinsgrove arch which crosses the river about five miles below Sunbury. The section on the south side of that axis exhibits a structure for the Hamilton quite different from that shown in Columbia county.” Olive-brown'Shalesics oes toe loans lebie repair eer 450 feet Selinsgrove upper SandStone...........-.eeceereeeeee. 202: = Dark olive Shales: ..ycccreccwisie stereo lonesteiel els ele one miensnetete Ts heb es Selinsgrove lower sandstone............--+-ssecsscees aa Brown and dark: SHalessr ns oj. ces «she erences sreeieeneleelets soo * Again Prof. White writes: ‘*The southern typeof the Hamilton beds. is reached after passing south of the Georgetown axis near the southern border of Northumberland there being a progressive coarsening of the series in that direction from the locality of the last section near Selins- grove.” Selinsgrove upper sandstone... . 2 2. enwnwiec t+ cen atin 100 feet Olive=DrOWH SHAIES. 5...) . sie rein: «cn date erekelotetaty sie ete aeinis satel BOO es Selinsgrove lower Sandstone............0-+sveeereeces DOs ace Palwozoic History of Pennsylvania.—Claypole. 155 Prof. White adds: ‘‘ The Selinsgrove upper sandstone is one of those intercalated beds which here makes its appearance in the middle of the Hamilton group and is so thick and massive as to change entirely the character of the topography, for instead of a wide level valley as in the north, it is now found making a high ridge along the strike of this sandstone. ‘There is not an inch of this sandstone represented in the bed on Fishing creek. (Fishing creek drains nearly all of Columbia Co. north of the Susquehana and is therefore to the northeast of North- umberland Co.)’” Again we find in Mr. Platt’s report on Blair Co. the following evidence. (T, p. 31): *“*In Blair Co. the whole of the Hamilton formation is composed of dark shale with calcareous layers.” And further Prof. Lesley adds a note in the report of Rye township (F, p. 310) to this effect : “The outcrop of the Hamilton sandstone crosses the Susquehanna river eastward from Perry Co., and runs through Dauphin, Lebanon and Schuylkill counties,” that is northeastward. It thus appears that the Hamilton sandstone gradually thins away from a point near or on the south line of Perry Co., to the northeast, north and northwest, in which directions alone it can be traced. In thus thinning out it splits and. becomes a lower and an upper sheet of which the latter is the more persistent, extending even into Northumberland, while both underlie much of Hunting- don Co. Its color is usually gray or whitish, seldom yellow and never red, and it is usually not very hard. It is not conglomeratic. At the south line of Perry Co. it stands vertical and is even somewhat overthrown as may be seen upon the Susquehanna a few miles north of Harrisburg. When this is the case it forms very rough and almost mountain territory. Its southernmost outcrop is known as Little mountain anc is cut by the Pennsylvania Rail- way near the bridge across the Susquehanna at Rockville. How much farther it may have extended to the southeast is of course unknown. The contortion and erosion which the country has suffered since its deposition have utterly destroyed all trace of it. Moreover along the line of its last southern outcrop in Little mountain lies apparently the edge of a great overthrust plain which has brought the Onondaga red shale against the Hamilton sand- stone, cutting out, that is covering up, the intervening strata though a thousand feet in thickness. These only reappear to the 156 The American Geologist. September, 1891 eastward near the Labanon Co. line after a concealment of 20 miles. So large a semilenticular mass of sandstone intercalated in a group of soft strata must have had some local cause and in seeking this we may be aided by recalling the geography of Pennsylvania at the time under consideration. In the early Devonian era the interior states, generally speaking, consisted of an open ocean extending from the Atlantic land on the east in what is now eastern Pennsylvania to an unknown dis- tance westward and limited to the northward by the Archzean High- lands of Canada. In this palzeozoic ocean a gentle elevation was taking place along a line from northeast to southwest through Ohio, whereby what is now known as the Cincinnati ridge or arch was brought into existence. Ultimately, and probably before the Devonian era closed, this ridge partly severed the eastern portion of this ocean from the rest and formed the Appalachian strait or gulf. The continued subsidence of this strait or gulf allowed the deposition in it of sediment from the adjoining land on the east but the nature of the sediment on the area now in question would indicate by its fineness, being mostly sandy shale, that the land was not very near, or if near not very high. The latter is more probable. Such deposits do not indicate shallow water or strong currents. The actual margin of the Appalachian gulf or strait has apparently been destroyed by the corrugation and erosion that have ensued, so that the present Hamilton deposits are those which were deposited off shore, but neither in deep water nor on the border of the land. But so great and sudden a change in the nature of the strata implies some great and corresponding change in the physical geography and especially in the attitude of the land—a change that would allow the Hamilton sea to assort and arrange coarse sand where it had previously deposited only fine shale. The arrangement of this sand appears to indicate a center of distribution from which it was spread over the whole area that it now occupies and it seems a not improbable supposition that this centre was the mouth of some large river which bore into the Ap- palachian sea its tribute of sand and mud. The former was as- sorted and distributed over the region around the river-mouth, and the latter carried out to a greater distance where it ultimately be- came a bed of shale. That the ancient Atlantic land was drained by a system of streams goes without saying, and it may be that Palwozoie History of Pennsylvania.—Claypole. 157 we here catch a glimpse of one of them, or at least of the place where it entered the sea. In making this supposition to explain the occurrence of the Hamilton sandstone, it is not at all necessary to assume that this ancient river came into existence at that epoch and then passed out of being. Far from it. The river may have existed ages be- fore that day and may have continued to flow long after the Ham- ilton era passed away. All that is necessary is to suppose an ac- cession to its carrying power. And this is not difficult. The palzozoic geology of the eastern states indicates beyond all doubt constant and great oscillation of the land and the seabed. Inter- mittent depression to immense extent caused the accumulation of the massive sediment of that era. Such accumulation likewise in- directly proves elevation of the land, for had not this taken place the whole area must have been eroded and removed. It is less easy to detect elevation of the land than depression of the sea bottom, because the former leaves no direct evidence of its occur- rence. But if the Hamilton sandstone is in truth the monument of some old and extinct river, it records a time when through ele- vation of the coast the eroding and carrying power of that river were largely increased so as to form the Hamilton. lower sand- stone. Next it indicates a time when probably by the work of the river, but possibly by ensuing subsidence, the current was again slowed down and the sand dropped near shore, its quantity being also diminished. Thirdly, it reveals another sharpening of the stream by a second elevation whereby it was enabled to erode from the land and scatter over the ocean bed the Hamilton upper sandstone thicker than the lower. Lastly, the action of the river destroyed its own velocity by eroding its channel or a second sub- sidence ensued with the same effect. All these episodes are to be read with great probability in the Hamilton sandstone, and if our argument is well founded we gain a peep at one of the changes of which the paleeozoic era was made up. Possibly though this is little more than a supposition; the ab- sence of lime from the Devonian formation through this part of Pennsylvania may be an indication in the same direction. The beds show a preponderance of the earthy and mechanical over the chemical deposits such as is usual near the mouth of a river where the wash from the land predominates over all other materials. 158 The American Geologist. September, 1891 The fauna of the Hamilton in middle Pennsylvania contains the following species : Brachiopoda. Spirifera ziczac Hall. Strophodonta perplana Con. o mucronata Hall. Strophomena rhomboidalis Wahl. = medialis Hall. Orthis penelqpe Hall. acuminata Hall. Chonetes setigerus Hall. $s granulifera Hall. f coronatus Con. Rhynchonella horsfordi Hall. Tropidoleptus carinatus Hall. es congregata Conrad. Atrypa reticularis L. Rensselria sp. Pteropoda. Tentaculites attenuatus Hall. Lamellibranchiata. Glyptodesma rectum Con. Actinodesma subrectum Whit. Aviculopecten princeps Con. Gasteropoda. Loxonema delphicola Hall. Echinodermata. Ancyrocrinus bulbosus Hall. Cephalopoda. Nautilus liratus Hall. Crustaced. Phacops rana Green. Homalonotus delphinocephalus Green. Vertebrata. Coccosteus ? : Most of these fossils are forms which would be naturally looked for by the paleontologist in a middle Devonian formation. They characterize the Hamilton group of Pennsylvania and adjoining states. But there are one or two on the list which are less famil- iar on this horizon and require a moment's notice. Rensseleria is one of those genera whose existence, even in- cluding its allied forms, Amphigenia and Newberria, is, so far as yet known, confined between the limits of the Lower Helderberg below and the Corniferous limestone above. ensseleria was es- tablished in 1859 by Prof. Hall to receive a number of peculiar shells of the type of R. ovoides. In 1867 one of these was re- moved by the author of the genus and made the type of the new genus Amphigenia. The range of these was as follows : Corniferous limestone Amphigenia elongata. Rensselwria johanni. Schoharie grit Amphigenia elongata. Oriskany sandstone Amphigenia curta. Rensselwria condoni. Paleozoic History of Pennsylvania.—Claypole. 159 . cumberlandiz. . intermedia. . marylandica. . OValis. . ovoides. - Suessana. . equiradiata. . elliptica. . levis Hall. - mutabilis. . portlandica. Prof. Hall has recently taken his R. johanni from its old posi- tion and has made it the type of a new genus Newberria, charac- terized by the slightness or absence of external radial striation of the two strong dental plates, and the thick hinge plate and inter- nal loop of Rensseleria. To this new genus is also referred the R. levis of Meek which is reported by Whiteaves from several places in the Mackenzie River district. * When the writer, at the meeting of the Am. Ass. for the Adv. of Science at Minneapolis, in 1883, announced his discovery of these fossils in the Hamilton sandstone, he spoke of the difficulty which he had felt in separating them from some of Prof. Hall’s species, such as R. marylandica and R. johanni. He was not willing in this state of uncertainty to coin a new name and left the matter in doubt. These fossils are now in the hands of Prof. Hall for description and the difficulty will doubtless be cleared up. It may very probably prove that they will also belong to the new genus Newberria from their close resemblance to R. johanni. Whether this should prove to be the case or not, they will at any rate carry this type of shell up from the Corniferous limestone to the middle of the Hamilton, _ The last name on the list also calls for a short notice. It is a cast of the dorso-median plate of Coccosteus or some nearly allied placoderm, but its exact relationship has not yet been determined. Its occurrence in these beds is interesting because, so far as I am aware, no fish fossil has yet been described from the Hamilton group in Pennsylvania, though a scanty fish fauna has come to light from the rocks of similar age in adjoining states. At some future time more details may be given regarding this solitary specimen. Lower Helderberg HAHN NDAWDDAHDAA *See Contributions to Canadian Paleontology. Vol. I, pt. 3. 160 The American Geologist. September, 1891 NEOLITHIC MAN IN NICARAGUA. By J. Crawrorp, Managua, Nicaragua. Numerous evidences of panic and fright among men and domestic animals in Nicaragua, in one of the past geological epochs, are deeply impressed on stratified rocks many feet below the earth’s surface, under the city of Managua, extending south and southeastward from lake Managua to a distance of over one mile, possibly further, as far as has been examined, in the direc- tion of the extinct voleano Masaya (1), ten miles distant. The footprints indicate haste, confusion and excitement, and are im- pressed from 1} to 2 inches deep in the stratum, the toes of the feet in every footprint made the deepest mark and pushed the mud back toward the heel, as usual from running in shallow mud; all are pointed, many directly, others obliquely, toward lake Managua, as if to seek shelter in its waters from a storm of burn- ing hot voleanic ashes and cinders, or some equally dangerous occurrence. A few roughly polished arrow heads and barbed harpoons, but no skeletons nor bones have been found in that nor in any of the superimposed strata(2). A short topographic and stratigraphic description of the local- ity will enable a comparison to be made with similar conditions of (1) This volcanic classification of “ extinct ” is not based on any theory about the interior constitution of the earth, but, on such facts of my own observation as, when in my examinations I found that I must adopt some classification. The plane of invariable annual ( also daily) temper- ature beneath the earth’s surface on and near to this large mass of vol- canic materials is isogeothermal with planes of similar situations and altitude in that country; on inactive but not extinct volcanic masses no isogeothermal plane can be found, or, it is too irregular and indefinite for determination. The selection of homes and hiding places by wild animals and birds on extinct but never, so far as I have observed in this and in South American volcanic countries, on inactive hot top nor on active volcanoes. (2) Since this paper was written, Nov. 1890, there has been found ( Feb’y 10, 1891 ), the dust and small disentegrating parts of several crani- um bones and three or four teeth of some human being, in an urn of oblate oval form made of voleanic, iron-colored clays and sand and burned. The dimensions of the urn are: depth 68 c. m., greatest diameter 68 c. m., diameter across opening at one end 43 c, m., thickness in walls 14 to 3¢ of an inch. This was discovered in a quarry in southern part of the city of Managua, about 15 feet below the earth’s surface and resting on a stratum composed of volcanic ejecta hardened sufliciently to be quarried and used in the construction or all kinds of walls for resi- dences and public buildings in the city of Managua; about sixteen feet beneath the urn, four hard conglomerate strata intervening, is the stratum on which human footprints were found in large numbers. The bones and urn were purchased by the consul for Austria, and will be sent to the museum in Vienna, Austria. Neolithic Man in Nicaraqua.— Crawford. 161 surface and strata in other countries, whose geology is better known, in order to determine the epoch when these people lived, and possibly to decide on the cause of their flight. For a few feet south from the water margin of the lake, the formation is a coarse sandy beach, then an abrupt cliff 8 to 12 feet high above the surface of the water, thence south and south- eastward for more than a mile, the surface ascends to about 180 feet above the level of the water in the lake, then commences a series of volcanic montecules, cones, craters, and cerros, some- what degraded by erosion, extending 25 to thirty miles eastward to lake Nicaragua. The stratum bearing impressions of human feet is near lake Managua, about fourteen feet beneath the surface of the soil, and on a level with the high water mark. It is not much inclined but nearly horizontal with the present surface of the earth as it ascends south and east from the lake. The mineralogical composition of the strata from at least twenty feet below the stratum retaining footprints of man and other mammals, up to the surface of the soil is about the same. The larger proportion of more acid minerals are near the soil, the general composition of all are rhyolite, trachyte, lipardite, phono- lite, pumice, basalt, dolerite, audesite and black, also light colored, scoriz, all in particles (large grains or small fragments) and bodies, mixed by water with volcanic ashes (and ores of iron ) into a conglomerate whose contained grains and fragments are weakly cemented by the ashes and oxides into strata varying from six inches to four feet thick and consolidated to a hardness when in place, of from 2 to 23 (excepting the upper stratum which has not yet hardened sufficiently to be separable, from top to bottom, into blocks ), containing four or more cubic feet; exposed to a dry atmosphere these rocks soon harden to 3.25 to 4. Each stratum is separated from the one above it and, also the one below it, by a fine grained, /oose sand, colored light brown by iron oxides and varying in thickness from 24 to 4 inches. Stratigraphically, the deposits, from at least ten feet below the stratum impressed by human feet, up to the surface of the earth, are: (a) Superficial, 4 to 10 feet thick uncompacted or partly hardened ejecta conglomerate (3) containing numerous patches or small areas of (3) Ejecta conglomerate in distinction from fused volcanic conglomerates and “ shingle * and from ‘‘ conglomerate” as defined by Lyell, Dana, Lo Conte, Prestwich 162 The American Geologist. September, 1891 small fragments of pumice, also of colored clays and sands which when mixed with lime (CaO,H, ) is used as a hydraulic cement which de- velopes nearly as much tensile, torosile and adhesive strength as Roman cement; this is an acid conglomerate of grains and small fragments of volcanic materials the majority of which represent the early and middle part of the ashes-and-cinder-eruption in some period of explosive volcanic activity. (b) A stratum of fine sand, 4 to 4% inches thick, loose, uncompacted, slightly colored, light orange brown by hydrous oxides of iron. (c) Astratum 2 to 214 hard, of ejecta conglomerate, 4 to 4% feet thick, coarse grains and small fragments well mixed, of a dark grey color spotted with hard black fragments of metamorphosed hornblende. (d) A stratum of fine sand, uncompacted, resembling (b) in color, 216 to 3 inches thick. (e) A stratum of the same composition, hardness and color as (¢c) above described, 244 to 3 feet thick. (f) A stratum of fine, loose sand, 2 to 3 inches thick of a light orange color. (g) Astratum 2 to 21 feet thick of the same composition and color as (c) and (e) above described but harder, nearly 3 hard. (h) A stratum of fine, uncompacted sand, 11% to 2 inches thick, light, reddish brown color. (i) A stratum composed of the same kind of materials and of the same color as (c) and(e), and about as hard as (g) above described, bearing intaglioes in the upper surface of numerous deep impressions of the feet of man and domestic animals, also containing, sunken until nearly covered, in its surface a few roughly polished stone implements, arrow heads, etc. (j) A stratum of fine sand, uncompacted, the interspaces filled with water two and a half to three inches thick (4); it is colored light reddish brown by iron oxides, and has changed position and associates more than once since the Miocene period of the Cenozoic era. (k) A deposit, below the usual level of the water in lake Managua, more than ten feet thick, of unknown thickness (I excavated only about ten feet, into this stratum when the water came in so rapidly as to cause work to cease), but, probably it is several hundred feet thick, wncom- pacted materials of the same composition as the harder strata above it; the water appears to have prevented the hardening of this deposit of volcanic ejecta conglomerate. The different strata of sand in the above described, were de- posits from the ordinary currents of water after the usual rains; and other authorities, in being composed of grains, particles and fragments of rocks of irregular shapes, and pieces of minerals from the size of a MM. diameter to diameters of several CM., all ejected from volcanoes, and some particles softened: afterward by meteoric influences, then transported from the sides of volcanic masses and the valleys between them, as floods of Ee and deposited stratigraphically. (4) This stratum has, strangely, been mistaken for ‘* Miocene-period sand,” and so published in Europe; it figured prominently in an article published in the Proceedings of the Victoria Institute, London, 1887, declaring the existence of man, these footprints, in Nicaraugua in the Miocene period. See Proc. Victoria Institute 1886 or 1887. Neolithic Man in Nicaraqua.— Crawford. 163 they are too thoroughly sorted or separated according to their densities to be ashes immediately from volcanoes falling on the hardening stratum of rock. The strata of hardened volcanic conglomerate ejecta were de- posited, each stratum most probably from large deep floods of mud brought down in continuous flow during one season, by tor- rents after long continued heavy rains, from the adjacent monte- cules, cones and cerros of materials erupted from volcanoes. The superficial deposit (four to twelve feet deep, uncompacted ) was formed by several small floods of mud, occuring at intervals of several years. That these floods of mud occurred and that they were so thick in this locality is confirmed by vivid deserip- tions by some of the most eminent, educated and reliable citizens in Nicaragua who describe a similar occurrence on October 4, 1876. In this locality the city of Managua, the local name of these torrential floods of mud is ‘+ aluvions de barro;” this alu- vion de barro filled the open houses, streets and plazas near the lake five and one-half feet deep with thick mushy mud composed of materials similar to those that are formed into hard conglom- erate, hereinbefore described. Much of the slowly moving mud which remained in the city was washed into the lake by subse- quent rains, but large masses were left in protected places, which have dried and hardened into isolated areas about twenty-four inches thick. Some of its upper surface, probably was washed away by rains because when these isolated parts, now hard and 24 inches thick, were prevented from flowing further, they were fully five and one-half feet deep, slowly flowing masses of thick mud. Several large boulders, some of them fully twelve tons in weight, were moved from depressions or conecavities on the mountain’s side, about one mile to the south of the city, where they had hardened. They were not hard enough to have been rolled even for 100 yards without breaking into fragments, but were deposited in the streets of Managua. A canal that once extended for two miles from east to west, and was forty feet wide and ten feet deep, was filled up by the mud flood, October 4, 1876, and is now one of the principal thoroughfares for traffic. At this date natural forces were acting on a grand scale, in this locality, changing the position of large quantities of material, yet the forces were small in comparison with that enormous flood of mud, which transported from the adjacent monticules and 164 The American Geologist. September, 1891 cones sufficient loose fragmentary material ( which had, long pre- viously probably, been erupted from volcanoes ) to their present position, where dry and hard the stratum (c) is now four and one-half feet thick. The people whose footprints are found so numerous on stratum (i) must have removed from that locality before the occurrence of the ‘+ aluvion de barro” which formed the now hard stratum (g), because that flood of mud must have been over fifteen feet deep. These strata dried slowly in a moist atmosphere; they are not fissured, consequently they did not dry rapidly; they show no in- dications of having been schisted, nor have any cracks afterwards been filled up by washed materials. The time when men, dogs and horses* fled to Managua to shel- ter themselves from the highly heated cinders and ashes ejected from voleano Masaya, was most probably very long ago. We may go back, in time, toward that epoch guided by such facts as the following. From intelligent and _ reliable witnesses we learn that voleano Masaya, about ten miles eastward from the city of Managua and on the west side of the city of Masaya, commenced on the 10th of November, 1858, emiting ( from a fissure inits side about four hundred feet below the rim of its crater containing a lake of water) aqueous vapors, sulphurous acid gas, chlorine gas, carbon dioxide, etc. This continued for about ten dayst then ceased, and, although a part of that fissure still exists, gapping and ugly, yet the entire voleanic mass is now so cool that its sides and the outer and inner edges of its crater are coy- ered with small green trees and flowering plants, accompanied by many birds (5 ) which appear to consider that volcano extinct. From history we learn that on the 10th of March, 1762, ¢ fissure opened inthe sideof this voleano Masaya about three hun- dred feet below the rim of the crater, and poured out lava, at intervals, for several days, which covered an area about one-half *No impression of the side toes of horses have been found in this stratum (i), in the two or three inch deep impressions of horses’ feet. +The statements are various. (5) I here noticed in the volcanic part of Nicaragua and in other countries, that birds seldom or never visit volcanoes that have hot tops and have no isogeothermal plane corresponding with the surrounding country; birds and wild animals appear tc have an instinctive knowl- edge of the natural causes, dynamic and kinetic, at work in the mysterous depths of the earth. _ Neolithic Man in Nicaragua.— Crawford. 165 mile wide, near the fissure, and widening gradually, for an extent of three or fourmiles into a forest of large exogenous trees, leay- ing over its course a mass of scorie, obsidian, vesicular lava and stones, which now look as if fresh and hot. Many trees along the edge of this flow of lava were carbonized, and parts of them are yet standing. The ashes and cinders then sent out with explosive force through the fissure, have been washed away down into the lakes. The volcanic activity created no great dis- turbance in the present city of Masaya, situated on the side of the volcanic mountain, opposite to the fissure, and the ashes reached tothe city of Managua ten miles distant, only by occasional gusts of wind, not of sufficient quantity or temperature to cause any other unpleasantness than great apprehension of danger. Anterior to this activity in 1762 we have no reliable human record of any other outburst from this volcano, and physical evi- dences indicate that it had been quiet for very many centuries, possibly for one or more geological epochs. In comparing these facts in reference to the eruptions with other volcanoes the history of which is better known, but which have far more deeply eroded sides, of which facts are obtained, we find, that the materials forming, in considerably large part, the montecules, cones and sides of Etna, are easily loosened by rains and can be washed down in large quantities by torrents as at voleano Masaya; also that each, in its own locality, has sea- sons of heavy rains; but the lava which poured from Etna four hundred years B. C., and stopped the Carthagenian army in its march against Syracuse, is now, much of it, exposed on the earth’s surface where it flowed and is not covered by sedimentary materials, washed down, from Etna’s side, nor covered by floods of mud. Yet, in less than ten miles from voleano Masaya, the stratification near lake Managua of materials ejected from vol- canoes and washed down and deposited, is hard and more than twelve feet thick at its least depth, above the hard stratum deeply impressed by human footprints, and these impressions of feet were made when the surface of that stratum was only partly hardened orin a stiff, muddy condition. Any estimate in years of thetime necessary toform and then to harden an ejecta conglomerate so slowly as not to fissure, such as each of these strata near lake Managua, and the time intervening between the drying and D> 166 The American Geologist. September, 1801 hardening of one stratum before commencing the deposi- tion of another, would be solely speculative. I have not sufficient data from my own or,others’ observations of volcanoes as to the average quantity of matter annually washed down from their sides, either by ordinary rains or during seasons of extraordi- nary floods, to make from the annual erosion an estimate of time necessary to form such deposits as the conglomerate strata beneath the city of Managua and extending toward the extinct voleano Masaya. There certainly has been an epoch of great elevation and glaci- ation in part of Nicaragua, and a subsequent epoch of subsidence in all, and much ice melting and torrential floods in parts. There are many evidences here of the occurrence of the Glacial, Cham- plain and Terrace epochs. Probably this stratum containing human footprints, and the superimposed strata, were deposited during the later elevation and depression of the Champlain epoch and early part of the Terrace epoch; if so, then there is in Nicar- agua evidence of men in large numbers and congregated in large towns or cities of thirty thousand or more, during the later Cham- plain or early Terrace epoch. And, if we accept M. Foret’s calculations in reference to the time occupied in silting parts of lake Geneva by the river Rhone in an effort to get at the date of the conclusion of the glacial period there, as a basis for the hardening of the stratum underneath the city of Managua, we can probably say more than fifty thousand years ago. Managua, Nicaragua, Nov, 10, 1890. THE POST-ARCHAEAN AGE OF THE WHITE LIME- STONES OF SUSSEX CO.) N:-J3.* A REPLY TO A REVIEWT Frank L. Nason, Jefferson City, Mo. In the review of the above paper the writer feels that Prof. Dana has laid undue stress upon some of the evidence adduced in support of his views and not enough on other. It does not seem to be logical to assume, because a limestone contains chondrodite, magnetite and the oxides and silicates of zinc, together with intruded granite, that no amount of evidence *Ann. Rep. State Geologist of N. J., 1890, +Notice of Ann. Rep. State Geologist of N.J., 1890, July Number of Am. Jour. Sci., 1891; J. D. D. a Post-Archwan Age of White Lime-Stones.— Nason. 167 will prove these limestones to bea locally metamorphosed fossilifer- ous limestone. In other words, if positive and direct evidence can be found showing a transition from blue to white limestone, the fact that the white limestone has the above concomitants does not militate against the proposition in the least. The problem simply assumes another and a totally different phase. Instead of a question of geological age it becomes a study in metamorphism. In the following paper the writer wishes to present, as con- cisely as possible, the evidence which led him to the conclusion that the white limestone of Sussex county is but the metamor- phosed form of the fossiliferous blue limestone. The evidence can be summed up under these heads: Ist. The topographic features of the two rocks. This will include, (a) the nature of the dips and the foldings of the rocks; (b) the axes of special disturbance. 2d. The associated rocks. This will include, (a) the accompanying bedded rocks, (b) the eruptive rocks. 3d. The transition of one limestone into the other. This will include, (a) breccias in the white limestone, (b) breccias in the blue limestone, (c) graphite and fossils, (d) the actual trac- ing «cross the strike and a/ong the strike from white to blue, this occurring in long lines, (e) occurs in many localities, (f) the breccias form the boundary lines. 1. Topographical features. The white and the blue limestones are intimately associated with eachother. Large areas of white limestone are never widely separated from the blue, and nota single outcrop of white lime- stone is known by the writer wholly independent of the blue. (a.) In former reports and papers on this subject, the dis- tinctive feature of the white with respect to the blue, has been ‘the universal southeast dip” and the northwest dip of the blue. Neither of these statements is in accordance with facts. It is us- ually difficult to observe the dip of the white limestone on account of the extreme metamorphism. Yet the fact that the white lime- stones do dip northwest is plainly to be observed. It frequently happens that one end of the slope of a hill is white limestone and the opposite end of the slope of the hill is blue. But whatever the direction of the dip, they both dip in the same direction. The 168 The American Geologist. September, 1891 argument from southeast dip is farther shown to be worthless from the fact that the white limestones are proved anticlines in structure as well as the blue. (b.) The white limestones occupy axes of great disturbance as denoted by the intrusion of eruptive rocks; by excessive shatter- ing; by sudden and great disturbance of dip and strike. The force of this point will be more strongly felt if one ob- serves the /solated patches of white limestone between Franklin Furnace and Andover. Here the blue limestones lie against the gneiss with numerous outcrops of sandstone. When there is an area of white limestone, it is not far removed from the blue, but it is accompanied by great masses of granite and other eruptives and the sandstones are usually graphitic. 2. The associated rocks. (a.) One of the strong ties which bind the two limestones to- gether is the sandstone. This sandstone is found so abundantly and at such critical points as to form an evidence quite as strong as the actual passage of the blue into the white limestone. These sandstones, in many places, form the axis of hills which are anticlinal in structure and which have one end of a flank blue limestone, and the other end white. These sandstones lie wider the blue limestones and can be traced till they disappear wader the white limestone. These sandstones are graphitic when near either a white lime- stone or near a granite dike accompanied or unaccompanied by white limestone. . Prof. Dana is perfectly right when he says, ‘‘evidence drawn from graphite is of uncertain value,’ but that is a general state- ment. In the case at hand the writer believes that the conditions under which the graphite occurs make its testimony not only strongly corroborative, but direct and positive. The presence of graphite in the blue limestone will be mentioned under 3. (b.) The white limestones, as already stated, are characterized by eruptive rocks. The most characteristic of these is the granite. There is hardly an area of white lime- stone which is not accompanied by granite; even where gran- ite is not visible on the surface the white limestone is filled with intrusive sheets of it. Thisis proved by the drill borings, 1,100 feet deep at Franklin Furnace. There were eight holes in all, and each had successive layers of granite. Post-Archwan Age of White Lime-Stones.—Nason. 169 The blue limestones are almost wholly free from eruptives and granite is never present. Taking these facts in connection with the disturbed areas as shown by the topography, the presence of granite in the white limestone and its absence from the blue is as easily accounted for as the fact that the white limestone occupies areas of great disturbance, while the blue area is comparatively undisturbed. 3. The transition of the blue limestone into the white. The writer regards this gradation as absolute proof of the synchronous horizon of these two limestones and that this fact alone is sufficient to establish the point at issue even were there no other confirmatory facts. That this gradation or transition actually exists no one will doubt if once he visits the localities in question. (a) Breccias in the white limestone are not always readily observable, but localities are found where great masses of limestone are made up entirely of angular fragments. The interstitial matter is coarsely crystal- line with scales of graphite. The angular fragments are bleached and some have a distinctly crystalline structure with scales of graphite and cloudy aggregations of the same mineral. In some, the angular outline of the original fragment is plainly observable, but near the center the crystalline structure is lost and the core is a rounded, comparatively unchanged mass. Were it not for the abundance and variety of these breccias one might regard them as a kind of concretion, (b.) The breccias in the blue limestones, like those in the white, are found near the boundary line, or are, rather, the actual boundary line; the white limestones being found on one side and the blue on the other. The breccias are filled interstitially with crystalline graphitic limestones. The fragments themselves, while as dark as the blue limestone, have occasional scales of graphite. The degree of alteration depends upon the size of the fragment. The boundary line between the blue and. white, when they ap- proach each other, is either brecciated rock or a line of easy gradation as noted under 3 (d). (c),The presence of graphite and fossils in the blue limestone and in the sandstone, standing as isolated facts, do, as Prof. Dana says, have but doubtful significance, but this particular case stands as_ fol- lows:—The fossils show these rocks to be among the oldest of fosiliferous rocks and thus more liable to metamorphic action; the 170 The American Geologist. September, 1891 presence of graphite in the rocks and actually replacing these fos- sils shows that metamorphic action has actually operated to some extent; and the invariable proximity of these blue limestones and the sandstones when graphitic to either white limestone or granite is exceedingly strong evidence in support of the proposition thfat the metamorphism which changed the white limestone operated in a less degree, but at the same time, on the blue limestone and the sandstone. (d) The actual gradation from white to blue across and along the line of strike. In the case in hand there is no possibility of mistaking super-position of a younger blue limestone on the white. The actual facts are that going from west to east there is encountered, first a coarsely crystalline white, graphitic limestone; last a blue lime- stone, plainly bedded and jointed. Between these two points, no more than fifty feet apart, these limestones shade into each other in color, in degree of crystallization, in the presence of graph- ite. That is, the graphite exists in every stage from the bright crystalline stage to cloud aggregations of carbonaceous matter which give the blue color to the blue limestone. (e.) This gradation is not confined to a single locality, but the localities are numerous. In no locality is actual contact observed between white and blue limestone, but wherever exposure is of such a nature as toallowsuch contact to be observed, if it existed, the above facts are observed instead. The transition rocks are not taken from several localities and transition ¢nferred from this series; but by going across a given exposure the complete series is seen and in place. No series of samples can give aperfect idez unless a continuous strip of rock were taken. Using the locality at Franklin Furnace as a point of departure, the localities at which this transition may be observed are as follows:—West of the Rude- ville quarries four miles; on a hill east of McAfee, six miles; on the hills southwest of McAfee, numerous localities, five miles; on a small hill then north of McAfee, nine miles. These localities are all in the Vernon and the Wallkill valleys. In other locali- ties near Oxford, Jury Jump mountain, and Andover, changes fully as convincing may be observed, and these point to the fact that the conclusions reached in the study of the Sussex county limestone may safely be extended to these also. In conclusion it may be well to state that the two limestones are separated by one of two marked types of rock; either the band Genus Trinacromeruni.— Cragtir. Let of transition limestone or by a band of brecciated limestone rock ; and that in no place does the limestone change from blue to white across a continuous exposure without one of these transition rocks. NEW OBSERVATIONS ON THE GENUS TRINAC- ROMERUM. By F. W. Craarn, Colorado Springs, Colorado. The type-skeleton of this genus, discovered in the summer of 1888, and partially described by the writer a few months later*, was nearly perfect when first seen by the workmen who found it, but was afterward broken in pieces by vandalic curiosity seekers, and had been scattered over portions of two counties before it came to the writer's knowledge. It was with great difficulty that the task of getting together such parts as had escaped utter de- struction was accomplished, some of these being obtained by rock excavation at the original locality, others by dint of considerable perseverance in travel and moral suasion. The expenditure of much time and labor in freeing the bone- fragments from the more or less silicified limestone matrix and in matching them, has resulted in restoring to a condition avail- able for study, several parts which once seemed hopelessly in- complete. A study of the type, as thus renovated, and of parts of several other specimens, has enabled me to supplement my preliminary paper with the following descriptive notes. THE SKULL.- Besides the very imperfect skull of the type (represented by the muzzle and a number of other fragments, of more or less importance ), the writer has secured two skulls which belong—oney? certainly, the other probably—to this genus. For convenience of reference, these three skulls may be designated respectively as A, B, and C, As all preserved parts of the skeletal structure of 7r/nacrome- rum will be fully treated in an illustrated memoir, which is in preparation, a detailed consideration of the skull will not now be undertaken; but a few of its more conspicuous features may here be noted. The skull is very large (B,C) and long (A, B), *Preliminary Description of a New or Little Known Saurian from the Benton, of Kansas. American Geologist, December, 1888. +This skull seems to have pertained to an individual of about the same size as the type, with which it agrees perfectly in several parts pre- served in both specimens. I regard it as not only congeneric but also co-specific with the type. 172 The American Geologist. September, 1891 rather broad posteriorly (B, C), and gradually contracting an- teriorly (B) to the greatly produced, high, and narrow muzzle (A, B). The fromto-parietal region is but moderately elevated, and slopes either way from the obtuse median ridge (B, C). There is a rather large elliptical or narrow-ovate parietal foramen (B,C). The orbit is large and ovate (B) in outline. The mandible has a long symphysis (A, B ), posterior to which the rami are quite straight till at and near the posterior end, where they curve inward (B). The teeth ( A, B) resemble in form and sculpture that to which Leidy has given the name, Piratosaurust, but are smaller and less curved, and their strizform folds of enamel reach much nearer the summit and are lacking entirely on the antero-exterior segment (A, B). Tue PecroraLt Arcu.—The coracoids are divided into a stout, saddle-shaped, anterior segment, and a thin, scoop-shaped pos- terior segment by two broad foramina which are either confluent anteriorly across the symphysial axis or separated by only a nar- row symphysial prolongation of the posterior segment. The anterior segment is thickened in the interglenoid axis as an opposed pair of deep, massive abutments whose symphysial faces are marked with broad pits for the attachment of a median cushion of cartilage. It is anteriorly produced in advance of the glenoid fossze and is posteriorly limited by the abrupt recession of the inner coracoideal borders from the symphysial axis at the foot of the steep posterior slope of the abutments. The thus formed inner-posterior angle of either abutment presents a complex in- wardly directed articulation difficult to describe, but which, viewed from the slightly concave dorsal side of the abutment, presents the appearance of two short processes, the posterior of which is pedicellate. The posterior segment of the coracoid is characterized, like the anterior, by a transverse thickening culmi- nating at the symphysis, but shallower than that of the anterior segment. It crosses the anterior end of the segment. While this posterior segment, as a whole, is concave upward, the trans- verse thickening is concave below and convex upward, reversing the conditions which obtain in the thickening of the anterior segment. The pre-glenoidal processes of the coracoids are long and blade-like, but are so broken in the type-specimen as not to tCret. Rept. of U.S. Genus Trinacromerum.— Cragin. 173 show their full length and outline. But on the block of stone bearing skull C (and which bears vertebre indistinguishable from those of Trinacromerum ) there is a perfect pair of anterior cora- coideal blades. These lie mostly posterior to the skull and are directed agreeably with it, but their anterior end rests upon the posterior parts of the dorsal surface of the parietals, the skull having been accidentally turned over. These blades are about a foot in length and rather more than half an inch thick along the straight inner margins, diminishing, except near the end, to a thin outer edge. They gradually diminish in breadth ( to two and one-eighth inches each ) in the proximal two-thirds of their length, beyond which they have moderate lateral expansion. The distal parts of the ventral plates of both scapulo-precora- coids are likewise preserved on the parietals of skull C. They are flat expansions, somewhat broader than those of the distal ends of the anterior coracoideal blades, whose outer borders they meet on either side in a straight articulation two or three inches long, being thus held some five inches apart, instead of meeting in the mid-line as do those of Cimoliosaurus. This articulation includes nearly the posterior half of the obtuse-angled extremity of the scapulo-precoracoid, the remainder of the extremity form- ing (as preserved) a free antero-exteriorly directed border which is squared like those of the articulation, and which may, therefore, have joined an omosternum placed anterior to the coracoideal blatles. The stout, extero-posteriorly directed end of the left scapu/o- precoracoid remains, in the type specimen, in natural relation to the coracoid, which it joins to form the glenoid fossa, A large and elongated fragment of the middle part of the former bone presents three faces: one concave, the others repre- senting the outer aspect of the ventral and dorsal ( precoracoid and scapular ) plates, nearly flat and making a rounded angle of about 100° with each other. THE Petvic Arcu.—Of this, there are preserved in the type- skeleton the perfect right and imperfect left ilium, the greater part of the right pubis, the acetabular extremities and necks of both ischia, and part of the right ischial blade. On the right side, the union of the ischium and pubis, and on the left, that of the ischium and ilium remain undisturbed. The ilium is a clavate bone, rudely elliptical in cross-section of the shaft, and having the much enlarged lower end bent inward and forward. 174 The American Geologist. September, 1891 The general outline of the pubis and ischium is much like that in Plesiosaurus as figured by Huxley*, though its details differ. The blade of the pubis is a warped plate, presenting, when viewed from above, two concavities separated by an antero-posterior axis of convexity, the major convexity embracing a large part of the middle and inner anterior regions, the minor occupying a small outer-anterior part. But the pelvic arch possesses one feature that distinguishes it from any described sauropterygian pelvis with which the writer is acquainted?, The ilium does not articulate with, nor even closely approach, the pubis, being separated from it by the acetabular portion of the ischium, of whose acetabular face its own forms a posterior continuation, Thus the three elements of the acetabu- lum are brought into line. Tue VERTEBR#®.—To what has been published concerning the vertebrae, there is but little that need be added here. As would be inferred from the great size of the skull, the afiterior cervical vertebr are not greatly reduced in size. The atlas and axis and their intercentrum are anchylosed, but their sutures persist. The cervical ribs are suturally adnate to the centra by single facets. ON THE CONFOUNDING OF NASSA TRIVITTATA SAY ia AND NASSA PERALTA (CON. SP.) By Gitpert D. Harris, Washington, D. C. Nussa trivittata, a recent species inhabiting the eastern coast of the United States, was described in the second volume of the Journal of the Philadelphia Academy of Natural Sciences, in 1822, by Thomas Say. ** Kight years later, a somewhat similar though very distinct form obtained from the ‘*‘Upper Marine” (Miocene) formation in the vicin- ity of St. Mary’s River, Md., was inadvertently referred by Conrad to ‘‘Nassa Trivittata, Say.’ tt Morton repeated this error on page 2 of the Appendix to his Synopsis of the Organic Remains of the Cretaceous Group, published in 1834. The species is again re- ferred to by Conrad in 1842 under the name ++ Bucetnum trivitta- *Vertebrate Anatomy, p. 182. tIn Hlasmosaurus, the ilium is described by Cope as articulating with the pubis only. Extinct Reptilia, Batrachia and Aves of North America, p. 52. **QOp. cit. 1822, p. 231. t+tIbid., v1., 1830, p. 211. Confounding of Nassa Trivittata.— Harris. 175 tum, Say.”* Tuomey and Holmes’ use of this designation fifteen years later in their Pliocene Fossils of South Carolina seems correct insomuch as both the description and the figure they give indicate a species identical with Say’s NV. trivittata.2 In his catalogue of the Miocene Shells of the Atlantic Slope, Conrad questions the identity of the Miocene “7ritia (Nassa) trivittata’” with the specimens referred to by Say, Tuomey and Holmes. || The following reference occurs in Meek’s Checklist of Miocene Invertebrates, published in 1864:{ ‘683. Tritia trivittata (Say?) Conrad. Md.; Va.; 8. Car.” The Maryland and South Carolina forms are here confused and con- sidered identical. The specimens in the collection of the U. S. National Museum, from St. Mary's river bear the name *77/tia trivittatum, Say’ in Meek’s hand-writing; the identification is moreover initialed by Heilprin. In 1867, Conrad described a new species under the name of Ptychosalping (Tritiara) peralta.** Although no locality is given for this species, the description, the figure, and the facts that it is a Miocene form and is, according to Conrad, the equivalent of Tritia trivittata Conrad (not Say) leave little room for doubting that the species here described is that occurring so abundantly in the vicinity of St. Mary’s river, Maryland. Heilprin has overlooked this name altogether in his Tertiary Geology of the United States, published in 1884, and continues to refer this Miocene form to Nassu trivittata Say.+t He uses the same designation in his list of Miocene species of New Jersey, published in the Proceedings of the Philadelphia Academy of Natural Sciences, 1887,7 but whether in this case Ptychosalpinx (Tritiara) peralta (more properly Nassa peralta) or Nassa trivit- tatoides Whitf'd (MS.) is referred to, one cannot decide without seeing the specimens themselves. Professor Clark of Johns Hopkins University has also over- looked Conrad's NV. pera/ta, for, in 1888,¢ and again in 1891 he refers this form to Nuss trivittata of Say. 2 The foregoing facts may be thus summarized :-— #24 Bull. Proc. Nat, Inst., 1842, p. 186. Proc, Phila.Ac. Nat. Sci. 1862, p. 562. SOp. cit. P. 135, pl. 28, fig. 4. +t+Op. on pp. 58 & 61. “Smithsn. Mi-cl. Coll. No. 183. p. 20. 19, fig. ** Amer. Jour. Conch., iii, p 264, pl.tOp. cits pp. 398, 401. tJ. H. Univ. cir. vii. D. 66. SIbid., x. p. 107. 176 The American Geologist. September, 1891 Nassa trivittata Say, Jour. Phila. Ac. Nat. Sci., (1) ii, 1822, p. 231. de “ Conrad, Ibid, vi, 1830, p. 211..... wea Wass peralta, e “ Mort., Synop. Org. Rem. Cret. Gp., "18384, ‘App., Di eucr see SLL Rs GePhacs Fie bie nie eck ek bo anagem Wee Te ae =Nassa peralta. Buecinum trivittatum Con., 2d Bull. Proc. Nat. Inst., 1842, p. 188705 t SP mcnaReoS St conaais asc mntana ae Nassa peralta. : $6 fe T. & H., Plioc. Foss. §. C., 1857, p. 1385—=J. trivittata Tritia(Nassa) trivittata ? Con., Proc. Ph. A. N. 8., 1862, p. 562...... \ Nassa peraltad 1 N. trivittata. Tritia trivittata Meek Check List 1864, p. 20........ — § Nassa peralta & VN. trivittata. Ptyc hosalpinx (Tritiaria) peralta Con. Am. Jr. Con, 1867, p. 264, pl. 19, fig. 5. Nussa trivittata Heilp., Tert. Geol., 1884, pp. Ly jas aS fe & 2 “ «. ‘Proc, Phila. A. Nun. 1880 pp..deo, 2017. —?N. trivittatoides. Nassa (Tritiaria) trivittata Clark, J. H. Univ. Cir., 1888, p. 66—N. peralta. Nuassa trivittata Clark, Ibid., 1891, Dew o Wrae micemeeeiacrs =N peralta. Washington, D. C., August, 1891. eee ese tees rere een seese se tees ees seseerseseeereteeeee EDITORIAL COMMENT. DIMINUTION OF NATURAL Gas, Prof. J. P. Lesley has contributed a paper of much interest and value to the proceedings of the American Philosophical Society on the Grapeville gas wells. From it we condense the following: A table showing the futility of all attempts to pipe natural gas to any great distance is a sufficient answer to the hopeful tone so often assumed in regard to its conveyance to towns far from the wells. It shows the initial pressure, size of pipe and loss by friction in conveying gas from the powerful gusher at Grapeville to the Cambria Iron Works at Johnstown, Pa. Distance from Size of 1856 1887 haaa well. pipe. Noy. 13 Mar. 15 ‘ 0 10 200 Ibs. 333 Ibs. poe 4 oF iheerp 3 320 13 8 4. ibd) 2h 995, st 25 12 ietsyy 261 = 34 16 as 129 * PH PAO. 49 20 ee LOO) 5 16345 44 24 12 San 130) 38° 28 sf IU 2s: 95° « 55 32 16 58 * 16 as 19 36 és aku Sue 39 40 20) Pa ae 12 The diminution of pressure in 40 miles from 200 lbs. and 333 Editorial Comment. Uae Ibs. respectively to 25 lbs. at the works sufficiently proves the im- possibility of successfully conveying the gas in pipes to any great distance, at the same time the striking irregularity in the rate of diminution precludes the hope of discovering any rule, and raises the suspicion of considerable error of observation. Another interesting fact illustrated in the same paper is the steadily diminishing pressure at the wells, foreboding ultimate failures at no distant date, a fact on which the GroLoGIsT has repeatedly insisted. The following table extracted and condensed from the same source establishes the assertion. The pressures are those attained by the wells after they have been closed for one minute, GRAPEVILLE—TABLE OF MINUTE PRESSURES. Well. Depth. At April, Dec., May., Nov., Dec., Jan., Feb, feet. first. 1889. 1889. 1890. 1890. 1890. 1891. 1891. Klingensmith.1100 460 390 250 180 100 9 7 65 LOOEY iy... iitse 400° 380") 260° 170°) 105-— 100* Ts . 70 LU ie ane 1149 4460 390 260 175 ~~ 100 Qo MTs, 6a Menosinger ...1466 410 390 240 170 95 85 55 40 Kipple........1360 260 260. 260 165 100 95.) 4a 6a EVES ise..0-.L000 ~ 125 — - - — 60 MeneW ..'....'. 1420 75 —_ — 65 ~~ 65 This loss of pressure and consequently of gas in less than two years, points unmistakably to one conclusion—the disappearance of high pressure gas before long and the sinking of the great gushers to low pressure wells. They will then probably be very durable and the rate of diminution will itself diminish. Though useless for manufacturing purposes, they may still be very valu- able sources of gas for domestic consumption. At the same time it is quite possible that even this hope may be disappointed and that the pressure will run so low as to yield practically nothing. This is indicated by the fact that the rate of diminution is at pres- ent nearly constant as is shown by the following table: RATE OF DIMINUTION OF PRESSURE PER DAY. * From April 29, 1889 646 days 321 lbs. 0.5 lbs. per day “Dec. 16, 1889 413 * 133.. * 0.455 mS ¥3 May 26, 1890 252 * LOS 0.4 e a NOV, 8, 1890 Giles aaa & 0.4 ag # Dec. 1, 1890 Gor st oe 0.48 - Sy > Jan;.0, .1891 28 nst tes 0.25 j Professor L. points out that this falling off indicates that the gas * In borrowing this table we have taken the liberty of correcting a slight mistake in Prof. Lesley’s calculation by which he had brought out thediminution much too high. The last figures may be doubtful. 178 The American Geologist. September, 1891 issues under the force of its own expansion and not by hydrostatic pressure. If this is really the case, we must, as said above, an ticipate a steady falling off in the rate of diminution until it be- comes practically constant and the well becomes a low-pressure source of gas. The following deductions are of great economic importance: “The steady decline in pressure from 390-380 lbs. on April 20, 1889 to 65 lbs.on February 2, 1891, predicts a speedy extinction of the use of natural gas at the Cambria Iron Works.” “*One of the wells at Grapeville was recently deepened to reach the ‘Gordon Sand’ and a small quantity was found, but not enough to warrant any hopefulness of its maintaining the supply. A part of the works at Johnstown are yet supplied with natural gas from Grapeville, but it is weakening so fast that we supplement it with artificial gases,’” Feb. 26, 1891. Again: “At the Cambria Works we are using the Archer oil gas to take the place of the natural gas and find this a very good substitute. The Archer process consists in vaporizing oil and mixing steam at a very high heat with the oil. We have also opened our mines again and are using coal in a great many sections of the works.” March 13, 1891. SupposED TRENTON Fossit FIsu. During the past few months several notices have appeared of a discovery of fish fossils in lower Silurian ( Ordovician ) rocks in Colorado. At the recent meeting of the American Geological Society, Mr. Walcott, of the U. 8. Geclogical Survey, exhibited some of these, and gave a few notes on the mode of their occur- rence. They are found in a red sandstone, more or less mottled with white, and in a calcareous layer of similar color near Canon City, and were first collected by Mr. Stanton two or three years ago. They consist of a few entire plates and innumerable frag- ments, mostly white or reddish ; and of long and apparently articulated columns reminding the observer of crinoidal stems. They are referred by Mr. Walcott to various kinds of fish and he has named several of them in accordance with this view. Thus one of them has received the designation of Holoptychius? americanus (preoccupied by Leidy many years ago ), another that of Asterolepis? desiderata, while a third is styled Palachimera prisca. These statements are of course surprising to the palentologist, kditorial Comment. 179 though he is fully prepared to see the earliest vertebrate life car- ried downward through the paleozoic rocks far beyond where it is now known, But each step in the progress must be taken only after the most careful and thorough investigation and on the most satisfactory evidence. In regard to the stratigraphy, Mr. Walcott has apparently ex- amined the locality with great care, and has accumuiated a large mass of evidence. Assuming the correctness of his observations there appears to be little room for doubting his conclusions. No ground exists for suspecting an overthrow or inversion of the strata, and some of the fossils as named by Mr. Walcott, though not exhibited, are of undoubted Ordovician ( lower Silurian) age. Such fossils, according to the author, are found both above and below the beds containing the supposed fish remains. It is not easy therefore, on the assumption of these facts, to impugn the accuracy of the stratigraphical conclusions. * But in regard to the paleontology the evidence is less satis- factory. There is no doubt that some of the specimens exceed- ingly resemble fish plates, as fish plates occur in the Catskill rocks. But it is not to Catskill species that a likeness would be expected, but to others more nearly approaching in date the epoch in ques- tion. Such species are those composing the genera Preraspis, Cyathaspis, Palewaspis, Diplaspis, ete., and to these the fossils exhibited by Mr. Walcott bear not the slightest , resemblance. The plates above mentioned certainly simulate the seutes or scales of certain Devonian and later fishes. But we may strongly insist on the deceptive nature of such merely external characters and ask for other evidence, before accepting the ichthyic nature of the fossils. In this respect Mr. Walcott’s paper was disappointing, inas- much as it contained no proof of his proposition that these plates are the remains of fish. We must, however, await the ap- pearance of his memoir before coming to a decision on the ques- tion. But it would have been more satisfactory to the palee-ich- thyologist had he learned at least the nature of the evidence. *The paleontologist will feel some surprise at finding /ulysites cute- nulatus mentioned among this fauna. Though this species has been reported from the Lower Helderberg ( see p. 7 of the 2nd. Geol. Sur. of Pa.) yet its occurrence so low as the Trenton is scarcely less surprising than the presence of fish. 180 The American Geologist. September, 1891 Mr Walcott’s claim that his fossils though of Lower Silurian age yet resemble those of Upper Devonian strata, will doubtless be subjected to criticism, but the fact must be borne in mind that in several parts of the continent of Europe the fish are distinctly Devonian in type, though the molluscan fauna indicates Upper Silurian age. This combination is of course very different from finding similar fossils in Lower Silurian strata, but may serve in a slight degree to lessen the incongruity. Microseopic examination was not reported. This lack is to be regretted inasmuch as such evidence is really of the first import- ance. We hope’ that it will be supplied later. In addition to the plates already mentioned, Mr. Walcott ex- hibited certain crinoid-like objects which he believed to be noto- chordal or at least to indicate a spinal column. In our opinion, however, their appearance does not warrant such a reference, and the ichthyologist will feel grave doubts regarding the preservation of such objects from so low an horizon. Further examination will, we think, result in a change of opinion, MAN AND THE MAMMOTH. Among the most interesting exhibits at the recent meeting of the International Geological Congress, was that of M. Max Lohest of Ligge, Begium. Although unfortunately M. Lohest’s paper was crowded out, and consequently the members had not the advantage of hearing it, yet his photographs and pamphlet were ex- amined by several of those who combine archeology with geology. M. Lohest’s paper read before the Anthropological Con- egress gives an account of his investigation of the grotto of Spy, near Liége, on the property of the Count of Beauffort, In this cavern M. Lohest found under a thick bed of rubbish and fallen fragments of limestone, three distinct ossiferous beds. The uppermost of these was in part stalagmitic, and contained a few bones of an undetermined species of deer, a bear’s tooth, and some pieces of the bones of the mammoth. Beside these and mingled with them were great numbers of flint implements of various patterns, some of them resembling the type known as ‘«Mousterian,” from the cavern of that name, and others are like those found in the well known Engis cave, in Belgium. Some are notched like saws and of very thin and delicate workmanship. They consist of scrapers, points, blades, knives, ete., worked on Editorial Comment. 181 one face, some apparently intended to be set in handles and others not. No instruments of bone or of ivory were found in this upper layer and the flints are mostly covered with a white or bluish patina sometimes very thick. Under this stalagmitic layer was a second ossiferous bed, usually red from the presence of iron ore, many fragments of which were found. Here occurred the following fauna: Rhinoceros tichorhinus, abundant. “Equus caballus, ( horse ) very common. Sus scrofa ( pig ). Cervus elephus (red deer). f canadensis? (elk). s megaceros ( Irish elk). “ tarandus ( reindeer). Ovis aries (sheep). Bos primigenius (bison). Bos priscus (aurochs). Elephus primigenius (mammoth ) very abundant. Ursus speleus (cave bear ) scarce. Meles taxus ( badger). Canis vulpes (fox). Canis lupus? (wolf) familaris? (dog). Mustela foina ( weasel). Hyena speliea (cave hyena) very abundant. Felis spelzea ( cave lion) a few teeth. Felis catturs (cat). These determinations are due to M. Fraipont, professor of paleontology at the University of Liége. Numerous hearths were also found on this layer composed of stones, and containing burnt wood and ashes. The materials used by the old inhabitants of this grotto were flint, phthanite, sandstone, chalcedony, opal, ivory, bone and horn, and the total number of implements obtained was very large. There are 140 ‘‘ mousterian” points, most of them thick at the base and not intended for setting in handles, whose average dimen- sions are 4 inches long by 3 inches wide; a number of fine flakes and awls, and arrows or dart heads, of very fine workmanship, and some of them 5 inches long, resembling in type the ‘‘solu- trean” implements of the Dordogue, a single small core from which flakes have been taken, and numerous blocks rejected on 183 The American Geologist. September, 1891 account of some defect after a flake or two had been struck off, and 300 serapers of various sizes and types. Implements etc., of ivory were more numerous in this layer than in any other known cave in Belgium, Chips were so abun- dant as to form a breccia in one place. The objects found were for the most part for dress or ornament, and the material had often degenerated into a chalky substance. Many of them were un- finished or the different stages of manufacture were revealed. Some of them were marked with striation as was also the case with the implements of horn and of bone found with the ivory. On arib of the mammoth or rhinoceros was found a series of ‘* circumflex accents ” ranged one above another, of which a figure is given in the pamphlet. One hollow horn was filled and stained with iron oxide, and is supposed by M. Lohest to have been a receptacle of this material for coloring the persons or the imple- ments of the cave men. These with four fragments of pottery, found by another investigator, complete the list of relics from the second ossiferous layer. The third contains a fauna so far as it goes, identical with that of the second bed. Rhinoceros tichorhinus, abundant. Equus cabailus, very abundant. Cervus elephus, rare. Cervus tarandus, very rare. Bos primigenius, common. Elephus primigenius, common. Ursus speleus, rare. Meles taxus, rare, Hyena spela, abundant. In this bed, however, were found as in the other, abundance of flint implements, but somewhat differing in form and material from those above mentioned, The great interest of this layer, and indeed of the whole find is the discovery not only of the works of man, but of man himself, in the form of two partial skeletons, one skull of which is nearly perfect. This of course forms the central point of M. Lohest’s paper, and he justly goes into detail concerning it. We will condense his account written by Dr. Fraipont. ; “The human relics belong to the most ancient fossil race, that of Neanderthal or of Canstadt. The skulls, fairly complete, present all the ethnic characters of that race, whose remains are known from France, Review of Recent Geological Literature. 183 Italy, Austria, Germany and Sweden. Hitherto only a single jaw has been obtained from a cave ( Naulette ) in Belgium.” One of these skulls is apparently that of an old woman, the other that of a middle-aged man. They are both very thick. The former is clearly dolichocephalic (index 70), the other less so. Both have very promi- nent eyebrows and large orbits with low retreating foreheads, exces- sively so in the woman. The lower jaws are heavy, the older has almost no projecting chin. The teeth are large, and the last molar is as large as the others. These points are characteristic of an inferior and the oldest known race. The bones indicate, like those of Neanderthal and Naulette, small square shouldered individuals.” M. Lohest adds: “The skeletons from Spy are one of the most important discoveries relating to the oldest known race of men.’’ “The cave shows three ossiferous layers, and remains of the mammoth occur in all three.” “Stone implements chipped only on one face indicate the ‘mousterian ’ ‘type of industry.” “The relics of the three layers indicate an advance in the character of the workmanship.” “The second layer by its association of chipped tools with ornaments of ivory and bone shows its close relationship to the ‘mousterian’ type, and at the same time is free from all suspicion of accidental mixture.” “The study of the bones of the lowest leve) proves beyond doubt that the earliest race of men as yet known in Belgium, had a skull of the type of ‘ Neanderthal’ and used instruments of.the ‘mousterian’ pat- tern.” In the above discovery we have at last clear and indisputable traces of the men whom up to now we have known almost entirely by their tools. A few disjointed bones not free from suspicion, are now fortified by evidences that cannot be gainsaid, and the old Canstadt or Neanderthal race stands before us as an extinct but real ancestor. BEVIEW- OF RECENT GEOLOGICAL LITERATURE. Congres Géologique International. Compte rendu de la 4ime Session. London, 1891. This volume, which appeared in America but a few days before the opening of the fifth session of the international congress, ‘consists of four parts and four appendixes. It has six geological maps and eighty figures ; also a plate of five profiles through the crystalline schists of the western Alps. Part I. is a historical account of the Congress and its origin. Part II. embraces the daily record of the meetings of the Congress. Part III. the most important and valuable, embodies the actual new work which was transacted by the Session. Here are papers 1s4 The American Geologist. September, 1891 on the crystalline schists by Hunt, Heim, Lory, Lehmann, Lévy, Lawson,,. Powell, Irving, Chamberlin, Van Hise, Becker, Dutton, Lossen, and Reusch, followed by synopsis of the discussion on the same by many of the attending geologists. Following these are miscellaneous discussions of the classification of the Cambrian-Silurian-Taconic, or primordial rocks of the world, and of the Tertiary and Quaternary. Part IV em- braces extended papers on the geology of the different portions of the British islands by Hicks, Marr and Tiddeman, Strahan and Reid, Fox-Strangways and lLamplugh, and Reid, and shorter notes by Topley, Drew, Goodchild, Blake, Woodward and Winward— all grouped under the general title “ Explication des Excursions.’” Appendix A consists of the report of the American Committee on classi- fication and nomenclature, the reporters being Frazer, Winchell, Wil- liams, Stevenson, Cook, Smith, Cope and Hitchcock. Appendix B is the report of the British sub-committees made to the third session of the Congress at Berlin in 1885, distributed at that time separately, but omitted from the Compte rendu of the session. It now appears asa “second edition,” with an explanatory “review of the position” by T. McKenny Hughes, the separate reporters being Woodward, Reid, Gard- ner, Jukes-Browne, Topley, Huddleston, Blake, Irving, Morton, Strahan and Marr. Appendix C is the report of Prof. Dewalque, secretary of the international committee on unification of nomenclature, in which he says that no national committee, exceptthat of the United States, had rendered any report to the general committee. Hecalls attention specially, and fa- vorably, to the recommendation of the American committee respecting the nomenclature of the lower paleozoic, viz: Taconic for the primordial, Cambrian for the second fauna, and Szluréan for the third fauna, At another time (in the discussion of the classification of the Cambrian- Silurian-Taconic, p. 227,) Prof. Dewalque commends the conclusions of the American committee in the following terms: Les réunions précédentes du congrés et de la commission de nomencla- ture ont montré qu’ une trés-grande majorité de géologues est favorable i une division en trois parties; on constate le meme fait aujourd’hui. Pour ces parties on a proposé les noms Cambrien, Ordovicen et Silurien. L’orateur ne pent ¢tre consideré comme hostile a 1’Ordovicen car ila eu lV’honneur de le patronner dans la commission, qui l’a admis. Toute- fois, dans son rapport pour le congrts de Berlin, il a cru devoir tenir compte des revendications produites en Amérique au sujet du Taconique de M. Emmons. Les controverses qui se sout produites depuis lors aux Etats-Unis auraient pu faire hesiter un géologue comme lorateur, qui n’a jamais vu ce pays; mais la lecture du rapport du comité Am¢ricain suffit, 4 ses yeux, pour lever tous les doutes, et le nom de Taconique a pour lui la priorité et a droit & désigner la division in- férieure. La division moyenne est le Cambrienne, la supérieure reste- Silurienne. Cela contrariera quelques usages, mais cela a d’autres. mé¢rites sur lesquels l’orateur n’insiste pas. L’honorable M. Walcott acombattu cette division,proposée par ses com- patriotes; mais son argumentation ne parait pas irréfutable. L’orateur- Review of Recent Geological Literature. 185 admet volontiers que M. Walcott ait découvert une riche série de fossiles de la faune seconde sur certains points du territoire appelé Taconique, mais ce progrés dans nos connaissances ne pent avoir d’influence sur la question. Ce q’il faut savoir, c’est la position réelle du Taconique @Emmons. Or, il semble incontestable que c’est une série 4 faune primordiale. Si ce nom doit ¢tre conservé, il ne pent étre appliqué qu’ Ace que l’on’proposait d’appeler Cambrien. Il faut le conserver parce quwil ala priorité. L’orateur ajoute volontiers qu’ il sera charmé de voir rendre cet hommage a la géologie Americaine, laquelle nous a appris tant de choses sur le grand ensemble de couches dont nous cherchons la meilleure classification.” Appendix D contains lists of the members of the congress. Mesozoic and Cenozote formations of eastern Virginia and Maryland. By N. H. Darton, U.S. Geological Survey. Bull. G.S.A., vol. ii, pp. 431- 450, with a map and sections; April 14, 1891. The formations here described, successively separatad from each other by erosion intervals, are the Potomac, of late Jurassic or early Cretaceous age; the Severn, of later Cretaceous age, being the southern extension of the New Jersey greensand series; the Pamunkey, of Eocene age; the Chesapeake, be- longing to the Miocene period; the Appomattox, referred provisionally to the Pliocene; and the Columbia, regarded as early Pleistocene. It is ascertained that the transverse depressions of the coastal plain region were first excavated during the interval between the Chesapeake and Appomattox formations; for the earlier members of the series bear no marks of transverse drainage. Ata later date, the Appomattox and Columbia formations were separated by an epoch of great uplift and erosion. “This epoch,” according to Mr. Darton’s observations, “differed from its base-leveling predecessors by greater rela- tive emergence and consequent stream-action which developed the greater part of the present physiography of the region. This erosion deepened and greatly widened the transverse drainage depressions, and trenched the side drainage depressions, cut into the edges of the terraces to an extent gradually increasing northward from North Carolina, and in north- ern Maryland resulting in the removal of wide areas of the coastal plain formations, especially he Chesapeake and Appomattox.” On the Triassic of Massachusetts. By BENJAMIN K. Emerson. Bull., “G.S. A., vol. ii, pp. 451-456, with a map; April 23, 1891. Marine currents probably produced by tides of the bay of Fundy type, are shown to have distributed arkose from south to north, derived from the granites and schists along the west side of the Triassic bay or estuary in Massachu- setts; and on the east a strong ebb current spread a coarse conglomerate, transporting its materials from north to south. In more quiet water along the central part of the basin, sandstones and shells were deposited. An artesian boring at Northampton passes through the arkose to a depth of 3,000 feet. Professor Emerson finds evidence of monoclinal faulting with upthrows on the east side of the faults, like the structure discovered by Davis in the continuation of this basin in Connecticut. 186 The American Geologist. September, 1892 Glacial grooves at the southern margin of the Drift. By P. Max FosHay and Rrewarp R. Hes, Bull., G. 8. A., vol. ii, pp. 457-464, with a plate and one figure in the text; April 27, 1891. This interesting paper des- cribes the terminal moraine, kames, terraces, potholes, and glaciated rock surfaces near the drift margin, in the valley of Beaver river, north- western Pennsylvania. Powerful glacial erosion is shown two miles or more south of the terminal moraine mapped by Lewis and Wright, upon the area of “the fringe” of frequent boulders, which extends some miles in front of the moraine in this neighoohood. Post-pleistocene subsidence versus glacial dams. By J. W. SPENCER. Bull, G. S. A., vol. ii, pp. 465-476, with a map; April 30, 1891. Shortly before the deposition of the glacial drift, there is shown to have been an elevation of the drift-bearing areas over 3,000 feet higher than now, and probably for a brief time to over 5,000 feet. Succeeding this uplift, the author believes that a subsidence of the land carried it so far beneath the sea level that the now raised beach lines partially surrounding the great lakes of the St. Lawrence were shores of the ocean. Recent emergence of the land, according to this view, is recorded by the suc- cession of these beaches at different levels; and the alternative explana- tion which attributes the beaches to glacial lakes of fresh water dammed by a receding ice-sheet is disputed. A reprint of this paper, with slight changes appeared in the June number of the Geological Magazine. On the Geology of Quebec and environs. By Henry M. Amt, of the Geo- logical survey of Canada. Bull. G.S. A., vol. ii, pp. 477-502, with seven sections; April 30,1891. The intricate and much debated structure and relations of the Cambro-Silurian terranes of Quebec and its vicinity are here carefully discussed, with lists of the fossils collected in numerous. localities by the author and others. Mr. Ami advocates the retention of the name Quebec group, and considers the group to comprise three natural and well-marked parts, lying next below the Trenton limestone in the following descending order: The Quebec, or upper division; the Lévis or middle division; and the Sillery or lower division. The rocks thus grouped are referred by Selwyn to the Hudson-Utica horizon above, instead of below, the Trenton. Some New Species of Crinoids and Blastoids. By Pror. R, R. ROWLEY and Sip. J. Hare. In The Kansas City Scientist for August 1891, we have what is practically a continuation of the paper on Some New Species of Echinodermata by the same authors in the same magazine for July. The present paper contains descriptions of twelve new species, all of which are illustrated by figures drawn by professor Rowley. Advance sheets from the 17th Report of the Geological Survey of the State of Indiana, Prov. 8. 8. Gorsy, State Geologist. Palwontology. By 8. A. Minter. Mr. Miller’s contribution to the 17th Report of the Geologi- cal survey of Indiana, embraces 95 pages of text, and 20 plates with ap- propriate descriptions. 130 species of fossils are described, and of these 126are new. The paper opens with remarks on the geologic formations Review of Recent Geological Literature. 187 of Indiana. The lower part of the Niagara group, in Indiana, is char- acterized by the presence of the remains of cystideans; while the upper part abounds with crinoids, brachiopods, bryozoa and other fossils.” Most of the cystideans belong to the very variable genus Holocystites. It is stated as a fact worthy of note that half of all the species of cysti- deans known from America occur in the Hudson River and Niagara groups of Indiana. There are remarks on the scientific value of fossils and on rules for nomenclature. Of the fossils described there are three species of sponges, and from the head lines it would appear that Mr. Miller stands with Saville-Kent, in op position to the views of a majority of competent zoologists, in referring sponges to the sub-kingdom Protozoa. There are twelve species of corals, one of which, the Leptopora gorbyi, nu. s., is doubtfully referred to the Tabulata. Seventy-eight species belong to the Echinodermata , mostly cystideans and crinoids. Of the genus VHolocystites alone there are fifteen species. Among the echinodermata the following new genera are proposed:— Stribalocystites, Zophocrinus and Blairocrinus. Among sponges there is one new genus, Cyclospongia. The remaining genera and species embrace a few species of brachiop- oda, one Conularia and a number of mollusca. The Pleurotomaria hari, page 83, Plate XIV., Figs. 3 and 4, might properly and profitably have been compared with P. curbonaria, N. and P., and P. newportensis White. Second Annual Report of the Geological Survey of Texas, 1890, E. T. DuMBLE, F. G.S8. A. State Geologist. Carboniferous Cephalopods. By AupHeus Hyatr. The paper on Carboniferous cephalopods by professor Hyatt embraces pages 329 to 356 inclusive, in the Second Annual Report of the Geological Survey of Texas. The forms described were collected in part by the Geological Survey of Texas, part belong to the National Museum, and a few belong to private individuals whose names are given in connection with the specific descriptions, The genera represen- ted are divided between the Nautiloidea and Goniatitinw. To the first group belong V'emnocheilus, represented by five species; Wetacoceras, by five species; 7’ainoceras, one species; Domatoceras, a new genus to which is referred one species; Asymtoceras, one species; Phacoceras, one; Ephippioceras, one; and Hndolobus, one. To the Goniatitinze belongs the genus Gastrioceras which is represented by the new species G. compres- sum. As stated in the prefactory note the paper comprisesa larger num-, ber of species of Carboniferus cephalopods than had previously been got together in a single publication. Excellent outline figures ac- company the descriptions. In the Second Annual Report of the Geological Survey of Texas, page 552, professor W. F. Cummins describes a very beautiful and interesting little coral from the Carbonifersus strata of Texas, under the name, /Hadro- phyllum aplatus. H, aplatus is certainly very closely related generically to Microcyclus discus Meek and Worthen, and it is possible that this last species will have to be referred to //adrophyllum. Six good figures illustrate Prof. Cummins’ species. 188 Th e Am eCriCan Geologist. September, 1891 LIST OF RECENT PUBLICATIONS. V. Foreign Publications. Records of the Geological Survey of New South Wales, Vol. II, Part 8, contains: Notes on a Collection of Rocks and Minerals, from Mount Morgan, near Rockhampton, Queensland, collected by Mr. C. 8. Wilkin- son, by T. W. Edgeworth David, and William Anderson. With an intro- duction by C. 8. Wilkinson. Laboratory Notes on some N.S. Wales Minerals, by J. C. H. Mingaye. On the Occurrence of Microscopic Fungi, allied to the Genus Palwachlya Duncan, in the Permo-Carbonif- erous Rocks of N. 8. Wales and Queensland, with Plate VII, by R. Etheridge, Junr. The Associated Minerals and Volatility of Gold, by T. W. Edgeworth David, B. A. Analysis of Samples of Coal and Coke, manufactured from the various Coke-producing Coals in the Northern, Southern, and Western Coal Districts of N.S. Wales, by J. C. H. Min- gaye. Note on Mr. J.C. H. Mingaye’s Analysis of N. S. Wales Coals and Cokes, by T. W. Edgeworth David. Lepidodendron australe M’Coy—Its Synonyms and Range in Eastern Australia, by R. Etheridge, Junr. Ecloge geologice Helvetix, Vol. 11, No. 4, contains: Revue geologe- que suisse ponr 1890, Favre et Schardt; Programme des Excursions d’aout 1891 dans les Prealpes romandes, avec pl. 9-12. Mittheil. d. Naturforsch. Gesell. in Bern, contains: Notizen iiber den Lias von Lyme Regis, J. B. Thiessing. Annalen K. K. nat. Hofmuseums, Band VI, No. 2, contains: Meteor- eisen-Studien, Cohen u. Weinschenk; Die Gasteropoden der Schichten von St. Cassian der siidalpinen Trias, Kittl; Ueber Nephrit und Jadeit- gegenstiinde aus Centralasien, Haberlandt. Foéld, Kéz. (Budapest), Vol. XXI, Nos. 4 and 5, contains: Awaruit, ein nickeleisen-mineral, Szabo; Beitrage zur Foraminiferen-fauna der Alttertiiiren Schichten von Kis-Gyor, Kocsis. CORRESPONDENCE. THE SO-CALLED SAND-DUNES OF East Hampron, L. I.—In a letter re- ceived from Geo. R. Howells, of South Hampton, of date January 21, 1886, my attention was called to certain sand ridges at East Hampton, L. I. The writer said: ‘‘ Were you aware, I wonder, of the existence of two sand dunes, like small amphitheaters in form, right along, or in the midst of the richest farm lands a mile from the present shore line—per- haps not quite a mile—in the outskirts of East Hampton? These are veritable sand dunes of white sand covered with a growth of ordinary beach grass, and a geological puzzle. If we could say they were de- posited there by a cyclone, it would shorten matters, but we can’t, and there is a difficulty in holding that they are signs of an old beach line. It is with me a standing puzzle.” Correspondence. 189 The study of the drift phenomena, on the west end of the island led me to suspect that the sand dunes in question were formed by subglacial ‘streams issuing from the front of the ice-sheet that stretched along the Atlantic border during the Ice Age. It was not until last July, however, that I had an opportunity of visiting the place in person, and it was gratifying to find my conjecture confirmed by actual observation. The sand dunes referred to are really kame formations. This can be seen at a glance by any one familiar with glacial phenomena. Similar formations occur along the whole extent of the south side of the Island; but in general they are not quite as well defined as those at East Hampton. The so-called sea beaches in front of our bays, as at Rockaway, Great South beach, etc., are the same in origin. This hardly seems possible, but the more this phenomenon is examined the more evident the fact becomes. There is a beautiful system about these beach or kame formations, and their study had led me to suspect, some years ago, that the system extended for miles beneath the waters of the sea, and it was very gratifying to find this view partially confirmed by Prof. Agassiz. In his Life and Correspondence, edited by his wife, page 448, in a letter to Elie DeBeaumont, he says: “ Mr. Dezor recognized all the modifica- tions of the osars of Scandinavia. The deposition of the osars, as seen here, is evidently due entirely to the action of the waves, and their frequency along the coast is a proof of this. In a late excursion with captain Davis, on board a government vessel, J learned to understand the mode of formation of the subinarine dikes bordering the coast at various dis- tances, which would be osars were they elevated.” The italics are our own, as the statement seems to confirm what I had conjectured, but I think Prof. Agassiz is in error in regard to their origin. Prof. G. F. Wright and others who have studied these kame-deltas along the southern front of the terminal moraine, in New England, as well as in Long Island, could see that these formations—osars—as Prof. Agassiz calls them, are not the result of wave action, but are due to subglacial currents issuing from the front of the glacier. At Montauk, for a distance of some twelve miles, the waves of the ocean break directly upon the base of the ridge or terminal moraine. At this point the whole south side of the Island has become submerged, and we can readily imagine what the floor of the ocean is like some distance from the present shore line. The sea is evidently gaining on the land along the whole extent of the Island, and it is only a question of time when the whole plain, south of the central ridge, will be washed away, unless something is done to check the inroads of the sea. If this invasion of old ocean has been going on for the past ten thousand years, the south side of the Island must have been at one time much more extensive. There is evidence to show that at South Hampton, two hundred years ago, the shore line was at least half a mile farther south. At the same rate of erosion four hun- dred years would bring the waters of the sea over the so-called sand -dunes at East Hampton, and these osars or kame-deltas would become the submarine dikes referred to by Prof. Agassiz. It is true that the waves of the sea would somewhat modify the contour of the plain in 190 The American Geologist. September, 1894 the process of submergence, but there is no doubt but that the same sys- tem of ups and downs would exist as now characterizes the south side of the Island. There may be some other explanation found for the formation of the beaches at East Hampton, but as I stood on their summits and looked northward, the old lines of drainage from the moraine to the sea were plainly traceable, and I am very confident that they are glacial in origin. The study is full of interest,as much so as the coral formations of tropical shores, as remarked by Prof. Shaler, and many problems con- nected with it remain to be solved. Future discoveries, I think will prove that oscillation has had little to do with the formation of either. Eastport, L. I., August 9, 1891. JoHN Bryson. Viejo range of Nicaragua. Y have just arrived here from an examina- tion of the 18 mile long volcanic mass, V¢ejo—in front or north of this: town—and found at a distance of about three leagues from the south base of its cones, fifty-six large springs of water issuing from fissures,. all along the south side, at elevations of 40 to 80 feet above the Pacific ocean; also one spring of cool water flowing from a small clay-bottom: basin, at an altitude of about 4,000 feet above the ocean, the highest cone, except one toward the west, which is 5,670 feet above the ocean. On the north side of the cerro are several (8 or 10) large springs of tepid water, two of which contain so large a percentum of CaCO, as to» have deposited hundreds of thousands of tons of calcareous tufas— nearly pure—6 to 18 inches thick. In many places in this tufa the lime has substituted organic matter in perfection so as to display the most delicate venation of leaves, molds of annelids and insects, the tissues of trees, etc. These springs on the north side of the volcanic mass, flow into a tide-water estuary which extends for about 70 miles eastwardly from the gulf of Fonseca and “heads” at several springs of hot water, at the N. E. base of the cerro,in a valley which extends for about 20- miles eastward to lake Managua. I have drafted the skeleton for a paper descriptive of this volcanic cerro. J. CRAWFORD. Chichigulpa, Nicaragua, 27th June, 1891. PERSONAL AND SCIENTIFIC NEWS. THe Kansas City Screnvist for July, 1891, has a paper de- scribing Some new species of Echinodermata, by Prof. R. R. Rowley and Sid. J. Hare. A plate containing twenty figures drawn by Prof. Rowley accompanies the paper. Fifteen new species are described. The despairing paleontologist is disposed to ask how many more new species of crinoids the Subcarbonifer- ous strata of the Mississippi valley are going to furnish! THe University oF Iowa has received from Prof. C. A. Whit- Personal and Scientific News. 191 ing, of the University of Deseret, a castof aslab containing some undescribed footprints. The slab was first used as a door-step by a citizen of Salt Lake City. While serving ‘‘ such base uses ”’ it was discovered by Dr. John R. Park, president of the Univer- sity of Deseret and secured for the University museum. The casts were made by Prof. Ward, of Rochester. The tracks are three inches long and about three inches wide. There is in each the impression of three stout, clumsy toes, behind which is the imprint of a thick, well developed pad. The impressions of the fore and hind feet do not coincide, nor do they overlap to any appreciable extent. The stride of the animal was about eighteen inches. So far as learned from Prof. Whiting no description of the tracks has been published. The relations of the animal, and the geological horizon from which the slab was obtained have not been determined. IN THE ANNALS AND MAGAZINE OF NATURAL HISTORY FOR JULY, 1891, Dr. P. Herbert Carpenter has asomewhat caustic review of 8. A. Miller’s Description of some Lower Carboniferous Crinoids from Missouri, published by the Geological Survey of Missouri, and Miller and Gurley’s Description of some new Genera and species of Echinodermata from the Coal Measures and Subcarbon- iferous Rocks of Indiana, Missouri, and Iowa, published at Dan- ville, Ill. The papers referred to contain descriptions of six new genera and over ninety new species of Crinoids. In sum- ming up his review Dr. Carpenter expresses himself thus severely: ‘¢ Three at least, and probably four, of his [S. A. Miller’s] last six new genera of Crinoids would never have been proposed had he taken the trouble to make himself properly acquainted with the bibliography of his subject; and I suspect that quite half of his ninety new species will prove to be synonyms when they come to be revised. Careless and ill-informed authors of this class are the terror of systematists in all branches of biology. Their sole object seems to be the association of their names with as many ‘ new species” as possible, and one’s first impulse on seeing ‘ A Description of Some New Genera and Species,’ ete., is to parody ‘The Bogie Man,’ and say with bated breath, ‘Hush! Hush! Hush! Here comes the species man.’ ” Dr. J. Kost IN HIS PRELIMINARY SURVEY OF FLORIDA discov- ered in the channel of the Ichetucknee river, the remains of six mastodons, an elephant, one camel, and teeth of two species of rhinoceros, with many bones of animals still living, in a higher deposit. Two of the mastodon skeletons are nearly perfect. At Heidelberg University, Tiffin, O., the Polytechnic Department is engaged in making plaster of Paris restorations of these and of 192 The American Geologist. September, 1891 all other extinct life types available, and will furnish them to in- stitutions at not over one-fourth the cost of originals. AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE. Of the many papers read in the geological section during the late meeting at Washington, not all can be specially noticed. Dr. Foote, of Philadelphia, gave an account of the discovery of dia- monds ina meteorite from Arizona. In slicing the meteorite something hard was struck that destroyed the corundum wheel, and was only cut with great trouble. On examination of the layers a nest of small black diamonds was discovered, and the mineral recognized by its in- tense hardness. A very small and clear crystal was also found, but was lost during the operation. This, said Dr. Foote, was the first example of the occurrence of diamonds in an iron meteorite, though it had been twice reported from stony ones in Russia. Mr. Wm. Hallock related to the section the story of the deep boring now in progress at Wheeling. It was begun in the hope of finding gas or oil, but when the depth of 4,500 feet had been reached without any success, the projector determined to abandon it and an order was given to that effect. Prof. I. C. White,of Morgantown, W. Va., hearing ofthis order and realizing the importance of the opportunity, set off immedi- ately for Wheeling, and obtained a countermand only just in time, as the contractor had already begun to draw the casing. He persuaded the owners to give up the well, which was entirely dry. for the purpose of scientific experiment. This they did and generously offered to con- tribute the amount needed to deepen the hole to 5,000 feet. The U.S. government then agreed to furnish a new cable, and as soon as this has been received the work will recommence. According to experiments already made with the thermometer, appar- ently with all due precautions, the result is new and unexpected. A rate was obtained below the 100 foot plane of 1° in 90 feet, increasing down- ward till at the bottom it amounted to 1° in 60 feet. As this contradicts nearly all the data obtained elsewhere it is more probable that some local cause of error or some exceptional condition prevails at the well, at least in its upper part, for the lower figures do not differ much from those obtained elsewhere. Prof. Lester F. Ward read two valuable papers on the plant life of the Trias and the correlation of strata by vegetable fossils. He showed that our knowledge of these organisms has been until lately, and is indeed even now to a less degree, too imperfect to allow of their use in the cor- relation of strata, but maintained that as the gaps in fossil botany are filled they will become available for the purpose in the same way as are now the remains of animals. He illustrated his point by tables showing the distribution of plants in the richer floras, especially in the Carbonif- erous and Mesozoic. He further dwelt on the identity and dissimilar- ity of the fossil plants found in the American Triassic basins, and ex- hibited tables giving the number of species peculiar and common to each. In conclusion Prof. Ward pointed out a few of the conclusions that could be deduced from the facts given. Lersonal and Scientific News. 193 Prof. Safford exhibited some bones of Megalonyx, lately found in Big Bone cave, Tenn. These he believed to be complementary to those described many years ago from the same place, by the late Dr. Leidy. Some of these, as in the former case, retained portions of cartilage indicating no very ancient date. In the account of this animal recently given in the pages of the GroL- OGIST, it was stated that the pelvis of Megalonyx was unknown. As Prof. Safford’s specimens showed the two iliac bones and a small part of one pubis the above statement is no longer true. Considerable discussion took place on the existence of the “ Cincin- nati ice-dam,” but little progress was made in settling this vexed ques- tion. In this connection we may notice another topic on which consid- erable difference of opinion was manifested, namely, the attitude of the continent during the Pleistocene era. The extreme party on one side advocated an elevation of 3,000 feet, and hinted that twice as much was possible, while the other party could see cause and evidence for no changes of level so great. Testimony on this subject is coming gradu- ally to light, and the Pleistocene is assuming a more and more complex character and history from day to day. Some deep borings, for example, one at Rochester, N. Y.,and one at New Portage, near Akron, were de- scribed, the former by Prof. Fairchild, and the latter by Prof. Claypole. Mr. Van Hise presented a paper on the relations of the Algonkian and Archean in the Northwest, and Capt. Shufeldt one on the avifauna of Oregon, giving an account of some very large fossil birds. Several other papers of considerable interest by various authors, con- cluded an interesting and useful, though not an eventful meeting. GEOLOGICAL Socrety oF AMERICA. Following the Association or rather imbedded in it came the meeting of the Geological Society of America. A new and large detachment of American geologists mustered to reinforce those previously present and work began again with new energy but in a slightly different direction. Numerous foreign geologists also began to arrive for the Congress that was to meet in a day or two and great confusion of tongues prevailed in the halls and corridors. A very agreeable feature of these gatherings is the opportunity which they afford of seeing the faces and feeling the handgrasp of men with whom correspondence and community of employment have long made many familiar. A very fitting commencement of the proceedings was the read- ing of amemorial of the late president of the society by his brother, Prof. N. H. Winchell. This presented to the members an excellent sketch of the life and works of one of the most emi- nent geologists of this country, who did much to popularize the science among teachers and in the general community. A very valuable and closely condensed account of the geology of §, America was presented by Dr. Gustaf Steinmann of the University of Freiburg, Germany. In it was brought out the fact that the well recog- nized Glossopteris flora of Australia, etc.,also occurred in S, America, 194 The American Geolog ist. September, 1891 so that the land over which this flora extended was wide enough to in- clude 8. America. This gives a Mesozoic cast to the fossil Carbonif- erous flora of the greater part of the southern hemisphere and probably to some parts of the northern and indicates apparently, as Prof. L. F. Ward pointed out, that in or after the Permian period of glaciation the old cryptogamic and coniferous flora yielded to its more adaptive successor and retreated to the northward where it held its ground for awhile. The Carboniferous of 8. America is in many places, said the speaker, covered with marine Liassic beds, often conformable and containing genera such as those of Europe. And the whole Mesozoic series is inter- calated with immense masses of volcanic material. ‘ Dr. August Rothpletz of the University of Munich, read an able paper on the Mesozoic formation at the E. Indian islands, Timor and Rotti. A rich Carboniferous flora is found there also characterized by Glossopteris, and the speaker indicated that the southern .area had been long isolated from the northern so that passage either way was not possible. Mr. A. Harker, of Cambridge, England, read a learned but technical paper on thermometamorphism in igneous rocks. Prof. L. F. Ward presented a paper on the relations of the fossil plants of the Triassic in America, in which he pointed out with the aid of tables the nature of species peculiar and common to the different Triassic basins not known in this country. Mr. Joseph F. James gave a summary of the literature and history of Scolithus pointing out its little value in the classification of rocks and suggested that the species should be named from their horizon rather than the horizon from the species. A paper by Mr. R. A. F. Penrose, on the Tertiary iron ores of Ark. and Texas., gave the physical and stratigraphic details of their occurrence. Mr. Hay described some “sandstone dykes” in northwestern Nebraska. The evening was at first given to two papers on orographic geology. The first was read by Mr. Cadell of Edinburgh on some experimental reproductions of Scottish mountain structures and the second by Mr. Bailey Willis on the mechanics of Appalachian mountain structure. 30th were illustrated by lantern views and were intended to show the production of faults and thrust-planes in strata under tangential com- pression. A series of beautiful and very instructive views of the Muir glacier in Alaska by Mr. Cushing closed the evening. These were shown by the lime light and formed a marked feature of the meeting to all who saw them. M. Cushing’s estimate, it may be remarked, of the rate of motion of the glacier reduces the figures of Prof. Wright from 70 feet per day to 7 feet and even to less, and he also stated that it had retreated a full half mile in the four years since Prof. Wright’s Visit. On Tuesday morning Dr. Fredrich Schmidt, of the Academy of Science, St. Petersburgh, read a paper on the Eurypterus beds of Oesel compared with those of N. America. Personal and Scientific News. 195 The Baron de Geer, of Stockholm, gave an interesting and valuable account of the Quaternary changes of level in Sweden which elicited several remarks on their resemblance to contemporaneous changes in this country. He instanced several extensive oscillations be- fore, during or after the Gracia) era, during some of which great part of the country was below the sea and other parts reduced to the form of islands. Prof. Krassnof discussed the “black earth” of southern Russia, and its resemblance to the soils of the American prairies. This elicited a discussion on the complexity of the problem of these soils, and the morning session closed with a short paper read in French by Prof. Stefanescu, of the University of Bucharest, on the occurrence of Dinotherium in Roumania. Pres. T. C. Chamberlin in the afternoon summarized the standing of sev- eral of the theories which have been suggested to explain the occurrence of thelIce age. After stating that the hypothesis of Croll now fails to account for the phenomena, at least on this continent, he hastily sketched the theory of elevation as the cause of the cold, and offered as in his view most probable a change of the axis of the earth’s rotation. In the discussion that followed some opposition was developed and it was ‘apparent that the geologists present were far from agreement on the subject, a result that might have been anticipated. The society was divided into two sections in order to render the com- pletion of the program possible. Papers on the drift and kindred subjects were readin one room and the rest in another. Mr. R. D Salisbury mentioned the occurrence of the preglacial Orange sand of the Mississippi in Illinois and Indiana and at levels considerably above the present river, indicating the attitude of the country at that time. He also stated the occurrence of an older drift outside the so-called terminal moraine in New Jersey and referable tothe earliest drift of which we have any knowledge. Mr. 8. suggested further that though we are accustomed to speak of two glacial eras, yet there may have been three, the earliest of which is represented by the deposits which he described, the second by the silt layer and the third by the mo- raine. Petrographical papers were presented by Mr.J.F. Kemp and Mr.0O. A. Derby. Mr. R. T. Hill contributed one on the geology of Texas and New Mexico and Mr. Winslow another on the condition of deposition of the Missouri Coal Measures. Prof. Safford exhibited some interesting specimens consisting of the bones of a Megalonyx, from Big Bone lick, Ky. These he considered to be the remainder of the skeleton of the animal discovered by Leidy in his “Contributions.” Like those some of them showed the remains of cartilage indicating no excessively ancient date. In a short address Prof. E. W. Claypole related the discovery of a deep preglacial channel previously unsuspected. It is about five miles from Akron, O. The auger went down nearly 400 feet before the rock was reached showing that at this point the old river bed was cut down to the level of lake Erie though 40 miles distant. 196 The American Geologist. September, 189 The society is now in the third year of its existence and numbers more than 200 members scattered over the country from the Atlantic to the Pacific. Two volumes of transactions have been published embodying the results of researches in almost orery: field of geology. They may be obtained from the secretary, Prof. H. 8S. Fairchild, of Rochester, N. Y., to whom also should be addressed all applications for membership. A SPECIAL PARTY will study the Pleistocene of the southern coastal plain from Alabama to Mexico, leaving Washington im- mediately after the adjournment of the International Congress of Geologists.’ The party embraces the following: W. J. McGee, E. W. Hilgard, Eugene Smith, J. A. Holmes, Lester F. Ward and Robert T. Hill. Subsequently the relationsof the ‘‘ Trinity’ of Texas, and the ‘‘ Potomac” of Virginia, will be investigated in the field by Messrs. Ward and Hill. OF THE NINETY FOREIGN DELEGATES to the International Con- gress of Geologists present at the Washington session, sixty- three participated in the western excursion to the Yellowstone Park and the Rocky mountains. AT THE MEETING OF THE COMMITTEE OF ORGANIZATION of the National Association of Government Geologists, Saturday even ing, August 29, the secretary, Mr. Arthur Winslow, was instructed to draft : a Constitution and By-Laws, to be submitted to the com- mittee at a meeting to be called in connection with the Annual meeting of the Geological Society in December next. The secretary was further requested to notify all State Geolo- gists of this movement towards organization, and to invite them to be present at the next meeting. Pror. O. C. MARSH HAS CROSSED THE Rocky MouNTAINS twenty-seven times, in quest of fossil vertebrate skeletons, first in 1868, and remarked that he hopes to cross them as many times more. Pror. E. H. BArBour, GRINNELL, Iowa, has accepted the pro- fessorship of geology in the State University of Nebraska, at Lincoln. Dr. THEo. B. Comstock, oF THE TEXAS GEOLOGICAL SURVEY, has been appointed director of the School of Mines, Tucson, Ari- zona. THE BASIN OF ITASCA LAKE, which flows northward and is en- closed on all other sides by morainic accumulations, was formerly filled by a lake of much larger dimensions. Mr. J. V. Brower, in his official report on the new Itasca park, established by the last session of the Minnesota Legislature, describes the valley, and proposes for the extinct lake, which doubtless subsided to the dimensions of the present lake on the withdrawal of the ice of the Glacial epoch from the region, the name ‘‘lake Upham,” in recognition of the efficient work of Mr. Upham on the glacial geology of the state. THE AMERICAN GEOLOGIST Vou. VIII. OCTOBER, 1891. No. 4. BEECHERELLA A NEW GENUS OF LOWER HELD- ERBERG OSTRACODA. By E. O. Utricu, Newport, Ky. About the beginning of this year I was greatly pleased at re- ceiving from Dr. C. E. Beecher, of New Haven, Conn., a not only bountiful but an exquisitely preserved lot of Lower Helder- berg Ostracoda; and in a few days thereafter another series of the same, scarcely less extensive and excellent, from my well-tried friend, Mr. Charles Schuchert. To both of these esteemed gentle- men | am under the greatest obligations because of their untiring efforts to aid me in my studies of these minute fossils. The extreme liberality with which they have supplied me with spec- imens, the picking out of which has doubtless consumed much of their time, is conclusive evidence of an unselfish desire to advance science that is as unusual as it is commendable. These Lower Helderberg specimens are all silicified and have, by the judicious useof acids, been freed from the hard, stony matrix that originally enclosed them. They are, therefore, unusually perfect in their preservation, and exceptionally adapted for detailed study. In these respects they are but little, if at all, inferior to the beautiful things washed out of the Falls of the Ohio ‘‘ Bryozoa bed,” some of which I described lately (Jour. Cin. Soc. Nat. Hist. Vol. XIII, 1890-91). In the ‘‘ introduction ” to that paper I made some remarks on the distribution of the known American paleozoic Ostracoda, stating also that numerous forms may be looked for in our Upper Silurian and Carboniferous deposits. The truth of this predic- 198 The American Geologist. October, 1891 tion, in the first case at least, has received almost startling confir- mation by these discoveries of Dr, Beecher and Mr. Schuchert; and in the second case a good beginning has been made by Dr. Herman Herzer, who recently sent me a quantity of shales and limestones, from the Coal Measures of Ohio, that are largely composed of the shells of Ostracoda. In the present paper I am obliged to restrict my observations to a small but very remarkable group of species, not represented, so far as we know, outside of the Lower Helderberg rocks of New York. They seem clearly to indicate a new genus that | propose naming Beecherella, in recognition of the discoverer’s paleontological labors. From a collector’s standpoint, a striking feature about these species is the rarity of the individuals rep- resenting the six or seven distinguishable forms. Of only one have we as many as five valves, while of the others the number seen is three, two, or only one! The associated species, on the contrary, are in most cases numerously represented. Especially is this true of -Hehmina, of which there are at least two species, probably identical with the English and Scandinavian 4. bovina and #1. cuspidata, Among the others we may mention Beyrichia, Kloedenia, Bollia (?), Moorea, Bythocypris, ete., each with from one to four or more species, and most of them, if not all, with more or less obvious relations to Wenlock species. But this bears upon a too impor- tant question—/. ¢., the correlation of American and European strata—to permit of definite assertions previous to much more careful and detailed comparisons than I have yet found time to make. Iam however now, through the kindness of Mr. G. R. Vine and Prof. T. Rupert Jones, fairly well equipped to enter upon such comparisons, and hope in the near future to undertake them. Beecherella, n. gen. Carapace small, elongate, boat-shaped to ovate, moderately convex, more or less inequivalve. Dorsal margin varying from nearly straight to strongly convex; back sometimes flattened, with a sharply defined carina on one or both valves, giving them a triangular shape in cross-sections; in other cases the dorsal slope is merely convex. Antero-dorsal extremity acuminate, often drawn out into a long spine; spine strongest on the right valve, sometimes absent entirely on the left valve. Posterior extremity Genus of Lower Helderberg Ostracoda.— Ulrich. 199 acuminate or rounded. Ventral edge gently convex, occasionally straightened in the middle. Hingement simple, the dorsal edge of the right valve especially somewhat thickened and in the central portion slightly overlapping the left valve, Type, Beecherella carinata, 1. sp. Some of the species about to be described under this generic name deviate rather widely from the one selected as the type. Only one feature is common to them all—the anterior spine. The value of this character as an indication of true generic affinity may have been over estimated, and it is therefore possible that more than one generic group is represented. This is however a point that cannot as yet be determined, since, without more material of these and other species that sooner or later is certain to be discovered, it is not possible to pick out with certainty the really diagnostic characters. B. ovata may seem the farthest removed from B. carinata, but BL. subtumida is clearly an intermediate form, as is also B. cristata. Bb. navicula and angularis, however, differ from all the others in this, that the anterior spine is a prolongation of the dorsal edge instead of the dorsal carina or of the anterior slope. It is here, perhaps that another genus is indicated. Respecting the position of Beecherclla 1 find myself quite unable to arrive at any satisfactory conclusion. Many of the Cypridinide it is true, have an anterior spine or hook, but here the resemblance ceases. The thin shells of the Cypridz also are quite different, though one form of Cypris has been described as having a front spine ((. cornigera, Jones Geol. Mag. 1888, p. 336, fig. la-f), and Bairdia occasionally presents resemblances. And then the Leperditiide, a family that already includes many odd forms, does not, so far as I can see, contain anything throw- ing light upon the question. At present, therefore, I am obliged to view Beecherclla as one of those groups of fossils, so frequently presented to the student of paleozoic paleontology, that baffle the most careful efforts of the systematist to classify successfully. Beecherella carinata, n. sp. PLATE II, FIGS. 1-4. Size: a large right valve; greatest length, 3.60 mm.; greatest hight,0.77 mm. ; greatest thickness, 0.50 mm.; length of anterior spine about 0.65 mm.; greatest length of valve at inner edge, 2.90 mm. 200 The American Geologist. October, 1891 Valves elongate, boat-shaped, extremities acuminate, subequal the anterior spine strong, projecting greatly beyond the end of the hinge margin; from this spine a sharply defined thin, and gently curved dorsal ridge or carina, extends backward to and a little beyond the angular postero-dorsal extremity. A sharp impression extends a short distance obliquely downward from this extremity of the ridge. Back flattened except where it runs into the ter- minal spines; a faint channel- along the edge. Ventral edge nearly straight, curving uniformly upward at each end. Surface without ornamentation, with point of greatest convexity ( thick- ness ) at the dorsal carina about midway of the length, In a view of the inner side the dorsal edge is strongly convex, and the anterior junction with the ventral edge very acute and oc- curring beneath or about the middle of the hight. The largest and best of the valves seen presents a feature about which I could not satisfy myself that it really belongs to the valve. I refer to the thin oblique diaphragm-like structure shown in the right half of fig. 2. If it is really a normal structure then it appears to be restricted to the right valve, as I fail to notice any sign of it ina well preserved left valve. Nor can I detect any sign of such a diaphragm in the other species. The elongate form, sharply carinate back, acute posterior end, and the strength of the anterior spine are the distinguishing features of this species. It should require but a glance to sep- arate it from all of its known associates. Formation and locality: Lower Helderberg group, Albany county, N.Y. Types in Dr. C. E. Beecher’s collection. Beecherella subtumida, n. sp. PLATE II, FIGS. 5-7. Size of right valve: greatest length, 1.90 mm.; greatest hight, 0.70 mm. ; thickness, 0.55 mm.; length of valve at inner edge, 1.53 mm. ; projection of spine beyond anterior edge about 0.35 mm. Valves elongate-ovate, slightly widest in the posterior half; extremities, excluding the anterior spine, subequal, the posterior a little the bluntest of the two. Dorsal margin straight, sharply rounded at the postero-dorsal angle, and very slightly bent down where it passes into the strongly projecting anterior spine. Antero-ventral margin (in a side view) straight or faintly concave to the end of the spine. Ventral edge, uniformly convex, from Genus of Lower Helderberg Ostracoda.— Ulrich. 201 base of anterior spine to point on posterior edge one-third of hight of valve beneath the dorsalline, thecurve corresponding to something near a one-third segment of a circle. Posterior end most produced above, with a flattened border or flange projecting beyond the inner or contact edge; flange widest above, vanishing in the lower third. Back strongly convex, without carina, but with a shallow channel close to the edge. Surface smooth, valves tumid, with point of greatest thickness a little above the middle. In a view of the inner side the contact edges form an elongate- oval, with the anterior end sharply rounded or sub-acute, and the dorsal side straighter than the ventral. This species is too obviously distinct from the preceding to require comparisons. #. ovata has much wider valves, with quite different surface contour; while 4. cristata has the dorsal margin more convex, and a thin carina or crest on the dorsal slope. ‘ormation and locality: Same as preceding. Type in Dr. C. E. Beecher’s collection. Beecherella subtumida, var. intermedia, n. var. PLATE II, FIG. 19. Size of right valve: Length (excluding spine) about 1.17 mm. ; hight, 0.63 mm. This name is proposed provisionally for a single right valve, that, being a little imperfect at the anterior end, I think it wisest to view with conservative judgment. At first I was inclined to regard it asa young right valve of 5. ovata, but-on re-examination that view lost probability, and I now believe that its relations are nearer B. subtumida, withthe chances strongly in favor of ultimate specific separation from both. A comparison of figs. 5 and 15 shows that the latter is comparatively shorter, the antero-dorsal angle abruptly curved instead of gently declining, the anterior end probably blunter, and the ventral edge a little more convex. In the two points last mentioned the shape is more nearly as in B. ovata (see fig. 14) with which it agrees further in having the anterior spine less produced beyond the end of the valve, and its base situated farther back on the antero-dorsal slope—not however as much so as in that species. Its surface is less and more uniformly convex than #4. subtumida, while B. ovata has a low vardinal ridge running backward from the spine, and a shallow 202 The American Geologist. October, 1891 depression beneath it, neither of which is represented in var. intermedia, Formation and locality: Same as preceding. Collected by Mr. Chas. Schuchert, but now in the author’s cabinet. Beecherella ovata, n. sp. PLATE II, FIGS 13 AND 14. Size of left valve: Length, about 1.87 mm.; hight, 1.10 mm. ; greatest thickness, 0.50 mm.; length of spine, about 0.60 mm. ; projection of same beyond anterior edge, about 0.30 mm. Of this species the left valve illustrated on the accompanying plate is all that has so far been discovered. It is a little imper- fect at the posterior end but the remainder is in sufficiently good condition to justify description. Left valve ovate, widest posteriorly, with point of greatest hight, about midway between the extremities. Dorsal edge gently convex, posterior end semicircular, anterior end sharply rounded and most prominent just beneath the spine; ventral edge rather strongly convex, with the curve in the antero-ventral region somewhat straightened. Anterior spine rather long and slender, but projecting only about half its length beyond the anterior edge; continuing backward from base of spine a low rounded dorsal ridge is traceable across the middle third of the length of the valve. From this ridge to the dorsal edge the slope is abrupt, while just beneath it a shallow depression, widest and deepest at a point a little in front and above the center of the valve, is noticeable. Just behind the center an obtuse elevation constitutes the point of greatest thickness. Anterior, ventral, and posterior slopes gently convex. Surface without ornamentation. Formation and locality: Same as preceding. Type in Dr. C. E. Beecher’s collection. Beecherella cristata, n. sp. PLATE II, FIGs. 16-19. Size of entire carapace: Length, including anterior spine, 1.27 mm, ; length, without spine, 1.10 mm.; hight, 0.49 mm.; thick- ness, 0.47 mm. Carapace elongate ovate, narrowly rounded behind, acuminate in front. Dorsal and ventral sides nearly equally convex. In a ventral view the two valves are about equally convex, with the point of greatest thickness near the middle. Valves unlike, the left without spine or crest, but with a narrow flattened border at Genus of Lower Helderberg Ostracoda.— Ulrich. 208 each end. Right valve with a faint dorsal overlap, a rather small subterminal anterior spine, and behind itathin crest-like longitud- inal ridge situated about midway between the center of the valve and its dorsal edge. This is the only species of the genus of which the two valves have been found in conjunction. They are so different that if found separate they would scarcely have been referred to the same species. Indeed, the spineless left valve would most likely have been regarded as Bythocypris. The two valves are known also of B. carinata and B. navicula, but in these the anterior spine of the left valve is merely somewhat smaller than that of the right, while the B. ovata, of which the left valve only is known, this spine is very well developed. B. subtumida, known only from right valves, is evidently a related form, and it is possible that in it too the left valve is spineless, which may account for its non-recognition. Formation and locality: Same as preceding. Type picked from fine residue sent me by Mr. Chas. Schuchert, and now in my cabinet. Beecherella navicula, n. sp. PLATE II, FIGS. 8 AND 9. Size of left valve: Length from extremity of spine to posterior margin, 3.4 mm.; hight, 0.7 mm. Valves elongate, boat-shaped, the dorsal and ventral margins sub-parallel, the former long, gently convex, anteriorly drawn out into a long spine projecting forward and a little upward like the bowsprit of a boat; posteriorly bending down into the sharply rounded posterior margin. Anterior end sloping backward from the base of the spine into the ventral edge. The latter is straight in the middle, and gently curved upward behind. Surface mod- erately convex, the dorsal slope the most abrupt. The spine of the right valve slightly stronger and longer than that of the left. On the inner side the dorsal edge is thickened, especially in front where it forms the projecting spine. Running nearly parallel with the anterior edge a ridge, quite distinct in the left valve, but much less so in the right, is tobe observed. From the nature of the parts forming the anterior half of the valves it appears that when joined and the carapace closed an opening must exist just beneath the spines. There is little probability of confusing this with any of the 204 The American Geologist. October, 1891 preceding species. The internal differences are so striking that a generic rather than specific separation is suggested. Formation and locality: Same as preceding. Types in Dr. C. E. Beecher’s collection. Beecherella angularis, n. sp. PLATE U, FIGS. 10-12. Size of right valve: Length 1.45 mm.; hight, 0.75 mm. ; thickness, 0.38 mm. Valves obliquely acuminate-ovate, in a side view, triangular in cross-section, the dorsal side being nearly straight, with a wide, subtriangular flat or slightly concave back, the posterior third semicircular, the anterior margin gently curved and sloping back- ward from the pointed antero-dorsal extremity into the neatly rounded ventral margin. Point of greatest thickness’ just beneath the dorsal ridge from which the surface slopes with a gentle convexity to the free margins. The general expression of the only valve of this species seen except that it is inequilateral, resembles that of the ventral valve of aminute Spirifera with a wide flat area. The possession of sucha flattened back recalls B. carinata, but the relationship can only be remote since they differ so greatly in all other respects. Nor do any of the other species approach B. angularis sufficiently to make comparisons either necessary or desirable. Formation and locality: Same as preceding. Type in Dr. C. E. Beecher’s collection. EXPLANATION OF PLATE. * BEECHERELLA CARINATA, D. Sp. Fig. 1. Nearly perfect right valve. Fig. 2. Interior view of same. Fig. 3. Dorsal view of same. Fig. 4. Interior view of a small left valve. BEECHERELLA SUBTUMIDA, 0. Sp. Figs.5,6and7. Respectively interior, side and dorsal views of a right valve. BEECHERELLA NAVICULA, 0. Sp. Fig. 8. Interior view of a perfect left valve. Fig. 9. Interior view of the anterior half of a right valve. BEECHERELLA ANGULATA, D. Sp. Figs. 10,11 and 12. Interior, end and dorsal views of a right valve. (The dorsal view is too long.) 3RECHERELLA OVATA, D. Sp. Figs. 13 and 14. Dorsal and side views of the only specimen, a left valve, seen. BEECHERELLA SUBTUMIDA, Var., INTERMEDIA, 0. var. Fig. 15. View of the interior of a right valve. BEECHERELLA CRISTATA, D. Sp. Figs. 16,17, 18 and 19. Respectively right side, left side, ventral and dorsal views of a perfect carapace. * All the figures are enlarged 20 diameters. PLATE II. MOL V LEE AMERICAN GEOLOGIST. %. ha) aha i oe : y Mis Yom Pv, f Me he vant | i es i Vee al 2 \ s* _ STAAVWHD ONINNOY-YAAO YAIOVTO HIOW AHL LSINOTOMN*) NVOIMANY ‘HI StvtTd “WIA “WA 207 NOTES ON THE MUIR GLACIER REGION, ALASKA, AND ITS GEOLOGY. By H. P. Cusurine, Cleveland, O. CONTENTS. Page Page PPTREMOITICULON ye se\caleac's)c suc!) ajcje'> aise #08 207 Changes Of Jeveli.. ccc ccssccecsecees 2el Description of the Region.. Pee och om CLO, Ola HOLGRL ote.L.).c ban ed o's wines wom eee Tributaries to Muir glacier... See eel AGH SOTMCR CRONE. Cece ccrinces pconcecs Ore Northern and Western branches..... 209 Dis MSstPUChON y's tes icdade bono ubn Lae 22 Eastern branches. . Sasha doe Melee Its bearing on the awe of the MPIBIGSIACIOL nee rines.osivci se ccorc cc cient 210 glacier. aahedene Mecile ean BED White glacier... SEAS Os nie) Disintegration ‘of the rocks around Southeastern branch. ............... 210 Muir glacier,. THEVA SEY Bin 5-928 eee Main cca and Main lake.. ......... 210 ta Amount eve onions a eee cae oe 224 Bere lake cn. ie, ‘ Tb ASE PS Agen 4 4 Debris on Glacier-swept mountains. . 225 Girdled glacier.. Miia’ abva sisletaarewee cle Size of moraines..... 225 Granite canon. .... 213 Surface features produced by Muir gla- Recent recession of the “glacier... .. 214 (Ui Nigthn 5 Rare ee Ne Stes ae Sarina nee 226 ETE CHOVAGOHCO.\.615 =. a \20s b> osice vole 214 Surface produced on ridges at right Freshness and extent of the striw ... 216 angles to the movement..........+. 226 Condition of the eastern eecies of Lakes..... Blood he anctae a ue the glacier.. Seta a eter Islands in Glacier bay.. cote ebs CW Land slip on White glacier. . .... 217 Erosive power of Muir glaci ier. ae eee Dying glacier.. : SE BeOS ioe pee a Xe The gravels along Muir inlet.......... 228 Glacial deposits. Wa eon teleas ciee oe? 219 Old surface features not obliterated. . 228 PAPE UIIOIE Soe Co melsainedis casts pecepce e. SLD Sediment brought down by streams... 229 OMOTRUTM DY ICG Noo. foie cel deciles tenes ERO ROCK PDARINB Ss eat coca s eirdee aitoinal eae MAPA Ewes ce sgsn oss cg scenes ascse 220 INTRODUCTION. In the spring of 1890 a party was organized by Dr. H. F. Reid, of the Case School of applied Science, Cleveland, O., to proceed to Glacier bay, Alaska, for the purpose of mapping the basin of the Muir glacier, and of making as thorough an explora- tion as the time at their disposal would permit. The party con- sisted of Dr. Reid, Messrs. H. McBride, J. F. Morse, C. A. Adams, of Cleveland and R. L. Casement, of Painesville, O., and the writer. We reached Glacier bay on the 1st of July, and were fortunate in finding Prof. John Muir already in camp there, with Mr. Loomis, of Seattle, Wash., as a companion. Our stay was made vastly more pleasant and profitable by Mr. Muir's presence and knowledge of the region. He made the first ex- ploration of the amphitheatre occupied by the main mass of the glacier (see map), leaving camp in the middle of July, and in a solitary trip of ten days duration, passing completely around this amphitheatre. Our party had been preceded in work at this point by Prof. G. F. Wright, who spent a month here in 1886. His retults are well known and his work was of value to us in many ways. Work in an unknown and difficult region of considerable extent must necessarily be largely the work of the scout. Detailed ob- 208 The American Geologist. October, 1891 servations are out of the question. It is believed that more gen- aural ones are of sufficient interest to be worthy of record. DESCRIPTION OF THE REGION. (Glacier bay is a narrow arm of the sea about thirty miles long and five to eight miles wide projecting northwestwardly from Cross sound, Between it and the Pacific lies a rather narrow peninsula occupied by the Fairweather range of mountains, and two minor ranges west of it. Kast of the bay is another narrow and mountainous peninsula separating it from Lynn canal. Near its head it bifurcates into bay Glacier proper and Muir inlet, the lat- ter projecting from the main bay in a northerly direction. It is from three to four miles long and from one to two miles wide. Into its head Muir glacier advances. The mountains adjoining the bay are mainly low, rounded spurs rarely exceeding 3,000 feet in hight, but present occasional sharp peaks rising from 5,000 to 6,000 feet above tide. Their northern slopes are often permanently snow-clad, but southern exposures are entirely free from snow in summer, and gay with a profusion of flowers. To an observer on one of the spurs on the eastern side of Muir inlet a spectacle of unparalleled grandeur is presented. To the west across Glacier bay rise two low ranges of mountains and beyond loom up the giants of the Fairweather range, beautiful white, snow- clad peaks. To the east and northeast are the White mountains lying between Glacier bay and Lynn canal. To the north and northwest the whole of the vast amphitheatre occupied by Muir glacier lies before the eye, with its encircling mountains, and the larger number of the many valley glaciers that pour their ice into this amphitheatre. The great branches that come in from the north- west may be followed by the eye for great distances. As the ice in the amphitheatre advances toward Muir inlet it becomes con- fined within narrow limits. The amphitheatre has a breadth of from twelve to fifteen miles or more. In order to reach the inlet the ice occupying it is forced through a mountain gap less than three miles wide. At the present time the ice front barely reaches the narrowest portion of this gap. The waters of Muir inlet do not wash the bases of the mountains. A deposit of sand and gravel with a width of from one-half to three-fourths of a mile lies between the two on each side of the inlet. As a result only the central portion of the glacier terminates in the water. This central portion is tremendously crevassed and broken. On _ each Muir Glacier Region, Alaska.— Cushing. 209 side the glacier ends “upon these soft deposits, diminishing in thickness to an edge. These side portions of the glacier, espec- ially the eastern side, are as notably smooth as the central portion is broken. Near the front of the glacier three low mountains protrude from the ice which entirely surrounds them. On _ these were Dr. Reid’s stations G, Hand I. The western one, G, is much the largest and highest, and forms a conspicuous feature in the landscape seen in looking toward the ice from the bay. TRIBUTARIES OF MUIR GLACIER. The greater portion of the ice which reaches the front of Muir glacier at the present day is supplied by the two great ice-streams which enter the basin from the northwest,* Muir glacier proper and the northwestern branch. The former is the larger, has a length of certainly thirty-five miles and probably more, and is deeply and abundantly crevassed for a great distance back from the ice front. The central and larger portion of the ice front derives its ice from this source. The northwestern branch is only second insize to this one. Its length is not so great nor its crevasses so numerous and profound. Its ice reaches Muir inlet to the west of the ice from Muir glacier proper, The next most considerable tributaries are the two northern branches. These have great length but will not compare in size with the last two. They fur- nish the ice which breaks away into the water at the eastern cor- ner of the inlet. The Western branch is quite completely sepa- rated from the rest of the glaciers by the numerous low mountains that protrude from the ice. Its interesting features are its nu- merous connections with its Northwestern branch through the mountain gaps, and its source on a saddle from which ice flows in both directions, a feature shared by other g!aciers in the basin. The ice from this branch does not enter the water, but dies out on the gravel deposit which forms the western shore of Muir inlet. Eastern branches. —That portion of the amphitheatre of Muir glacier lying east of a line drawn from Snow dome to the eastern corner of the inlet is occupied by a mass of ice nearly inert, and slowly rotting where it lies. Stakes placed across it about half a mile back from the front, at the end of three weeks showed either no motion at all, or else an extremely slight one. The surface of all this portion of the glacier is extremely smooth. Crevasses *See map. 210 The American Geologist. October, 1891 occur, but in general are mere cracks. None are found which are not readily to be stepped over. Everything points to rapid de- radence, Points of interest increase as the various valleys tributary to this part of the glacier are examined. The Dirt Glacier,—The first valley opening into this part of the glacial amphitheatre as its edge is followed is occupied by asmall glacier, to which the name Dirt glacier was applied, because the ice in the whole lower half of the valley is completely and heavily covered with debris from the rapidly disintegrating mountains at its sides. The upper half of the valley discloses an extremely pretty, small, white glacier with heavy lateral moraines which gradually increase in width with the result mentioned above. This glacier at the present time has not sufficient vitality to send itsice beyond its own valley. Its lower portion is without per- ceptible motion, and has melted away considerably from the mountain sides. The White glacier.—The next valley is occupied by a very beautiful little glacier of a dazzling white appearance, with two medial moraines which present a very striking appearance from a distance on account of their graceful curves. This glacier still possesses considerable vitality, sending its ice clear to the Dirt glacier valley. In entering the main basin its ice makes a_ sharp turn of 90°, causing a depression of its surface at the concave side of the bend with a corresponding slight elevation at the convex side. The Southeastern branch.—For our present purpose the point of interest of this next succeeding glacier is its present vitality. It really comprises two glaciers, the first of which is somewhat the larger of the two. This sends its ice not quite to the White glacier valley, dying out against the mountain side just before that valley is reached. Ice from the other branch extends but little further, pinching out between ice from Main valley and the White glacier, opposite the entrance to White glacier valley. Main valley.—The greater portion of the ice occupying the eastern part of Muir glacier amphitheatre has emerged from the large valley called Main valley. At present many curious features are exibited here. No ice is visible in the upper portion of this valley or in the valleys tributary to it. The comparatively narrow ridge back of Tree mountain which separates Main valley from the snow fields of the Southeastern branch is deeply Muir Glacier Region, Alaska.— Cushing. 211 snow-covered on the one side, and perfectly bare on the other. Some cause not evident has locally produced a greater and more rapid disappearance of snow and ice from the vicinity of Main valley than has elsewhere taken place. Snow fields occur on Mt. Young, the highest and most imposing mountain in the vicinity. But these form very small glaciers and the valleys enclosing Mt. Young are free from ice. The ice occupying the upper part of Main valley terminates abruptly at the edge of a long, narrow lake—Main lake—whose long axis is at a high angle with the trend of the valley, and which occupies nearly its entire width. The eastern shore of the lake is made up of glacial debris modi- fied by water, and such deposits exist in considerable force in the tributary valleys beyond. Small bergs, evidently derived from the end of the glacier, float in the waters of the lake, and strand on its shores. From its lower end a stream of water issues, flowing away toward Lynn canal. The lake is held in place by the thickness of the soft deposits on its eastern shore. The moraines in Main valley run directly to the shores of Main lake, there ending abruptly. That the rock masses from which they derived their contents, lie to the east, is clear from the nature of the contents. Hence the ice must formerly have completely filled Main valley and come from the tributary valleys to the east. At the present time the supply of ice in the valley is renewed from no source whatever, except for the snow which falls upon its surface in winter. The highest part of the surface of the ice at present is some distance west of thelake. Somewhere beneath this ice, lies the divide for this valley between Glacier bay and Lynn canal. The stream flowing from Main lake flows into Lynn canal. It is possible that Main lake lies just on the Glacier bay side of the divide. That being the case, the draining of the lake would be indefinitely postponed. In the period of greater life of the glacier, the glacier occupying the stream valley, and the upper part of Main valley must have had a rising slope for its floor, and the reason for its movement in this direction furnishes an interesting problem to be solved. At the present time the whole mass of ice is practically inert, but it seems inevitable that there must be a slow flow of the ice in both directions away from the highest point. This movement would add to the general lowering of the surface of the ice produced by melting. It mustalso tend to an attenua- tion of the moraines spread upon the surface. 212 The American Geologist. October, 1891 Another testimony to the inert condition of the ice in Main valley and vicinity is the shrinkage of the ice away from the mountain slopes which border it. This shrinkage must be par- tially counteracted by the slow movement just spoken of, but it is very conspicuous. The ice is rarely in contact with the mount- ains, but has withdrawn a few feet, leaving gaps into which an astonishing amount of debris has been tumbled. Berg lake.—Two small valleys open into Main valley from the northeast. The most easterly of these is occupied by Berg lake, presenting an excellent example of a valley lake whose waters hold their position in virtue of an ice barrier across the valley mouth. In this lake also float ice bergs derived from the ice barrier which holds the lake in place. Two enormous moraines extend from the mouth of this valley to the ice front. Their great size compared to the size of the valley in which they must originally have been formed is a matter worthy of comment Here also the slow creep of the ice away from its highest point must be felt, and accounts for the occasional berg which the ice furnishes to the lake. What becomes of the surplus water of the lake is not known, but it seems probable that it must find its way into Main lake. A comparatively slight extension of the latter would cause the two to coalesce. The same cause that has re- moved the ice from the upper part of Main valley has removed it from Berg lake valley. Glaciers ordinarily retreat up their val- leys. Here the opposite course of proceedure seems to have obtained, and the glaciers have disappeared from the small val- leys while thick ice remains in the larger one into which the others formerly poured their supply. The Girdled glacier.—The westerly of the two valleys spoken of is occupied by a very beautiful little white glacier, with a very steep slope. The clean character of its surface and the small amount of debris which it brings down, are as astonishing on the one hand, as are the great moraines which have come out of Berg lake valley on the other. This glacier received its name from Dr. Reid because of the curious disposition of the moraines around the end of its valley. A moraine curves gracefully around its front, from the end of the ridge on the west, to the end of the ridge on the east side of itsvalley. Another moraine. parallel to this, emerges from Granite canon to the west, curves around outside of the first, and dies out against the mountain Muir Glacier Region, Alaska.— Cushing. 213 side just to the west of Berg lake valley. These moraines both lie on the surface of the ice lying in the main valley. Ice from the Girdled glacier seems just to reach this, but does not pass into Main valley, nor can:it have done so for some little time. Granite canon.—The valley to which Mr. Muir applied this name is, barring Main valley, the largest one opening into the eastern part of the Muir glacier amphitheatre. It is a rather gloomy looking valley, bordered by low mountains with some- what precipitous slopes. These are dotted with patches of snow lying in sheltered depressions, but at present give rise to no glaciers. Hence the ice lying in Granite canon presents the same features as that in Main valley. The ice is inert. It has no feeders. It has disappeared from the upper portions of the val- ley while yet lying in considerable force in the lower portion. — It diminishes in altitude toward the head of the canon, the highest point in the vicinity, lying nearly three miles south of the en- trance. About four miles up the canon the end of a lake is visible, lying in a side valley opening into the western side of the eanon. Though only the end of the lake was visible the nature of the country surrounding it clearly indicates that the lake bears thesame relation to Granite canon that Berg lake does to Main val- ley, viz: that its waters are held in place by the ice barrier across the front of its valley. The same cause has been at work in both places. That the ice formerly moved out of Granite canon, and did so for avast length of time is indubitably shown by the material of which the great moraine that issues from it is composed. The great proportion of this material is diorite which is only found in place in the mountains enclosing the up- per portions of the valleys that open into the glacier’s amphi- theatre from the east and _ north. Ice certainly flowed out from Granite canon long enough to carry this moraine clear to the present front of Muir glacier and beyond. The outward flow of the ice from Main valley must have ceased before the stoppage of the flow from Granite canon. The moraine which emerges from Granite canon and passes around the front of the Girdled glacier proves this. On the cessation of the flow from Main valley the ice must have receded somewhat from the moun- tain flanks. The eastern portion of the ice flowing out from Granite canon would then have encountered less resistance in this direction, and a portion of it would deflect from the main mass 214 The American Geologist. October, 1891 and follow this new direction. The short moraine which passes just across the front of the Girdled glacier inside of this one was formed at the same time, mainly from material from the rapidly disintegrating mountain ridge west of the mouth of the Girdled glacier. That the outward flow of the Granite canon glacier did not continue long after the stoppage of the flow from Main valley, is shown by the short distance traversed by the moraine emerging from the canon and flowing in this direction. If there is the present slow flow of the ice in Main valley al- ready spoken of, a flow in both directions from the highest point of the ice, there must be a corresponding slow flow of the ice back into Granite canon. Starting at the front of Muir glacier, and proceeding toward the canon, the surface of the ice is found to slowly increase in hight till, about ten miles from the front, an altitude of about 1,300 feet A. T. is reached. From this point further progress to the northwest is over a descending surface. This descent continues up Granite canon as far as the eye can see. Two small glaciers appear on the southern slope of the moun- tain mass lying between Granite canon and the First Northern branch. The most western of the two—marked Glacier 9 upon the map—merits brief attention. It has retreated some little distance up its valley, and its lower portion is covered from one side to the other with debris, after the manner of the Dirt glacier. Upon the ice of the main mass in the amphitheatre which lies across the opening of this glacier’s valley, a moraine appears curving across the opening from one side to the other, the coun- terpart of the one in front of the Girdled glacier. The motion appears to have been from the west, the material being supplied from the southern slope of Snow dome, the mountain to the west of this glacier. A recent flow of ice from the First North- ern branch across the opening of this valley must have taken place, carrying with it the disintegrated material that fell from Snow dome upon the surface of the ice. RECENT RECESSION OF THE GLACIER. The evidence that very recently Muir glacier has had a vastly greater extent is remarkably plain, and has been well summed up by Prof. Wright. The reason for its consideration here, is that further evidence has been procured. Direct evidence.—Prof. Wright's measurements, and photo- graphs taken by Mr., Baldwin of his party furnish a means of Muir Glacier Region, Alaska.— Cushing. 215 comparing the position and extent of the glacier in 1886 with its condition in 1890. Mr. Baldwin’s photographs of the ice front show that in 1886 its position was at least half a mile further to the south than was the case in 1890. No direct measurements on the ground were possible, and the ice front was of such en- tirely different shape at the two periods, that, at best, only an average could have been ascertained. The amount of retreat has been greater in the central part of the glacier which terminates in the water, its ice breaking off and floating away, than at the sides, which retreat only by slow melting where they lie. Wright’s map and photographs show the seaward portion of the ice extending further to: the south than the wings on land, the most southerly point of all being in the centre. In 1890, on the other hand the most southerly points of the ice front were the wings—see map—and the water front was deeply concave, the greatest recession, probably not far from a mile, being near the centre. The amount which the wings have retreated has been comparatively small. The testimony of the officers of the steam- ers which have been entering Glacier bay since 1883, is unani- mous that the ice has retreated considerably since that time, the estimates running from one to two miles. The testimony is cred- ible as a new place for anchorage must be sought every year. Half a mile in four years is a tolerably rapid rate of recession, should it prove to be at all an average one. The hight of the central portion of the ice front above the water in 1890 was about 250 feet, the same that Prof. Wright records.* This, however, was the hight of his projecting point. To points on the front somewhat back of that, he gives a hight of 300 feet. Soundings as close to the ice front as practicable show about the same depth of water, somewhere in the neighbor- hood of 600 feet on an average. There has evidently been a con- siderable shrinkage in thickness in the four years interval. The ice front in 1890 was not farremoved in position from the line along which Prof. Wright states it to have had ahight of 408feet in 1886.7 Its greatest hight in 1890 was 250 feet. Wright's photographs indicate also a greater thickness of the ice in the Western branch, judging from the hight to which it rises on the mountain sides adjoining, as compared with that exhibited in the photographs of *Ice Age in North America. p. 43, tIbid., pp. 43 and 49. 216 7) he American Geol Og ist. October, 189% the same taken by Dr. Reid and Mr. Morse. As a result of his measurements of the rate of motion of Muir — glacier near its front, Prof. Wright announces an average forward move- ment of the ice into the inlet of forty feet a day, with a maxi- mum of seventy feet.* His method was by sighting on various pinnacles of the deeply crevassed portion of the ice, from day to day. Under Dr. Reid's skillful guidance our party made several efforts to completely cross the ice front and plant flags to serve as accurate points on which to sight. The attempt to entirely cross was unsuccessful, proving a task of the most extreme diffi- culty, if not impossible. By working out from each side toward the centre, however, the last flag on one side was planted so near to the last flag on the other, that the space between the two was less than the average interval left between the others.. The most rapid motion found by Dr. Reid by triangulation upon these flags, was seven feet a day. Undoubtedly the ice was in more rapid motion at the time of Prof. Wright’s visit. Its greater thickness and the fact that it was further advanced into the com- paratively narrow valley in which Muir inlet lies would necessi- tate this. But the increased rapidity must have been compara- tively smail in amount. Freshness and extent of striw.—The sides of the mountains bordering Muir inlet are polished and striated with the freshest possible marks up to hights of 2,000 feet. The same is true of the sides and tops of the two low islands which project above the surface of Muir inlet. Naturally the striations decrease gradually in number and strength as the altitude increases owing to the rapid disintegration of the rocks. Above 2,000 feet striz are occasionally found up to hights as great as 3,500 feet. Only oceasional peaks have hights over 3,000 feet, hence when glaciation was at its hight the whole region must have been covered with an icy mantle with only here and there a small steep crag projecting above the general level. In the upper portion of Glacier bay the same freshness of the striz is observable on the mountain sides and the islands in the bay. Going down the bay the same decrease in number and freshness is observed that is found on increase of altitude. Yet the differences are not as marked as would be the case had the retreat of the ice been a slow *Ice Age in North America, pp. 48—51. Muir Glacier Region, Alaska.— Cushing. Q17 and prolonged matter. The evidence furnished by the striz is of a recent and rather rapid retreat of the glacier from a condition of much greater extent. Condition of the Eastern portion of the glacier.—Tnis has already been treated in considerable detail. The evidence there presented of the great decadence of that portion of the glacier will readily be recalled. 5 Land slip on the White glacier,—The extension of the White glacier into the main amphitheatre is clearly marked by its very white color and the heavy moraine at its outer side. It ends in front of the Dirt Glacier valley. About two miles above its end its entire breadth is covered for a short distance by a coating of loose debris, which increases in thickness and coaresness toward the mountain side, upon which masses ‘of the same material lie. Some sudden flood or avalanche has hurled this mass of material down the mountain side, and scattered it broadcast over the sur- face of the ice. The present surface of the ice covered by this material now stands well above the level of the ice not so pro- tected, and presents the characteristic surface of ice so covered; great differences of level appear according to the thickness of the covering, with the prevalent tendency toward the production of sharp ridges and cones. ‘To produce the existing difference of level and character of surface exhibited, a length of time would be nec- essary which must at least be measured in months. Yet the material lying on the glacier is directly continuous with that onthe mount- ain side, so that little movement can have taken place since the slide occurred. THE DYING GLACIER. The Dying glacier lies in a valley from half a mile to a mile wide, which extends from the western shore of Muir inlet through the mountains toGlacier bay. The glacier is a mass of ice nearly three miles long, of unknown thickness, occupying the middle third of the valley. From its eastern end a stream flows into Muir inlet, three and one-half miles distant, through the soft de- posits occupying this portion of the valley. The western end of the glacier lies very close to tide water from Glacier bay which ex- tends up the valley for two miles and a half. The highest point of the ice, about 800 feet A. T., is near the centre. From this point the surface slopes evenly in both directions. Two small glaciers, the one north of Pyramid peak, and one from the south 215 The American Geologist. October, 1891 were formerly tributary to this glacier, but it has been some time since either has supplied any ice to it. Its moraines lie in perfectly straight lines from one end of the ice tothe other, neces- sarily being the remnants of the old medials that lay on its sur- face during a time of greater extent. No moraines appeared traceable to the two glaciers coming in from the sides. There are several of these medial moraines lying on this glacier, indi- cating its formation from a considerable number of small ice streams. They present one very peculiar feature, that of disap- pearing for a certain interval. On following one of them it would suddenly be cut off sharply, be absent for a certain distance, and then reappear at the surface with equally startling sudden- ness. This has taken place once on every moraine. Sometimes two or three moraines exhibit this phenomenon at about the same point, but more often the points of disappearance and reappearance on the various moraines seem independent of one another. Close examination revealed the missing portions of the moraines lying beneath the surface of the ice, their present position being dis- closed by means of the narrow crevasses. They were *sometimes covered by a thickness of ice of at least six feet. They keep their direction perfectly when beneath the surface. The effect produced is as if a long shallow block of ice had been lifted up, its load of debris deposited in the depression produced, and then the block replaced upon it. No explanation of this occurred to me, and I present it as a curious fact not observed before so far as L know. The situation and direction of the moraines on this glacier in- dicate a former flow of the ice from one end of the valley to the other. There are, however, certain difficulties in the way of this view. The material composing the moraines is here of little as- sistance in determining the question. The mountains adjoining this valley and the neighboring shores of the bay and inlet are all of the same material, and of this the moraines are made up. Occasional large pieces of coarsely crystalline white calcite oc- cur on the moraines. These are supplied from the deposits of calcite found in fissures in the vicinity. I know of none of sufficient size to have furnished these pieces in the mountains ad- joining the eastern portion of the valley, and do know of several to the west. This denotes a probability of a former easterly movement of the glacier in this valley. There are many Muir Glacier Region, Alasha.— Cushing. 219 points of interest in this valley, requiring a careful examination for their elucidation. GLACIAL DEPOSITS. Description.—On each side of Muir inlet a deposit of sand and gravel of varying width lies between the water and the mountains —see map. The deposit on the western side is more extensive. It has a width varying from half a mile to a mile, which is great- est opposite Dying glacier valley and diminishes rapidly to the south, having a length of about five miles. That on the eastern side has a width of about half a mile for the first mile of its length and then diminishes to a point, dying out about three miles south of the ice front. For a considerable part of their ex- tent these deposits rise quite abruptly from near the water’s edge in steep cliffs with an average hight of one hundred feet. ' The faces have been chiseled by the rains into very picturesque shapes. They have a talus slope at their base, and are separated from the water by a narrow sand beach. A channel has been cut in each of these deposits by the sub-glacial streams that issue, one from each end of the ice front. The sides of these channels are marked by rough terraces marking occasional local flood plains formed by the streams as they rapidly cut out their channels. These terraces rise rapidly in the direction of the ice and then die out, an effect produced by the retreat of the ice and the consequent shifting of the source of the stream. These deposits possess firmness to a surprising degree, it being in places extremely difficult to make any impression on them with the foot. But their lack of consolidation renders them, especially when water- soaked, an easy prey to running water. They were deposited by swift currents. The material is all coarse, alternating beds of gravel and sand, the gravel largely predominating, and with little or no admixture of clay. Rapid alternations of horizontal and cross bedding characterize them, A considerable number of the pebbles in the gravel are derived from the eruptive rocks far to the north. They have their edges rounded but are much more angular than are stones which have suffered attrition in water for any considerable length of time. They have rather the aspect of somewhat water-worn glacial pebbles. The altitude reached by these deposits increases as the mount- ain sides are approached, they having there an elevation of 400 220 The American Geologist. October, 1891 * feet. In a steep gully on the side of Mt. Wright they reach a hight of 600 ft. These deposits overrun by the glacier, —These deposits below the front of the glacier are overlaid by a stratum of varying thick- ness of true morainic material, rough boulders of varying sizes, few of which showany evidence of attrition, lying on or embedded inalayerof sandand clay. The surface presents numerous “ kettle- holes” and kames, its whole configuration being evidently due to a re- treating ice sheet. On each side of the inlet the glacier overruns these deposits. (Plate III.) This is best shown on the eastern side, where by passing down the beach to the ice front, a beauti- ful longitudinal section of the ice lying above the gravels can be seen. The length of this section is a quarter of a mile. At its upper end this ice has a thickness of one hundred feet at least, thence diminishing gradually to an edge. This section is made possible because the wings of the glacier on land, reach further to the south than the seaward portion. On reaching the main front the gravels are seen to pass under the ice, so that their extent in this direction cannot be told. There is something more here than the snout of an advancing glacier riding up over its moraine. This glacier is retreating, and all the evidence shows that it has been doing so for a considerable lengthof time. That these beds were deposited before the advance of the glacier, from which it is now retreating, took place, is proved by the buried trees shortly to be described. That the present retreat has been long continued, is shown by the condition of the eastern portion of the glacier. ). Estuarine. c. Lacustral. 2. At base level. a. Littoral. b. Marsh. c. Alluvial (certain teriaces, etc.). 5. Above base level. a. Torrential. »b. Talus (including playas), B. Glacial: 1. Direct. (Chamberlin’s class I.) 2. Indirect. (Chambertin’s classes II to V, in part.) Aqueo-Glacial: (Chamberlin’s classes II to V, in part.) Eolic: (Chamberlin’s class (?) VI.) Volcanic: 1. Direct. a. Lava sheets. »b, Cinder cones. c. Tuffs, lapilli sheets, etc. 2. Indirect. a. Ash beds. b. Lapilli sheets. Prof. Chamberlin, in closing the discussion, said that there was great difficulty in applying a chronological classification, and that such a classification might even act as a barrier to observation and to the recog- nition of the truth. Chronological classification is the ultimate goal of glacial studies, but it is something for which we are not as yet prepared. Red, oxidized sub-soils are not developed in northern latitudes. Organic deposits between glacial layers are abundant in the West, but do not belong to a single horizon. Many facts of erosion and physical geology indicate that the glacial epoch in America was widely differentiated and of long duration. How many distinct periods it embraced we do not as yet know. Prof. Cope: An abundant tropical fauna is found in the “Equus beds, which, if they be of interglacial age, indicates at this time a very warm climate. This fauna is succeeded by a truly boreal fauna, In this is Ayo ” kditorial Comment. 249 contained material for a chronological sub-division of Pleistocene ‘deposits. , SESSION OF AUG. 28, 1891, 11:40 a. M. Prof. J, Le Conte, Vice-President, in the clair. Announcements by the General Secretary, Mr.S8. F. Emmons, relative to the minutes of yesterday and to various excursions. Announcement by major Powell in regard to the essays on correlation to be published as bulletins of the U. 8. Geological Survey. The President then announced as the subject for discussion, the Cor- relation of Geological Formations. Mr. Gilbert opened this discussion by presenting a general classifica- tion of methods of correlation. Strata are locally classified by superposition in chronologic sequences. Geologic correlation is the chronology of beds not in visible sequence. For convenience in discussion, methods of correlation are classed in ten groups, of which six are physical and four biotic. PHYSICAL METHODS OF CORRELATION. 1. Through visible continuity. The outcrop of a bed is traced from point to point and the different parts are thus correlated one with another. 2. Strata are correlated on account of lithologic similarity. This method, once widely prevalent, is used where the distances are small. 3. Correlation by the similarity of lithologic sequence has great and im- portant use where the localities compared fall within the same geologic province, but it is not safely used in passing from province to province. 4, Physical breaks or unconformities, have a limited use, especially in conjunction with other methods. The practice of employing them in the case of localities wide apart is viewed with suspicion. 5. Deposits are also correlated with their simultaneous relations to some physical event; for example, a beach with the lake beds it encircles; a base level plane with a contiguous subaqueous deposit ; and alluvial, littoral, and subaqueous deposits standing in proper topographic relation. In the Pleistocene, glacial deposits are widely correlated with reference to a climatic episode assumed to arise from some general cause. 6 Deposits are correlated through comparison of changes they have ex- perienced from Geologic processes supposed to be continuous. Newer and older drift deposits in different regions are correlated according to the relative extent of weathering and erosion; induration and metamor- phism afford presumptive evidence of age, but yield to evidence of other character. Metamorphism holds prominent place in the correlation of Pre-Cambrian rocks where most methods are inapplicable. These physical methods are qualified by the geographic distribution of Geologic processes of change and of geologic climates. BIOTIC METHODS OF CORRELATION. 7. A newly-discovered fauna or flora is compared with a standard series of faunas and floras by means of the species it holds in common with them severally. 250 The American Geologist. October, 189% 8. It is also compared by means of representative forms, or through genera and families. Ja and 8a. These comparisons are strengthened if two or more faunas in sequence are found to be systematically related to the faunas of a standard series. 9. Two faunas or floras otherwise related are compared in age through their relation to the present life of their localities. This method was ap- plied by Lyell to Tertiary rocks. 10. Faunas are correlated by means of their relation to climatic episodes, taken in connection with station. For example, boreal shells found in latitudes below their present range are referred to glacial] time. In general the limitations to accurate correlation by biotic methods arise from the facts of geographic distribution. Correlations at short range are better than those at long range. Biotic correlation by means of fossils of different kinds may have different value. In general, the value of a species for the purposes of correlation is inversely as its range in time, and directly as its range in space. The value of a biotic group depends (1), on the range of its species in time ayd space; (2), on the extent to which its representatives are preserved. Prof. K, von Zittel spoke in reference to the biotic methods and gave his opinion of the relative value of plants and animals for purposes of correlation. He. regarded plants as relatively unimportant. Among animals those which are marine, lacustrine and land animals may be distinguished. Of these classes marine invertebrates are most value- able for purposes of correlation. The vertebrates change rapidly but are frequently altogether wanting. For instance, no vertebrates occur in the Alpine beds corresponding in age to those which contain the mammalian fauna of the Paris basin. In certain lacustrine deposits invertebrates. may be absent, and in such cases the vertebrate fauna is the surest guide- Baron de Geer emphasized the importance of a numerical comparison between different species. The actual counting of individualsin a given formation is of great value. Prof. Marsh expressed his agreement in general with the conclusions communicated by Prof. von Zittel, but would give special weight to vertebrate fossils. In the Mesozoic and Tertiary beds of the Rocky Mountains he had found that the vertebrates offer the surest guide for correlation. This is in part because invertebrates are either wanting or are lacustrine. Prof. Marsh in 1877 named a sequence of horizons after the most characteristic vertebrate genus in each which is confined exclusively to it. He presentedan outline of such classification brought down to date with a section to illustrate vertebrate life in America. AFTERNOON SESSION, Mr. ©. D. Walcott spoke of the value of plants for purposes of geo- logic correlation. Prof. T. McK. Hughes spoke of the present and growing tendency toward a natural classification. The evidence is complex and includes a Editorial Comment. 251 considerable variety of diverse relations. He pointed out exceptions to the normal conclusions deduced from superposition, lithological char- acter, and similarity of sequence. We must have a system of criteria so varied that if one or more fails others can be employed. All classes of ' evidence are useful, both positive, negative, and circumstantial. Major J. W. Powell spoke of the necessity of specialization on the part of geologists engaged in the work of correlation. The evidence derived from physical and biotic facts might apparently disagree. But that asatisfactory result may be reached, these two classes of evidence must be brought into harmony. He cited an example from his own experi- ence of how an identification of synchronous formations might be made over a wide area through a union of physical and biotic methods. Mr. W. J. McGee remarked that in the costal plain of the United States physical correlation alone is employed. The bases accord with those outlined by Mr. Gilbert with certain minor modifications and an important addition, as follows: \ Visible Continuity: For local discrimination and correlation - Lithologic similarity; { Similarity of sequence. \ Physical breaks viewed as indices of geography For correlation throughout the province ue and topography. | Relation to physical events, For correlation with contiguous provinces, / including continental movements, 7 | transportation of materials, land sculpture, etc. For general correlation, - - - Homogeny or identity of origin. By correlation upon these bases the physical history of a considerable fraction of the continent may be so definitely ascertained as to permit fairly accurate mapping of the geography, and even the topography of each episode in continent growth. After these episodes are clearly de- fined, and the fossils found in the formations are studied, it will be pos- sible definitely to ascertain the geographic distribution of organisms during each episode, then paleontology may be placed on a new and higher plane. Prof. W. M. Davis showed thatit was possible to decipher geological history not only through the records of deposition, but also by processes of degradation. As an example of this method he explained a topo- graphical section from the city of New York westward. In this we have evidence of the existence of an ancient “penepluin,” or base-level lowland of Cretaceous age. This surface was subsequently elevated (more toward the west than toward the east) at the end of Cretaceous, or at the beginning of Tertiary time. It has since been dissected by the excavation of more recent valleys. The Hudson valley lowland was cited as an example of this recent dissection Prof. E. W. Claypole considered that the different methods of geologic correlation differed very greatly in their value. It is improbable that the plant or mammalian record will ever equal in its perfection that of the marine invertebrate fauna. The marine faunais to the geologist what a primary triangulation is to the geodosist. It marks out the main divi- sions, which are subsequently further subdivided through the aid of ther fossils, such as plants and vertebrates. 959 The American Geologist. October, 1891 Prof. C. R. Van Hise spoke of the methods of correlation employed for pre-Cambrian rocks, which occur in widely separated areas and are devoid of fossils. Physical data only are available for correlating these formations. Experience has shown that among all physical methods, unconformity is by far the most important. Other physical criteria,such ~ as the degree of induration, metamorphism, and relation to eruptives, are valuable for the subdivision of single areas, but cannot be safely used in identifying synchronous formations in widely-separated areas. The idea that lithological character is any direct proof of geological age has retarded the scientific subdivision of pre-Cambrian rocks. The re- searches of Pumpelly and others in the eastern United States have demonstrated that Silurian, Devonion, and even Carboniferous deposits might become, under certain physicai conditions, as highly crystalline as much more ancient rocks of the West. For this reason it has been found necessary to abandon such tern as //wronian and Keweenawan. Evidences of life are not lacking in pre-Cambrian rocks, and it isto be hoped that the paleontologist will succeed in differentiating several separate formations below the Cambrian, as the Cambrian itself was differentiated from the base of the Silurian. SESSION OF AUG. 29, 1891, 10 A. M. Prof. Albert Gaudry, Vice President, in the chair. Mr. 8. F. Emmons, General Secretary, made announcements. M. Alexis Delaire presented two communications in behalf of prince Roland Bonaparte relating to the phenomena of the Aletsch glacier and upon an excursion to Corsica. Prof, Chas. Barrois presented a communication on behalf of Prof. Michel Lévy upon the geologic history of the Auvergne volcanoes, con- taining a classification of eruptive rocks as represented by symbols. Prof. E. W. Hilgard laid stress upon the importance of the abundance or scarcity of species in the correlation of strata. He thinks some quantitative estimation of the species should be made. He is of the opinion, also, that as compared with marine fauna, plants have but little value, for purposes of correlation owing to their local distribution, their accidental proximity to water, transportation, and preservation. Plants can be so used only after large areas are worked over. Prof. Zittel was called to the chair, and Prof. Lester F. Ward then con- tinued the discussion. He developed two of the more general princi- ples of correlation by means of fossil plants, as follows: I. That the great types of vegetation are characteristic of the great epochs in geology. This principle is applicable in comparing deposits of widely different age when the stratigraphy is indecisive. For example, even a small fragment of a Carboniferous plant proves conclusively that the rocks in which it occurs are paleozoic, or a single dicotyledonous leaf proves that they must be as late as the Cretaceous. II. That for deposits not thus widely different in age, as for example, within the same geologic system or series, ample material is necessary to fix their position by means of fossil plants. Editorial Comment. 253 Neglecting this principle has led to the greater part of the mistakes of paleobotanists, and has done most to bring paleobotany into disre- pute. Geologists have expected too much of them, and they, in turn, have done violence to the truth in attempting to satisfy extravagant de- ‘mands. On the other hand, where the material is ample, fossil plants have often corrected the mistakes of stratigraphical geologists, and solved problems concerning geologic age, which seemed impossible of settlement by any other class of evidence. Mr. Chas. D. Walcott spoke upon the correlation of the Cambrian rocks of North America. The principles used now are the same as those used by the New York survey prior to 1847 except that those principles have been somewhat modified by the theory of evolution. Both physical and biotic data are available in the correlation of the Cambrian rocks on the Atlantic coast, of the Rocky Mountain areas, and of the interior continental plain. Throughout the Appalachian prov- inces the physical data suffice to correlate the Lower Cambrian from Vermont to Alabama, but such data are not sufficient to correlate it with that North of the St. Lawrence valley. The correlation of the deposits of the Appalachian and the Rocky Mountains troughs were by biotic data alone, and of’the great extent of the Upper Cambrian over the continent the biotic data correlated the Rocky Mountain Upper Cam- brian with that of the interior and the Appalachian area. The correlations made indicate that in Lower and Middle Cambrian time a‘great continental area existed over the interior, and all the Cam- brian sediments were accumulated in troughs west of the Appalachian and Rocky Mountains. In Upper Cambrian time the interior of the continent sank beneath the ocean, and the sandstones of the upper Cam- brian were deposited, and the result of these correlations add a chapter to the history of the evolution of the North American continent. Prof. James Hall spoke of the difficulties encountered in the earliest attempts at correlation of the rocks even in the state of New York. He urged the importance of taking into consideration both physical and faunal characters of the rocks. In some cases, however, the physical characters of the rocks change greatly in passing from one region to another—sandstones grading into limestones, and limestones into shales —and these beds may also vary greatly in thickness. Fossils are of unequal value in such correlations; Lamellibranchs are near shore forms and fail in deep water; they are not, therefore, so valuable as Brachio- pods, which have a wider distribution, for purposes of correlation. Prof. Henry 8. Williams laid stress upon the relations of species to the conditions of deposition. The abundance of a species varies with environment, and a study of correlation should embrace a study of these conditions. Sandstones deposited near shore may have a fauna different from that of a limestone deposited off shore at the same time, and a change of fauna may be induced by a change of the conditions of deposition. The age of beds should be determined by comparing species of the same genera rather than by comparing those of different genera. There are centres of abundance which exhibit great variability 254 The American Geologist. October, 1891' in their characters; outside of these centres the species exhibit varieties. which may be called extra-limital, and which are not typical though they have often been published as types. Dr. F. Frech said that in comparing the middle paleozoic fauna of Europe with that of North America, there were two principal points of especial interest: A. The identity of some comparatively small horizons. B. The far greater differences that exist in these same beds. The similar faunas are— 1. That of the Niagara and of the Wenlock shales. 2. In the Upper Devonian the Rhynchonella of the Tully limestones. and the Goniatites of the so-called Naples beds. 3. The Goniatites at the base of the Carboniferous in Iowa, in Spain,. and in middle Germany. : The Hamilton fossils are of especial interest because we have on the Rhine, in the so-called Lennenschiefer, a fauna of the same facies. But while these rocks were deposited under similar physical conditions,, the number of identical species in the two countries is very small, and there are many genera in each country not found in the other. All the Lower Devonian is wanting in European Russia and part of it is want- ing in middle Germany, but the great physical change which followed is sufficient explanation for the differences which characterize the junc- tion of the Devonian and Silurian. Prof. Barrois thinks it impossible to compare in detail American and European rocks. Soma individual zones of the American series can be correlated with European horizons, but it is quite impossible to estab- lish in detail the ideatity of other and adjacent zones. Prof. C. R. Van Hise spoke of the distribution, character, and succes- sion of the pre-Cambrian sedimentary rocks of North America. All rocks are regarded as pre-Cambrian which are earlier than the Olenellus fauna. These rocks contain the evidence of abundant life as shown by thick beds of carbonaceous shales, by various distinct fossils, and in many other ways. When a less highly developed fauna is found, as different from the Cambrian fauna as the Cambrian is from the Silurian, itis best to give this fauna a new name. There are in many areas in North America great thicknesses of little altered pre-Cambrian sedimentary rocks. In many regions these rocks have been separated into series by wide-spread unconformities, and these series have been farther divided into formations. Some of the more important pre-Cambrian regions are Lake Superior and Lake Huron, Central Arizona, New Brunswick, Newfoundland, Southwestern Montana. Asan illustrative example of the successions may be cited the first. In this area the descending order is Lake Superior sandstone ( Potsdam ), unconformity, Keweenawan, unconformity, upper Huronian, unconformity, Lower Huronian, unconformity, basement crystalline com- plex. Each of these series is divided into several formations. In individual regions it is possible to correllate series and formations upon a physical basis. In different regions the series have variable Editorial Comment. O55. lithological characters and unlike successions. Because of the absence of a well-known pre-Cambrian fauna it is impracticable at present to make correlations in far-distant regions. Hence the term Algonkian has been proposed by the United States Geological Survey to cover the ‘whole of the pre-Cambrian clastics. No working geologist in America now holds the indivisibility of the pre-Cambrian in all regions. If the foregoing conclusions are correct, the invariable succession ad- vocated by Hunt, evolved almost wholly within the laboratory, is value- less. It is shown to be untrue at one or more fundamental points by the observed order of the rocks in every region in which there are tolerably full successions. Prof. R. Pumpelly confirmed the observations of Prof. Van Hise in so far as he had been over the ground mentioned. He referred especially to observations made in the Green mountains, where in one locality metamorphism has completely masked the original character of the rocks, and thus rendered impossible correlation by lithologic characters, Asan example he cited a formation which is a quartzite, at one point. a white gneiss containing new feldspars at another, a conglomerate with- out any schistose structure at another, and a mica schist at a fourth locality. Prof. Chas. Barrois, referring to the remarks of Prof. Van Hise, said that there was no general basis, either biologic or lithologic, for the correlation of the pre-Cambrian rocks of Europe with those of North America; even the terms applied to these rocks were liable to be mis- understood. Certainly the divisions used in France cannot be correlated with those now used in the United States. General correlation cannot, as yet, be based upon non-conformities; autopsy is the only basis upon which a comparison can be instituted. He pointed out certain parallelisms between the histories of the crystalline schists of America as illus- trated by Mr. Pumpelly and the gneissic rocks of Brest, where the Cam- brian slates are altered to gneisses of Archean aspect, while the alternat- ing fossiliferous quartzites are changed to crystalline quartz. Geologists must see the beds together in order to reach a common understanding of the crystalline rocks. Dr. Chas. A. White was called upon, but in view of the divergence of the discussion from the topic as originally taken up, excused himself from speaking upon the subject. Prof. E. D. Cope discussed the question from a general point of view with especial reference to the value of vertebrates for purposes of corre- lation, particularly for inter-continental correlation. He pointed out that there is a marked difference in the present vertebrate faunas of conti- nents, and that the variation of such forms must be sought in vertical rather than in horizontal ranges. Such study shows that we have had invasions of a given region by a fauna from without; for example, a South American fauna invaded North America at one time and then retreated, while a North American fauna once invaded South America and traces of it still remain in that country. He is inclined to believe that certain vertebrate forms did not spread over the earth from a single 256 The American Geologist. October, 1891 place of origin, but that they originated at different places upon the earth. We have parallelism in separate places, but the parallelism is defective in the Laramie. Mr. G. K. Gilbert was of the opinion that many methods of correlation must be used. He doubted the trustworthiness of the correlatiun of non- fossiliferous rocks by comparative change, even locally. He thought the abundance and scarcity of fossil forms comparable with lithologic differ- ences, and considered the simple occurrence of a species as valuable for purposes of correlation as its abundance. Prof. Van Hise explained that the distinction between the Algonkian and the Archzean has not been widely made in Europe, because there, as in the Appalachian region, later and powerful dynamic movements have repeatedly occurred. Prof. E. D. Cope added that life in its progress on the earth differed from minerals and rocks in that it has its own laws, which give it an indepen- dent element. Announcements were made by Secretary Emmons, and the meeting adjourned at 1 o’clock until 11 o’clock a. mM. Monday, August 31st. SESSION OF AUG. 31, 1891, 11:25 A. M. Prof. James Hall, Vice-President, in the chair. ~* Announcements were made by Mr. 8S. F. Emmons, General Secretary. Subject for discussion: Map-coloring and Cartography. Major J. W. Powell exhibited charts illustrating the color system used by the U.S. Geological Survey, explained the methods of using the colors, and gave the reasons for them. The colorsassigned to rocks of different ages are as follows: Period. Period color. Mark. 1. Neocene..... eae akeere ree OPangs 202. Vue he wae te ee eee ci Be CCNE’.<,.. sacs Soe Nemo sa 0 oo Seale colton seen E. A EOLACGOUR . Loc rac ee ees Yellow-freen .., .ss ths catsoveeue ee Board ATIAS ..} Lore ese cos ah Blve-ereen, ... ss tose epee PACATDONITETOUS 3 ae eee cece Blueme. « sica os bine oaihele oe ER Tee C. Peeve VONIAN ; «- =. eee ene WIDGET. c:cro cs demise cooeers aeeteetee D T SMGMAR. ... .. 2 els aoe ee Purples. 2A: oiise cee eee S See DIAAL J... von cei eneee PINK fetes toe eter arches to etree ee OUIAN os ib aameeeets Med. w Si me wees ave eee meee A. The colors are used to designate geologic periods, patterns of these colors designate formations ; -minor divisions are usually relegated to the text. The number of patterns for designating formations can be indefinitely enlarged, but follow a definite system. * Mr. Joseph Wilcox showed that in the scheme described by major Powell the colors were uot evenly distributed through the chromatic scale. Prof. C. R. Van Hise pointed out that Archzean rocks are shown by a brown underprint, and that m+tamorphic rocks of known age are given the color of the corresponding unaltered rocks. Major Powell explained that it was not attempted to select colors Editorial Comment. 957 equally distributed through the chromatic scale, but to use those that may be most readily recognized. Mr. H. M. Cadel] asked why black and gray were not used. Major Powell replied that blue was used in place of the dark shades for the Carboniferous; that dark colors are misleading in regard to the: occurrence of coal, which occurs in the Cretaceous and Tertiary as well as in the Carboniferous. Mr. Christie found the black color very inconvenient because it often made the details of the map covered by such colors illegible. Mr. H. M. Cadell said that the maps of the Geological Survey of Great Britain were colored by hand,aad that the system used by the U. 8. Geological Survey could not for this reason be economically employed. Major Powell explained that the U.S. Survey system is very econom- ical when the color patterns are transferred to stones. Prof. T. McK. Hughes thought it very difficult to devise a scheme that will meet the demands of everyone. Some reference must be had to the permanence of the colors, the readiness with which they can be applied, and the distinctness with which they show what is desired. He thinks the fittest scheme must survive. Mr. 8. F. Emmons made announcements. On motion of major Powell, the program for the afternoon was changed so that the geology of the country to be traversed by the long excursion might be briefly described by those the most familiar with it. Adjourned till 2:30 P. M. On re-assembling at 2:30 P. M., Prof. Le Conte in the chair, brief lectures were given by Prof. Chamberlin, Mr. Gilbert, major Powell, and Mr. Emmons upon the geology of the country to be traversed by the long excursion. Adjourned at 4:40 P. M. As may be seen from the foregoing, the Congress was occupied with the problems proposed for discussion by the Committee of Organization, as was announced in the GEoLoaGistT (Vol. vin, p. 62), but there was an apparent lack of orderly preparation and of consistent succession in the proceedings from day to day. For instance, the topic which was expected, according to the pro- eram announced by the Committee of Organization, to come /asf, was called up the first thing the first day, and parties who might have wished to participate in the discussion were thereby pre- vented, or were obliged to offer their facts undigested and per- haps unarranged, or without the graphic illustrations which they otherwise would have employed. It was quite evident, also, that some of the gentlemen who led in the discussion of the daily topics were compelled te do so on too short notice. It might be well for future Committees of Organization to assume more 258 The A merican Geologist. October, 1891 thorough direction of the doings of the Congress, as least so far as to see that parties are at hand with well prepared papers to bring the topics of discussion fully before the Congress. It is manifest that each new ‘‘ Bureau” elected after the session opens, is in no degeee prepared to provide for this necessary guidance of the deliberations of the Congress. It is a precaution which ought to be taken several months, or perhaps several years, before the Con- gress convenes. The practice of national ‘‘ nomenclature re- ports,” which in this case might have been correlation reports, from the countries participating in the Congress, but which was apparently not attempted and not encouraged by the American organizing committee, would certainly subserve this purpose per- fectly. This would be more likely to be satisfactory, being more ‘¢democratic,”” than that plan which was entered upon by the English organizing committee n re the crystalline schists. That committee solicited contributions from individuals on that specific topic. While this resulted in the production of a number of learned and very valuable contributions which grace the volume lately issued by the English committee, it cannot be considered as the best way to promote harmony and to extend and perpetuate an interest in the Congress. If the Congress be in fact an “ in- ternational ” one, the various nationalities should have system- atized participation in its doings, and the organizing committee should be empowered and directed to take steps to facilitate such general participation. The late Congress passed otf with the sim- ple presentation, largely or entirely, of some American views on American geology, followed by such desultory comment or dis- cussion as happened to spring up. If such a practice be perpet- uated in future sessions, the Congress will finally degenerate to an elementary school of geology, wherein the visiting geologists will learn the outlines and general principles of the geology of the countries where the separate sessions may be held, and it will be a question of a short time, a very short time, whether the use- fulness and the purposes of the Congress, as set forth by the founders, be not so far lost sight of or so remotely subserved that the sessions had better be discontinued. The next session will be at Berne, Switzerland, and we wish to appeal to the intelligent geologists of that little republic, to early take measures to make the next session a truly ‘international ” and representative one. 259 REVIEW OF RECENT GEOLOGICAL LITERATURE. The Comanche series of the Tevas-Arkansas region. By RoBert T. H11. Bulletin, Geological Society of America, vol. ii, pp. 503-528; May 5, 1891. ‘The main area of the Comanche series is stated to extend from western Arkansas through southern Indian Territory to the meridian of 97°30, thence southward and southwestward across Texas to New Mexico, a distance of more than 1,000 miles, and then southward indefinitely into Mexico. The series, as studied by Mr, Hill in central Texas and north- ward, is made up of eleven terranes, classed under three divisions in -ascending order, as follows: A. The Trinity division, comprising 1. Trinity or basal sands, which Dr. C. A. White provisionally regards as the base of the North American lower Cretaceous; and 2. The Glen Rose or alternating beds, consisting of abundantly fossiliferous magne- sian limestones, fine sand, chalk, and almost pure crystalline limestone. B. The Fredericksburg or Comanche Peak division, comprising 3. The Paluxy sands, about 100 feet thick, containing no fossils excepting silicitied wood; 4. The Gryphwu rock and Walnut clays, the former being a stratum 10 to 50 feet thick, composed entirely of the shells of a small Gryphwa, and the latter being associated clay marls which enclose myriads of Hvogyra terana Roemer; 5. The Comanche Peak chalk, about 100 feet thick, rich in many species of fossils; 6. The Caprina limestone of Shumard, an indurated chalk, 30 to 40 feet thick, preserved as the capstone of many buttes, mesas, and plateaus; and 7. The Good- land limestone, apparently an equivalent of the last two. C. The Washita or Indian Territory division, comprising 8. The Kiamitia clays or Schloenbachia beds, so named from their characteristic Ammonites; 9. The Duck Creek chalk, about 100 feet in thickness, composed of crumbl- ing chalky limestone and marls, with a unique fauna; 10. The Fort Worth limestone, which with the last was described by Marcou at Fort Washita as typical Neocomian; and 11. The Denison beds, made up of sandy clays and occasional limestones, Huogyra arietina being the characteristic fossil of the clays. At Denison and throughout northern Texas, these beds are unconformably overlain by the Dakota sandstone, the base of the upper Cretaceous series which is so widely developed on the plains farther north. Carboniferous fossils from Newfoundland. By Sir J. Wrtt1am Dawson. Bulletin, G. 8. A., vol. ii, pp. 529-540, with two plates; May 27, 1891. The plants described or catalogued with annotation in this paper are from St. George’s bay, in western Newfoundland, the most noteworthy species being Lepidodendron murrayanum, nearly like L. cliftonense of Nova Scotia. The strata are similar to those of the coal formation of Cape Breton, and have a total thickness of probably 11 000 feet. Accord- ing to Mr. James P. Howley, now director of the Geological Survey of Newfoundland, they contain six beds of coal, ranging from fourteen 260 The American Geologist. October, 189¥ inches to eight feet in thickness, three of them having over four feet of good coal, apparently a free-burning bituminous variety, resembling that of the Cape Breton mines. A proposed sysem of chronologic cartography on a physiographic basis. By President T. C. CHAMBERLIN. With The geological dates of origin of certain topographic forms on the Atlantic slope of the United States. By WiiiraAmM Morris Davis. Bulletin, G. 8. A., vol. ii, pp. 541-544, and 545- 586, with six figures in the text; July 2, 1891. Increasing attention has been given during recent years to topographic forms as time indices and means of geologic correlation. President Chamberlin therefore pro- poses a cartographic system, in which plains shall be represented by lines, and slopes by dotted surfaces, both to be put on in colors varying according to the geologic date of these topographic forms. The direc- tion of the agency by which they were produced may also be shown. Thus, a fluvial plain will be indicated by arrows (without feathers). pointing in the direction of the current, while a lacustral plain will be mapped by parallel lines headed with arrows-points on the margin shore- erosion by waves having been the most characteristic agency in its pro- duction. Inthe case of subaerial plains or peneplains, parallel lines. will be used without arrow-heads. To distinguish between a plain and a peneplain, which may be quite rolling and yet clearly determinable, continuous lines may be used for the former and broken lines for the- latter. Professor Davis recognizes a Cretaceous peneplain in southern New England, New York, New Jersey, and southward, into which the rivers of the Atlantic slope have cut broad and deep valleys during the Tertiary era. The Hudson river, for example, is shown to have excavated the whole gap between the Catskill and Berkshire plateaus since the early Tertiary uplifting of this peneplain. The level crests of the- Appalachain ranges are remnants of the Cretaceous base-level, into which streams have channeled the great intervening valleys during Tertiary and Quaternary time; but the White mountains of New Hampshire and the Black mountains of North Carolina have existed, constantly under- going denudation, from much earlier dates. Variations in the Cretaceous and Tertiary strata of Alabama. By DanreL W. Lanepon, Jr. Bulletin, G. 8. A, vol. ii, pp, 587-606, with one plate; July 8, 1891. This paper presents detailed descriptions and sections observed during the boat journeys down the Tombigbee, Tusca- loosa, and Alabama rivers, with which the sections exposed farther east by the Conecuh, Pea, and Chattahoochee rivers are compared. Special attention is directed to variations in the strata on account of different conditions of sedimentation,to faunal changes,and to unconformities due to the total absence eastward of formations that are well defined in the- western part of the state. On the Tombigbee the Cretaceous beds measure about 2,560 feet in thickness, and the Eocene about 1,655 feet ; while on the Chattahoochee these are reduced respectively to about 1,440 and 1,145 feet. Recent Publications. 261 Bulletin of the Geological Society of America, Proceedings of the third annual meeting, held at Washington December 29,30 and 31,1890. J. J. STEVENSON, Secretary. pp. 607-662; August 7, 1891. Besides a record of the order of presentation of the various papers which have been separately printed by the Society and already reviewed in this and preceding numbers of the GEOLOGIST, six short papers are here printed in abstract or fully, as follows: On the occurrence of Megalonyx jeffersoni in central Ohio, by Edward Orton ; On the family Orthide of the Brachio- poda, by James Hall; On a jointed earth auger for geological explor- ation in soft deposits, by N. H. Darton; On the occurrenceof diamonds in Wisconsin, and on the occurrence of fire opal in a basalt in Washington state, by George Frederick Kunz; and A fallen forest and peat layer underlying aqueous deposits in Delaware, by Hilborne T. Cresson. The first annual report of the committee on photographs | gives the titles, with descriptive notes, of 293 photographs received by the Society in 1890, of which 21 were donated by Prof. J. F. Kemp of Ithaca, N. Y.; 269 by the U. 8. Geol. Survey, through the director, major J. W. Powell; and 3 by Prof. W. B. Dwight of Pough- keepsie, N. Y. Arkansas Geological Survey, J.C. BRANNER, state geologist; Annual report for 1890, Vol. 1, Manganese, its uses, ores and deposits, R. A. F. PENROSE. Octavo, 642 pp., geological map. Little Rock, 1891. This volume is a valuable one for the manganese industry in Arkansas, and secondarily forall who make use of manganese. It gives an account of the early and modern uses of manganese, and brings out vividly the remarkable recent increase of its mining and manufacture (in spiegelei- ° sen and ferro-manganese) in the United States. In 1875 the net tons produced were 7,832, in 1885 34,671, and in 1890 149,959 tons. The methods of use of manganese in the arts, including its alloy with iron in the Bessemer and Hadfield processes of steel-making are fully de- scribed. Small amounts of manganese ore were mined in the United States (Tennessee) as early as 1837, but at the present time Virginia, Georgia and Arkansas produce over nine-tenths of the total output of North America. “The United States is the next largest producer of manganese ore in the world, being second only to the Caucasus region of Russia.” “England is the largest consumer of manganese in the world, using not only its own production, but also 74,906 tons from out- side sources. The United States is not only the second producer but the second largest consumer, using its own production as well as that of Cuba, and most of that of Canada.” All the various ores and minerals of manganese, together with their places and manner of occurrence, are described, embracing also chemi- cal analyses. In Arkansas there are two manganese regions, one in the northeastern part of the state, known as the Batesville region, of which a detailed geological map is given, and the other in the southwestern part extend- ing from Pulaski county through Polk county to the Indian Territory 262 The American Geologist. October, 1891 border. Inthe former occur nearly all the large and workable deposits. The ores of the Batesville region occur in a residual clay, derived from the decay of a limestone which, according to Prof. H. 8. Williams, occupies a position intermediate between the Trenton and the Niagara limestones. The ores of the southwestern part of the state are in novaculite probably of Lower Silurian age, perhaps Trenton. The ores in both regions are in the forms of the various oxides of the metal. These ores were mentioned by Owen and Cox, and Featherstonhough mentioned manganese in the southeastern part of the state, but it is only within a few years that there have been systematic working and descriptions of the deposits. Between the ore-bearing St. Clair limestone, which is of about the age of the Trenton, and the Boone chert which is a part of the lower Car- boniferous, is a curious clayey deposit which is partly the result of sur- face decay of the lower limestone, and partly apparently of the nature of eruptive ash. This has been but partially investigated, but it seems to be widespread, and points to a long land exposure in this region between the close of the Lower Silurian and the age of the Carboniferous Boone chert. This had already been suggested by Dr. Branner from examina- tions in the field. Like the Cincinnati anticlinal, therefore, this part of the country experienced an elevation, but not like that, this remained dry land through the upper Silurian and the Devonian, and was subse- quently again sunk beneath the ocean. In the careful description of the manner of occurence of the ore in the Batesville region is ample proof of the thoroughness and ability with which the investigation has been carried on. It is a comparatively new ‘field, and it has been most satisfactorily worked. The ore occurs in a clay which is the residuum of the St. Clair limestone. The ore was first in the limestone. The decay of the rock, and the removal of the soluble part has concentrated the insoluble, this embracing the ores—which, however, have to some extent been converted from carbonates. This process of decay began after the last elevation of the region above the ocean and is still going on. This residual clay has nothing to do with the layer of residuum which naturally intervenes between the St. Clair limestone and the Boone chert already mentioned, as to its age and stratigraphic relations, however closely they may be related genetic- ally. The report embraces a review of the manganese mines of the United States, with a view to comparison with those of Arkansas, for the pur- pose, evidently, of arriving at some conclusion as to the origin of the ore in the rock from which it is now plainly derived by natural concentra- tion zm situ through slow decay. In the course of this review, Dr. Penrose describes, with more fullness and correctness than has ever been done before, the manner of the occurrence of the iron and manganese ores of Vermont, and their stratigraphic relations. In this he adopts the late conclusions of United States geological survey (by J. E. Wolff), that the associated rocks are of the age of the Lower Cambrian, or Taconic of the region, as has been claimed from the time of Emmons Recent Publications. 263 till now, except by those who reject the Taconic system. He finally reaches the conclusion that the ores (in particular the ore of manganese, although the conclusion involves that of iron because of their intimate association) were the result primarily of chemical precipitation in the ocean at the time of the formation of the rocks themselves, and that the oceanic waters obtained the manganese prircipally from the disintegra- tion of the older crystalline rocks of the region. The report is faultless in method and execution, and the value of its scientific conclusions, and of its accurate and conscientious descriptions of Arkansas localities cannot fail to be highly appreciated by the citizens of that state. It is, moreover, a real contribution to the geology of the country, and adds one more to the series of valuable results of the Arkansas survey. RECENT PUBLICATIONS. I. State and Government Reports. Geol. Sur. of Missouri, Bulletin No.5, contains: The age and origin of the crystalline rocks of Missouri, Erasmus Haworth; Notes on the clays and building stones of certain western-central counties tributary to Kan- sas City, G. E. Ladd. Advance sheets from the 17th report of the Geological Survey of the State of Indiana; Pateontology, 8. A. Miller, 113 pp., 22 plates. Geol. Survey of Georgia, First report of Progress, 1890-91. J. W. Spencer. Bulletin No. 80, U.S. Survey. Correlation papers, Devonian and Car- boniferous, Henry 8S. Williams. Second annual report of the Geological Survey of Texas, E.T. Dum- ble, contains, besides the report of the state geologist, the following papers: Reports on the iron ore district of East Texas; Carboniferous cepholopods, A. Hyatt; Report on-the geology of northwestern Texas, W. F. Cummins; Report on the geology and mineral resources of the central mineral region of Texas, Theo. B. Comstock; Report on the geology and mineral resources of Trans-Pecos Texas, W. H. Von Streerwwitz. II. Proceedings of Scientific Societies. Trans. N. Y. Acad. Sciences. Feb-March, contains: The man of Spy, or newly discovered paleolithic skeletons from the vicinity of Liege. Belgium. J.S. Newberry; The tin deposits of North Carolina. John H. Furman. April to June: Amber, its history, occurrence and use, J. S$. Newberry; Remarks on recent discoveries in local Cretaceous and Quaternary geology, N. L. Britton; The Pipe-creek meteorite, A. R. Ledoux. Jour. Cin. Soc. Nat. Hist., July, 1891, contains: On the age of the Pt. Pleasant, Ohio, beds, Jos. F. James. 264 The American Geologist. October, 1891 Appalachia, July, 1891, contains: A classification of mountain ranges according to their structure, origin and age, Warren Upham. Recent discoveries bearing on the antiquity of man. G. F. Wright. (Bibliothica Sacra, Apr., 1891.) Description of a skull of Megalonyx leidyi, nu. sp., Josua Lindahl. (Am Phil. Soc., Read Jan. 2, 1891.) _ ILL. Papers in Scientifie Journals. Kansas City Scientist, July, contains: Some new species of echino- dermata,R R. Rowley and Sid. J. Hare. August: Some new species of crinoids and blastoids, R. R. Rowley and Sid. J. Hare. Ottawa Naturalist, July, contains: Extinct Canadian vertebrates from the Miocene rocks of the Northwestern territories of Canada, H. M. Ami. American Naturalist, July, contains: A review of the “ Discovery of the Cretaceous Mammalia,” H. F. Osborn; Notes on Mesozoic mammalia, O. C. Marsh; The coming man, §. V. Clevenger; On the relations of Carettochelys, Ramsay G. Baur; on some new fishes from 8. Dakota, E. D. Cope. IV. EHexeerpts and individual publications. On paramelaconite and the associated minerals, Geo. A. Koenig. (Proc Acad. Nat. Sci. Phil. April, 1891.) Geological Guide-book of the western excursion of the Fifth Interna- tional Congress of Geologists, 8. F. Emmons, 8vo. pp. 156, Washington. On an important boring through 2,000 feet of Trias. in eastern Penn- sylvania, J. P. Lesley. (Am. Phil. Soc. May 23, 1891.) Manual of the paleontology of the Cincinnati group, Jos. F. James. (Jour. Cin. Soc. Nat. Hist. Apr., 1891.) The development of a paleozoic poriferous coral, and Symmetrical cell development in the Favositide, Charles E. Beecher. (Trans. Conn. Acad., Vol. VIIT, 1891.) The universalty of man’s appearance and primative man, Edward L. Anderson. 8vo. 28 pp. Edinburgh, 1891. Cincinnati, Robt. Clarke & Co. On the Grapeville gas-wells, J. P. Lesley. (Am. Phil. Soc. Apr. 27, 1891.) Notes on Central-American Archeology and Ethnology, J. Crawford. (Bos. Soc. Nat. Hist. Feb., 1891.) s V. Foreign Publications. Proc. and Trans, Nova Scotia Institute of Science, Vol. VII, Part 4, contains: Glacial Geology of Cape Breton, Honeyman; Geological Gleanings in Nova Scotia and Cape Breton, Honeyman; The Geological Writings of Rev. D. Honeyman, Gilpin; The Devonian of Cape Breton, Gilpin; Surface Geology of the Pictou Coal Field, Poole; A Contribu- tion to the Theory of Earthquakes, Maury. Bul- Soc. Sci. Nat. d. l’ouest de la France, Tome I, No. 1, contains: Etude du metamorphisme aux environs de Nozay, Loire-inférieure, Davy; Archéen et le Cambrien dans le Nord du Massif Breton et leurs Recent Publications. 265 équivalents dans le Pays de Galles, Bigot; Sur la présence du Car- bonifére en Bretagne, Lebesconte; Sur un gisement carbonifére de l’¢tage de Visé reconnu 4 Quenon, en Saint Aubin-de-Luigué, Bezier. Tome I, No. 2, contains: Etude petrographique des eclogites de la Loire-inférieure, La Croix; Archiv d. Ver. d. Freunde d. Naturgeschichte in Mecklenburg, t890, contains: XII. Beitrag zur Geologie Mecklenburgs, Geinitz; Ueber das angebliche Vorkommen Geschieben des Hérandsteins in den nord- deutschen Diluvialablangerungen, Nathorst; Das meteor von Kropelin, Geinitz; Fold. K6z. (Budapest). Vol. xx1. Nos. 4 and 5 contains: Awaruit, ein nickeleisen-mineral, Szabo; Beitriige zur Foraminiferen-fauna der Alttertiiiren Schichten von Kis-Gyor, Kocsis. Boletim da Commissao geographica e geologica do estado de 8. Paulo, No. 7, contains: Notas sobre zeolitas do augito-porphyrito de S. Paulo e Santa-Catharina, Hussak. Cursu elementaru de Geologia, de Gregoriu Stefanescu, pp. 256, 8vo, Bucharest, 1890. A manual of the Geology of India, Part IV, Mineralogy (mainly non- economic), F. R. Mallet. Calcutta, 1887, pp. 179. Roy Oct. Die landeskundliche Literatur iiber de Grossherzogtiimer, Bachmann, Giistrow, 1889, pp. 511. Report of the inspector of mines for North Wales and Isle of Wight, for 1890, C. Le Neve Foster. London, 1891. List of mines worked in 1890 in the British Islands. By the inspectors of mines. Ueber den Sagvandit. H. Rosenbusch, (Neues Jahr, 1884.) Die Urvierfiissler (Eotetrapoda) des Siichsischen Rothliegenden, Hermann Credner. (Natur. Wochens. Berlin), 1891. Zur Auffassung des Grundgebirges, H. Rosenbusch. (Neues Jahrb. Bd. 1. 1889. Heidelberg.) Ueber Monchiquit, ein camptonitisches Gangestein aus der Gefolg- schaft der Eliolithsyenite. Hunter and Rosenbusch (Tschermak’s Mitth. Min. und Pet. 1891.) Zur Auffassung der chemisches Natur des Grundgebirges, H. Rosen- busch. 1891. (Tschermak’s Mittheil. Wien.) An outline of Mr. Mellard Reade’s Theory of the Origin of Mountain Ranges by sedimentary loading and cumulative recurrent expansion; in answer to recent criticisms. T. Mellard Reade. (Phil. Mag. June, 1891). PERSONAL AND SCIENTIFIC NEWS. THE GEoLoGicAL Map or Europe. ‘‘I received an invitation from Berlin signed by Be; rich and Hauchecorne, to meet them at Saltzburg (Austria) as a member of the committee of the geologi- 266 The American Geologist. October, 1891 cal map of Europe, of which I have heard nothing for three years. Besides the two Prussians Mojsisovics came from Austria, and Renevier from Switzerland, and nobody else of the committee. No one came from England, nor from France, npr Russia, Only Capellini joined me as an Italian friend. Nothing new worth noting was said or done, except that the announcement was made that very likely the first sheet of the map, scale 1. 500,000, will be issued before the year is over.’’ GIORDANO, director of the geo- logical survey of Italy, Aug. 18. WaAsHINGTON UNIVERsSItTy, St. Louis, has just chosen a science- bred president, W. 8. Chaplin, late professor of Engineering at Harvard University. PRESERVATION OF THE GLACIAL GROOVES OF KELLY’s ISLAND. Through the active interest and intercession of Prof. G. F. Wright, Mr. M. C. Younglove, president of the Kelly’s Island Lime and Transport Company, has been empowered to deed to the Western Reserve Historical Society of Cleveland, a portion of the land on Kelly’s island, ‘‘fifty feet wide and one hundred feet long,” on which is preserved a part of the remarkable ice- grooving, which was visited by an excursion of the American Association for the Advancement of Science at the Cleveland meeting in 1888. These grooves are certainly the most remark- able ever discovered in this country, and they are to be preserved as an object lesson to future generations. Quarrying has already proceeded nearly all around this specimen, and soon the monument preserved will be a monument indeed; the groove being left to cap a pedestal about thirty feet high, and conspicuous from every side. About one-half the surface will be cleared of debris, so as to show fifty feet of the length of the groove, while the other half will remain as it is, beneath its protective covering of pebbles, gravel, sand, and mud, which acted as the graving tools in the firm grasp of the ice. Originally a large area of this glaciated surface was exposed to sight. But in the progress of work upon the extensive quarry, the larger part of it has been removed. What is left, however, is ample for an object lesson. The portion of the groove pre- served is thirty-three feet across, and the depth of the cut in the rock is seventeen feet below the line extending from rim to rim. Originally there was probably here a small depression formed by preglacial water erosion into which the ice crowded the material which became its graving tool, and so the rasping and polishing went on in increasing degree, until this enormous furrow is the result. The groove, however, is by no means simple, but pre- sents a series of corrugations merging into each other by beauti- ful curves. When exposed for a considerable length it will re- semble nothing else so much as acollection of prostrate Corinthian columns, lying side by side on a concave surface, THE AMERICAN GEOLOGIST Wor; VUE. NOVEMBER, 1891. No. 5. THE ATTITUDE OF THE EASTERN AND CENTRAL PORTIONS OF THE UNITED STATES DURING THE GLACIAL PERIOD.* By T. C. CHAMBERLIN, Madison, Wis. Aside from the inherent interest which lies in the determination of any general fact in geology, a special interest attaches to the determination of the attitude of the glaciated area during the ice invasions because of its bearing upon their explanation. I pro- pose to discuss hypotheses of the cause of the glacial period in a separate paper; my present effort will be merely to set forth, somewhat synoptically, the leading phenomena, and the conclus- ions I draw, relative to the attitude of the eastern and central portions of the United States during that period. The special data appealed to have been gathered chiefly by the members of the glacial division of the United States Geological Survey, largely by Messrs. Salisbury, Leverett and myself. I. Glacio-fluvial deposits of the lower Mississippi valley. The material of the lower Mississippi valley derived from glacial waters is divided into two sharply distinct classes; first and old- est, that which caps the bluffs of the Mississippi and mantles all the upland for 50 miles or more back on the east and which occupies the summit of Crowley’s ridge that rises from the midst of the Mississippi bottoms in Arkansas. The second division occupies the trench in which the present bottoms lie and rises but _*Read before Section E, Am. Association for the Advancement of Science at the Washington meeting, August, 1891. 268 The American Geologist. November, 1891 little above these bottoms, if at all, and is distinguishable from the modern fluvial deposits with difficulty. The deposits of the first or earlier class are wholly silts, so far as determined by us. Our special investigations have been chiefly confined to the 150 miles next below the drift border, but they have reached, in a less consecutive way, to Mississippi and Louisiana, After careful and protracted search, renewed on successive sea- sons, we have entirely failed to find any coarse drift connected with glacio-fluvial formations that lie above the bottom lands, al- though the area is great and the exposure by gullying phenomenal. The ++ orange sands and gravels” which underlie the glacio-fluvial silts are non-glacial in character and seem to us to be demon- strably pre-glacial. At any rate, the absence of glacial pebbles, and even glacial sand and silt, from them removes them from any need of special consideration in this connection, even if they be supposed to be contemporaneous with the earlier glacial stages, for the absence of the glacial material may be taken as showing the incompetency of the upper Mississippi to bear such material southward at that time. Silts being then the only demonstrable representatives of the glacial products borne south during the ealier stages of glacia- tion, it is a necessary inference that the land from the border of the drift to the gulf was so flat and so low that only slow-moving, silt-bearing currents were formed. The present current of the Mississippi is competent to carry coarse sand and small pebbles. The currents of the earlier glacial period were therefore less com- petent and the country was flatter than now. Concerning the glacio-fluvial deposits that lie beneath the pres- ent river bottoms, or lie so low as to be indistinguishable from the fluvial deposits of the present river, little of a positive nature can be asserted. So far as known from borings and other evi- dences, they are not notably coarse. To the northward, in the glaciated region, they rise above the present river bottoms and have been traced back to their origin, so that we know the ap- proximate attitude of the surface at the time that they were formed. They may therefore be set aside here and discussed later. IT, Phenomena of the Drift Border. The nature of the drift border in the axis of the Mississippi basin, where it reaches fartherest south, is in itself significant of the attitude of the sur- During the Glacial Period.— Chamberlin. 269 face at the time of its formation, if I interpret the phenomena correctly. The drift does not terminate in any well-defined morainic ridge, such as the ancient glaciers formed at several later stages. On the contrary, the termination is found ina gradual thinning out of the drift unattended by marks of forci- ble action on the part of the ice. The inference is therefore drawn that the ice crept out slowly upon a low slope, the gentle- ness of which accounts for the lack of vigorous action or forcible heaping of material. This inference, which by itself might have but slight value, is supported by the fact that the sheets of till in this border region to a large extent graduate upwards into pebbleless clays and thence into loess-loams, or true loess, making it appear certain that slack drainage was a prevailing phenomenon. This is further supported by the absence, in general, of coarse wash from the edge of these outermost drift sheets. At some points near the edge, but more commonly at points remote from it, there are beds of gravel, often taking a lenticular form, but these may be attributed to waters acting in channels in the ice or beneath it, where by confinement and by the peculiar conditions of glacial drainage they were forced to a vigorous action which they lacked when once they had issued from the border of the ice. As a summary statement, it may be asserted that the phenomena of the border drift in the Mississippi valley present everywhere evidences of slack or slow drainage, with only such exceptions as may be rationally referred to enforced vigor through the immediate agency of the ice; and that there is nowhere evidence of powerful or specially rapid currents of water such as must inevitably have issued from the glacial border, in the axis of the great Mississippi basin, had the slope of the surface been at all considerable. — It is therefore a firm and safe inference that at the time of the form- ation of the drift sheets that reach farthest southward there was no considerable slope of the surface; not even so much as now exists. HII, The Smooth Contours and Silt Aprons of the Older Moraines. Inthe axis of the Mississippi basin on account of the planeness of the surface and the great extent to which the ice stretched forward, the successive glacial stages are better deployed than in most regions east or west where later invasions overrode the territory of earlier ones and obscured the phenomena. The 270 The American Geologist. November, 1891 region is therefore peculiarly fitted to the inquiry in hand. — If we follow northward along the axis of the central ice-lobe in Lllinois, we encounter, within about one hundred miles of the drift border, a broad ridge of drift, identifiable as a marginal moraine; and farther to the northward, similar ridges representing later stages of glaciation. The first eight of these bear common characteristics, all significant of the attitude of the surface at the times they were formed. They are all broad swells of gentle slope and smooth, though undulating, contours with the exception of a few local departures. They are not pushed into rough indented ridges, as is the fashion with terminal moraines forced up by vigorous glacial action. They appear rather to be the submar- ginal accumulations of a sheet of ice creeping gently down upon au plain of slight inclination. This interpretation, which in itself might be questioned, is supported by the significant fact that on the outer side of these moraines there are fringing belts of silt produced by the waters that crept over them while pressed on the inner side by the ice. These bordering silt-sheets terminate in and on the moraines and reach out to varying distances upon the plain to the southward. It would appear, therefore, that we have in these phenomena evidences that cannot be gainsaid, that during the several suc- cessive stages that these moraines represent the attitude of the country was low, and that the drainage was more slack than at the present time. Le the Rugged Ridges and) Gravel Aprons of the Later Mora‘nes. The preceding phenomena represent the earlier and much the longer portion of the glacial period. But when, in coming northward along the Illinois river, we reach the moraine which crosses at Marseilles, and when, in ascending the Wabash river, we reach the moraine which crosses at Attica, we find a notable change in the phenomena. The moraine is not only more rough in contour and rugged in constitution but is accompanied by much more abundant evidences of washand assortment in the form of gravel hills and gravel tracts. On the outside of the moraine, instead of aprons of silt indicating quiet overwash, there are aprons of gravel indicating more vigorous overwash. These fring- ing gravel tracts gather themselves somewhat promptly into the leading river valleys and flow down these in the trenches now oc- cupied by these streams, which are cut into the older sheets of During the Glacial Period.— Chamberlin. OT Y drift. It is worthy of note that these trenches are cut through the older moraines and their overwash aprons of silt and are sunk down into them or below them. The later gravel-bearing floods ran at lower levels than the earlier silt-bearing waters; a clear demonstration of a change of attitude. It is clear from a study of these phenomena that at the time this moraine was formed the action of the ice was more forcible and the drainage more vigorous. The glacial waters ran away from the whole margin of the ice with measureable precipitancy, bearing coarse material. They gathered into definite channels previously cut in the older drift and ran along these at a rate which enabled them to carry gravel and sand far down their courses. Here we have for the first time in the history of glaciation, so far as now worked out on this the most favorable line on the continent for such study, an indication of an altitude and slope of the surface sufficient to pro- duce vigorous drainage. The question now becomes pertinent, how vigorous? How great a slope was indicated ? On the Illinois river, overwash was sufficiently strong to spread out, on the outer side of the moraine, plains of graveland sandof moderate degree of coarseness. Immediately next the moraine cobble stones of three inches in diameter are not uncommon. But only a few miles away from the moraine, even in the main axis of the gravel stream, the material becomes predominantly sand, the gravel becoming fine and subordinate. Near Chillicothe, for reasons not well under- stood, the material is again coarse but beyond becomes chiefly sand. On the Wabash similar facts present themselves. Within two or three miles of the moraine the deposit is chiefly fine gravel and sand and maintains this constitution far down the stream. If I have correlated the moraines correctly, phenomena of the same kind and occuring at the same date are found on the Rock river, starting about twenty miles northof the Wisconsin line near Janesville; on the Wisconsin river in Sauk county, Wis., below its great’ bend; on the Chippewa river a few miles above Chippewa Falls; on the St. Croix river a few miles above its mouth; on the Mississippi river a short distance below St. Paul; and on the Des Moines river, at the city of Des Moines. Similiar phenomena also occur on all of the important tributaries of the Ohio and the Alle- gheny from eastern Indiana to northwestern Pennsylvania. In all 272 The American Geologist. November, 1891 of these the facts are essentially the same; the wash was vigorous near the ice-edge and became less strong southward. The slope of the glacial flood plain has been determined ap- proximately in the most of these instances, and it is found that the descent was considerably more rapid than that of the present streams near the edge of the ice, but beyond that the descent was only slightly greater than that of the present streams. For instance, the terraces which represent the glacial flood plain on the upper Mississippi stand, at the mouth of Chippewa river, about 100 feet above the present stream. At the latitude of the southern line of Wisconsin, 150 miles south, the terrace is scarcely 50 feet high, indicating a slope of four inches to the mile more than the present. Between St. Louis and the southern extremity of Illinois the discrimination of the glacial flood plain from that of the present stream requires attention. as it only rises about 25 feet higher and is scarcely above the extreme reach of modern floods. Below the mouth of the Ohio it is not certain whether the glacial flood products under con- sideration have been successfully distinguished from deposits formed by the modern river. Declines of a similar nature are found on the Wisconsin, the Rock, the Illinois, the Wabash, the tributaries of the Allegheny and the Allegheny itself. On the Little and Great Miamis Mr. Leverett has found that the glacial flood plains descend less rapidly than the present streams. But before conclusions respecting the slope of the general sur- face are drawn, it is to be noted that all these glacial streams were depositing and not eroding, and that their currents were not sufficient to enable them to carry away the burden of material furnished to them, so that they built up their bottoms until sufficient slope was gained. The deposits of gravel on these streams near the ice-margin, reach in several instances, beyond 100 feet in depth. The increased slope of the flood plain near the moraine is obviously due to the greater load of material and not to any upward curvature of the general surface. These being the essential facts, judgment will perhaps differ as to the precise amount of slope which the general surface pre- sented at the glacial stage in question, but I think no one, who duly considers the phenomena, will maintain that the slope was very much greater than the present. The existing streams are eroding their bottoms, even with their lower gradient, and the During the Glacial Period.— Chamberlin. 273 glacial streams must have been very greatly overloaded with detritus to have been depositing streams, to the extent I have indicated, if their slopes were notably greater than the pres- ent, especially in view of the greater volume of water which the streams then undoubtedly bore. V. Phenomena of the Latest Moraines. Within the outer mo- raine which bears this overwash apron of gravel are other and later moraines which present like phenomena, but in no case are they more striking, except locally and narrowly, and in most cases the overwash and drainage phenomena are more feeble. The moraine next succeeding is almost equally coarse and rugged in its develop- ment and is accompanied by almost equally coarse and abundant drainage drift, indicating the existence of about the same topo- graphic conditions; but the later moraines generally display feebler drainage phenomena indicating a return to the flatter con- dition of the earlier glacial epoch. VI. Lacustrine and Marine Phenomena, Contemporaneous with some of these later moraines and extending thence down to the close of the glacial period there was a succession of glacial lakes occupying the north-sloping basins. The presence of these lakes, the attitude of their shore lines and the position and char- acter of their discharges indicate that low elevation prevailed during the closing stages of the glacial period. The same fact is proved more conclusively by the marine deposits on the Atlantic coast which were contemporaneous with the presence of the ice. The facts under this head are too familiar to require more than a passing reference here. In the sketch thus far, I have followed the phenomena of the Mississippi basin because the drift is there deployed so advan- tageously and because its indications seem so conclusive, but the phenomena on the Susquehanna and Delaware rivers, as brought out by the studies of Lewis, MeGee, Salisbury and others, as well aS our own, testify to a like general fact, though in far less detail. The ealier glacial deposits there, as in the Mississippi valley, appear to have been accompanied by less vigorous drain- age and to have been coincident with the submergence of the coast region. The later deposits were accompanied by somewhat more vigorous drainage than the present, precisely as in the Mississippi valley, but the glacial streams were there also deposit- ing streams, and the phenomena do not seem to me to indicate 274 The American Geologist. November, 1591 much greater slope of the general surface than the present, pos- sibly no greater. In the discussion thus far the aft/tude of the surface has been considered and a harmonious altitude has been assumed as a necessary factor. Abstractly it might be held that the whole region was lifted bodily without disturbing its flat surface atti- tude, but the drainage at the edge of such a plateau, formed of erodable material, like that of the lower Mississippi region would speedily revolutionize the whole drainage phenomena and the topographic aspect of the valley. It is utterly incredible that the silts that cover the west half of the state of Mississippi were deposited at even their present hight by a stream fifty, if nota hundred, miles wide. Nosuch stream could exist on the brink of such a plateau of soft material, or, if once formed, could main- tain itself for an appreciable fraction of the silt-depositing period, It is equally incredible that the broad trenches of the Mississippi and its tributaries could have been formed under plateau con- conditions. The whole phenomena show that low altitudes went with flat attitudes. - VII. General Conclusions. From this survey, which has necessarily been hasty and synoptical, since the details are multi- tudinous to the last degree, I draw the following inferences : First. That throughout all the earlier stages of glaciation thus far determined in the Mississippi basin, the attitude of the land was lower and flatter than at present and the drainage slacker. Second. That during the earliest stages of what I have been ac- customed to interpret as the later glacial epoch, the attitude of this region was not far different from the present; possibly somewhat more elevated, and sloping somewhat more rapidly to the south, but the gradient could not have been very considerably greater than the present. Third. That during the inter-glacial epoch the attitude of the country was such as to permit erosive drainage to the depth of one hundred or more feet below the present flood plains of the leading streams, but that the elevation of this period was not ex- cessively great is inferred from the fact that the trenches so cut were broad as well as deep. Fourth. That during the closing stages of the later glacial epoch the attitude of the country was again flat, being toward its close, more depressed than at present. Origin of Mountain Ranges.—Reade. 275 I invite attention to the fact that the area covered by these phenomena is broad both in longitude and latitude, and that it covers the larger part of the territory that has been critically studied with reference to such determinations. This territory ‘is sufficient to constitute a large factor in any conclusions that can rationally be drawn respecting the attitude and altitude of the general area of glaciation of northeastern North America during the Ice age, and this area is the great area of glaciation and must form the central ground upon which the ultimate question of the cause of the glacial period, and the relationship of the altitude of the land to that cause, must be settled. AN OUTLINE OF MR. MELLARD READE’S THEORY OF THE ORIGIN OF MOUNTAIN-RANGES BY SEDIMENTARY LOADING AND CUMULA- TIVE RECURRENT EXPANSION. IN ANSWER TO RECENT CRITICISMS. By T. Metiarp READE. From the Philosophical Magazine for June, 1891. INTRODUCTION. It is now four years since the ‘‘Origin of Mountain-Ranges”’ was written, and during that time it has been subjected to consid- erable criticism by many able men in various parts of the globe. -I have purposely refrained hitherto from answering any of the objectors to my theory, feeling that it would be better to wait and weigh them. It appears to me now that most of the criti- cisms primarily spring from an imperfect realization of its prin- ciples, scope, and details. The misconceptions no doubt largely arise from the complex nature of the problems and the difficulty of keeping the various threads of the argument unravelled. Under these circumstances, I have thought that the best reply I can make is to restate in a shorter manner the various salient points of my theory. Prob- ably, if I had given the theory a name, and properly christened my bantling before sending it forth in the world to seek its for- tunes, | might have been saved from paternal difficulties. To prevent further misconceptions, | now name my theory the ‘Origin of Mountain-Ranges by Sedimentary Loading and Cumu- lative Recurrent Kxpansion. ” 276 The 4 Linertean Geologist. November, 1891 The outline here given is of the barest character, and for illus- trations, details, proofs, and quantitative calculations I refer those who want to know more to the work itself, as also for those portions which deal with other theories, and are of a destructive rather than constructive nature, ; CONDITION OF THE KARTH'S LNTERIOR. The Earth a Solid Spheroid. The latest mathematical investigations go to prove that the earth, taken as a whole, is solid, having a rigidity between that of glass and steel. The facts of physical geology are in accord with this view; for if the interior be wholly fluid, as some few contend, or if the nucleus be solid and the exterior shell solid with a zone of molten matter between, as others assume, the explanations of the physical conformation of the surface, its mountains and ocean-basins, become questions of flotation only. The crust of the earth would be like a sheet of ice. This fact seems to me never to have been fully realized by those theorists who favor either of these views. The Nucleus of the Barth possesses a high Temperature. There is such a general consensus of opinion that the earth at a depth of from 25 to 30 miles below the surface is at a tempera- ture equal to that of molten rock at the surface that it is unnec- essary for me to go over the arguments in favor of this widely prevalent view. If we assume that it is so, a very little caleula- tion will show that matter at the depth of say 30 miles is subject to an enormous pressure, to which we can find no parallel by ex- perimental methods at the surface. Thirty miles= 158,400 feet; so that if we estimate that a column of the crust of the earth one inch square has a mean weight per foot of 1.5 pounds, the pres- sure at the depth of 30 miles will be in round numbers not less than 100 tons per square inch, or 14,400 tons per square foot. It has been proved by the experiments of the late Mr. Hopkins that there is in certain solids a relation between the melting- point and the pressure; so that, if the rock at the depth of 30 , miles is at a temperature sufficient to melt it under ordinary pres- sures at the surface, the additional pressure of 100 tons per square inch may solidify it by raising its melting-point, or at least render it plastic. If the pressure increase more rapidly Origin of Mountain Ranges.— Reade. 277 than the temperature as the earth is penetrated, what may be only semi-solid at 30 miles may become rigid at greater depths. These points, from their nature, are incapable of direct demon- stration, but possess a high degree of probability. Shell of Greatest Mobility. Although not accepting the hypothesis that there is a fluid zone under the earth’s crust, it would follow from the preceding con- siderations that the shell occupying the space between the solid rigid crust and the compressed rigid nucleus would respond to changes of pressure or temperature more readily than either the crust or the nucleus. Facts oF PuysicaAL GEOLOGY. All great Mountain-Ranges are composed of great thicknesses of Sedimentary and other Deposits. That all great mountain-ranges are composed of great thick- nesses of sedimentary and volcanic deposits and igneous intru- sions is a fact admitting of demonstration. It is true of the Alps, the Andes, the Himalayas*, the Rocky mountains or North- American cordillera, the Appalachians, the mountains of the Caucasus, and the Urals. The question at once arises in the mind, ‘‘Is this cause and effect?” If not, it is a coincidence somewhat in the nature of a miracle. If any one example to the contrary could be quoted, the argument of relation would be weakened, certainly not disposed of, but, so far as_ present knowledge extends, not one can be found. *Mr. C. 8S. Middlemiss, in his extended criticisms on the “Origin of Mountain-Ranges” (Memoirs of the Geological Survey of India, vol. Xxiv, part 2; Physical Geology of the Sub-Himalaya of Garhwal and Kumaun), calls in question this principle, though it is admitted by nearly all geologists since Dr. James Hall established the fact as regards the Appalachians in 1857, Quoting my words in the “Origin,” “It is impos- sible to point to a range of mountains which has been built up of old denuded rocks,” he completely misinterprets my meaning, which I had thought was plain enough from the whole tenor of the work. ‘To give an illustration in the form of a prediction, I aver that no mountain- range will ever be built up out of any portion of the present land-area of Europe unless, and until, a basin of deposition has been established, and a thick sedimentary series deposited thereon. The old rocks may then be forced up along with the new, and form a constituent part of such arange. Unfortunately, as regards the Himalaya, information is meagre; but the granitic axes pointed to by Mr. Middlemiss as forming the highest peaks of the Himalaya are just what are required by my theory. 278 The American Geologist. November, 1891 Sedimentary Deposits out of which Mountain-Ranges have been built up extend over Vast Areas. The deposits out of which great mountain-ranges have been elaborated by foldings, intrusions, and up-heavals are not con- fined to the ranges and their immediate neighborhood, but extend over vast areas. Speaking generally, modern geological investi- gation goes to prove that the thickest deposits lie, or have lain, towards the axes of the chains, though they may have been de- nuded from the actual axes*. Beyond the more folded and dis- turbed portions of the cham which often, so far as the newer sediments are concerned, lie on the flanks, the strata take on more gentle curvatures until, as in the case of the Urals, the Ap- palachians, and elsewhere where observable, they become nearly horizontal, or only have dips due principally to faulting. The Tertiary and Cretaceous rocks extend from the Alps to the Caucasus and across the Mediterranean to the African coast, and may lie far beyond, as little is known of the geology of that part of the continent. They reappear in the Himalayas, and may be *Mr. Arthur Winslow, State Geologist of Missouri, in a paper just published in the “Bulletin” of the Geological Society of America, en- titled “The Geotectonic and Physiographic Geology of Western Arkan- sas” (vol. ii. pp. 225-242), has applied the principles enunciated in the “Origin of Mountain-Ranges” to the explanation of an area in the Western part of the state tributary to the Arkansas river, 100 miles long in an east and west direction by fifty miles broad in a north and south direction. It is shown in an admirably concise and clear manner that thesystem of parallel interlocking anticlines and synclines having a general axial direction east and west is essentially Appalachian in char- acter; that the Carboniferous strata of which they are composed in- crease in thickness from Missouri southwards into Arkansas; that the lateral movement has come from the South, and that the thickest strata are the most flexed. Mr. Winslow shows—a point that I have strongly insisted upon as characteristic of anticlines—that these geological features are elongated canoe-shaped domes having quaquaversal dips. He considers that the expansion of the lower layers of rock produced by the rising of the isogeotherms and their consequent protrusion in the form of anticlinal cores has fractured the apices of the arches, and thus exposed the upper layers to energetic denudation. He infers also that the developed sections of such foldings are no measure of the original horizontal length of the beds—a principle I have strongly upheld, and which is being conceded by most geologists who have studied mountain- structure. The district seems to be one in which the first principles of the dynamics of mountain-building can be well analyzed, as there is not such a complexity of causes to be considered and discounted as in the more colossal disturbances of the great mountain-ranges of the world. A few careful studies of mountain physiography such as this by geolo- gists who have the opportunity and are equipped with the necessary physical knowledge would be of infinite service. Origin of Mountain Ranges.—Reade. 279 continuously connected, though this has not yet been proved. The same formations extend far to the eastward of the Rocky mountains and the Andes, and most probably to the westward under the Pacific ocean. The greatest ranges of the world have been elaborated in Cre- taceous or Tertiary times, and the connection between sedimenta- tion and upheaval is here most striking. Sediments out of which Mountain- Ranges have been elaborated were laid down in Basins or Troughs formed by the bending of the earth's crust. The thickness of the rocks, mostly conformable, composing some great mountain-ranges has been estimated by competent geologists at from eight to ten miles. The bulk of the rocks, as judged by their constitution, are usually considered by geologists to largely indicate either a moderate depth of water or actual shallow conditions. These rocks are intercalated with others ex- hibiting signs of a more oceanic origin. All the mountain- ranges mentioned may be pointed to in illustration of this state- ment. There is thus evidence that regional fluctuations of level in the earth's crust have taken place on a large scale often suc- ceeded by, as in the case of the Coal-measures, continued down- ward subsidence combined with shallow-water conditions. It is evident, from these facts, that the great earth-troughs, in which these materials for mountain-building were accumulated, were in some cases, on the final completion of sedimentation, double the depth of the deepest known oceanic troughs, which do not reach more than five miles. Considering that there is a strong development of Cretaceous and Tertiary rocks extending along the western coast of North and South America, it is seen that these operations have there been carried on on an unusual scale. Deposit and alteration of level, elevation and subsidence, but preponderantly subsidence. progressed for an immense length of geological time in these areas, occupying not a mean portion of the earth’s history. It is not, however, to be assumed that this was a continuous trough at any one time, rather that it consisted of a series of con- nected basins which underwent independent changes of level, the area being part of the time low-lying land interchanging with con- ditions of submergence. 250 The American Geologist. November, 1891 Voleanie action often contemporaneous with the laying-down of materials for Mountain-building. Contemporaneous intrusive sheets of volcanic rock are a com- mon occurrence in some part of the sedimentary history of a mountain-range. In addition, it is frequently found that vol- eanie ashes laid down in water, or subaerially, have a large de- velopment in rocks composing mountain-ranges; and necessarily, if these occur, dykes and volcanic rocks of the same age must exist in the foundation materials of the range. DYNAMICAL PRINCIPLES. Every theory which has hitherto been proposed to account for the elevation of mountains and the folding of the stratified beds forming the earth's crust hinges finally on changes of tempera- ture. Thus the tangential force generated in a rigid crust of low temperature by the cooling and shrinking of the earth's nucleus has been invoked to account for the crumpling of the crust into mountain-ranges; the crumpled skin of a dried apple being the stock illustration. In this case, the force called in is continuous contraction by loss of heat. The theory which I have elaborated is one dependent upon a/ternations of temperature in the crust, - contraction and expansion both being agents of uplift and lateral pressure. Basins of Deposition and Loading of the earth's crust. It has already been shown that the establishment of basins of deposition is the condition precedent to the building of a moun- tain-range. There can be no deposition if there is not land-area enough either in the shape of continents, islands, or active vol- canic orifices, or all combined or successive, to yield the neces- sary sediment. This furthermore implies considerable stability of conditions over lengthened periods of time combined with local mutations and changes of level, and, as I have.indicated, we have the history of these mutations within the rocks of a range. The distribution of sediments is dependent upon the depth of the water surrounding the land and the currents of the sea (when they are not laid down in lakes or subaerially by rivers); but, whatever the conformation of the coast and sea-bottom, a con- tinuous discharge of sediment upon it must in time load it, and, as proved by the enormous thickness of rocks composing great Origin of Mountain Ranges.—Reade. 281 mountain-ranges, bend the crust below the maximum depth of any oceanic depression. This necessary subsidence again insures the establishment of the basin of deposition and its continuous existence. Displacement of matter in the Shell of Greatest Mobility. If the matter in a shell of the earth between the nucleus and crust is in the condition [I have postulated, it is evident that a lateral displacement of the matter of the shell must take place to some extent through weighting by sediment, and this will have its effect in raising the levels of the earth’s crust surrounding the basin of deposition; but will not be an agent in mountain- building. Movement of the Isogeotherms. It is evident, from the variations in the rate of increase of temperature that exist in various localities as the crust is pene- trated, that the lines of equal temperature (isogeotherms) in the earth's crust are subject to change, for it is not to be supposed that the temperature gradients have remained in their existing re- lations for all time. It is also evident, as first shown by Babbage and Herschel, that the covering of any particular area of the earth with sediment will necessarily raise the temperature of the crust below*. — If, therefore, we assume a thickness of 10 miles of sediment to be laid down in a basin of deposition or earth-trough, and the rate of increase of temperature to be one in fifty, what were originally surface-rocks possessing a surface-temperature determined by the climate of the locality will be raised in temperature over 1,000° Fahr., and eventually the whole of the underlying rocks of the earth’s crust even below the shell of greatest change will be pro- portionately affected. The 10 miles of overlying sediments under such conditions would be raised 1,000° Fahr., at the base, dimin- ishing to zero at the surface. Le iffects of the rise of temperature on the Foundation Rocks. Ini- tial Stage. The section of the crust of the earth weighted ‘and heated at the same time will be subjected to a gradually increasing com- pressive stress. So long as the actual expansive force of the heated crust is insufficient to raise the weight of sediment being *This is well explained both by Babbage and Herschel in the 9th Bridgewater Treatise. 282 The American Geologist. November, 1891 piled upon it, it will continue to sink, though subject to vertical pulsations of level due to other causes, which it is not my object to treat_of here. But there will eventually come a time when the accumulated stresses of the expanding rocks will overcome the weight of sediment, and then the upheaval, folding, and building of the mountain-chain will begin. But it is not to be supposed that the rise of temperature takes place with the mathematical precision described here for mere purposes of explanation*. I have shown that voleanic action often contributes to the founda- tion materials of a mountain-range, and that intrusive sheets and dykes penetrate the sediments, and ash beds are laid down before the initial movement ushering in the birth of the range takes place. It is evident from this that there will be great variations of temperature taking place in the foundation crust and the sedi- ments during their laying down. The whole series of rocks, volcanic and sedimentary, will form a complex which will besimultaneously, but differentially, affected by the folding and elevation when that begins. Unlocking the igneous forces of the earth. When once the elevation initiated only by piling-up of sedi- ment, the sinking of the crust, and its consequent heating— otherwise by the rise of the isogeotherms—is established, a move- ment of the interior heated matter of the earth must take place towards the axis or axes of the range. This is proved by the frequency of granitic cores in great mountain-ranges, by the vol- ‘anic action accompanying their elevation, and its persistence or recurrence in a range even late on in its history, as instanced by *This seems a fruitful source of difficulty with some minds, beginning with Hopkins and ending with Hutton, Fisher, and Middlemiss. Their position seems to be this: if the rise of the isogeotherms into the new deposits eventually wrinkles and lifts them, why does it not begin at once? Why, for instance, should not 100 feet in thickness cause a rise, and if it does, how can thick beds ever be deposited? But there are thick beds, so the alleged primum mobile never acts. Q.E.D. After making, as I fondiy thought, full explanation of the modus operandi, | never anticipated the establishment of what a sense of humour compels me to call another pons vsinorum. Even supposing the isogeotherms rose as rapidly as the deposits were laid down, the deposits could not be lifted until sufficient force accumulated to overcome the gravitation. Butin a sinking area,as I have pointed out, if there be anything in the principle invoked, the presumption is that the isogeo- therms are in process of sinking also, and it may take a lengthened period of sedimentation before they begin as a series to move upwards. There are many other possible conditioning causes. A practical mechanical mind should soon see through this imaginary difficulty. Origin of Mountain Ranges.—Reade. 283 the Andes, Rockies, and the mountains of the Caucasus, where voleanic cones surmount some of the highest granitic peaks, show- ing that these are the lines of least resistance through which the interier forces of the earth expend themselves. Heating of the rocks of the Mountain-Range recurrent and con- stantly renewed during its history. It is thus seen that the heated interior matter of the earth is constantly being drawn towards and injected into the constituent framework of a mountain-range. When once the elevation of the sediments consolidated into rocky matter in the earth-trough begins through the influence of lateral pressure and the expand- ing mass beneath, a reduction of pressure and increase of volume takes place in the underlying fused rock. The compressive stresses of the rigid rock are partially relieved by folding and upward flow, and the temperature of the mass falls. Additional fused matter has been drawn from the interior, and in process of time the rocks of the range begin again to rise in temperature. Such fluctuations of temperature are well shown in the intermit- tent character of volcanic action. After a great outflow of lava, a voleano is quiescent, sometimes for centuries. It has lost so much matter and so much heat, but the forces accumulate during the time of quiescence to burst forth with renewed vigor. Such intermittent activity I conceive is what takes place on a larger scale in the history of a mountain-range, but with greater time-intervals. Dynamical Hifect on the strata of the crust by Rise of Temperature. The effect of a rise of temperature on the rocks of the earth is, excepting in the case of unconsolidated clays, to increase their bulk. From a great number of experiments made by me on sandstone, slate, limestone, and marble, I have estimated the co- efficient of expansion of average rock at 2.75 feet lineal per mile for every rise of 100° Fahr.; but there is every reason to believe that the coefficient of expansion rises at higher temperatures than those at which my experiments were conducted. It has been urged by some of my critics that | have not allowed for the com- pression of the sediments filling the earth-trough into denser masses, but have credited all the expansion to mountain-building*. *Hutton, Presidental Address, Section C, Melbourne Meeting of the Australasian Association for the Advancement of Science, p. 89. 284 The American Geologzst. November, 1891 It has been overlooked that I have already explained that the weight of the mass alone will, by compressive extension, consoli- date the beds below by reducing their thickness. Also the denser sedimentary rocks are often denser only by infiltration. This is particularly the case with sandstones, where the conversion into the final stage of quartzite is by the deposit of secondary silica in the interspaces of the grains, not by condensation, Clays contract on heating; but, according to my views, the contraction of such beds in an earth-trough will be vertical only, by reason of the superimposed weight. A stage of metamor- phism is at least arrived at, as we see in clay-slate, when the ma- terials of that rock, originally clay, become metamorphosed so as to behave like other rocks, and expand with a rise of temperature. Even if these criticisms possess much force, they do not apply to the rocky crust of the earth already consolidated forming the ‘arth-trough in which the sediments are laid down. ‘There will Ye little or no loss by condensation in them, only straining or change of form, It is obvious that deep-seated rocks must be so compressed by simple gravitation, that lateral pressure will have little effect in further condensing them. Recurrent expansion cumulative in its effects. If a given area of the crust of the earth is raised in tempera- ture, when the limit of elasticity is reached the surplus material must be disposed of by a change of form; it will rise in the line of least resistance. Assume that the surplus due to the cubical expansion of a horizontal sheet is thrown into a ridge, and that then a fall of temperature takes place to the same extent. The material ridged up can never besdrawn back again; it becomes a permanent feat- ure of the earth’s surface. The contraction must be satisfied in another way, either by breaking up into blocks, faulting and sub- sidence extending through its substance, or by vertical contrac- tion alone, and the lengthening of the beds by compressive exten- sion due to the weight of superimposed materials. | Probably both these principles generally come into operation together in nature. The earth is bound to retain its solidity in whatever way that may be satisfied. If a rise of temperature then succeeds, the effect will be as before, and deformation will result, its locality being determined by the line of least resistance. In the case of a mountain-range it will take place along or Origin of Mountain Ranges.—Reade. 285 parallel to its axis, and the range will receive another accession of bulk. Thus we see that the effect of alternation of temperature in the earth’s crust leading to the establishment of mountain- chains is cumulative. This cumulative effect of small alterna- tions of temperature may be seen in the ridging-up of any old lead gutter, lead flat, or lead-lined bath or sink. It has been likened to a ‘‘rachet” movement, which is not an inapt illustra- tion if taken with the necessary qualifications, EFFECTS OF CONTRACTION. —NORMAL FAULTING, Normal faults, that is faults that hade to the downthrow, are the result of contraction, and are posterior to the first plica- tion. Any section of a mountain-range traversed by normal faults shows the folds sheared in a way that proves this. Nor- mal faulting is, however, most prevalent in the less disturbed strata that flank a range. The mountain-range pushed up by successive lateral thrusts or recurrent expansions acting over a great length of time and the folds thrown back and further com- pressed by the cores of gneiss and granite intruded into them, becomes a solid mass which cannot be drawn back by contraction, Contraction therefore has its maximum effect on the more hori- zontal deposits that flank the range, and extend for considerable distances on either side. As the crust of the earth must remain solid, the condition is satisfied by shearing and -wedging-up by gravitation,—otherwise by normal faulting. Contraction of igneous masses beneath may induce this faulting in some cases, but it is not a necessary condi- tion. Cubical contraction of the solid crust is suflicient. Answers to some objections. The object of this outline of my theory is to focus its salient points, as many of my critics for some reason or other have failed to grasp them. What they critcise is frequently not my theory, but some rather vague notion called the ‘:Herschel-Babbage”™ theory. What is exactly covered by this description I have a difficulty in ascertaining. On the other hand, one writer calls Mr. O. Fisher's theory, with which mine has no analogy, the “Herschel-Babbage’ theory. I trust I shall give no offence by repudiating this labelling and claiming the theory as my own. Neither Herschel, Scrope, nor Babbage ever advanced so far as PSO The American Geologist. November, 1891 to elaborate what could be justly called a theory of Mountain- building. They gave to the world some fruitful suggestions, and acute reasoning thereon, which have been of considerable use to a succession of speculators in geological physics, and to myself among the rest*. One of the most frequently urged objections to my theory is the supposed inadequacy of expansion by rise of temperature to account for the excessive folding some mountain- chains have undergone, linear expansion only being considered, My reply to this is that even linear expansion alone places at our disposal more lateral movement than any other theory. It is true that those speculators who have invoked tangential thrust through the assumed shrinking of the earth's nucleus, have had at their command any amount of lateral movement their imagina- tion liked to draw upon, hence the simplicity and success of the theory—for a time. It has, however, been shown pretty clearly that the bank upon which these cheques have been drawn is one of very limited liabilityt, and quite unequal to honoring them. Prof. Hutton, in his very able address to Section C of the Mel- bourne meeting of the Australasian Association for the Advance- ment of Science, gives an excellent résumé of the various hypotheses that have been suggested to account for mountain- building. I confidently appeal to his description to show that, omitting the theory of secular contraction of the earth’s nucleus, which he disposes of very effectually, none of the suggestions, theories, or hypotheses except the one [ support provides any lateral movement other than that due to intrusions of molten rock, Prof. Hutton, in his description of my theory, doubtless given in the greatest good faith, leaves out what are in my view some of its vital and essential portions. I gave as an illustration the cubical expansion of an area of rock 500x500 x 20> miles, and showed that it would, if raised 1,000° Fahr., have an_ etfective increase of bulk of 52,135 cubic miles}. Prof. Hutton seems to assume that this is the ALpHa and OmrGa of my theory—the beginning and the end. T cannot but think it strange that he *Until after my work was published I had read nothing of this but what was contained in Lyell’s “Principles” and letters, and Babbage’s paper, read before the Geological Society in 1834, nor had I read Scrope’s views. +See Hutton’s examination of this theory in the Address referred to. t “Origin of Mountain-Ranges,” p. 116. Notes on Cambrian Faunas.— Matthew. 287 should take this view, as one of the first chapters? details illus- trative experiments to give the reader the first conception of re- current expansion. The fact is, that there is no limit to the lateral movement pro- vided by recurrent expansion, excepting the natural limit of the number and intensity of the successive changes of temperature. I can assure Prof. Hutton that if I had advanced no further than the single constructive conception of cubical expansion as an agent in Mountain-Building, in itself original—or, at all events, not contained in the Herschel, Babbage, Scrope, or Lyell conceptions of the effects of expansion on the earth's crust—the “Origin of Mountain-Ranges” would never have been written. CONCLUSION, The object of this outline being to correct some prevalent mis- conceptions of my views, | have confined myself principally to restating in a shorter form the essential principles of my theory of mountain-formation by sedimentary loading and cumulative recurrent expansion. For all the details, proofs, illustrations, and numerical calculations [ must, as before stated, refer those interested to the original work. Perhaps it may lead some who have already read the ‘Origin of Mountain-Ranges” to again read and reconsider it, when I trust the points [ have touched on in this outline will add to its lucidity. Honest criticism, even if severe, is one means of elucidating the truth, and [I not only invite but welcome it. Park Corner, Blundellsands. Liverpool. NOTES ON CAMBRIAN FAUNAS. By G. F. Marruew, St. John, New Brunswick. I. The Taconic Fauna of Emmons compared with Cambrian horizons of the St. John Group. In view of the discussions now going on or that have been held, in regard to the vexed questions of Taconic and Cambrian, a few words of comment on this long imperfectly-understood and little known fauna, may not be considered out of place from one who has been at work on the lower paleozoic rocks 6f a neighbor- ing region. Emmons’ original types have at length been fully elucidated, *Thid. Chap. III. 288 The American (reologist, November, 1891 and to them have been added many species from Lower Cambrian horizons by various authors and especially of late by Mr. ©. D. Walcott until we now have what seems to be.a very formidable array of species. These are all classed together as the ‘+ Olen- ellus fauna’, but there appears to be room for a considerable im- provement on this general classification in the future, when the relations of the different groups of strata shall be better under- stood. To the writer it appears that there are indications of more than one horizon of life in the assemblage of forms that have been collectively designated the Olenellus Fauna, This appears to me to be indicated by the fauna of Washington county, N. Y., the source of Emmons’ types, and which has been recently studied by Mr. Walcott. * Until lately, and in fact until Mr. Waleott undertook this ex- ploration, this fauna was so imperfectly known, that except as regards Olenellus asaphoides no use could be made of Emmons’ discoveries for the exact Comparison of faunas. It is true that Mr. 8. W. Ford pronounced Atops trilineatus a Conocoryphe, but without a figure and without knowing the sense in which he used the name no definite advantage came therefrom, This term Conocoryphe had been so loosely used in England and elsewhere that it had lost its generic value when cursorily used. Mr. Walcott’s figures however enable us to see that tops trilineatus is a true Conocoryphe. In taking up the most prominent genera of this Washington county area one may begin with Conocoryphe trilineata.t This species is of especial interest as combining the head of a Conocoryphe with the pygidium of a Ctenocephalus. It is not a Ctenocephalus however, because the characters of the head shield should receive the first consideration, and these make it a Conocoryphe. As a Conocoryphe it should have but fourteen to sixteen segments in the thorax; the seventeenth segment in this species will represent the first segment of the pygidium of an *Fauna of the Upper Taconic of Emmons in Washington Co., N. Y. C. D. Walcott, Am. Jour. Sci. Vol. xxxrv, Sept., 1887. +The author fully agrees with Mr. Walcott that it would not be wise now to attempt to restore the name Atops for Conocoryphe as it would upset the nomenclature of the latter genus, largely used for more than forty years. Atops was not defined so as to be recognizable, either at the first, or for many years afterward, Notes on Cambrian Faunas.—Mattherw. 289 ordinary Conocoryphe in which this segment is anchylosed in the pygidium, and not free as represented in (. trilineata. Wherever known (except in this district of Washington county) the home of the Conocoryphea is in the Lower Paradoxides beds. This is the casein the south of France, in Spain, in Wales, and even in Sweden. In this latter country a species has been found in the Upper Paradoxides beds, but still the great swarms of these trilobites are found in the lower beds. This is also strictly the ‘vase in the St. John group. Qlenellus asaphoides.* The fact that this species is not intermingled at any locality with the Olenelli of Vermont, seems to me significant; and proba- bly shows that we are dealing with a fauna of a different horizon from that where 0. thompsoni and O. (M.) vermontiana oceur. Had this species been found in a region distant from the two Vermont species, it might be regarded as a cotemporary regional variation of the type, but being so near at hand the probablilities are in favour of a difference of age between the Olenelli of the two places. QO. usaphoides is the species whose development was so well shown by Mr. Ford, and by him compared to that of Paradoxides. Microdiscus connecus. This species shows points of close resemblance to those of the Lower Paradoxides beds. It is a composite of the characters of M. dawsoni of the St. John group on M. encentrus of Sweden. Dr. Linnarsson in his essay on the Lower Paradoxides beds of Andrarum, gives a careful analysis of the layers which make up these beds, and of the faunas which they contain; and it may be seen that MV. eucentrws comes from beds which by the contained fauna correspond to the highest of our Div. 1. ¢ beds and the low- est of 1, d+. Thus the form appears to have shown itself a little *This species was originaly described by Emmons as £illiptocephala asaphoides, and it appears to me now, that this name should have been retained; but I use the name by which the species is commonly known. For the convenience of those not familiar with the series of faunas found in the St. John group, the notation is given below: Division 1 (Acadian). : a. No fauna known. ). Fauna with Agraulos articephalus. c. 1. Fauna Paradox. lamellatus, c. f. oelandicus. c. 2. Fauna Paradox. eteminicus c. f. rugulosus. d, Fauna Paradox. abenacus ec. f. tessini. 2O0 The American Geologist. November, 1891 later in Sweden than in New Brunswick (Canada), as MW. datesoné characterizes the lower beds of Div. 1, ¢. But still the form in both countries is within the Lower Paradoxides beds. Linnarssonia taconica, Mr. Walcott speaks of this as a Lower Cambrian (7. ¢. Para- doxides beds) type, and says it is related to J transoera (of the St. John group) and J sagittalis (of the Menevian group). The resemblance to the St. John species, which ranges from Diy. 1 + to d, is well marked. Orthis salemensis. This form may be compared with Orthisinu pellico of the Par- adoxides beds of Spain, and with 0. («. 7.) hicks’ of the St. John group. The latter is found in Div. 1, ¢. 7. Leperditia dermatoides. This agrees in form with an undescribed species from Div. 1 b. J of the St. John group. Without going into the comparison of other species of the Washington county fauna, which also resemble forms of the Paradoxides beds, it appears to the writer that those already mentioned prove a very close alliance between the Washington county fauna, and that at the base of the Paradoxides beds; and hint at the probable cotemporaneous or nearly cotemporaneous existence of the two faunas; not in the same area perhaps, but in districts not very far remote from each other. As already remarked the partial independence of the fauna with O. asuphoides from that with O. thompson’ points to a dif- ference of age between them. These are points which future investigation will determine. To summarize the bearing of these remarks on the age of the e. Upper Paradoxides beds, no fauna known, Division 2 (Johannian). a. Agnostus pisiformis,* supposed place of. b, Fauna with Lingulella starri c. f. davidis. e. Fauna with Lingulella radula c. f. lepis. Division 3 (Bretonian). «. Fauna with Parabolina spinulosa. }. Fauna with Peltura scarabeoides. e. Fauna with Dictyonema flabelliforme. , § Black shales—Fauna unknown. / Place of Tremadoc (Ceratopyge) Fauna. d. Fauna with Tetragraptus 8-branchiatus, etc. *“Agnostus pisiformis is not found in the St. John Basin but further inland. i) nm ete Tol «3 = $0} eSe3 oh :| -ass F&)*s8 5 & ee ee é ~ Le} pos io Lot KF “=DISTANCE BY GOVERNMENT SURVEY, 8350 F. — ~~~ ~~ Townami Line, 144 N., R. 96 W. oF 5TH Pa) Base Lint OF JV. Browen's Suavey Sj acne s Weg ACTUAL DISTANCE, 8476 F.. - yet PaMTe -ace iw WN Woes WS P48 6 1g eae! 6 recom ee ere TIN " ANON w)) sam 1 ANY Ne i we iN ANN A Elevated — Broken and Hilly with numerus Smaté Lakes ALTITUDE ABOVE THE SEA.” REFERENCES. OBEILLIERS Lake. - 1,470 Feet ALTITUDE ABOVE LAKE ITASCA. ~ Laxe Irasca, Mary Lake 36 Feet Joseruise Lake, Eve Lake, NICOLLET's 3 wlOAN3S3y o igh MMe Lage pe Texaz, Sovrm or Hex- NANDO DE SOTO Lake SIBILANT LAKE Ucrimate Raszavois, beyoed Sariace Channel, Lessee Ucrimate beyond Surtac “ Exraswe Loar, GaeaTen DISTANCES FROM THE GULF OF MEXICO, Gy THE CHANNEL OF THE MBESHOR MVER, REsKA Vor Many Lake. “ Heao ov Howann Caenx, q qu yo ra ii by. bis Ng éax On: es Extaewe List, ONSCOVERIES AT THE SOURCE. Eaatiest Prosaste Occurants, Eanuiest Known Occurants. Frest Known of Werte Maw 5 Aboriginal, Willlam Morrisos, Toul. . Prehistoric. Fiest Actaexric Drscoveny, Lake cArce Map) TRAP THE ART ENG.CO_SEP- Latitude 4" & ov”. Longitude West from G... $6" 12° 48°” H.R. Schoolcraft, 1402, ~ Julius Chambers, 1872. North Latitude 47° 1 107. | Longitude West from G., 95° 12". ina |] nice APH es pnaestiiiNer TT rH HAM AN @ oo mn ee ay LA Lia ae eS me “aes Sa DETAILED HYDROGRAPHIC CHART“ MISSISSIPPI RIVER O , a4 : g . - 2 73 ag =) 38 1G ap ar = iO) Bas 2 ical ges 3 iS alas : Wh 2 Bates £ A> CE ap z ~ SE Ree é My pauae Za 8 Ss pi) ill hs ane ij : O-g infie | FF SIP an 3 2 8S Saar >a es oe = ‘fm PHBE | a) i ye a .= 2 Ms Aetna = ; S in2ds ee 2 "gf fo , es a eeishieyy 1 sy gs od ¥ Eaves A = = “ gs2*2 yy f ear | iy : SEE ae } 5 2352 23 —, 553 i Fic & ~ 8 a3 3 6 a = Sena: Eeali a E i¢ i oer M Source of the JMississi ppt River.—Brower. 29) Washington county fauna, one may tabulate the range of the related species in the St. John group, as follows: Diviston 1 (ACADIAN). Band. fh. Peteeet Wee." | od Conocoryphe trilineata | eel Olenellus asaphoides Microdescies connexus x Linnarssonia taconica i ox ste Mees x Orthis salemensis | | The affinities of these species are thus as far as one can see with species of the Lower Paradoxides beds, both American and European, but we may also note that there are no species recog- nized as identical. This may be accounted for either by regional diversity, or by a slight difference of age. DHE SOURCE OF THE MISSISSIPPI RIVER. J. V. Brower, St. Paul, Minn. Geographical discoveries in the state of Minnesota having been erroneously questioned and persistently misrepresented, the Min- nesota Historical Society and citizens caused a detailed hydro- graphic survey of the Itasca basin to be made, and an exhaustive report thereon has been completed. Antedating the publication of the report, the following information is given in advance, for the information of those who desire the perpetuation of geo- graphic facts and the truth of history, the same having been “ulled for by his excellency, the governor of the State, and duly reported. | copy. | MINNESOTA HISTORICAL SOCIETY, St. Paun, Feb. 12, 1889. To J. V. Brower, St. Paul, Minn. Sir: Reposing especial confidence in your ability, integrity and good judgment, the Minnesota Historical Society, together with other similar societies who may unite with us for this object, does hereby appoint and commission you to make a careful and scientific survey of lake Itasca and its surroundings, with the view of determining, by a thorough ex- amination of the spot, and of all its physical features, under all circum- stances, what is the true and actual source of the Mississippi river. We therefore request you to select such a corps of assistants as you may need to properly carry on such survey, and proceed to lake Itasca, prior to the opening of spring, to take the necessary observations with the above object. . . a . y ‘ 292 The American (r ecologist. November, 1891 On the completion of your survey you will please make a report to us of the result of your investigations. On behalf of the Minnesota Historical Society: Henry H. Sipie8y, Pres/dent. [L. s.] J. FLETCHER WILLIAMS, Secretory. [copy.| STATE OF MINNESOTA, ExecutivE DEPARTMENT. William R. Merriam, Governor of said State, to J. V. Brower, of Ramsey County, sends greeting: Reposing especial trust and confidence in your prudence, integrity and ability, I have appointed you, the said J. V. Brower, as commissioner of the Itasca State Park, pursuant to an act of the Legislature of this State, approved April 20, 1891. You are therefore by these presents appointed and commissioned commissioner of the Itasca State Park, as aforesaid, to have and to hold the said office, together with all the rights, powers and emoluments to the said office belonging or by law in anywise appertaining, until this commission shall be by me or other lawful authority superseded or an- nulled, or expire by force or reason of any law of this State. In testimony whereof, I have hereunto set my name and caused the Great Seal of the State of Minnesota to be affixed at the capitol, in the city of St. Paul, this fourth day of May, in the year of our Lord one thousand eight hundred and ninety-one, and of the State the thirty-third. By the Governor, Wititam R. MeRRIAM. F. P. Brown, [. s.] Secretary of State. THE GOVERNOR’S REQUEST. STATE OF MINNESOTA, EXECUTIVE DEPARTMENT, Sr. Pau, Aug, 3, 1891. Ilon. J. V. Brower, Commissioner of the Ttasea State Park, 460 Jackson Street, City. Srr: Publications in the papers of the state have been made within a few days past regarding the reputed discovery by a citizen of the State of New York of a new source of the Mississippi river, which he claims to have made in 1881, and has since widely published his right to be considered as its original discoverer, and causes changes to be made in the maps of our state in support of such discovery. My attention has been called to these statements by citizens interested in the truth and correctness of the geography of our state, and it is de- sirable to have some definite and correct statement officially made as to Source of the Mississippy River.— Brower. 293, the hydrographic and other features of the Itasca basin, authorized by law to be set apart as a public state park, gained from a therough physical knowledge of the same, to the end that facts regarding the ultimate source of the Mississippi river may be established and pub- lished for the benefit of the people of this state. I therefore request you to report to this department any facts in your possession which may be deemed pertinent tothis question which has come to your knowledge as commissioner or otherwise. Yours respectfully, Wititam R. MERRIAM, Governor. THE COMMISSIONER’S REPORT. SrTavTE OF MINNESOTA, ITASCA STATE PARK, COMMISSIONER S OFFICE, Sr. Pau., Minn., Aug: 13, 1891. His Excellency, William R. Merriam, Governor of Minnesota, Srr: I have the honor to acknowledge the receipt of your favor of the third instant, requesting me to report to your de- partment any facts in my possession, as commissioner of the Itasca State Park, or otherwise, descriptive of the hydrographic and other features of the Itasca basin, authorized by law to be set apart as a public park, to the end that facts regarding the ultimate source of the Mississippi river may be established and published. During the year 1889, as a special commissioner of the Minne- sota Historical Society, a co-ordinate branch of the State govern- ment, | made a detailed hydrographic survey of the source of our great river, and formulated an exhaustive report thereon, which has not as yet been published. From the field notes then taken, the correspondence, and all examinations and researches made, | have the honor to report the following facts for the use of the executive department of Min- nesota. The drainage basin of the Mississippi river extends from the eulf of Mexico, at the mouth of the river, to an ultimate limit above and beyond Itasca lake in this state. This great basin, more than 1,000,000 square miles in extent, is bordered on the east by the Alleghany and other ranges, and on the west by the tocky mountains, and contains about 100,000 rivers and streams, 294 The American Geologist. November, 1891 which flow toward and finally discharge their waters into the Mississippi, principally through the mouths of the larger and more important confluent and affluent tributary rivers. These waters are entirely supplied by the copious precipitation char- acteristic of the fertile basin drained from north to south by the Mississippi, as its principal and most important river. To follow the proper rule in ascertaining, under commission. the true and actual source of this principal river, for geographic purposes, [ consulted European and American geographers, scientists and authorities, gaining the following varied informa- tion as to what constituted the source of a river: ‘That the main stream of a river is that which flows along the lowest depression of the basin, and that a tributary which de- scends into it from a higher elevation, even if longer, is not to be considered the main stream.” -‘A river cannot have a source but many sources.” ‘-All our rivers have their source in the clouds.” (This authority does not say that the clouds emanate from the oceans of the earth, or whence came the oceans. ) ‘The head of the longest continuous channel.” ‘-The sources of a river which are in a right line with its mouth, particularly when they issue from a cardinal point and flow to the one directly opposite.” Other authorities, some remote, and but a few reliable, sug- gest that the source must be a lake; must be the largest lake: should be the inner flanks of the hights of the land surrounding it; should be the source, because it was next to the historic pass, by which one river had, from ancient times, been left to reach another; because it was furthest from the mouth of the system: because it led down tothe axis of the general valley of the basin; because it was at the head of the stream of largest volume; be- cause it was geologically oldest, ete. This widespread variance of authorities, good, bad and inditfer- ent, gave me but little comfort in an interesting geographic and historic research, the source of no two principal rivers of the world being alike, and I arbitrarily adopted a reliable rule of no uncer- tainty. a rule of nature, in ascertaining where the waters were gathered which form the ultimate source of the Mississippi, and for that purpose the length of the main river in statute miles. up through the valley of the basin, was ascertained from the Source of the Mississippi River.— Brower. 295 official records of the United States government and otherwise, with the following result: Miles. From the gulf of Mexico, at the southwest pass, up the chan- nel of the river to city of New -Orleans................... 111.00 From city of New Orleans to mouth of Ohio river.......... 965.50 From mouth of Ohio river to city of St. Louis.............. 182.00 Brometty OL st. Louis to city of St.-Paul..........5. 6.0. c00- 728.75 From city of St. Paul to falls of St. Anthony................ 13.00 From falls of St. Anthony to Winnibigoshish lake........... 432.50 From Winnibigoshish to range 36 west of fifth principal me- RE id hnt since a as ted vie ota cere 6)< sesh 4, 2) ais'h ons Sm es 96.50 From range 36 west of fifth principal meridian to foot of NE as ts fala ata al eid aide tetmatel ain st aise sind Oro Sain ns. tin ewe 17.27 Beer atid ais dine ein ata’ Sar ealsieehs alas sie's oie» Rohe oeoowoet 2,546.52 Thus it appeared that the main river of the Mississippi basin extends from the gulf of Mexico to the Itasca basin, a limited, permanent depression upon the surface of the earth at the ulti- mate source of the river. The geologic and natural features predicating this conclusion are so well known and established that no reference to them seems necessary in this communication, excepting the possibility that the Missouri river, remotely suggested by occasional in- quirers, might be called the main river; but inasmuch as it is a confluent branch of the main stream, coming in at one side, sim- ilar to the Ohio and Red rivers, I see no good reason for discus- sing that question at this time, nor do I deem it necessary to fol- low the historic data, however interesting, which has brought to our notice and knowledge the existence of the main river extend- ing from the gulf to the Itasca basin, where it takes its rise, for there can be no well-founded disagreement as to that facet, be- vause the discovery of the Mississippi, by piecemeal, is co-ex- tensive with the discovery of the coast line of North America, and the facts are indisputable, in consequence of which I must base my reply to your executive communication upon the facts as they have been found to exist at and above Itasca lake, which has been for so many years recognized as the true source. ‘To defin- itely determine those facts it became my official duty to ascertain whence came the waters of Itasca lake. This required a line of *(The official surveys of the United States extend, upon the main river, only to the point where range 36 west of the fifth principal meridian intersects the channel of the river to and beyond Itasca lake. The fractional miles are taken from the record as it exists.) 296 The American Geologist. November, 1891 levels in the field with the following result, to ascertain elevations above the sea: FEET AAU OL LOZNGCO! Adis. arcu ocsbie: he Speen Pata lemnandorDe SOLO IAKG)) 0 asc .cee cece cadre Sasha aeekersiaceraistoue eis lets 1,571 Summits of Hauteur de Terre...... ASA caOr Sea are tS Wie a 1,670 The summits of the Hauteur de Terre (hight of land), imme- diately west of Hernando De Soto lake, divide the ultimate waters of the Mississippi from those of the Red river of the North. The first surface flowage in the greater ultimate reservoir is a tiny brook connecting Whipple lake with Floating Moss lake. Down the incline from Floating Moss lake the Mississippi springs send forth a surface channel to Nicollet’s upper lake, while three hundred feet west and twenty feet lower the channel again appears ina continuous surface flowage to Itasca lake, which is 9,200 feet to the north. It might be well to mention the fact that the head of Howard creek, a small and picturesque little stream with several miniature waterfalls, in connection with the infant Mis- sissippi, constitutes the longest surface channel shown as follows: J Feet. Miles. Guilt of Mexico to Itasca lake... .....2..02s0s- 2546.52 Thence to the mouth of Nicollet’s infant Mississippi.. 17 pat inence: torhead of Howard: creek. 22. .2.0.2-c5cs0.2.< . 11 29,052 5.50 From Gulf to head of Howard creek.......... ies 2 552.02 Other channel distances are: Miles. From the gulf to the head of Mary creek. ald aie shaie ts 0's: tcles) «x 2,551.50 From the gulf to the head of Boutwell ¢ IOS a ial 2,550.74 From the culf tothe Bik lake ooo. sc .cae. Melee srs cece sus 2,549.90 From the “eulf to the extreme limit of the creater ultimate reservoir it is. padelie A rataate sth eit mate thelas iataetareccls “6 area 2,555.25 From the gulf to the. e xtreme limit of the lesser ultimate reser- voir it is. 4 ACU RE RARE Se SMiatateth sects alg etaieietal s als.e sx os CHO EE 300 The American Geologist. November, 1891 The great river having now been actually measured in its entire channel length by connecting surveys, the distances given, for the first time, are certainly more accurate than mere guess-work, Since the greater ultimate reservoir is the extreme limit of the Mississippi basin, and the largest, longest and most important stream above Itasca lake takes its rise therein as a perennial sur- face drainage, | have reported the same to the Historical Society as the ultimate source of the Mississippi. ELK LAKE AND ITS DISCOVERY. In 1836 scientist and astronomer Nicollet laid down Elk lake as an estuary of Itasca, but since that time the alluvial stratum at the outlet of [tasca has been diminished by the constant flow of the water current until the latter lake has receded from the former to a lower level, and the two lakes are now connected by a short creek. The original discovery of this creek and of Elk lake must be awarded to Julius Chambers, who, on the ninth of June, 1872, while encamped on Schoolcraft island, explored the shores of Itasca, passed up the channel of Elk creek in his canoe to Elk lake, crossed to the southern shore of the lake, and, mak- ing a map of the lake, wrote: ‘‘Here, then, is the source of the longest river in the world in a small lake, scarcely a quarter of a mile in diameter, in the midst of a floating bog, the fountains which give birth to the Mississippi. He found the lake much larger than he at first sup- posed. The world was notified by Mr. Chambers of his discovery in the columns of the New York //era/d, page 8, July 6, 1872. Mr. Chambers then passed down the Mississippi, from School- craft island to the gulf of Mexico, in his canoe. The next explorer to declare Elk lake the source was A. HL. Siegfried, who, on the thirteenth day of July, 1879, reached the lake, and, taking a photograph of the same, declared it to be the “highest tributary to the Mississippi,” in the columns of the Louisville Courier Journal, August. 1879. The lake and creek were also visited in 1875 by Edwin S. Hall, in 1880 by O. E. Garrison, and in 1881 by Rey. J. A. Gilfillan. Whatever significance may attach to Elk lake as the source, Mr, Chambers must be awarded the honor of a first and original dis- covery, to the exclusion of all others, except Indians, known in our history, and the name +-Klk,” officially promulgated by the authorities of the United States, is the proper and legitimate Nource of the A Lississspyt River.— Brower. 30] naune for this body of water, acquiesced in by legislative enact- ment, and Elk creek takes its name from the lake. No one of the several brooks flowing into Elk lake are of any great import- ance, and all of them were completely closed with ice in March, 1889, and all of them were dry in August of the same year. (reographic discoveries at and above Itasca lake prior to my survey in 1889, of authentic record, worthy of consideration and belief, are as follows: WaolkanMormison:first.of white mem 62% ...0.06..2. ines sce cs caeees L808 Pie eonoolcratt, [tasca lake). 2 f..c.5..c.0005 seen segs occ etederatet te LOO Rereee MICOMeL MIVEG IMCS: . cscs se castes es\sccdccearccs see Jaeeneeleou Jolimus Chambers; *Hlk lake and creek ......... 2... cece cceccece 1872 epee a PO OVETMIMEN TG SULVEW s cy sictclnis« cove oj sfa-crouets ee 2 oats ne oew'ec Lolo Hopewell Clark, special survey ............. CBee hein a oe Ciaveirae ese LOU Itasea lake is at the lowest depression of the basin and Hern- ando de Soto, Morrison and numerous other lakes are at the sum- mit of the basin, and the water pressure from the lakes above Itasca, the whole being exclusively supplied by precipitation, sauses a contributary inflow into Itasca lake, which is increased or decreased from time to time, according to the quantity of rain- fall or duration of drought, as either may prevail. One peculiar significance is demonstrated by the fact that Itasca lake has a flood plain of but little more than three feet in eleva- tion above the natural surface of the lake. The flood plains of the lakes higher up are ten, fifteen and twenty feet. Thus, while Itasca lake is always supplied and sometimes rises during dry weather, the lakes at the summit dry down rapidly to a lesser surface area, depending upon rainfall to resupply them. During the summer of 1890, copious rainfall caused lake Itasca to rise a foot or more above Elk lake, and Elk creek flowed into, instead of out from, Elk lake. The outflow of lake Pepin, through which the Mississippi takes its course, is controlled by the inflow. and lake Itasca presents a striking similarity. Infinitesimal deductions are necessarily drawn, however, from ascertained facts in order to discover the location of the ultimate source. Itasca lake lies at the pit of the basin and receives the waters discharged into it from summits surrounding it, which in return pass out into the channel below, forming the main water course of our country, to the gulf. Consequent inferences may (*Elk lake and creek, discovered by Mr. Chambers in 1872, are constituted of waters erroneously claimed to have been discovered in 188i by the person referred to in your communication.) 302 The ad Lmerican Geologist. November, 1891 therefore be drawn by those who. still believe that Itasca lake is the source of the river, it being situated at the pit of the lowest depression of the limited Itasca basin, but I know it to be a fact that there is a greater ultimate reservoir there at the summit, and it constitutes the ultimate source. To prevent unauthorized, erroneous and deceptive changes in our state map, I suggest that a reswme of the historical and geo- graphical facts which led up to the final determination to locate the State Park at the source of our great river be included in my forthcoming report, and then, by legislative enactment, prohibit, within our own state, the illicit changes in the state map so assid- uously persisted in from mercenary motives. The law requires me to report a detailed chart of the park, and topographic field notes for that purpose will be completed in due time. The map accompanying this paper is reduced from that prepared for the Minnesota Historical Society. Very respectfully your obedient servant, J. V. Brower. ADDENDUM. The Itasca State Park contains thirty-five square miles, includes the territory shown in the accompanying map, is singularly picturesque in nature’s abundant scenery, high hills and summits, pine and balsam forests and deep lakes prevailing. The nomenclature, as far as completed, as directed by an order of the Minnesota State Historical Society upon a report of its committee, is as follows : Omoskos (Elk) Sogiagon (Lake), Ojibway. Lac La Biche, = - The French translation. Elk Lake, - = - The English translation. Itasca Lake, - = = From Ver-ctas-cu-put. Schoolcraft. Schoolcraft Island, = - Named by Lieutenant Allen. Infant Mississippi, - - Named by Jean N. Nicollet. Nicollet’s Lower Lake, Nicollet’s Upper Lake, | Nicollet’s Middle Lake, — { Nicollet’s Valley, - After Nicollet. Bear Point, - - - Named by Peter Turnbull. Turnbull Point, - 2 - So called by residents. Floating Bog Bay, - - J. V. Brower’s party, 1888. Ozawindib Point, - - After Schooleraft’s guide. Garrison Point, : - After O. E. Garrison. Rhode’s Hill, - - After D. C. Rhodes, photographer. Morrison Hill, - - After William Morrison. Island Creek, - - Opposite Schoolcraft Island. Nource or the Mississippe River.— Brower. 303 Mary Creek, = - After Mary Turnbull, now deceased. Mary Lake, \ She gave birth to the first-born fof Mary Valley, white parents at Itasca Lake. Ek Creek, = = - Named by Committee. Boutwell Creek, - = After Rey. W. T. Boutwell. Crescent Springs, = - Crescent shaped. Elk Springs, - = = Named by Committee. Elk Pool, = = - ‘Named by Committee. Clarke Creek, - - After Hopewell Clarke. Siegfried Creek, - - - After A. H. Siegfried. Demaray Creek, = = After Morrison’s daughter. Howard Creek, - = - After Schoolcraft’s daughter. Mississippi Springs, - = The Committee. The Twin Lakes, = - The Committee. Danger Lake, - = The Committee. Ako Lake, - a - After Accault. A companion‘ofjHen nepin. Josephine Lake, - = J. V. Brower’s party, 1888. Sibilant Lake, - - - Form of the letter S. Clarke Lake, - : - After Hopewell Clarke, by A. J. Hill. Little Elk Lake, - - - The Committee. Hall Lake, - - - After Edwin 8. Hall. Groseillier’s Lake, | - - After first of white men to discover Radisson Lake, ) the upper Mississippi. Floating Moss Lake, - The Committee. Whipple Lake, - - - By Rev. J. A. Gilfillan after Bishop Whipple. The Triplet Lakes, - = The Committee. Morrison Lake, - - - After William Morrison. Lake Hernando de Soto, —- In honor of the discoverer of the Mississippi. Brower Island, - = - Named by the Committee. Mikenna Lake, = - Named by A. J. Hill. Allen Lake, - > - After Lieutenant Allen. The Picard Lake, = - - After Hennepin’s companion. The Lesser U Itimate Reservoir, ‘ Named by J.V. Brower, Commissioner. The Greater Ultimate Reservoir, ) Itasca lake was known as “Elk lake” prior to 1832. Surveyor General J. H. Baker, for the United States government, continued the name “Elk” to another lake in 1876. The committee of the Historical Society was constituted as follows: Captain R. Blakeley, Hon. I. VY. D. Heard and Hon. Charles D. Elfelt. Upon submitting their report of names selected, the report was adopted. The rule adopted by which to ascertain the source of the Mississippi proved most satisfactory and brought to the knowledge of the world the xreater Ultimate Reservoir, heretofore unknown to exist as such, although a portion of the lakes there situated have been known for many years, notably, Nicollet’s lakes since 1836, and other lakes since 1875. 504 The American Geologist. November, 1891 The discovery of Elk lake and creek was accomplished in the follow- ing manner: Jean N. Nicollet, in 1836, found what is now Elk lake, to be a part of Itasca lake, as shown by his map now of record at the city of Washing- ton, from which is taken the following: AN NTE is > i US ifs l SS L Wong x Ve BR NICOLLET’S SOURCE OF THE MISSISSIPPI, TRACED FROM OFFICIAL RECORDS AT THE CIty OF WASHINGTON. After the lowering of the river bed at the north end of lake liasen since 1856, Elk lake was left as waters gathered at one side, one foot higher than lake Itasca, and after the process of nature had separated the two bodies of water and formed a short creek, of no great importance, between the two, Mr. Julius Chambers was the first to discover Elk lake and creek, and he declared it to be “The Source” of the Mississippi, July ), 1875, and to him must be awarded whatever honor is due therefor. His map, first published by Ivison, Blakeman, Taylor & Co.,is here- with reproduced, p. 305. The report made to the Minnesota Historical Society by its commis- sioner was referred back for the purpose of having the same properly ed- ited for publication, and the same is not yet published. When published, as a geographical and historical record, it will contain about forty-three chapters, the last three of which are yet to be supplied, descriptive of the formation of the State Park, and botanical and other observations, The fact that formerly one large lake, with bays and islands and beaches, existed where now is found the several lakes at the Itasca basin, is beyond the inference of a mere conjecture, and to future explorers and geologists must be left the privilege and opportunity to locate its boundaries and determine its former importance; and until some further or more definite action, it has been designated lake Upham by Prof. Geo. B. Aiton and J. V. Brower. SOUree of the Mi ssissi ppt River.— Brower. 305 The importance of the several streams flowing into lake Itasca in length, depth, width and flowage is as follows: SKETCH MAP OF THE ITASCA LAKE REGION PRAIRIE Julius Chambers. Woodland, soilLdry Large trees, traces of forest fi- 9P fi une ‘sana. poom 149° 6 sosoys aun CHAMBER’S DISCOVERY. First--Nicollet’s Infant Mississippi river, also called by him the “Cradled Hercules.” Date of discovery, 1836. Second—-Mary creek. Third —Elk creek. Discovered by Julius Chambers in 1872, when he declared it to be the Mississippi river. Fourth—Boutwell creek. Fifth—Island creek. Sixth—Creek at Floating Bog bay. Serenth—Small creek at extreme southwest point of Itasca lake. 306 The American (eologist. November, 1801 Careful observers will note the importance of the greater ultimate reservoir, containing twenty or more lakes, at an elevation above lake Itasca. ‘These lakes impregnate the earth with water and numerous flowing streams abound as a natural result, Itasca lake and Elk lake each drawing its supply from above with the following difference in peculiarity: Itasca lake receives all the waters flowing down from the summits, while Elk lake receives and discharges less than one-half. The creeks entering Elk lake are completely frozen in winter and have been found to be dry in summer. EVIDENCES OF A GLACIAL EPOCH IN NIC- ARAGUA*. By J. Crawrorp, Managua, Nicaragua. None of the mountain ranges in Nicaragua rise to the altitude of the frost-line, and only four have peaks whose highest apexes are 6,500 (one 6,700) feet above the Pacific. The average alti- tude of the Cerros in this country is about 2,800 feet, and would not awaken a suspicion that any of these mountains had ever been deeply covered with ice. At the present time the night temperature on the summits of the Cerro Peia Blanca during the season when the trade winds are moving eastward, is frequently as low as 12° Cent., and occasionally 8° Cent. The western or lake region of Nicaragua, the only part about the geology of which anything reliable has, until recently, been known, appears to have been formed of materials ejected from volcanoes which were active during all of the Quaternary, and at least parts of the Tertiary and of the Recent epocht. But we find Pinus sylvestris and some other cold climate coni- fers, dwarfish or attaining medium size, on some of the highest mountains of northern Nicaragua, and retaining, with some mod- ifications, the distinctive features of their more northern types. In at least one valley of those Cerros is a large deposit of the petrified bones of Tertiary, and probably earlier period mammals and reptiles, as Llephas, Ursula, Machairodus, ete., and across that valleyt, at the foot of a canon, are small hills, having long *The publication of this article, received in March last, has been unavoidably delayed. +I have not found ‘Miocene sands.” “Miocene gastropods,” nor other evidences of the Miocene in western Nicaragua, such as have been described by others as occurring there. See Proceedings of the Victoria Institute, 1876. {The valley of Sebaco, lat. 12° 40’ N., long. 85° 58’ W. The petrified bones are 50 to 100 feet beneath the surface, in sand and partly hardened sediment. Glacial Epoch in Nicaraqua.— Crawford. 307 connected ridges composed, so far as examined, of irregularly mixed angular and rounded rocks of various sizes, together with smooth and rough-edged pebbles, clays and sands. As we look from the valley of silicified bones, across the un- assorted deposits, up the cafion, and along the sides of the mountains to the dwarfed pine trees growing between the rocks on the crest of the Cerros, we are led to inquire how and when these habitants of a colder climate were introduced to this half temperate, half tropical Jatitude, and when and how this canon was excavated and the unassorted deposits were formed only a few miles beyond its lower end. -The facts seem to indicate a greatly increased elevation and a much colder climate at some former epoch, In 1889 and °90, during reconnaissance conducted for the government of Nicaragua, the writer discovered evidences which, taken in connection with others previously discovered, strongly indicate a Glacial epoch in this country, synchronous with that of the United States and Canada. Some of these evidences are here presented. On the top of the monogenetic series of mountains known in various parts of its extent as Cerro Yalli, Cerro Jenotega, and Cerro Pena Blanca, following an irregularly sinuous line from about lat. 13° 25’ N. and long. 87° W. to about 13° 30’ N. and 84° 55’ W.*, are several mesas, the largest, but not the highest, of which, is near the eastern termination of the series, and is named Mesa Turcos. The top of this mesa has an area of about twenty square miles of metamorphic rocks, granite or gneiss pre- dominating, across which, and diverging nearly at right angles, are three shallow valleys, each about one mile wide. They begin near the centre of the mesa and gradually widen and deepen till they reach its nearly perpendicular sides. One, which extends southeastward, is the hydrographic area for the larger number of *All these bearings are magnetic. This mountain system is south of that supposed to be referred to in Prestwich’s Geology, edition of 1886, vol. 1. p. 294, and designated “No. 25, System of Segovia. Cosequina and Cape Gracia-a-Dios.” Cosequina is a volcano on a point of land which it has formed that projects into the Pacific ocean atthe bay of Fonseca, and could never have formed part of the mountain system evidently referred to in the excellent work quoted. That system ex- tends from lat. 13° 22’ N., and long. 87° 5’ W. northeastward toward the Gulf of Mexico and terminates about lat. 14° 50’ N. and long. 84° 92/, magnetic, BOS The .. | merican (reologist. November, 1591 the head-water creeks of the Rio La Seibeta, whose waters, emptying into the Rio Tooma, and thence intothe Rio Matagalpa, enter the Caribbean sea. Near the centre of this valley a canon begins abruptly and deepens as we follow it for about three miles to the edge of the mesa, where it attains a depth of about 225 feet. ‘The canon is about 400 feet wide at top and sixty to sey- enty-five feet across its floor. The waters of a small creek, named Chomeha* which rises at the head of the valley, rush down over a few small cascades and falls, near the almost precipitous head of the canon, to two vertical falls of considerable hight. At the first of these, the water drops about forty feet into a basin perhaps ten feet in depth and a hundred and fifty in breadth, formed in a flat granitic or gneissic ledge, and from this basin, through a channel about fifty feet long, a foot wide, and three inches deep, to the edge of the ledge, where it makes the second fall, or one of about 160 feet, into a basin in the metamorphic floor of the cafon. Flowing thence southeastwardly, the stream descends rapidly, often over falls and cascades, through the nar- row rock-walled canon, for about two miles, to a valley alongside of the Rio Seibeta. Along the sides of this canon are many strange and beautiful forms of smooth-faced rocks, some pro- jecting their oval surfaces for a few feet at right angles to the face of the canon and extending for several yards parallel with its direction, others carved out into long intaglios. Above the falls and during the dry season, the stream does not exceed two inches in depth by fifteen feet in width, and its hydrographic basin does not embrace over five square miles. In that part of the valley are found many mouvtonnéd masses of granite and striated and polished masses and large flat loose rocks striated from one anda half to two inches deep in lines parallel with the flow of the creek. Near the termination of the canon in the lower or river valley, and extending across the valley to the Rio Seibeta, are several mounds and hills composed, so far as examined, of unstratified deposits of clays and sands containing rough and smooth-edged, large and small rocks and pebbles, indiscriminately mingled. *Chomeha, as I learned from:some old Indians of the Turcos and Amerrique tribes, is the name of a goddess of the aborigines, now sometimes invoked by the very small remnant of these once large Indian tribes. Glacial Tipoch ‘n Vicaraqua.— ¢ raupord., owe From each hill there projects, in the direction of the Rio Seibeta, a ridge, apparently composed of the same materials as the hills®. Another valley extends eastwardly from near the centre of Mesa Turcos, and is the head of the hydrographic area, whose waters flow through the Rio Tungla (+‘Prineapulka,”” on the gen- erally consulted but very incorrect maps, baileys. ete., of this country) into the Caribbean sea. This valley also has a canon cut out in it, the stream com- mencing in small cascades that continue in series for about two miles. Some of these series have a fall of from three to twenty feet. This canon is cut down through rock for nearly two hun- dred and fifty feet before entering an elevated plain of oval- backed rocky ridges formed on the eastern boundary of the mesa. Smooth oval-surfaced areas and deeply striated masses of rock are frequently visible in and near the bed of the small stream which flows through this valley and canon. Only a few scattered hills and ridges, but partially examined, were composed of un- assorted deposits of boulders, rock-fragments, sand and clay, but these, in some parts of the ridges, were cemented together. The third shallow valley on Mesa Turcos is the head of the watershed of several creeks which flow northward and then north- sastward through Rios Bokay and Segovia («*Wanx” or +*Coeo’’) into the Caribbean sea at Cape Gracias a Dios. At about a mile from its head. it divides into two canons, in which, at short in- tervals, occur series of cascades. These canons, like those pre- viously mentioned, continue to increase in depth and width, hav- ing, where they leave the granite or gneiss and enter the highly inclined later strata, a depth of about 125 feet, and thence deep- ening until several hundred feet deep before reaching the lower foot-hills. The width of each canon, while in the granite, is at top about 200 feet, and across the bed about forty feet, increas- ing locally to seventy or eighty. In the later formations, they widen rapidly, maintaining nearly perpendicular walls, and their channels resolve into labyrinths of passage-ways between numer- ous columns and smooth-edged boulders some fifteen feet high, so intricate that, during an examination made, accompanied by two Indians, in one of these labyrinths, several passage-ways were unsuccessfully attempted and much time was lost in trying to get *Doubtless these would be designated “moraines” in Minnesota, New York, or Canada. 310 The American Geologist. November, 180% out of the place. Both canons, in their northeasterly extension, obliquely bisect two ‘+ lodes,”’ respectively eight and twenty-one feet wide, of westwardly strike, dipping at an angle of about 35° (megnetic) north, and containing gold, sulphides, and arse- nates ina gangue of fragments of quartz, talco-slates, chlorite slates, iron-clay slates, ete.; the walls are diorite and diabase. About one hundred miles to the northeastward is a deposit of colored marbles, intersected by the Rio Segovia, and about the same distance eastward and fifteen miles north of the Indian vil- lage of Wylo-was (on the Rio Tungla), is the southeastern end of the rich gold placers of Princapulka, terminated by a small cerro of Carboniferous limestone*. On the Pacific ocean side of the dividing range of Cordilleras in Nicaragua, the mountains terminate in a large mesa, named Totumbla, whose summit area embraces about nine square miles: and across this, from north to south, is a shallow valley about two miles wide on which are exposed at several places large masses of rock having smooth rounded surfaces, and measuring fifty to two hundred feet long. Some of these masses are polished. Near the edge of this valley are numerous flat, striated boulders and loose striated rocks of local origin. The most numerous strize are parallel with the general direction of the valley. The locality of this mesa is about lat. 12° 42’ N. and long. 85° 55’ W. Its altitude above the Pacific ocean is 3,260 feet. It is com- all meta- morphosed. On the margin of the summit-plane of this mesa posed of gneiss and other rocks of the Kozoic series are many peaks fifty to two hundred feet higher than that plane and connected nearly continuously by high ridges. On the inner *The generally superficial examination of this Mesa Turcos, the val- leys at its sides and on its top, and the deep canons, was not easily made. This locality is fully one hundred miles from any human residence and ina dense, pathless, mountainous forest. In the valleys the vines and bushes were often so thick as to require cutting, step by step. Conse- quently we could take but very few tools, ropes, instruments, etc , with us, and all our provisions were carried on the backs of Indians. The scenery (when twice only we found mountain peaks with forests so thin that we could get a long wide vista) is almost incomparably beauti- ful. In some places on the sides of the cerros and in the lower valleys, groves of tall, large mahogany, sapote, nispero, Spanish cedars, walnuts, and liquidambar trees, standing as living columns encircled with vines, are covered with their own bright foliage, and with vines, mosses, and epiphyllous flowers; while at other places orchids and ferns and tlower- ing plants or bushes, in great variety are numerous and some of them very large. Glacial Lepoch in Mrearaqgua.— Crawford. aya a or table-land side of one of these peaks, on the northwest margin of the mesa, there nearly precipitously begins a cahon in the gneiss 1,100 feet deep and about 1,500 feet wide at top and fifty to one hundred across its usually dry bed. Near the head of this canon and about 320 feet below its ridge-like upper margin, is an oval- roofed cavern three to six feet high, eight to fourteen feet wide, and extending into the rocky side of the canon in a direction per- pendicular to the caion’s axis for over two hundred feet. This is a laceolite, having one of its ends broken or eroded off and this open end obscured by loose rocks. Access to it down from the top of the mesa or up from the bottom of the canon is very diffi- eult. This cafon enters the valley on the mesa about one mile from its southern margin and then descends in falls, cascades, and rapids over the steeply inclined side of the mountain to the valley of the Rio Veijo. For about the first two miles of its length, there is no water, save in the brief rainy season. The small stream in the valley into which this cafon enters flows through or down the Rio Veijo into lake Managua and thence through lake Nicaragua and the Rio San Juan del Norte into the Caribbean sea, thus forming in its route an are of about two- thirds of a circle and of several hundred miles, instead of flow- ing westward from the mouth of the Rio Veijo, through a flat country, into the Pacific ocean. At the lower end of this canon, as it enters the valley of the Rio Veijo, are numerous hills and knolls, many of them having long connected ridges that extend far into the valley. Those examined, and probably all of them, are composed of irregularly mixed, unstratified rocks, clays, pebbles and sangls, cemented in some places by iron oxides and elsewhere but partly hardened. Across this valley, in a crescent formed by the Rio Veijo, is the large deposit of petrified bones of Cenozoic (and possibly some of them Mesozoic) mammals and reptiles previously referred to in this paper. Between the town of Ocotal and the village of Depilto, eight miles distant from each other, in the Department of Nueve Seg- ovia, at about lat. 13° 35’ N. and long. 86° and 32’ W,. are found such apparent evidences of glaciers’ work*, as striated *The late Thomas Belt, F. R. 8., in his “Naturalist in Nicaragua,” second edition, declares these to be moraines and considers them indis- putable evidences of a Glacial Epoch here. When I made the examina- tion of that locality I did not know that he had previously been there. 312 The American Geologist. November, 1891 boulders, deposits of sands, clays, pebbles, and rocks, generally appearing to be unassorted; but in some parts they appear strati- fied, not as deposits made by recent floods, having well defined lines of separation, but as if made interruptedly and at the same time with the other large masses of (so far as examined) unas- sorted deposits. These moraines* are at the confluence of the three rivers, Segovia, Depilto and Maculeso whose aggregate hydrographic area is about eight thousand square miles. My notes, made after several examinations at intervals during a stay in that part of Nicaragua of about four months, state that possi- bly a large portion, if not all, of these deposits are moraines. Several large knolls and small hills are found north of the vil- lage of San Rafael del Norte, in the department of Matagalpa, at the southwestern foot of the Cerro Yalli, about lat. 13° 20’ N, and long. 86° W., each having extensions of from one hundred and fifty to six hundred yards long, declining into the Rio San Rafael del Norte, composed, so far as my examinations extended, of the unassorted, unstratified fragments of rocks and pebbles. some rough, others smooth-edged; all embedded in sands and clays. In some places the clays, in others the sands are in excess. These deposits were first discovered by the late Thomas Belt, F. R. S., and deseribed in the second edition of his «Naturalist in Nicaragua,”’ published within the past few years in London. — He declares them to be moraines, which if discovered in Canada would unquestionably be so considered. Cerro Yalli, at this locality, is tall and has steep sides, bat the hydrographic area is comparatively large, and although I found no narrow, deep ra- vines in the side of the mountain near these deposits of un- I believe it was his only trip (and one of only a few days) to this locality, distant for more than three or four leagues, from the mines near LaLibertad (that he superintended for a few years). He was a quick and close observer, but was hurried on this trip and did not note, prob- ably, the Jarge hydrographic area of the three rivers, Segovia, Maculeso and Depilto which unite, in this locality, their rapid currents. *T had doubts about these being moraines, until two months ago, when for the first time and only for a few hours, I had opportunity to exam- ine the work of the late Thomas Belt, referred to in foregoing note. I believe Mr. Belt was correct in designating these deposits moraines. My doubts occurred because we are sometimes liable to mistake de- posits made by water for those made by ice, unless after extensive ex- cavations, etc.; also, because the water-shed of these three rapid rivers is quite large, and in flood times they transport large boulders for log distances, and, because there are evidences that a part, if not all, of that valley has been overflowed. Glacial Kpoch in Nicaraqua.— Cranford. 3158 stratified materials. yet I could not persuade myself that the rocks, pebbles, clays, sands and pieces of lignite composing these hills, knolls, and rayines had been transported to and deposited in this valley by water. I found, it is true, many loose boulders at various places on the side of the mountain, too many, I thought, to remain in such places after a glacier had moved over them; but. possibly those boulders were deposited by some melt- ing ice-sheet. Other evidences in the Nicaragua of a Glacial epoch, subsequent to the Pliocene, have been discovered and examined by me, but none found to be so distinct and impressive as those herein de- scribed. Hydrographic charts, made by both the U. 8. Coast and Geo- detic Survey and the British Admiralty, of soundings of the Caribbean sea, from the coast of Nicaragua east to the Atlantic ocean, show (besides the bed of one, or possibly two, old lakes or inland seas whose present beds are 1,000 to 1,900 fathoms below the present surface of the sea) long, deep, wide holes in the bed of that sea, at intervals from the principal (really the old Plio- eene or ante-Pliocene rivers) mouth of each of the Rios Escon- dido (Bluefield), Matagalpa (Grande), Tungla (Princapulka) and Segovia, which holes are traceable eastward to the western margin of the Atlantic ocean, or to about 60° west longitude on the east side of the Antilles, indicating that the channels of these rivers once extended out fifteen hundred miles further than at present. These sub-marine fiords are now nearly filled up by debris of brachiopods, cephalopods, mollusks, ete., and in the shallow parts by corals. The average depth of this sea is about 5,500 feet. but if we consider the two very deep places as lakes existing in the early Tertiary period, then the average depth of the Carib- bean sea is less than 5,000 feet, or, less in depth than the altitude at present above its upper surface of several cerros in Nicaragua. The deep holes in apparent continuation of the former channels of some of the old rivers that emptied from Nicaragua into the Caribbean sea indicate, in connexion with the facts related in the foregoing part of this paper, that great elevation once occurred tu that latitude and locality sufficient to have raised, far above the surface of the water, almost all of the bed of the Caribbean sea, and to have extended the mountains in the central part of Nica- ragua far up into zones of snow and ice, producing a Glacial j14 The American Geologist. November, 1891 epoch, There are atolls and barrier reefs in that sea, which, in all probability, are continuations by corals, upward, at the rate of sea-bed depression, or subsidence of the tops of mountains that now are the sub-marine, but once were the sub-aérial parts of the Nicaraguensian continent. When elevation had com- pleted its work here, it is probable that subsidence deeply sub- merged the present Isthmus of Panama, _ No river flows from the deep, concave western side of Nicara- gua into the Pacific ocean of sufficient size to be considered a factor in connection with this subject. The foregoing facts indicate: (a) That, at least, two or three mountain ranges in Nicaragua were deeply covered by ice during a Glacial epoch contemporane - ous with that which existed in the North American continent. (b) That at that time there was, because of great elevation of land and sea-bed, a Nicaraguensian continent extending eastward, about fifteen hundred miles further than at present, over the northern and middle part of the area now occupied by that part of the Caribbean sea eastward from the Nicaragua coast, to the Atlantic ocean at about the 60th meridian west from Greenwich. (c) It is probable that the submergence of the Isthmus of Pan- muna was then sufficient to allow a large part of the south equato- rial current (which now carries so much heat to northern latitudes) to pass into the Pacific ocean, (d) Cosmie conditions, as irregularity in the amount of heat from the sun, equinoxial precessions, variations in the excentricity of the earth’s orbit, and extreme variations of the magnetic north and south poles, may have been factors; but the two latter were certainly of very moderate effect in producing a Glacial epoch. (rreat elevation of land appears to have been the potent cause in Nicaragua, (e) The movements of elevation and subsidence appear to have heen more rapid in this country, than in latitudes many degrees further north, and more frequent and vigorous in Glacial and Recent times. (f) It is quite probable that the extensive fracturing and fissur- ing during the early Glacial or late Pliocene epoch gave rise to sev- eral additiongl volcanoes along the western part of Nicaragua and added variety to the scenery of mountains clad in ice in the central part, ON CYCLES OF SEDIMENTATION. J. Lawton Wiiirams, Hornellsville, N. Y. The fact of cycles of sedimentation is well known to strati- graphical geologists. The following table, from Dr. Alexander Winchell, is a good illustration of what is meant by the term: TABLE OF CYCLES OF SEDIMENTATION. Calcareo- Fragmental. Palaeozoic Coarse ine Fragmental. |Calcareous. Systems Fragmental. Fine Fragmental eH Coal Measures. - Parma : Laramie ; Upper gare ato |(Broken into ret 4 , |Permian., Carboniferous. Conglomerate. small epoch.) Limestone. Lower Waverly Sandstone|Waverly Sandstone |Mountain False Coal Carboniferous.| (Marshall Phase.) | (Chouteau Phase.) Limestone. Measures. . Oriskany . Te ar Corniferous Hamilton svonian. Ye Schoharie Grit. Beronian Sandstone. |SChoharie Grit Limestone. |and Chemung Medina Sandstone fone 5 Niagara Shale Niagaré Loli Silurian. and Oneida ae car ate ; audetions |Salina. Conglomerate. ; ; i , | . Calciferous and Trenton Nea ‘ ‘ambrian. otsdam. . om : Cincinnati. Cambrian Potsdam Chazy. Limestone, |Cincinnati While these divisions may be somewhat artificial and arbitrary, they seem to illustrate the general fact of a definite sequence in sedimentary deposits. Similar relations have been observed in the strata of Great Britain. Mr. Hull (Quart. Jour. Sei., July, 1869.) makes a triple rather than a quadruple subdivision: Ist, a lower stage of sandstones, shales and other sedimentary deposits, representing prevalence of land with downward movement; 2d, a middle stage, chiefly of limestones, representing, prevalence of sea with general quiescence and elaboration of caleerous organic formations; 5d, an upper stage, once more of mechanical sedi- ments indicative of proximity to land. The identity between this and Winchell’s table is apparent. In both we may begin with a given stratigraphical. structure, and, after passing through a definite succession of intermediate struc- tures we again encounter one like the first. We are to bear in mind, however, that this succession is not a rigid one. Often- times we meet with intercalated beds which have no representa- tives in the other members of the series. Besides. there are wide 5316 The American Geologist. November, 1891 variations in the relative thicknesses of analogous beds, and in the aggregate thicknesses of different cycles. The facts with which we are impressed, however, are not the minor discrepancies and apparent anomalies, but the broad general fact of a definite sequence, And the conviction becomes irresistible that such a sequence, must be referred to a periodical recurrence of certain fundamental phenomena concerned in the evolution of our planet. These phenomena may be considered under two heads in relation to this subject: Ist, immediate causes; 2d, remote causes. The immediate causes are evidently, (a) the elevation and subsidence of land areas, (b) meteoric conditions affecting the rate of erosion of these areas (c) the mutual reactions of these separate forces. In the remote causes we must seek for an explanation of the periodicity of upheavals and subsidences, It is clear that with a given surface of the earth's crust, an elevation of a portion of land must either result in a depression of some other portion of land or of the sea bottom. Let us suppose an elevation of land to take place which results only in a depression of the sea bottom. There will then be a smaller surface of the waters of the globe exposed to the evaporative influence of the sun. Other things equal, there will, consequently, be a diminution in the amount of precipitated moisture. This will necessitate a diminution in the amount of erosion and atmospheric disintegration of the emergent areas, provided the rainfall be equable. But the amount of erosion depends not only upon the quantity, distribution and periodicity of rainfall, but also upon the angle of slope of the land subject to erosion. The effectiveness of erosion varies directly as some high power of the velocity of the eroding fluid, and the velocity is a direct function of the sine of the angle of slope. So that the diminished precipitation due to a diminution of the water surface might be more than counterbalanced by a disproportionate increase in the angle of slope, in the final results of erosion. Let us assume that in a given instance this was actually the case. Then the great angle of slope would necessi- tate a precipitous fall of torrents. Suppose the slope is such as to double the mean velocity of a given volume of water falling in a given interval of time. Then, whereas formerly this same volume of water transported to the sea fragments whose dimen- sions may be represented by 1° or 1, now it will transport frag- ments of 2° or 64, since the transporting power of a fluid varies On Cycles of Sedimentation.— Williams. 317 as the sixth power of the velocity. (Hopkins Q. J. Geol. Soe. VIII p. 27.) These last will have a size relative to the first as small cobble-stones to gravel. | Now let us suppose the process of erosion continues. The coarse fragments will be polished and rounded by their journey to the sea, and will be deposited in a soft matrix of mud and finer pebbles as a conglomerate. The largest fragments will be deposited first, and, with the wearing away of the slope, and consequent diminution of the angle of slope, the size of the pebbles of successive deposits will be smaller and smaller. | Finally, when the angle of slope be- comes such that the velocity is one-half what it was at first, the size of the fragments will be 1 instead of 64. © Such fragments will become a sandstone or shale according to circumstances. At length the land will be entirely eroded away. Meantime the sed- iments deposited along its shores will have accumulated to a vast depth. This accumulated weight will necessitate a submergence to restore the equilibrium of surface pressures (Babbage and Prof. Jas. Hall). The deposits will sink to a depth which will be con- genial to the development of vast populations of corals, crinoids and other lime-secreting organisms. Here they may continue to build through a long succession of generations, the increment of weight due to their accumulation producing just enough submer- gence to maintain a proper level for their growth (Darwin). A rast deposit of crude limestone will be the result. This is pre- cisely the succession found in the table at the beginning of this article. Conglomerate, sandstone and limestone are repeated over and over again. In the preceding discussion we have assumed the simplest conditions imaginable; an eminence of land, a given elevation subject to no oscillations of level during the long period of time while it is worn down to the level of the sea, an equable and uniform quantity of precipitation, and a suffi- cient weight in the accumulated sediments to effect a subsidence when the destruction of the land was completed, and, finally, a subsidence deep enough and not too deep to be favorable to the growth of lime-secreting organisms. It is astonishing to see how faithfully these ideal condi- tions have been repeatedly realized as recorded in the Pal- weozoic rocks of North America. And it is perfectly con- ceivable how a variation of these ideal conditions might lead to the discrepancies and anomalies already alluded to. We 31 Ss 7 he d { merican Geologist. November, 1801 assumed a uniformity of meteoric conditions, but such a uniform- ity is impossible from the very nature of the other conditions assumed, For when the land has a great elevation the moisture precipitated upon it will assume the form of snow and ice which will inaugurate various climatic changes. As the land is worn away there will be a greater surface of water exposed to evapora- tion, and this will react upon the quantity of precipitation. Again the disappearance of land will allow oceanic currents to pursue new channels which will directly react upon climate and indirectly upon precipitation. Finally the land will in most cases be subject to oscillations of level which will react upon climate in a complex and indirect way, and upon the rate of sedimentation in a direct way. Any one of these variations will interfere with the uniform- ity of the cycle, and when several of them are concerned simul- taneously it will be correspondingly complex. So much for the immediate causes. In the remote causes we must seek for an explanation of the periodicity of upheavals and subsidences which have given rise to cycles of sedimentation. For our present purposes it will not be necessary to enter into a discussion of the causes which have determined the existing con- figuration of landareas. Without doubt, Prof. Darwin’s appeal to astronomical influences suggests a general explanation of the leading facts. Also Dr. A. Winchell shows (World Life) how the lunar tides during the earth's early incrustive stages would impress meridional lines of weakness. The subsidence of the earth's equatorial protuberance due to the secular diminution of its rota- tional velocity would conspire to a like result. When such lines of weakness are once established every contraction of the crust due to the radiation of internal heat will give rise to rugosities along those lines, and these rugosities once established will tend to grow with every increase in the lateral pressure. So much for the generalities. But there are certain special and very remark- able phenomena which these hypotheses do not take into account. Such are the periodicities of upheaval and subsidence which have given rise to cycles of sedimentation. Mallet has argued in another connection that the contraction of the earth’s crust due to secular cooling would by the crushing of the rocks give rise to an enormous quantity of heat, and that this crushing would take place after long intervals of quiet, during which intervals the tension necessary to produce the crushing would be generated, On Cycles of Sedimentation.— Williaus. ald Doubtless here is one explanation of the periodicity of disturb- ances in land areas. There are others. Dr. Croll has shown how the precession of the equinoxes combined with variations in the eccentricity of the earth’s orbit must give rise to a secular recur- rence of periods of refrigeration. When winter in one hemisphere occurs in aphelion and the eccentricity is a maximum, the polar regions of that hemisphere will be covered with a cap of ice, anda climate of arctic severity will prevail. Meanwhile the other hem- isphere, beyond the equator, will have a torrid climate. This state of affairs will continue until the precession of the equinoxes shall reverse the conditions. Then the other hemisphere will suffer refrigeration and a tropical climate will dispel the ice-cap from the first. Dr. Croll shows how these changes would cause a shifting of the earth’s centre of gravity toward the pole which sustained the ice-cap, and thus the oceanic waters would rise on that hemisphere and deluge the land. Thus each hemisphere would undergo alternate phases of submergence coincident with the alternate periods of refrigeration. This oceanic oscillation, Dr. Croll argues, accounts for the alternate beds of coal and shale so characteristic of the Coal Measures in all parts of the world. (Climate and Time.) Here then we have another clear cass of periodicity. T would add in this connection that movements of the internal fluid arising from changes in the cen- ter of gravity, would, by virtue of the superior momentum of the central heavier masses inaugurate a motion which would churn the lighter peripheral fluid into the mountain arches and crevices, in some cases simply producing elevation, in others, giving rise to igneous eruptions upon the crust. If the interior of the earth had the rigidity of steel, a shifting of the centre of gravity would nevertheless lower the peripheral pressure on the far hemisphere, perhaps thus producing liquefaction, This might admit of lava outflows, and, in fact, evidences of such occurrences are not wanting in polar regions. Moreover, such a shifting of the sarth’s centre of gravity, even if ever so slight, might propagate spherical waves passing outward and imparting terrific impulses to the crust. Such waves would bring into contact different chem- ical elements separated before by their relative specific gravities, and this would promote intense calorific effects which would react upon the crust. It is possible that the rise of sea level, due to the ice-cap, would depress the sea-bottom and thus elevate the 520 The American Geologist. November, 1891 land by the superadded weight acting tangentially toward the shores. In the opposite hemisphere a new equilibrium would establish itself by the elevation of the sea-bottom and depression of the land. This would, in some degree, neutralize the relative differences of land and water areas to which the shifting of the seas would give rise. It is to be remembered that the intense pressure at the poles during periods of maximum glaciation would precipitate crustal convulsions when the contractile tension due to the radiation of internal heat should have become suffi- ciently great. These complex factors would all come into play periodically with the periodic recurrence of suitable astronomical conditions, There is yet another cause of periodicity which has oe- curred to me. In the deeper parts of the ocean, the hydro- static pressure must be enormously great. This pressure must force water very deeply into the rocky interstices of the ocean's floor, perhaps so deeply that its permeative power by capillarity is vastly increased (Daubrée ‘Géologie Expérimentale,’ p. 274). This water coming in contact with the heated rocks of the deeper crust would be vaporized and would also facilitate the evo- lution of explosive gases. These expansible products would press with tremendous force against their inclosures, and the crust would slowly yield to the irresistible pressure. This crustal movement would continue for a time until the original interstices should have swelled out into fissures sufficiently wide to admit the expansive products to escape as fast as they were formed. A period of quiescence, so far as this force is concerned, would then ensue until the gaps were filled in with sediment when the process would again be renewed. If the erosion of the land during the period of quiet were just sufficient to fill up the gaps we would then have the ideal conditions suggested at the beginning of this article. Itshould be remembered that the expansive force here considered would have a powerful tangential component which would react landward in each direction tending to produce continental upheavals. Such movements would cause a sub- mergence of the ocean's bed, and this bed would be _ still farther depressed by the superadded weight of the inrush- ing waters. Thus there would be an indefinite reciprocal action between the two initial tendencies, each elevation intensi- fying its correlated depression, and each depression augmenting ho _ On Cycles of Sedimentation.— Williams. 3 the already existing elevation. This reciprocity of effects would, however, be antagonized by at least three counter-tendencies: Ist, the earth’s tendency toward sphericity due to the combined action of gravity and its rotational movement. 2d, the rapid re- adjustment by erosion which would ensue from such enormous differences of level. 3d, the disturbed equilibrium of the inter- nal fluid which normally will assume concentric shells with den- sities inversely proportional to the distance from the centre. All these would oppose the distorting forces here contemplated (and all others producing like effects), and confine the surface move- ments within rigid limits. Here it should be borne in mind that when the upheaval and consequent expenditure of mechanical energy is great, the energy assuming the form of heat (due to crustal friction) is proportionately diminished, so that the result- ing evaporation of oceanic waters, and, hence, the violence of watery precipitations is diminished, but. so far as erosion is con- cerned this loss is offset by the increased angle of elevation of continents. [am convinced that the heat generated by crustal friction is an important factor in the processes of erosion: for, when developed in emergent land, it will increase the chemical effectiveness of atmospheric moisture coming in contact with it, and thus accelerate disintegration. Where, on the other hand, it is developed in the ocean's bed it will heat the cold polar cur- rents there, part of it being thus conveyed to the equatorial regions there to augment evaporation, and part of it will pass directly by convection to the surface producing a like effect. — In the reciprocal elevations and subsidences heretofore alluded to the heat of friction (and consequent evaporation resulting in erosion), would be developed on a prodigious seale. This would promote the rapid leveling mentioned above. Thus it appears that by an appeal to physical principles we can explain the fact of periodicity in the cycles of sedi- mentation as a result of several independent forces. While we cannot hope in any given instance to refer a partic- ular upheaval or subsidence to a specific category of causes, yet we may rest assured that one or several of these causes have been operative either isolatedly or conjointly in produc- ing the varied effects. Doubtless minor local disturbances are referable in some cases to purely local causes, although we should not trust too implicitly to such an interpretation. Be NO ryy . ’ : 322 The American (reologist. November, 1891 this as it may, there seems to be good reason for referring gen- eral and widespread movements occurring during protracted in- tervals, like those which took place on all the continents during the Carboniferous age to general causes. We have stated before that Dr. Croll refers the movements of this epoch to alternate periods of refrigeration on the northern and southern hemi- spheres, such periods favoring the formation of an ice cap, and thus, by changing the earth’s centre of gravity causing a rise of waters on the refrigerated hemisphere. No doubt this may ex- plain the fact of differences of consecutive strata, but it does not solve the problem of cycles of sedimentation, and it appears to me that a diminishing angle of slope inthe wasting land under uniform conditions of precipitation is the only adequate solution. But even this does not explain those grander divisions of geologic time like the Palaeozoic, Mesozoic, and Caenozoic. We may suppose that movements like the upheaval at the close of the Lower Silurian, in the Permian, or in Tertiary times were either the expenditures of accumulated tensions created by contractions in the earth’s crust, or a contemporaneous action of this with one or more of the other forces enumerated heretofore. Such a periodicity of major events separated by long intervals of time and interspersed by minor commotions harmonizes with the gen- eral hypothesis of a cooling and contracting globe. We would infer that in early times when the crust was thin, the radiation of heat was much more active than now, and general, peripheral convulsions were of frequent occurrence. But owing to the thin- ness of the crust it could not sustain any very marked elevations without a rupture and outflow of molten. matters within. Such outflows. if copious, would obliterate. any existing differences of level, and refuse the parts of the crust which were crumpled in- ward. This process would of necessity continue until the crust should have attained a sufficient thickness to sustain the eleva- tions impressed upon it. Assuming that this was the order of events we would expect that elevations would take place along lines of weakness (see wute); that the major contractions would be co-simultaneous on different parts of the globe, that the older mountains would have a smaller elevation than those that were formed later; and, finally, inasmuch as the rate of radiation of internal heat sustains an inverse ratio to the thickness of the crust. whereas the resistance to flexure sustains a direct ratio to On Cycles of Sedimentation.— Wi/lianis. 325 that thickness, we would expect that the epochs between succes- sive general disturbances would be progressively longer as the cooling of the interior advanced. On this hypothesis, other things equal, the Paleozoic won between the Lower Silurian and the Permian would be shorter than the Mesozoic, and this in turn shorter than the Cainozoic. But while these deductions seem well founded, we should be exceedingly cautious about applying them too literally owing to the manifold and intricate aspects of this problem. There seems to be good ground, however, for accepting the general views here set forth. A general synchronism of crustal movements is but a corollary from the doctrine of the identity of geological formations on different parts of the globe. The later formed mountains were undoubtedly colossal compared with earlier ones. We have but to compare the Green mountains (making due allowance for subsequent erosion) which were uplifted at the end of the Lower Silurian (Dana) with the Rockies, Andes, and Himalayas of Tertiary times to realize the greater effectiveness of orogenic forces with the aug- mented thickness of crust. While we seem forced to admit a general synchronism in the movements of continents as shown in the Eocene period, yet a close parallelism in the cycles of sedi- mentation should not be expected. Circumstances too numerous and complex to be here considered would modify in endless ways the minuter adjustments and readjustments of landand sea. But this absence of parallelism does not at all invalidate the general doctrine of cycles of sedimentation. Here it would be interesting to point out the relations subsisting between cycles of sedimentation and geological faunas. 1 priori we feel sure that intimate connections must exist between the two, and the general facts of pale- ontology seem to sustain the inference. The modifying in- fluences of such cycles must have profoundly affected the development of animal types. But we are too ignorant of the laws of life to speculate upon the modus operandi of such developments. We can conjecture this much, however, when the elevation of the land is greatest, the denudation is most ener- getic, the roily waters will then flow farthest out into the sea, and only mud-loving animals will frequent the neighborhood of the shores. Their remains will be imbedded in the resulting con- glomerate. With the diminution of erosive activities new con- 324 The ulimerican Geologust. November, 1891 ditions will prevail in adjacent seas, and a different class of or- ganisms will inhabit their waters. When the land has disap- peared altogether, the waters will be clear and well suited to the growth of lime-secreting animals. Thus there will be a cycle of living forms corresponding to each cycle of sedimentation, but owing to the long duration of those sedimentary cycles, and the mutability of animal types, the cycles of life will rarely if ever repeat themselves in consecutive cyeles of sedimenta- tion. In conclusion we may say that the general fact of cycles of sedimentation is well established. They are best explained as resulting from the secular elevations and differential rates of erosion of land areas. The elevations must have been periodic. This periodicity was due to other secular phenomena of a more general and fundamental character. The following are the most important of those phenomena: Ist. The secular cooling and con- sequent contraction of the earth’s crust. 2d. The alternate occurrence of periods of refrigeration at the northern and south- ern hemispheres due to astronomical events. 3d. The generation and expansion of gases and vapors at the bottom of the seas resulting in crustal disturbances. By the independent or united activities of these several forces there have resulted periods of profound and universal disturbances occurring at widely removed intervals of time. While those intervals have been marked by a prevailing quietude, yet there was a continuous succession of minor disturbances related in some complex way to those same general forces, which have given rise to cycles of sedimentation, July 28. 1891. EDITORIAL COMMENT. The study of geology is no light and easy task. Robert Mal- let once wrote that to be a geologist a man must first be a chem- ist, then a physicist, and lastly a mathematician. Geology can- not be mastered by reading the literature of the science, interest- ing and important as it is. Nor can the alternate loading and discharging of a few pages of a school or college text book make a geologist, (reologus nascitur, non fit, is a true parody of the original, No man can be a geologist unless the stuff is in him, bo Or kditorial Comment. > But possessing this he yet needs careful training. At the same time the subject is so large and the field so wide that scope is afforded for great variety of mental power and habit. The re- fiective mind can find ample room to usefully indulge his specu- lative tendency if he only keeps within the limits of reason and judgment. The observing realistic mind will be perfectly at home in a practical portion of the science. Nor are the graces of literary training foreign to the subject, for the power of the geologist to present his favorite theme to others is often and vastly helped by its possession. The stonemason of Edinburgh would never have become the Hugh Miller of geology and litera- ture had he lacked his elegance and power of diction and illustra- tion, But for success in any field of the science hard and continuous labor and thought are requisite—especially thought. Pondering on the problems before him and working them out in detail, whether in the field or the study, makes the geologist. To realize by the aid of a scientific imagination the past and the lost of the earth’s history, to conceive of the destroyed as still in existence, and to estimate and weigh the changes resulting from its destruction, all this involves a power of vivid mental imagery not possessed by many. Great geologists therefore have been and still are rare. Men who can gather up the work of others and focus it with their own in some grand generalization as Agassiz did for the Ice-age. never will be numerous. But the rank and file of the geological army is not to be despised because each one cannot be the great com- mander. Every one can contribute to the victory if by patient and careful drill he will fit himself for the work that geology demands, And this work is the investigation of the problems that lie at his own door. County geology, township geology and even the geology of smaller areas are the topics with which most must con- tent themselves. There is scarcely a county or township between Maine and Oregon, between Minnesota and Mississippi that does not atford enough problems to employ all who desire to work. ‘* But what shall I study? At what shall I look?” are the usual remarks. Are there fossils within your reach? ‘Then make an effort to secure all the species that occur there and learn to distinguish each one and every single part of each one so as to have a critical acquaintance with them. Are there none? Then 526 The American Geologist. November, 1891 study the river and stream. Why does this stream flow here and that one there? Has the present position been determined by the hardness and softness of the strata or by some other cause? Have the highlands been elevated or are they merely relies of larger masses that have been eroded? To what geological era do the rocks of the county belong, and for what reason are they ascribed to that date? These are a few samples of the problems lying before the local geologist and his attempts to solve them will give him more geo- logical knowledge than the reading of all the textbooks or the committal of their pages to memory. I have seen men who knew nothing of book geology, who could not tell whether the Silurian or the Carboniferous strata were the older, and who did not concern themselves with the theoretical questions that divide the geological world, but who were nevertheless, in my opinion, trained and educated men, who could reason closely and severely from their data, and whose queries, suggested by experience, often puzzled learned geologists who heard them. Such men are too scarce. I do not undervalue study of a wider kind. Let all who can enjoy it. But when it is out of reach let none sit down and say “IT cannot study geology.” . Such men as described above are often the life and soul of local societies, and it is from their careful and constant work that these societies derive a great part of their value. To both we look for great and increasing results in the future. REVIEW OF RECENT GEOLOGICAL LITERRAT URE: On the Vertebrata from the Tertiary and Cretaceous Rocks of the N. W. Territory.— . D. Corr. (Geol. Sur. of Canada, Vol.3 [Quarto], 1891, pp. 25,14 pls.) In this part (1) Prof. Cope describes “The Species from the Oligocene or Lower Miocene beds of the Cypress Hills.” The material, from which these species are described, was found in a bad state of preservation, the bones being much broken, which is accounted for by the fact that the formation from which they were derived is conglom- erate of a quartzitic nature. The beds are somewhat older than the White River beds of Dakota, which accounts for the presence of ITemipsalodon. Five new species of fishes are described, Ama. whit- Review of Recent Geological Literature. 327 eavesand, A. mucrospondyla, Rhinestes rhwas, Améiurus cancellatus, A, maconnellit, the three latter being somewhat doubtful; a new testudinous reptile, Zrionyx leucopotumicus is also given. A number of mammals are also described, .Wenodus being the principal. It is surprising to note the almost entire absence of the Oreodonts, only one tooth having been found. The British Tertiary Echinoid Faunas and their Affinities—J. W. GreGorY, F.G.S. 45 pp. I fig. in text. (Proc. Geologists’ Association, London, Pts. I and II, 1891.) This isa most important memoir, cover- ing, as it does, the entire Tertiary fauna of the British Isles; the work, however, is deficient in illustrations of the new species described. There is reference to two plates, and it is presumed that they will appear with the next number of the Proceedings. Six new species are de- scribed of which four are from the Eocene. According to this author, there are 7 genera and 14 species from the Eocene, 11 genera and 21 species, of which 9 are Hehénus, from the Pliocene, and five genera and seven species, of which 3 are Hehinus, from the Pleistocene. The author concludes that the cause of the small number of British echinoids is due entirely to climatic and lithologic conditions; in the Cainozoic, the British seas were cold and free from reefs, both conditions unfavorable to the growth of echinoids. The author also favors the view that a belt ef shallow water connected the south of Europe with America during the Cainozoic. A bibliography is appended in which are cited 49 authorities. The Mesozoic und Tertiary Insects of New South Wales.—R. ETHERIDGE, Jun. and A. 8. OLuIFF, 14 pp., 2 heliotype plates. (Memoirs Geol. Sur. New So. Wales, No. 7, 1890.) There are but few Tertiary insects (hardly a dozen) known from the Australian continent, therefore this contribu- tion is particularly timely and important. There are described two new genera (Wesostigmodera, belonging to the family Buprestide and Palwolycus belonging to the family Lumpyride, both Coleoptera) and five new species. On the Osteology of Pobrotherium—W. B. Scorr, Princeton (Jour. Morph. Vol. V, No. 1, June, 1891), pp. 74,3 pls. and figs. in text. This learned author’s “Contribution to the Phylogeny of the Tylopoda” is a beautiful illustration of systematic work. He first gives some interest- ing examples in evolution and then takes up the Pwhrotherium, which he is better able to describe than any other person, not only on account of his well known ability so to do, but also by the fact of the posses- sion of an almost complete skeleton: this skeleton having been discov- ered by that indefatigable collector, Prof. W. F. Magie, upon the ground which a few months later (in 1890) was made memorable by the Indiau outbreak. This skeleton, together with a number of other parts, has enabled Prof. Scott to render this important contribution, and the thorough study of Pwhrotherium is indicated by the large number of pages devoted thereto. There is, however, one fault to be found with this paper, viz: the method of giving references, which are numbered, 328 The American Gedlogist. November, 1891 and refer to the end of the paper, whereas it would seem much better and would afford easier reading, to have the usual foot references. The author says Protolubix is the connecting link between Procamelus and Pebrotherium, this latter being also the forerunner of the llamas as well as the camels. He thinks the two species of Procamelus, P. occidentalis and P. wugustidens, the starting points of the llamas and camels re- spectively. Leptotragulus is the forerunner of the White River Pwbro- therium. The Bridger Homacodon is connected with Pantolestes on theone hand and Leptotragu/us on the other. “If these conclusions are correct, it follows that the Tylopoda are but remotely connected with the true ruminants.” The points in which the modern camels agree with the ruminants and which are absent in the Pwhrotherium have been inde- pendently acquired. The monograph closes with a bibliography of thirty-four contributions to this and allied subjects. The three plates are magnificent expositions of the art. The Tudor specimen of Eozoon. J.W. Greconry, F. G.S. (Quart. Jour. Geol. Soc. Aug. 1891.) After a thorough examination of this specimen of Kozoon from Tudor, Hastings Co., Ontario, the author of this paper, supported by many authorities, comes to the already foregone conclusion that itis not of organic origin. It is further stated that the rock containing the specimen is not, as has been previously described, Lower Laurentian but “Huronian’’ of Selwyn and Vennor. Stones for Building und Decoration, by GEORGE P. MERRILL, Curator of Geology in the United States National Museum, Octavo, pp. 455. New York. John Wiley & Sons, 1891. All quarrymen and builders who use stone will welcome this volume. It is the first of its kind in America, and it will certainly serve a very useful purpose in the quarry- ing industry. Quarrymen and stone users are very apt to be ignorant of the mineralogy and geology of the rocks they handle, and the crudest notions concerning them are frequently current. In this volume the composition and other natural qualities of all the building-stones of the country are set out plainly in simple and non-technical, yet in accurate, descriptive, language. This will afford the information that is so badly needed by the ordinary builder, and will disseminate otherwise a more thorough and scientific knowledge of stone. Of course the scientific man does not look into such a work for anything new in science. It is not addressed to such, but it contains many generalizations and summary statements in convenient form which will make it also very useful to him in reference to those portions of the subject with which he may not be personally familiar. It is a compendious dictionary of the pro- duction and distribution of stone for construction and decoration in the United States, and also contains chapters on the weathering and preser- vation of building-stones, and on their comparative qualities. No one has had ampler facilities, and certainly no one could be better fitted for the production of such a work than the curator of geology of the United States National Museum, where samples of all the building- Recent Publications and Correspondence. 329 stones of the country were gathered through the agency of the census of 1880. Annual Report, Geological Survey of Arkansas, 1888, Vol. tv, J. C. BRANNER, state geologist, Little Rock, 1891, contains: The geology of Washington county, by F. W. Srmonps, and A list of the plants of Arkansas, by J. C. BRANNER and F. V. Covrtte. The report on Wash- ington county is very full. The county embraces a complete section across the Lower Carboniferous rocks (Chester, St. Louis, Warsaw, Keo- kuk and Burlington) to which the name “ Mississippian” is applied, after the recommendation of the late Dr. A. Winchell. In like manner the Coal Measures of the state, represented only by the basal portion—the Millstone grit—is named Pennsylvanian on the authority of Prof. H. 8. Williams. Mechan's Monthly, published at Germantown, Philadelphia, by Thomas Meehan & Sons, is devoted to general gardening and wild flowers, but it is much more than a gardener’s paper, being strictly scientific, and con- veying much general botanical information. LIST OF RECENT PUBLICATIONS. Foreign Publications. Surface straining of the earth in relation to the deep phenomena of voleanic action. T. Mellard Reade. (Geol. Mag. Aug. 1890.) Perched rocks near Austwick. T. Mellard Reade (Geol. Mag. July, 1891.) On the Killary bay and Slieve Partry Silurian basin, also notes on the metamorphic rocks of northwest Galway. G. Henry Kinahan, (Pro. Roy. Irish Acad. 3rd. Ser., Vol. I, No. 5.) On the Drifts of Flamborough Head, G. W. Lamplugh, (Quart Jour. 4xeol. Soc. Aug. 1891). VI. Setentifie Laboratories and Museums. Bulletin of Denison University, Vol. VI, partl, contains: Some obser- vations on the crushing effects of the glacial ice-sheet, W. G. Tight. CORRESPONDENCE. New Zealand Glacicrs.—The glaciers of Mount Cook (New Zealand) are not a whit behind those of the Alps in some respects. The longest is longer than the longest in the Alps. Then for one ton of superficial moraine matter the Alpine glaciers carry, the Mount Cook glaciers must carry five hundred. The Mueller glacier is a mile in width, and for its lowest three or four miles is completely buried under a load of stones of all sizes, from that of a railway carriage downward. I got about 8,000 feet up Mount Cook, and I think would have attained the summit if I 550 The American Geologist. November, 1892 would have spared another week. It will probably be surmounted in a year or two, as young New Zealanders are getting to get a pride in it, and it will be much easier now, as a “Chalet” has just been completed well up the Hochstetter glacier and will afforda convenient base of operations. Although there is evidence in old moraines, old high lake levels, and the like, of a former enormous extension of the glaciers, there is, strange to say, hardly any equivalent of the till or boulder clay marking an ex- tensive moraine profonde. On this subject I may say that when in Adelaide (South Australia), I went with professor Tate to Hallet’s cove, in Spencer gulf, to see his glacial markings. Much discredit has been cast on these, but with all the assurance derived from having mapped glacial striz in Scotland for ten years almost daily, I recognized these as genuine and unmistakable. There was just as little doubt that the ice which made them moved from south to north; let the fact be explained as it may—-whether the motive lay in a high land now submerged, or in the heaping up of ice round the south pole. Inthe latter case the ice should have impinged on other parts of southern Australia and on New Zealand. The marking may not have been recognized because of the prevalence of soft Tertiary rocks unfit to retain impressions, or perhaps because the idea would seem absurd. RoBert L. Jack. Townseiile, Queensland, Aug. 5, 1891. Mr. Cusine AnD THE Mute GiAcrer.—In the very instructive and in- teresting paper by Mr. Cushing in the October number of the AMERICAN GEOLOGIST I was specially attracted by his remarks upon p. 221 upon the slight changes of level which seem recently to have taken place at the head of Muir inlet. One indication of the yarying phases exhibited by the front of Muir glacier is found in the buried forests described by Mr. Cushing on the east side. During the summer of 1886, when I was there, those buried forests were not visible. Nor did we observe upon the east side any instance of the ice overlapping the sand and gravel, though we saw abundant instances of both phenomena upon the west side. In recurring, however, to a report of Mr. Lamplugh who visited the glacier in 1884, I find that his attention was attracted by the overlap- ping ice on the east side, and the officers upon the steamer told me of having seen buried stumps at low tide in the same vicinity. Evidently the annual changes going on at the front of the glacier, especially upon the east side, are very rapid and marked, and it would be well if arrange- ments could be made to have them accurately noted from year to year. I think Mr. Cushing is probably right in his criticism upon my ex- planation of the burial of the forests upon the west side of the inlet. My suggestion was that “the dying glacier” had pushed eastward during a period of general advance, so as to obstruct the drainage through Muir Inlet, and certainly the position of the moraine upon this singular glacier looks as though it were an offshoot from the larger ice-stream that at one time filled the west fork of Glacier bay, coming down from mounts Crillon and Fairweather. Mr, Cushing’s criticism is also supported by a vpsondl and Serentipic News. Sol fact which I mentioned but did not fully consider in my theory (see Ice Age in North America, p. 61), viz: that there were remnants of a buried forest on the south end of Ileadland island, which is below the “dying glacier.” A slight modification of my theory, however, would meet this difficulty, namely, that the ice-stream coming down the west fork of the glacier was for a time predominant, and pushed along so far in advance of that which enters the east fork as to obstruct the drainage of Muir inlet, and allow the accumulation of sand and gravel which we now find above the forests. While there is nothing in the way of supposing aslight subsidence to have occurred sufficient at least to carry down the buried forest on the east side below tide level many facts which have been brought to my observa- tion recently in England make me hesitate about bringing into the theory so large a cause for so small an effect. It has seemed to me that possibly those forests upon the east side, having grown upon an insecure founda- tion, may have slightly shifted their position, and that, as the inlet has been deepened by the active erosive agencies at work, there may have been a slight slip of extensive portions of the soil upon the east side, so as to carry the buried forests below the sea level. It is possible, also, that this lowering of their level may have been brought about with little or no lateral movement. The occurrence of a bed of quicksand upon which the forest strata rested may have suffered the foundations to be undermined through the action of springs, and thus brought about a local sudsidence sufficient to account for all the facts. Mr. Cushing’s presentation of evidence bearing upon the changeability of the conditions about the eastern sources of Muir Glacier seems fully to justify his criticism of my remark that these forests may have existed before the Glacial period itself. In connection with further study of the region I wish attention might be directed as soon as possible to the glaciers which enter the western fork of the bay, that we might learn whether the changes taking place there are correlated with those upon the Muir glacier. G. FREDERICK WRIGHT. Oberlin, Ohio, Oct. 10. PERSONAL AND SCIENTIFIC NEWS. THE UNIVERSALITY OF GOLD. Almost every cubic yard of granite, or in fact, of rock of any description, contains from mere traces to often appreciable quantities of metallic gold intermixed amongst the materials forming the rock. Also, it is a scientific fact, and one which has been proven by many actual experiments, that, for every avoirdupois ton of water in the entire bulk of the ocean, there will average about two grains of gold. Or, in other words, there will be found about two grains of gold in the form of a chloride of gold, in every ton of sea water, whether taken from the surface or at the bottom. And, therefore, there are un- 3392 The American Geologist. November, 1891 told millions of dollars of gold held in solution by the waters of the ocean, which have been dissolved out of the rocks of. the earth by the action of heated alkaline waters containing: silica, that have slowly leached and percolated their way throughout the crevices and porous substances of rocks, dissolving out the infin- itesimal particles of gold. The primary source of the gold found at the surface of the earth is found to be in the earliest azoic granite; and from these granites it has been altered and formed over and over again through all the succeeding geological horizons to the present period, Or, in other words, the gold of the ancient Archean granites formed during the cooling of the earth’s crust, has been dissolved and precipitated and re-dissolved and _ re-pre- cipitated, over and over, throughout all the rocks of the earth’s strata, from the very earliest Azoic to the most recent Quater- nary period. Therefore gold may be sought for in every geologi- eal horizon; and has thus been found in more or less paying quantities from the very earliest rocks, up to the recent alluvial and drift formations. However, in those veins of quartz which are found in the Cambrian and Lower Silurian strata, gold, in the metallic state, intermixed amongst the quartz, is found in far greater commercial quantity, than in any other of the preceding or subsequent geological horizons. Wherever gold has been found in very large quantity in either vein or placer form, it has been found to be either in a Cambro-Silurian series of slaty rocks and quartz, or else has resulted from the immediate decomposi- tion of those rocks. Dr. Wittis K. EVER re. Tue Catumer AND HEcLA MINE is now worked at a depth on the lode of over 4,000 feet with an extent in length of about two and one-half miles. This mine is operated by fourteen shafts, one of which is a six-compartment shaft, now sunk to a perpendicular depth of about 2,500 feet; and which when completed will be upward of 5,000 feet deep. The aggregate power of the steam plant in use and under construction is some 57,500 horse power, including one engine of 4,700 horse power and eleven other engines of an average of 2,000 horse power each. The stamp mills of this mine contain 18 improved Ball steam stamps, making from 95 to 98 blows per minute and crushing about 4,500 tons of rock of the lode in twenty-four hours. The three pump- ing engines have an aggregate capacity of 50,000,000 gallons in twenty-four hours; while another triple expansion pumping en- gine, now nearly completed, has alone the capacity of 60,000,000 gallons in twenty-four hours. Besides the two sand wheels forty feet in diameter capable of elevating some 16,000,000 to 18,000, - 000 gallons of water and 1,600 tons of sand per day, there is nearly completed another wheel fifty-four feet in diameter, de- signed to elevate 30,000,000 gallons of water and 3,000 tons of sand per day. Dr. M. BK. Wapswortn, APPENDIX. A CATALOGUE OF THE PALAZONTOLOGICAL PUB- Ec aTiONS OF JOSEPH LEIDY, W.,D.,,LL.D. By Joun EYerMAN, Easton, Pa. Dr. Henry C. Chapman in his “Memoir of Joseph Leidy, M. D., LL.D.” (Proc. Acad. Nat. Sci. Phila., 1891, pp. 342-388) gives a list of the recorded publications of this celebrated anatomist, in which there are no less than five hundred and fifty-three communications, principally to the Proceedings of the Academy of Natural Sciences of Philadelphia. It is a noteworthy fact that nearly one-half of these. communications relate to vertebrate paleontology. Dr. Chapman’s complete bibliog- raphy exhibits the wide range of thought, which Dr. Leidy enjoyed in the natural Sciences. At the conclusion of his memoir, Dr. Chapman pays this high tribute to his friend. ‘Possibly no country ever produced “a student whose knowledge was at once so accurate and comprehensive. “He was an excellent mineralogist and botanist without claiming to be “either, among the highest living authorities on comparative anatomy “and zoology, one of the most distinguished helminthologists living and “the equal of any paleontologist at home or abroad.” 1. On the Fossil Horse of America. Proc. Acad.* 3, 1846-47, pp. 262-66. ’ 2. Additional Observations on the Fossil Horse of America. Proc. Acad. 3, 1847, pp. 262-66. On the new Genus and Species of Fossil Ruminantia, Poebrother- ium wilsoni, Proc. Acad. 1846-47, pp., 322-26. 3a. Id. Ann. Nat. Hist. I, 1848, pp. 389-92. 3b. Id. Am. J. Sci.t V, 1848, pp. 276-79. 4. On a new Fossil Genus and Species of Ruminantoid Pachyder- mata, Merycoidodon culbertsonii. Proc. Acad. IV, 1848-49, pp. 47-50. 5. Tapirus americanus fossilis. Proc. Acad. IV, 1848-49, pp. 180-83. 6. On Rhinoceros occidentalis. Proc. Acad. 1850, p. 119. i. Observations on two new Genera of Mammalian Fossils, Eucrota- phus jacksoni and Archzeotherium mortoni. Proc. Acad. V, 1850- D1, pp. 90-94. On some Fossil Mammalian Remains. Proc. Acad. V, 1850-51, pp. 121-22. 9. Ona Fossil Tortoise, Stylemys nebrascensis. Proc. Acad. V, 1850- D1, pp. 124-26. 10. On Fossil Remains of Ruminant ungulates from Nebraska. Proc, Acad. V, 1850-51, pp. 237-39. 11. On the Fossil Remains of Balaena paleatlantica and B. prisca, from the Miocene formation of Virginia. Proc. Acad. V, 1850-51, pp. 308 9. ow : DP *Proceedings of the Academy of Natural Sciences, Phila. +American Journal of Science. 54 The American Geologist. November, 1891 On some Fossil Reptilian and Mammalian Remains. Proc. Acad. V, 1850-51, pp. 825-30. 3. Description of a new Species of Crocodile from the Miocene of Virginia. Jour. Acad.* II, 1850-54, pp. 135-38. 14. On the Osteology of the Head of Hippopotamus and a Denne tion of the Osteological Characters of a new Genus of Hippopot- amide. Jour, Acad. IT, 1850-54, pp. 207-24. On Bathygnathus borealis, an Extinct Saurian of the New Red Sandstone of Prince Edward Island. Jour. Acad. IT, 1850-54, pp. 327-30. On some Fragments of Paleotherium proutii. Proc. Acad. 1851, pp. 170-71. Report upon some Fossil Mammalia and Chelonia from Nebraska. Smith. Rept., 1852, pp. 63-65. Remarks on a Fossil Vertebra from Ouachita, La. Proc, Acad. 1852, p. 52 On the Osteology of Hippopotamus. Proc. Acad. 1852, pp. 52-53 20. On Fossil Tortoises from Nebraska. Proc. Acad. 1852, p. 59. On two Crania of Extinct Species of Ox. Proc. Acad. 1852, p. 71. Reference to a Fossil Tooth of a Tapir. Proc. Acad. 1852, p. 106. 23. Remarks on the Fossil Ox. Proc. Acad. 1852, p. 117. 24. Remarks on some Fossil Teeth of a Rhinoceros from Nebraska. Proc. Acad. 1852, p. 2 25. Ona Fossil Turtle from Nebraska. Proc. Acad. 1852, p. 34. 6. On a new Species of Fossil Delphinus and a New Saurian, Thoracosaurus grandis. Proc. Acad. V1, 1852-53, p. 35. 27. Ursus amplidens, a new Fossil Species. Proc. Acad. VI, 1852-53, p- 303, 28. Onsome Fossil Cetacean Remains. Proc. Acad. VI, 1852-53, pp. 377-78. 29. Description of the Remains of Extinct Mammalia and Chelonia from Nebraska Territory, collected during the Geological Survey under the direction of Dr. David Dale Owen. Rept. of Geol. Sur. of Wis., [a., and Minn., D. D. Owen, 1852, pp. 540-72. 30. Description of an Extinct Species of American Lion, Felis atrox. Am. Phil. Soc. Trans. X, 1853, pp. 319-22. 31. A Memoir on the Extinct Dicotylidie of America, 1852. Am. Phil. Soc. Trans. X, 1853, pp. 323-44. 32. Memoir on the Extinct Species of American Ox, 1852. Smith. Cont. V, 1853. 33. Remarks on various Fossil Teeth. Proc. Acad. 1853, p. 214. 34. On some Fossil Fragments from Natchez, Miss. Proc. Acad., 1853, p. 303. 35. Remarks on a Collection of Fossil Mammalia and Chelonia from the Mauvaises Terres of Nebraska. Proc. Acad., 1853, pp. 392-94. *Journal of the Academy of Natural Sciences, Phila. 44, a6, Publications ofr Soseph Leidy.—hyerman. 33D The Ancient Fanna of Nebraska; or a Description of Remains of Extinct Mammalia and Chelonia from the Mauvaises Terres of Nebraska, 1852. Smith. Cont. VI, 1854, 392-94. On Brimosaurus grandis, n. g. Proc. Acad. VII, 1854, p. 72. On Bison latifrons. Proc. Acad. VIT, 1854, p. 89. On Dinictis felina. Proc. Acad. 1854, p. 127. Hippodon and Merycodus, new fossil genera indicated. Proc. Acad. VII, 1854-55, p. 90. Synopsis of Extinct Mammalia, the Remains of which, have been discovered in the Eocene formations of Nebraska. Proc, Acad. VII, 1854-55, pp. 156-58. Description of a Fossil apparently indicating an Extinct Species of the Camel tribe. Proc. Acad. VIT, 1854-55, pp. 172-73. Notice of some Fossil Bones, discovered by Mr. Francis A. Lincke, in the banks of the Ohio river, Indiana. Proc. Acad. VII, 1854- D9, pp. 199-201. Remarks on the question of the Identity of Bootherium cavifrons with Ovibos moschatus or O. maximus. Proc. Acad. VIT, 1854-55, pp. 209-10. Indications of twelve Species of Fossil Fishes from New Jersey and §. Carolina. Proc. Acad. VII, 1854-55, pp. 395-97. Indications of five Species, with two new Genera, of Extinct Fishes. Proc. Acad. VII, 1854-55, p. 414. A Memoir on the Extinct Sloth Tribe of North America, 1853 Smith. Cont. VIT, 1855. On aso-called Fossil Man. Proc. Acad. 1855, p. 340. Description of some Remains of Fishes from the Carboniferous and Devonian Formations of the United States. Jour. Acad. IIT, 1855-58, pp. 159-62. Descriptions of some Remains of Extinct Mammalia. Jour. Acad III, 1855-58, pp. 166-71. Descriptions of Two Ichthyodurulites. Proc. Acad. VIII, 1856, pp. 11-12. Notices of some Remains of Extinct Mammalia, discovered by Dr. F. Y. Hayden in the Bad Lands of Nebraska. Proc. Acad. VITI, 1856, pp. 59-60. Notices of Remains of Extinct Reptiles and Fishes, discovered by Dr. F. V. Hayden, in the Bad Lands of Judith tiver, Nebraska Territory. Proc. Acad. VIII, 1856, pp. 72-75. Id. Am. J. Sci. XXI, 1856, pp. 422-23. Notices of Remains of Extinct Mammalia, discovered by Dr. F. V. Hayden in Nebraska Territory. Proc. Acad. VIII, 1856, pp. 88-90. Notices of the Remains of a Species of Seal, from the Post- Pliocene Deposit of the Ottawa river. Proc. Acad. VII[, 1856, pp. 90-91. Notices of several Genera of Extinct Mammalia, previously less perfectly characterized. Proc. Acad. VIII, 1856, pp. 91-92. The American Geologist. November, 1891 Notices of some Remains of Extinct Vertebrated Animals. Proc. Acad. VITT, 1856, pp. 162-65. Notices of some Remains of Extinct Vertebrated Animals col- lected by Prof. Cook. Proc. Acad. VIII, 1856, pp. 220-21. Notices of some Remains of Extinct Vertebrated Animals, discoy- ered by Prof. E. Emmons. Proc. Acad. VITI, 1856, pp. 255-56. Id. Am. J. Sci. XXIII, 1857, pp. 271-72. Notices of some Remains of Fishes, discovered by Dr. John E. Evans. Proc. Acad. VIII, 1856, pp. 256-57. Notices of Remains of Two Species of Seals. Proc, Acad. VIII, 1856, 265, Remarks on certain Extinct Species of Fishes. Proc, Acad. VITI, 1856, pp. 301-2. Notices of Remains of Extinct Turtles of New Jersey, collected by Prof. Cook. Proc. Acad. VIII, 1856, pp. 303-4. Notices of Extinct Vertebrata, discovered by Dr. F. VY. Hayden, during the expedition tothe Sioux country. Proc. Acad, VITT, 1856, pp. 311-12. List of Extinct Vertebrata, the remains of which have been dis- covered in the region of the Missouri river; with remarks on their geological age. Proc. Acad. IX, 1857, pp. 89-91. Notices of some Remains of Extinct Fishes, Proc. Acad. IX, 1857, pp. 167-68. On New Red Sandstone Fossils from the Gwynnedd Tunnel N. P. R. R. Proc. Acad., 1857, p. 150. Rectification of the References of the Extinct Mammalian Genera of Nebraska. Proc. Acad. 1857, pp. 175-76. On the Dentition of Mososaurus. Proc. Acad. 1857, p. 176. Notices of Remains of Extinct Vertebrata, from the Valley of the Niobrara river, collected during the exploring expedition of 1857, by Dr. F. V. Hayden. Proc. Acad. X, 1858, pp. 20-29. Remarks on Fossil Mammalia from Nebraska. Proc. Acad. 1858, p. 7. Notice of Remains of Extinct Vertebrata from the Valley of the Niobrara river. Proc. Acad. 1858, p. 11. Remarks on a Cast of a Mastodon Tooth. Proc. Acad. 1858, p. 12. Remarks on Fossil Remains from Nebraska, Proc, Acad. 1858, pp. 89-90. ,; Remarks on Hadrosaurus foulkii. Proc. Acad. 1858, pp. 215-18. On Hystracanthus arcuatus and Cladodus occidentalis. Proc. Acad. 1859, p. 3. Remarks on Tooth of Mastodon and Bones of Mosasaurus. Proce. Acad. 1859, pp. 91-92. Remarks on Teeth of Clepsysaurus, Eurydorus serridens and Com- sosaurus from Pheenixville Tunnel, Chester Co., Pa. Proc. Acad. 1859, p. 110. Remarks on Fossils from Bethany, Va., and also from the Green- sand of Monmouth Co., N. J. Proc, Acad. 1859, p. 110. 80. 86. ST. 88. — Publications of Joseph Leidy.—fkyerman. 337 Remarks on Ossite from Sombrero, W. L., and on skull of Ursus americanus from the drift of Claiborne, Ala. Proc. Acad. 1859, jor eal BLE Remarks on Fragment of Jaw of Mosasaurus. Proc. Acad. 1859, p. 150. On Specimens of Paleotrochus from sub-Silurian Strata. Proc. Acad. 1859, p. 150. Remarks on Dromatherium sylvestre and other Fossils from Chatham Co., N.C. Proc. Acad, 1859. p. 162. Remarks on the Antler of the Reindeer found at Sing Sing and Remarks on Freija americana from Newport. Proc. Acad. 1859, p. 194. Description of the Remains of Fishes from the Carboniferous limestone of Illinois and Missouri, 1856. Trans. Amer. Phil. Soc. XI, 1860, pp. 83-87. Remarks on Saurocephalus and its allies, 1856. Trans. Amer. Phil. Soc. XI, 1860, pp. 91-95. Observations on the Extinct Peccary of North America; being a sequel to “A Memoir on the Extinct Dicotylinae of America,” 1856. Trans. Am. Phil. Soc. XI, 1860, pp. 97-105. Remarks on the Structure of the Feet of Megalonyx, 1856. Trans Am. Phil. Soc. XI, 1860, pp. 107-108. Extinct Vertebrata from the Judith River and Great Lignite _ Formations of Nebraska. Trans. Am. Phil. Soc. XI, 1860, pp. 139-154. Remarks on Fossil Teeth of Hippotherium from Washington Co, Texas. Proc. Acad., 1860, p. 416. Remarks on an Extinct Peccary from Dr. D. D. Owen. Proc. Acad, 1860, 416. Cretaceous Reptiles of the United States, 1864. Smith. Rept. 1864, pp. 66-73. Id. Smith. Cont. XIV, 1865 (Art. 6). Id. Geological Magazine, V, 1868, pp. 432-35. Fossil Remains of Horses from California. Proc. Acad. 1865, p. 94. Fossil Remains of Rhinoceros from Texas and California. Proc. Acad. 1865, pp. 176-77. On Bones and Stone Implements from Guano deposits in the Island of Orchilla. Proc. Acad. 1865, pp. 181-83. Remarks ona Phalynx of an Extinct Reptile. Proc. Acad. 1866, Ded: Remarks on Human Relics at Petite Anse, La. Proc. Acad. 1866, p. 109. Remarks on Fossils presented June 5. Proc. Acad. 1866, p. 237. On Fossil Bones from Mauvaises Terres, Nebraska. Proc. Acad. 1866, 0. 345. Remarks on the Skull of Bison latifrons. Proc. Acad. 1867, p. 85 Exhibition of the skull of Geomys bursarius. Proc, Acad. 1867. Be Ot: The American Geologist. November, 1891 On the skull of Castoroides ohioensis. Proc. Acad. 1867, p. 97. Notices of some Vertebrate Remains from Hardin Co., Texas. Proc, Acad. 1868, pp. 175-76. Indication of an Elotherium in California. Proc. Acad. 1868, p. it Notices of some Reptilian Remains from Nevada. Proc. Acad. 1868, 178-80. Notices of some Vertebrate Remains from the West Indian Islands. Proc. Acad. 1868, pp. 178-80. Notices of some Remains of Horses. Proc. Acad. 1868, p. 195. Notices of some Extinct Cetaceans. Proc. Acad 1868, pp. 197-99. Remarks ona Jaw Fragment of Megalosaurus. Proc. Acad. 1868, pp. 197-99. Notices of American Species of Ptychodus. Proc. Acad. 1868, pp. 205-6. Notices of some Remains of Extinct Pachyderms: Dicotyles nasutus, Anchippus texanus, Anchippodus riparius, Lophiodon occidentalis. Proc. Acad. 1868, pp. 315-16. Notices of some Remains of Extinct Insectivora from Dakota. Proc. Acad, 1868, pp. 315-16. On Photograph of Fossil Bones from Topeka, Kas. Proc. Acad. 1868, p. 315. On the Extinct Mammalia from Dakota and Nebraska, including an account of some allied forms from other localities. Jour- Acad. VII, 1869, pp. 23-362. Synopsis of Extinct Mammalia of North America. Jour. Acad VII, 1869 pp. 363-472. Notices of some Extinct Vertebrates from Wyoming and Dakota. Proc. Acad. 1869, pp. 63-67. Elasmosaurus platyurus, Cope. Am. J. Sci. XLUX, 1870, p. 392. Fossil Sivatherium from Colorado Megacerops coloradensis. Proc. Acad. 1870, pp. 1-15. Remarks on Poicilopleuron valens, Baptemys wyomingensis, Emys stevensonianus and other Fossils from the Middle Park, Colorado. Proc. Acad, 1870, pp. 3-5. On Reptilian Remains from the. Cretaceous formation near Fort Wallace, Kansas. Proc. Acad. 1870, pp. 9-10. On a Fossil Mandible from near Fort Bridger, Wyoming. Proc. Acad. 1870, pp. 10-11: temarks on Xiphactinus audax and other Ichthyodorulites. Proc. Acad. 1870, pp. 12-15. Remarks on Asteracanthus siderius. Proc. Acad. 1870, p. 13. On Hadrosaurus and its allies. Proc. Acad. 1870, pp. 67-68. Descriptions of Oncobatis pentagonus and Mylocyprinus robustus. Proc. Acad. 1870, pp. 69-71. On Mastodon Remains of theWarren Museum and the Cambridge University Museum. Proc. Acad. 1870, pp. 96-99. On Crocodilus elliotti. Proc. Acad. 1870, pp. 100, 122. Publications of Soseph Leidy. Leyeriman. 339 On some Fossils from the Sweet Water river, Wyoming Territory. Proc. Acad. 1870, pp. 109-110. Description of a new Species of Oreodon: O. superbus. Proc. Acad.1870, pp. 111-112. On Anchitherium condoni and Cordylophora americana. Proc. Acad. 1870, pp. 115-118. Descriptions of Paleosyops paludosus, Microsus cuspidatus and Notharctus tenebrosus. Proc. Acad. 1870, pp. 113-114. Descriptions of Graphiodon vinerius, a fossil reptile. Proc. Acad. 1870, p: 122. Reptilian Remains from Wyoming; Emys jeanesi, E. haydeni, Bena arenosa. Proc. Acad. 1870, pp. 125-24. Fossil Remains of a Lacertian, discovered near Granger: Saniwa ensidens Proc. Acad. 1870, pp. 124-25. Fossil Fragment of the Lower Jaw of a small Pachyderm; Lophiotherium sylvaticum. Proc. Acad. 1870, p. 126. On the Humerus of a Sloth resembling Mylodon robustus and on Dromotherium sylvestre. Proc. Acad. 1870, pp. 8-9. On Specimens of Vertebral Bodies from the New Jersey Green- Sand. Proc. Acad. 1870, p. 10. On Ichthyodorulites. Proc. Acad. 1870, pp. 12-18. On Fossil Remains from Illinois. Proc. Acad. 1870, p. 13. On Discosaurus and its allies. Proc. Acad, 1870. pp. 18-22. On Fossil Bones from Dakota and Nebraska. Proc. Acad. 1870, pp. 65-66. On Fossil Remains from Idaho, Utah and Oregon. Proc. Acad. 1870, pp. 67-8. On Fossils from the vicinity of Burlington, Kas., and from the Rocky Mts. Proc. Acad. 1870, p. 69. On the Relations of European and American fauna. Proc. Acad. 1870, pp. 72-75. On aJaw Fragment of Ovibos cavifrons. Proc. Acad. 1870, p. 73. Nothosaurops occiduus. Proc. Acad. 1870, p. 74. On Mastodon Remains. Proc. Acad. 1870, pp. 96-99. On Fossil Remains in the Museum of Amherst College. Proc. Acad. 1870, p. 98. On Fossils from Bridge creek, Oregon. Proc. Acad. 1870, pp. 111-113. On Cordylophora. Proc. Acad. 1870, p. 118. On Fossils from Church Buttes, Wyoming Territory. Proc. Acad. 1870, pp. 115-114. On Fossils found under Table Mt. Cal. Proc. Acad. 1870, pp. 125-26. On some Extinct Turtles from Wyoming Territory. Proce Acad. 1870, pp. 102-103. Remains of Extinct Mammals from Wyoming. Proc. Acad. 1871, pp. 115-14. temains of Pal:eosyops from Fort Bridger. Proc. Acad. 1871, p. 115, 168a. 169. 170. age le 180. 181. The American Geologist. November, 1891 Remarks on a Fossil Testudo from Wyoming. Proc. Acad. 1871, p. 154. Remarks on Supposed Fossil Turtle Eggs. Proc. Acad. 1871, pp- 154-55. Fossils from Wyoming. Proc. Acad. 1871, p. 197. Remarks on Fossil Vertebrates from Wyoming. Proc. Acad. 1871, pp. 228-29. Notice of some Extinct Rodents from Wyoming, and description of Mysops minimus. Proc. Acad. 1871, pp. 230-32. Remarks on Fossils from Oregon; Hadrohyus supremus, Rhinoce- ros pacificus Stylemys oregonensis. Proc. Acad. 1871, pp. 247-48 - On a small Collection of Fossils from California. Proc. Acad’ 1871, p. 50. On Polydactylism in a Horse. Proc. Acad. 1871, p. 112. On Remains of Mastodon and Horse in North Carolina, Proc. Acad. 1871, p. 113. Remarks on Mastodon, etc., from California. Proc. Acad. 1871, pp- 198-99. Note on Anchitherium. Proc. Acad. 1871, p. 199. Remarks on Fossil Vertebrates from Wyoming. Proc. Acad. 1871+ pp. 228-9. : On some new Species of Fossil Mammalia from Wyoming; Pal- wosyops humilis Uintatherium robustum, Uintamastix atrox. Am. J. Sci. IV, 1872, pp. 239-40. Id. Proc. Acad. 1872, pp. 167-69. Remarks on Fossils from Wyoming. Proc. Acad. 1872, pp. 19-21. Remarks on some Extinct Mammals. Proc. Acad. 1872, pp. 37-38. Remarks on some Extinct Vertebrates: Felis augustus, Oligosimus grandevus, Tylosteus ornatus.* Proc. Acad. 1872, pp. 38-40. On anew genus of Extinct Turtles. Proc. Acad. 1872, p. 162. On some Remains of Cretaceous Fishes; Otodus divaricatus, Oxyrhina extenta, Acrodus humilis, Pycnodus faba. Proc. Acad. 1872, pp. 162-64. Remarks on Fossil Mammals from Wyoming; Uintatherium robustum, Paleeosyops major, Proc. Acad. 1872, pp. 240-42. Remarks on chipped stones from Wyoming. Proc. Acad. 1872, pp. 242-45, Remarks on Fossils from Wyoming; Paleosyops junior, Uintacyon edax, U. vorax, Chameleo pristinus. Proc. Acad, 1872, p. 277. Remarks on Mastodon from New Mexico. Proc. Acad. 1872, p. 142. Remarks on Fossil Shark Teeth. Proc. Acad. 1872, p. 166. Contributions to the Extinct Fauna of the Western Territories. Rept. U. 8S. Geol. Sur. of Ter. (Hayden), I, 1873, pp. 1-358, pls. I-XXXVII, Notice of Fossil Vertebrates from the Miocene of Virginia. Proc. Acad, 1873, p. 15. Notice of Remains of Fishes in the Bridger Tertiary formation of Wyoming. Proc. Acad, 1873, pp. 97-99. 194. 196. 197. 198. 199. 200. 201. 202. 203. 204, 205. 206. 207. 208. 209. 210. 211. 212. 2138. 214. 215. Publications of Joseph Leidy.—Eyerman. 341 Remarks on the Occurrence of an Extinct Hog in America: Proc. Acad. 1873, p. 207. Remarks on Extinct Mammals in California. Proc. Acad. 1873, pp. 259-60. Remarks on Fossil Elephant Teeth. Proc. Acad. 1873, pp, 416-17. Notice of Remains of Titanotherium. Proc. Acad. 1874, pp. 165-66. Remarks on Fossils presented. Proc. Acad. 1874, pp. 225-24. Description of Vertebrate Remains chiefly from the Phosphate Beds of South Carolina. Jour. Acad. VIII, 1874-81, pp. 209-61. Remarks on Bathygnathus borealis. Jour. Acad. VIII, 1874-81, pp. 449-51. Remarks on a Coal Fossil, etc. Proc. Acad. 1875, p. 120. Remarks on Elephant Remains. Proc. Acad. 1875, p. 121. On Petalodus. Proc. Acad. 1876, p. 9. Mastodon andium. Proc. Acad. 1876, p. 38. Remarks on Fossils fromthe Ashley Phosphate Beds. Proc. Acad. 1876, pp. 80-81, 86-87. Fish Remains of the Mesozoic Red Shales. Proc. Acad. 1876, p. 81. Remarks on Fossils from the Ashley Phosphate Beds. Proc. Acad. 1876, pp. 86-87. Remarks on the Vertebrate fossils from the Phosphate Beds of S. Carolina. Proc. Acad. 1876, pp. 114-15. On Fossil Fishes. Proc. Acad. 1877, p. 294. Fossil Remains of a Caribou. Proc. Acad. 1879, pp. 52-55. Fossil Foot Tracks of the Anthracite Coal Measures. Proc. Acad. 1879, pp. 164-65. Bone Caves of Pennsylvania. Proc. Acad. 1880, pp. 346-49. On Remains of Horses. Proc. Acad. 1882, pp. 290-2. On an Extinct Peccary. Proc. Acad. 1882, pp. 301-302. Fossil Bones from Louisiana. Proc. Acad. 1884, p. 22. Vertebrate Fossils from Florida. Proc. Acad. 1884, pp. 115-119. Rhinoceros and Hippotherium from Florida. Proc. Acad. 1885, pp. 32-55. Remarks on Mylodon. Proc. Acad. 1885, pp. 49-51. Mastodon and Llama from Florida. Proc. Acad. 1886, pp. 11-12. Extinct Boar from Florida. Proc. Acad. 1886, pp. 37-38. Caries in the Mastodon. Proc. Acad. 1886, p. 58 Toxodon and other Remains from Nicaragua. Proc. Acad. 1886, 275-77. Fossil Bones from Florida. Proc, Acad. 1887, pp. 309-10. Megalonyx jeffersonii. Proc. Acad. 1888, p. 275. The Sabre-tooth Tiger of Florida. Proc. Acad. 1889, pp. 29-51. Fossil Vertebrates from Florida. Proc. Acad. 1889, pp. 96-97. Notice of some Fossil Human Bones. Trans. Wagner Free. Inst- Sci. II, pp. 9-12*. *Transactions of the Wagner Free Institute of Science, Philadelphia. The American Geologrst. November, 1891 Description of Mammalian Remains from a rock crevice in Florida. Trans. Wag. Fr. Ins. Sci. I], 1889, pp. 13-17. Description of Vertebrate Remains from Peace Creek, Florida. Trans. Wag. Fr. Ins. Sci. II, 1889, pp. 19-31. Notice of some Mammalian Remains from the Salt Mine of Petite Anse, Louisiana. Trans. Wag. Fr. Ins. Sci. I, 1889, pp. 33-40. On Platygonus, an extinct genus allied to the Peccaries. Trans. Wag. Fr. Ins. Sci. II, 1889, pp. 41-50 Fossil Vertebrates from Florida. Proc. Acad. 1890, pp. 64-65. Hlippotherium and Rhinoceros from Florida. Proc. Acad. 1890, pp. 182-83. Mastodon and Capybara of South Carolina. Proc, Acad. 1890, pp. 184-85, AMERICAN GEOLOGIST, Vol. VIII, Plate IV. AMERICAN GEOLOGIST Vou. VIII. DECEMBER, 1891. No. 6. JEAN N. NICOLLET. N. H. WincHext, Minneapolis.* Of that little coterie of earnest geologists, who in the fourth decade of the present century inaugurated the system of public surveys inthe United States, and from whose occasional meet- ings together sprang the American Association for the Advance- ment of Science, and thence much of the popular interest in geology which characterizes the present decade, Jean N. Nicollet was one of the most learned and enthusiastic. In his intercourse with others, whether on the frontier among the rude settlers of the prairies, the officers of the frontier forts, or at the meetings of the Association of Geologists, his bearing was that of a cult- ured and modest scientist, and he won his rapid recognition by *For authority for the historic statements of this sketch, the reader is referred to the following: Transactions of the Association of Anrerican Geologists and Naturalists, 1840-42. Boston, 1843, pp. 32-84: Report in- tended to illustrate a map of the hydrographical basin of the Upper Mississippi river made by J. N. Nicollet, while in employ under the bureau of Topographical Engineers, Feb. 16, 1841, Washington, 1845, | Doc. 237, 26th Cong. 2d Sess.]; Pacific R. R. gas Vol. xt, p. 41; Minnesota Historical Collections, 1850-56, Vol. 1, p. 183; Ditto, Vol. vr, pp. 242-45, 1891; Am. Jour. Sci. (1), xivu, 139, Sketch by Prof. H. D. Rogers. Of all these publications, that in the V Ol. of the Minnesota His- torical Society’s publications, being a memoir of Nicollet by Gen. H. H. Sibley, is the most important, touching his Lg sce history. Memoirs of my Life, by John Charles Fremont, Vol. 1, pp. 30-72, contains some interesting details of Nicollet’s plans and life at Washington. Compare also Wheeler’s Geographical Survey west of the 100th Meridian. Vol. I, p. 548, Washington, 1889, and the Annual Report of the Smithsonian Institution, 1870, p. 194. The autograph seen under his portrait is taken from a letter dated St. Anthony Falls, Jan. 27, 1836, now in the possession of Dr. EH. D. Neill, St. Paul, by whose courtesy it is used. 544 The American Geologist. December, 1591 scientists in this country through the courteous kindliness of his demeanor, no less than through the earnestness of his zeal. Al- though but about eleven years of his life were spent in the United States, coming to this country wholly unknown and without recommendations or introduction, he entered upon a career which soon conducted him into the favorable consideration of the high- est authorities of the Government at Washington, and when he died he was in the service of the Bureau of Topographical En- gineers. Born in France, whence also came Guyot, and Agassiz and ‘Lesquereux, a brilliant group whose illumination the nineteenth century will always bear, he also brought to America and conse- crated to her service a ripe education and great skill in manipula- tion of scientific methods. He was born in 1790 at Cluses, in Savoy, between Geneva and Mont Blanc, and died Sept. 18, 1843, probably at the house of Prof. Ducatel, in Baltimore, Md. In boyhood he was obliged, through the poverty of his parents, to earn some portion of his livelihood. The musical ability which he displayed in later life, by which he enlivened the households of general Sibley and of Indian agent Taliaferro, at Fort Snel- ling, seems to have marked out for him the most successful means of gaining such subsistence. With a flute or a violin, at the tender age of ten years, he played at such public or private enter- tainments as needed his services. He subsequently was appren- ticed to a watch-maker, and remained with him until he was eighteen years of age. While carrying on this occupation at Chambry he prosecuted his studies in mathematics, in which he became so proficient that he was awarded a prize. Returning to Cluses he taught mathematics, and at the same time received les- sons in Latin and other languages. After two years he repaired to Paris where he was admitted to the first class in L’ Ecole Nor- male; and soon afterwards he was placed in charge of the mathe- matical course in the college of ‘+Louis le Grand.” ‘It was in 1818 that Nicollet published his celebrated letter to M. Outrequin Banquier, on ‘Assurances having for their basis the probable duration of human life.’ This little work gained for him a high reputation, affording to the Assurance Societies the prospect of establishing their regulations upon the more cer- tain basis of mathematical demonstration, and he soon found himself courted by financiers, while at the same time he was ad- Jean NN. Nicolla.— Winchell. 345 mitted into the higher circles of society. Shortly after he wrote for the ‘Modern Encyclopedia’ several articles on probabilities, and one upon assurances. It is stated that his knowledge of the English gave him a great advantage, in being able to consult writers in that language on the theory of assurances in applying it to every species of risks.” In 1819 and 1820 he made observations upon the lunar spot Manilus, and united them with those of Bouvard in 1806, with a discussion of the whole, published in 1822 and 1823 in Connais- sances des Temps. On the 21st of January, 1821, he discovered, between six and seven in the evening, a comet in the constella- tion Pegasus, seen on the same day and the same hour by Pons, of Marseilles. He subsequently computed its parabolic elements. In a later discovery of another comet (April 22, 1830) he was preceded by M. Gambart, of Marseilles, who saw it on the 21st of the same month. Weare also indebted to Nicollet for observa- tions and computations of other comets, among which may be mentioned that of 1823, whose elements he computed. He had already labored some time in the Observatory at Paris, when in 1822, he entered the ‘‘Bureau des Longitudes” as an adjunct. His position for the future was thus most honorably established. The publications of the Observatory will show the part he took in the observations. He participated in that great work, the de- termination of the figure of the earth, by comparing a measured terrestrial are with the celestial arc corresponding to it. These labors were published in +*Connaissances des Temps” for 1829. A memoir of his on a new computation of the latitudes of cer- tain places, to serve as a supplement to that great work, the <-Base du Systeme metrique,”’ was published in 1828. Nicollet was honored by the decoration of the Legion of Honor, previous to 1825, and had also the appointment of professor to the Royal College of Louis Le Grand. Having also been ap- pointed one of the Inspectors of the Naval Schools, conjointly with MM. Reynaud and Gerand he published a course in mathe- matics in three volumes, for the use of candidates for promotion, the second volume, containing geometry and trigonometry, being edited solely by himself. In 1831 he determined the comparative magnetic intensity of Brest, with reference to that of Paris and Brussels, and the re- sults were inserted in the first volume of the Bulletins. Several 346 The American Geologist. December, 189t . of his communications were inserted in the publications of the Royal Academy of Science and Belles Lettres of Brussels, of which he was made a corresponding member. In conjunction with this course of scientific promotion Nicol- let's financial suecess had kept equal pace, and he had acecumu- lated a considerable sum of money. New avenues of profit opened before him, and tempted by his uniform success, he launched boldly forth upon a sea of speculation, with firm confi- dence in his theory of probabilities. He failed, and with the disappearance of his own fortune the fortunes of others were involved. He was forced to seek refuge in the United States, his. former friends being found among his most bitter and implacable persecutors. He arrived in this country in 1832, apparently having landed at New Orleans. He was an entire stranger and with limited pecuniary means. In the progress of a systematic journey through the states of the lower Mississippi valley, he made the acquaintance of bishop Chanche, of Natchez, and a friendship sprang up between them which continued till Nicollet’s death. Through the agency of P. Chouteau, Jr., & Co., of St. Louis, extensive Indian traders in the Northwest, by whom Nicollet was entertained on the most cordial terms, and of major Taliaferro, Indian agent at Fort Snelling, the desire which Nicollet had ex- pressed of*exploring thoroughly the upper waters of the Missis- sippi, and accurately mapping the same, was made known to the United States Government. In 1833 the War Department furn- ished him letters of protection and hospitality, addressed to the commanding officers and Indian agents of the frontier, and at the same time the loan of certain instruments needed by him. Aside from these inconsiderable aids, however, Nicollet entered upon a great undertaking alone, and at his own expense and risk. He was everywhere received with great cordiality. He had been schooled to the social observances which make daily intercourse attractive. His mind was of the higher order. His mathemati- cal and musical abilities, his delicate physical frame, his unos- tentatious demeanor, his readiness to enter into social converse, and to impart information on topics which are the less under- stood and but seldom discussed in the unsettled communities in which he now found himself, and his general scientific attain- ments, conspired to furnish him a passport into the best circles. Jean N. Nicollet.— Winchell. 347 The late general H. H. Sibley, and Indian agent Taliaferro, tes- tify to the pleasure with which they received and entertained Nicollet during the winter months, at Mendota and Fort Snelling, when his active explorations were suspended, and he was engaged in constructing his preliminary map. ‘‘In those days when the nearest settlement of whites was nearly three hundred miles dis- tant, the advent of a decent and intelligent visitor was hailed with delight.” Until 1838 Nicollet was thereafter engaged in mapping the region of the upper Mississippi. He was accompanied by ex- perienced Canadian frontiersmen, selected usually by the fur companies, (Chouteau & Co., of St. Louis,) and frequently from their own men. He employed for the first time in this region those methods and principles which have been the basis of all the more recent surveys. The vastness of the area which he covered alone rendered it necessary to depend on more inaccurate methods for filling in the details between the points astronomically deter- mined. Wherever Mr. Nicollet went, he was indefatigable in the use of the telescope for observing occultations and eclipses, and of the sextant, with which he was very skillful. With these, a pocket chronometer, artificial horizon of mercury and barometer, he obtained astronomic and topographic results, possessing re- markable accuracy for the means employed. Mr. Nicollet was the first explorer who made use of the barometer in obtaining the elevation of our great interior country above the sea. An ab- stract of the methods and principles by which he was governed is given in his report, and these have served as a guide to many sub- sequent observers. The preliminary map which he thus constructed extended on the east from the longitude of Madison in Wisconsin to the one hundredth meridian, and from the northern international boundary to the parallel of 38 degrees and 30 minutes, which is just below the mouth of the Missouri river. It embraced not alone the ac- curate location of rivers and lakes, and the representation of the principal topographic elevations, but it showed many details of historic discovery and geography, and facts respecting the loca- tion of the Indian tribes, and the aboriginal names for streams and lakes. Nicollet familiarized himself with early discovery, and particularly with the early French explorations, and it was one of his aims to resuscitate and reclaim for his countrymen the 348 The American Geologist . December, 189 credit for what they had done, for at that time it had lapsed from common acknowledgement. This was freely communicated to bishop Chanche and to Chouteau & Co., as well as others, and it doubtless served to enlist all French citizens heartily in his aid. Col. Abert, chief of the engineer corps of the U. 8. army, had kept himself acquainted with the progress of Nicollet’s surveys, although there is no evidence of any official communications be- tween them. Hon. J. R. Poinsett, of S. Carolina, at the head of the War Department, was also informed of his self-instituted and self-sacrificing labors. At this time there was a general popular demand, for political reasons touching the controversy with Great Britian concerning the Oregon boundary, for knowledge of the nature of the country westward from the upper waters of the Mississippi, and when Nicollet, in 1838, with broken health and exhausted means, repaired to Baltimore, where he again enjoyed the friendly hospitality of bishop Chanche, at St. Mary's Col- lege, and of- Prof. Ducatel, he was soon officially called to Wash- ington by Mr. Poinsett for the inspection of his maps and jour- nals. Mr. Poinsett and Col. Abert were gentlemen of kindred spirits, and they appreciated and esteemed the character of Nicollet. They also saw at once the importance to the country of securing for the government the materials collected by Nicollet in his excursions. The result was that the chief of engineers was authorized to make arrangements with him for the transfer of his maps and journals to the government, and to secure his further services. Thus Mr. Nicollet found himself designated to under- take, the next season, under government employ, and with abundant means to carry out his projects, a final expedition to the Northwest for the purpose of completing his map. To this expedition was attached Lieut. J. C. Fremont, chief assistant in topographic and astronomie work, Mr. Charles Geyer, botanist, M. de Montmort, a French gentleman attached to the Legation at Washington, and Mr. Eugene Flandin, a young gentleman from New York. The eventful career of Fremont may be said to have commenced with this expedition, and Mr. Nicollet retained him as an assistant when afterwards he was engaged at Washington in reducing his astronomic observations and drafting his final map. Two years (1838 and 1839) were given to field examinations under these auspices. ‘The second season Mr. Nicollet had, on leaving Fort Pierre, in Dakota, a party of nineteen persons, in- Jean N. Nicollet.— Winchell. 349 eluding Lieut. Fremont, Mr. Geyer, and Capt. Belligny, an officer of the French army who wished to see the Indian country, thirty-three horses and ten carts. The years 1840 and 1841 were spent at Washington, where Mr. Nicollet had rooms for his work in the Coast Survey buildings on Capitol hill, and lived, with Fre- mont, in Mr. Hassler’s own house near at hand. Gen. Fremont, in his ‘‘Memoirs,” gives many pleasant reminiscences of his work here with Nicollet, and of the associations which they had with Nicollet’s personal friends in Baltimore, where Mr. Nicollet fre- quently retired for rest and recuperation—for his health was now seriously impaired, and he was able to make but slow head- way with his report. The map itself, executed under his immedi- ate eye, as the astronomical computations were made determining the chief points in his itinerary, was chiefly drawn by Fremont and Lieut. Scammon, both of whom, had been assigned to that work for the assistance of Mr. Nicollet. His official superiors were planning larger things for Mr. Nicol- let, while his more intimate friends saw with sadness the gradual but persistent decadence of his health. His map was completed in 1841, and submitted to Congress. ‘The Senate ordered its pub- lication under the direction of the Topographical Bureau. It was to be accompanied by a report embracing an account of the pliys- ical geography of the country represented, together with the most prominent features in the geology and mineral resources of other sections in the western part of the United States not embraced in the area of the map. Mr. Nicollet gave, in 1841, an account of his work, and of his plans, at the Philadelphia meeting of the Association of American Geologists and Naturalists, dwelling particularly on the geological discoveries he had made. He was now at work upon his report. Ile had the collaborative assist- ance of Dr. Harlan, Dr. Torrey (in Botany) and to some extent of Messrs. Conrad and Vanuxem of the New York Geological Survey, then recently instituted. But he was greatly delayed by ill health. The more extended explorations which were being planned for him had to be transferred to his principal aid, Lieut. Fre- mont, who, thoughthen young, was ambitious, and withal certainly better qualified physically, for carrying out the designs of the Government in western exploration. Had Nicollet’s health been equal to the task it is likely that the great interior of the North American continent west of the Mississippi, would have been ex- BDO The American Geologist. December, 1891 plored through the leadership of a Frenchman, and the eclat of French spirit and enterprise which characterized the early explora- tion of that portion east of the Mississippi, would have been ex- tended unbroken to the Pacific shores. Mr. Nicollet, meantime, grew restless and repaired frequently to St. Mary's college, Baltimore. He was not in condition to re duce to shape the materials for his report, which were varied and interesting, involving much information concerning the aborig- ines. Mr. Sibley says that he knows that Mr. Nicollet con- templated, when his materials should be elaborated, a work of several volumes, relating to the geology, topography and geo- graphical position of what is now Minnesota, and discussing many interesting topics connected withthe Indian tribes, and with the mound-builders. The only publication which resulted from this mass of material, was that small volume which was printed by order of the Senate, dated Feb. 16, 1841, descriptive of his map, and published in 1843. The short report which accom- panies the map was being printed. He was revising it, as it was returned to him for the purpose, but he never saw its completion in printed shape. He diedin the fall of 1848, and the ‘‘Intro- duction” was left incomplete. Col. Abert, to whom the report is addressed, adds this explanatory note, dated Sept. 13, 1843: Thus far Mr. Nicollet had written of his introduction, when death put an end to his labors, and before he had been able to revise his report, which had been returned to him for that purpose, and also to add the astronomical observations upon which his calculations were founded. These observations form parts of his journals which are to be deposited in the Bureau of the Corps of Topographical Engineers, Lieut. Warren speaks of having consulted these journals in 1857, when compiling a general map of the western territories for the Pacific Railroad surveys. He distinguishes the map of Nicollet, which is now a very rare and valuable document, as “one of the greatest contributions ever made to American geogs raphy.” Nicollet was rather an astronomer and geographer than a geolo- gist, yet he made (then) important contributions to the small fund of geological knowledge which was possessed of the Northwest, and he laid out in the form of his general map, a basis for future geological examination better than any enjoyed by the central and southern states of the Mississippi basin. His map and short ex- Jean N. Nicollet.— Winchell. 351 planatory report also serve as an invaluable perpetuating link, preserving with great accuracy, many aboriginal geographic de- tails and uniting early French exploration with recent known data through the agency of an appreciative and accomplished French scientist. When he last left the Northwest, after spending several weeks with general Sibley, at Mendota, he made his way, in the fall of 1839, to Bedford, Pa., to the home of his friends, major and Mrs. Taliaferro, where he remained through the winter, and where he was so feeble that he had to be carefully nursed and treated with the best medical attendance. It was doubtless dur- ing this visit that was made the small ivory painting, which has furnished the basis for the portrait which accompanies this paper. ‘Two photograph copies (vignette size) were presented to the Min- nesota Historical Society in 1867, by Maj. Taliaferro, and are now preserved in its archives. Of one of these this portrait is anenlargement. The original has the following inscription on ‘¢ Photograph the reverse side, in Maj. Taliaferro’s own writing :* from painting on ivory of J. N. Nicollet, 1836. | Photographed 1867 and presented to the Minn. Hist. Soe. by Lawrence Talia- ferro, Aug., 1867, R. T. Gettys, Bedford, Pa.” Of the last days of Nicollet we know but little. There is no doubt, however, from the statements of Gen. Sibley, and the facts recorded by Gen. Fremont, that his fine physical frame was over-taxed by the demands made upon it by the fiery spirit which animated it. and which drove him through the hardships and toils of his frontier campaigns. The burden which was upon his mind, again, arising from the lofty ideal he had formed for the publica- tion of his scientific report to the Government, wore on him con- tinually, and as time passed, and his nervousness did not dimin- ish, but rather increased, and the accomplishment of his purpose receded from him as the months wore away, he became irrita- ble and more and more prostrated. About this time, also, ac- cording to Gen. Sibley, through the hostility which yet pursued him on the part of some of his old associates in business affairs, he failed of election to membership in the Academy of Sciences, at Paris, an honor which he coveted. He had the support of *This has been still further enlarged into a life-size oil painting, by Mr. B.S. Hayes, an artist of Minneapolis, and hangs in the office of the writer. 352 The almerican Geologist. December, 1891 LaPlace, but the opposition of Arago, who was characterized by LaPlace as the ‘:great elector of the Academy.’’ This was a mortal blow and he faded away rapidly on learning of it, for he had been duly nominated by some of his scientific friends in Paris. | fain would dwell on the beauties of such a character. It was an exotic plant, forcibly transferred from luxuriance to the com- parative desert and harshness of our northwestern frontier. It bloomed for a short time, disseminating unstintedly its fragrance on the surrounding atmosphere, but the colds and common blasts of our unsuited social climate, though wholesome to the Ameri- can-bred spirit, were unfit to nourish his delicate constitution, and he drooped, faded and disappeared, leaving to us a remembrance a wearied fire-fly of a bright soul, a gleam of a pure character, struggling in the tempest, a rose that wasted its fragrance on the desert air. GENESIS OF IRON-ORES BY ISOMORPHOUS AND PSEUDOMORPHOUS REPLACEMENT OF LIMESTONE, ETC. By James P. Kimpatyi, Washington, D.C. (Continued from the American Journal of Science, Vol. xu, Sept , 1891.) Progressive studies of stratiform iron-ores throughout the almost uni- geologic series of stratified rocks, have led to a wide acceptance of explanations of their development as versal. products of chemical transmutations, or epigenesis. So far as based on unquestionable chemical reactions, these explanations differ mainly as to their application to given occurrences of iron- ores. What may be termed the replacement theory, has been held during the last decade to have a wide application, especially on this continent, to iron-ores on horizons of originally ferrifer- ous limestone and other calcareous material. However, the appli- cation of this theory may be restricted from considerations of synchronous, or immediately successive, accumulations of the two kinds of material—caleareous and _ ferriferous, it will ob- viously be much the wider if it may be believed that replacing salts of iron are often from extraneous sources, and that the pro- cess of replacement or chemical interchange is through cireum- stances of atmospheric and topographic, as well as stratigraphic Genesis of Iron-Ores.— himball, 353 or lithologic, environment. This I have endeavored to show in a recent memoir. By way of continuation of that memoir | proceed to instance a number of examples illustrating the general points under discussion, L. Iron Ores of the Sub-carboniferous Limestone of eastern Kentucky. Pseudomorphous replacement of Sub-carboniferous limestone by reddish brown limonite was recognized by Shaler as the mode of occurrence and genesis of well-known developments in eastern Kentucky.* The source of iron salts is referred to overlying coal-measures, all more or less pyritous, and mainly consisting of siliceous sediments. Replacement has taken place unequally, apparently as circumstances of environment have varied. This has proceeded from without inward, that is, from above down- ward. Cross-fissures and anfractuosities throughout the mass attest contraction. The degree of chemical replacement of limestone is in measure of vertical sections of ore-deposits. These often rise above the general level of the top of the lime- stone, owing to comparatively even shrinkage or chemical erosion of the limestone through solvent infiltrations. Occasion will be taken to refer to similar occurrences in Ohio on the same horizon. WY, Replacement of coral-rock (limestone), Cuba. In tracing the genesis of some very remarkable isolated bodies of mixed brown and red hematite (turgite) occurring on the south coast of the eastern peninsula of Cuba, I described them in the year 1884 as replacements of limestone in the form of elevated and disrupted coral-reef, or only partially indurated coralline limestone.t The replaced masses of limestone still retain sur- faces characteristic of planes of fracture such as may be ob- served in costal cliffs of emerged coral-reef. Indistinct casts of corallum partially transformed into hematite are occasionally found, the cells being filled with chlorite. The condition of form, therefore, almost indispensable to proof of pseudomorphous re- placement, is not altogether wanting. Some idea of the importance of the scale on which replace- ment in this instance has been effected may be formed from the fact that the ore-bodies referred to supplied during the year 1890, *Geol. Surv. of Ky. 1876 [3] 16. tAm. Jour.of Se. xxvii (3), 1884, 416. 354 The American Geolog ist. December, 1891 not less than 362,068 tons of iron-ore, the product of a single operation, that, namely, of the Juragua Iron Company. This product was over one-quarter of the total imports of iron-ores in the United States for the same period. The same examples of molecular replacement on a grand or petrographic scale will serve to illustrate dependence of this mode of epigenesis on circumstances of environment. These are seen to have been particularly favorable, as was also the extreme porosity or permeability of the original coralline material. Suffice it to mention (1) envelopment of masses of this material with basic eruptive diorite, rich in iron silicates; and (2) climatie con- ditions specially conducive to secular weathering of superficial rocks, Some of the iron-ore bodies exhibit concentric structure, a re- sult of progressive weathering—the same as exfoliation on a smaller scale sasily mistaken for quaquayersal dips. Numerous shrinkage fractures due to contraction incidental to alteration, as well as larger manifestations of mechanical fracture, are filled out with chloritic material from decay of the dioritic magma and detritus. Thus masses of iron-ore are reticulated with bands of chlorite. Incidental to secular decay of the mantle of diorite enveloping masses of limestone, chemical interchange or double decomposi- tion was effected between fixed calcic carbonate and dissolved iron- salts. Ferrous carbonate, directly passing into ferric hydrate, was left behind, and lime salts were dissipated. The partial de- hydration of ferric hydrate into ferric oxide (turgite), the product of further alteration, may, as shown by Davies and Rodman, proceed from only slight elevation of temperature.* There is no evidence, however, that these ore-bodies have been deeply buried. Indirect replacement in this instance has therefore been under exposure to an oxidizing atmosphere. The metasomatic development of the iron-ores at the base of the Sierra Maestra dates from an era no more remote than the Cenozoic, when this coast range was added to the island of Cuba. ITT, Replacement of Carboniferous and Silurian Limestones, Colorado. Mr. $8. F. Emmons has shown extensive replacement of Lower Carboniferous and Silurian limestones to have resulted in oceur- *Jour. Chem. Soc. tt, tv, 69. Genesis of Iron-Ovres.—himball. B55 rences of iron-ore, amixture of hematiteand magnetite, in Breece Hill, and of limonite as well as a more or less ferriferous gangue of epigenic silver ores at Leadville, Colorado. Here transmuta- tion has been etfected between limestone or dolomitic material and iron sulphates through aqueous infiltrations from adjacent intrusive porphyry. In the decay of the porphyry is involved vitriolization of pyrite, contained in this rock up to four per cent. The process of deposition of silver-ores as well as of ferriferous material, as concluded by Emmons, ‘‘was a metasomatic inter- change with the material in which they were deposited.” That is, ‘‘the material of which they were composed was not a deposit in a pre-existing cavity in the rock” (limestone) but ‘‘the solu- tions which carried them gradually dissolved out the original rock material and left the ore or vein material in its place.”* Occurrences of limonite near Hot Springs, Colorado, as de- seribed by Mr. C. M. Rélker, also afford striking examples of replacement of limestone. t IV. Replacement of Upper Silurian (Clinton) Limestones. Parts of thin fossiliferous limestones of the Clinton group of strata are often replaced by red and brown ferric oxides from extraneous sources. In the Appalachians of southern Pennsyl- vania, for example, where [ have long had opportunity of closely observing the mode of occurrence of these ores, especially in flanks of Tussey, Dunning’s and Will's mountains, fossil-ores, so- called, rarely oolitic, occupy the weathered zone of highly fos- siliferous beds of limestone intercalated with shales and sand- stones. This replacement has been wrought especially in steep dips by infiltrations from drainage of adjacent ferruginous strata, particularly of an inferiorseries outcropping topographically higher in the flanks of these parallel wall-like ridges. At or near water level or drainage level, and in topographical positions unfavor- able to weathering action, or to sources of infiltrations, replace- ment has been found to cease. Super-saturation as at water-level. and impenetration of solutions from topographical causes are equally unfavorable for this process. In portions of limestone beds bordering ravines down the mountain-side, dissolution of limestone sometimes has failed above immediate drainage level to be attended with replacement *U.S. Geol. Surv. xi, 1886, Pt. 2, 378, 540. +Trans. Am. Inst. Min. Eng., 1885, xrv, 266. 356 Lhe American Geologist. December, 1891 of ferric oxide. Yet in such circumstances the limestone has given way to the dissolving action of passing waters, leached insoluble residues retaining its original structure, as well as moulds of fossils, occupying its place along with creepings from adjacent strata. Here transmission of seepage water has proved too rapid for other than solvent or destructive action to have be- come sensible. Another local circumstance is also deserving of mention. — It is this. Opposed to a rapid transmission of infiltrations in water- sheds between successive cross-ravines is a barrier known as Red Ridge. Constituted of a compact series of arenaceous argillite, this is locally developed at the top of the Surgent shales, and stratigraphically above, but topographically in front of, the plane of the ore-limestone. Near where this barrier is scored by cross- ravines, underground as well as superficial drainage has become accelerated. Preservation of Red Ridge from local erosion has therefore come to be regarded in Bedford and Huntingdon coun- ties, Pennsylvania, as indispensable to a favorable development of the fossil-ore bed back of it, or to the absence of ‘‘wants.”’ Of these the distribution and extent are thus mainly determined by conditions of underground drainage as affected mostly by topographical features. Gentle dips under steep slopes are for obvious reasons inconducive to infiltration. The above remarks directly apply to the more or less hydrous fossil-ores of the Appalachian ridges in southern Pennsylvania, as distinguished from oolitic hematites, or dyestone ores, like- wise developed in favorable circumstances on lower horizons of thin crinoidal limestones within compass of the Clinton or Sur- gent formations. Both types of ores, and often both series of developments, are generally referred to indifferently as Clinton fossil-ores. The stratigraphical relations between these two series of developments, even where both may be recognized in a single ridge or section, are extremely variable. In southern Pennsyl- vania, where the Clinton shales attain a thickness of nearly 1,200 feet, the fossil-ore bed is about 400 feet above the horizon of the Frankstown oolitic or dyestone ore, which in turn is about 300 feet above that of the block-ore, so-called. Allof these ores owe their development, as I believe, exclusively to secular replace- ment of elevated parts of these limestones—not, as sometimes explained, to direct sedimentation in whole or in part. For - Genesis of Iron-Ovres.—himball. 357 wherever oolitic iron-ores are developed within the Clinton series, they are found to graduate into non-ferriferous limestones, more or less crinoidal, and usually in circumstances only moderately favorable to weathering action. An equally significant fact is the absence of valuable iron-ores where the Clinton limestone, as in southern Ohio, is massive and unaccompanied by a considerable thickness of overlying shales. Wherever, on the other hand, the limestone occurs in numerous thin beds, and so alternates with more or less ferruginous shales; or again, wherever overtopped by shales, it seldom fails, especially in steep dips, to graduate unequally into oolitic hematite by replacement. Even in Qhio, where the Clinton group is represented by a single but compara- tively thick limestone member under gentle dips, the upper por- tion of the limestone is sometimes replaced by hematite,* though of no economic importance. Imperfect replacement likewise oceurs where the limestone becomes shaly and expands in thick- ness. Non-ferriferous Clinton limestones, more or less magnesian, into which their associated iron-ores graduate, may be assumed to have been deposited in clear and moderately deep continental seas. That these seas were ramified by all but insulated land- surfaces is indicated by the abundance of intercalated siliceous sediments from sub-aérial rock-decay. It is sometimes held that these limestones, and at least the oolitic hematites developed upon the same horizons and passing into each other, were necessarily deposited together. Yet direct ferric precipitation from ex- tremely instable natural solutions of ferrous salts cannot well be believed to have taken place so far from inland sources as where conditions existed favorable to the accumulation of non-siliceous and expansive limestones. Again, notwithstanding the fact that the Clinton iron-ores merge into pure marine limestones, have they,on the other hand, sometimes been assumed to afford proof of wide-spread marshes. A theory of this kind, however, is likewise opposed by the necessity of at- tributing expansive limestones of the Clinton type to mid-sea, and inferentially deep-sea, deposition. And the objection still stands that ferric hydrate in suspension, no more than ferrous salts in solution, can have materially contributed to marine non- siliceous limestones. The conclusion therefore seems justified *Geol. Surv. of Ohio, vr, 12. KO : . y . 358 The American Geologist. December, 1891 that whatever considerable proportion of ferriferous material was. deposited within compass of the Clinton limestones, was alter- nately deposited in the form of siliceous sediments represented by intercalations of shale. Such intercalations are common in Pennsylvania and Virginia. A less theoretical objection rests on the fact that the distribution of the Clinton iron-ores clearly de- pends on secondary, and wholly adventitious, conditions connected with topography and environment. * The application to the Clinton iron-ores of the views discussed in the continued and present memoir, falls in with the conclusion of Mr. Aug. F. Foerste, published since the above was written. + Microscopic sections of Clinton, dyestone oolitic iron-ores from Pennsylvania, Georgia, and Ohio reveal, according to Mr. Foerste, all stages of replacement of calcic carbonate, both cement and oolitic granules, by ferric oxide, the granules being fragments of Clinton species of water-worn bryozoans. ‘‘In no case, however, was anything noticed leading to the opinion that concretionary segregation of ‘iron had taken place either around the bryozoan fragments or otherwise. Simple replacement of iron-ore was the rule, the attack being made first on the exterior parts of the b grains.”’ According to the same observer similar occurrences are found throughout the Clinton belt wherever oolitic iron-ores are developed. V. Replacement of Carboniferous Limestones. Upon any theory of epigenesis of siderite, sphaerosiderite, and sideritic limestone, their greater distribution would seem to he natural under conditions for their preservation unaltered, such as may be recognized in environments where atmospheric air is dis- placed by mixtures of hydro-carbon gases and carbonic anhydride, as in formations of the Carboniferous period. The so-called upper limestone-ore in eastern Kentucky, is, like the Sub-carboniferous or lower limestone-ore of the same region, deseribed by Shaler, a product of alteration of pseudomorphous siderite after limestone. This is a replacement of upper parts of the Ferriferous limestone dividing the Lower Coal Measures, and co-extensive with the same division of strata in western Pennsylvania, West Virginia, eastern Kentucky and southern Ohio, where although known under a common designation, it is *See Cut. by W. M. Chauvenet, Report Tenth Census xv, 1886, 396. yAm. Jour. of Sc. x1, 1891, 28. Genesis of Lron-Ovres.—himball. 359 also sometimes otherwise identified. According to Orton, this is the Gray limestone of Newberry, the Putnam Hill limestone of Andrews, the Ferriferous limestone of the same author, and the Gray and Hanging-Rock limestone of Orton. The iron-ore, with which parts of this limestone are replaced, both in the form of siderite and of its altered product, is identified with the Clarion ore and Buhrstone ore of western Pennsylvania, the Baird ore of the Hocking Valley, the Limestone-ore of southern Ohio and the Upper limestone-ore of north-eastern Kentucky. Over 200 blast-furnaces in these regions have drawn a supply of iron-ores from this particular horizon.* The average thickness of the re- placements in southern Ohio is, according to Orton, about 10 inches, and further to the north about 8 inches, though said by Hunt to be often two or three times these averages, as in Vinton County. 7 Superior portions of the Upper and Lower Freeport lime- stones of the Lower Coal Measures are likewise commonly re- placed with siderite. This passes by alteration into limonite, sometimes in the form of concretionary blocks or nodules from exfoliation or weathering of prismatic blocks, separated by con- traction due to chemical transformation. Several horizons of sideritic limestone are identified in the same series in Pennsyl- vania, West Virginia and Maryland, more or less distinctly graduating into non-ferriferous limestone. Among similar occur- vences in the Lower Barren measures is the Johnstown siderite or ferro-calcite, identified with the Mahoning sandstone group. Mr. Bayard T. Putnam, referring generally to the limonites of the Coal Measures of Pennsylvania, remarks that they occur along the outcrops of limestone-beds, and are in general simply the weathered outcrops of seams of carbonate-ore. t Above the horizon of the Sub-carboniferous limestone in Ohio, which has been shown to be replaced in part with siderite or its drivatives, that is, between this horizon and that of the Ferri- ferous limestone, several limestones of the Conglomerate series are likewise apt to be replaced with siderite in a more or less altered state. Such occurrences are notably the Zoar or Blue *Orton, Kev. of Stratigraphical Geol. of eastern Ohio, Columbus, 1880, 29. +Min. Res. of the Hocking Valley, Boston, 1881, 44. U.S. Census, 1886, xv. 202. 360 The American Geologist. December, 1891 limestone of Newberry, and the overlying Gore limestone of the Hocking Valley—both members of the Mercer group of strata, Many well known horizons of siderite in Pennsylvania and bordering States have been described by Stevenson. The Mount Savage ore-group of the Conglomerate series is worthy of men- tion.* One plate or more of siderite occurs in the Mauch Chunk red shale. In many places local lenticular stratiform plates of siderite extend for a few hundreds to a few thousands of feet with a thickness up to four feet. In the Vespertine of Green- brier Co., of Virginia, an occurrence of this kind has been de- scribed by Rogers, and more recently by Mr. W. N. Page.t Comparatively thin, lenticular or stratiform developments of this description may be assumed to be complete replacements of non- persistent limestones of estuarine origin. Incomplete replacements of Carboniferous and Sub-carbon- iferous limestones of the Appalachians are, on the other hand, devoid of terminal edges, or other well defined demarcations such as appertain to lenticular beds conformable tothe configuration of hydrographic basins. They are thus perceived to be wanting in characteristics of sedimentary or metamorphic deposits. This obviously would not be the case, if these developments were primarily due to mechanical or chemical deposition in the natural order of succession of beds by which they are enclosed. That they do not occupy pre-existing cavities produced by mechanical or chemical erosion is likewise certain from the fact that they sometimes merge into limestone. That they are not crystalline, or characterized by other phenomena of segregation, is conclu- sive negative evidence of some other origin. Thus, there seems to be no alternative but to consider these developments due to molecular replacement of limestone, of which mode of origin indeed there is no lack of positive and direct proof. Hence, in- ductively, again the conclusion that complete or strictly pseudo- morphous replacement of limestone has been wrought in the case of stratiform developments of siderite and its derivatives, the iron-ores still retaining perhaps physical features of the original limestone in common with stratified deposits. *Second Geol. Survey of Penn. KK. +Trans. Am. Inst. Min. Eng. 1888, Extract, p. 4. Genesis of Iron-Oves.—himball. 361 VI. Limonites (and crystalline iron-ores) of the Lower Silurian limestones. That epigenic relations of some sort subsistbetween the limon- ‘ites and the Lower Silurian limestones with which they are asso- ciated throughout the Appalachian valleys, was distinctly pointed out by W. B. Rogers over half a century ago. Their relation with ferruginous shales and sandstones alternating with the lime- stones is almost equally intimate. Not only was the epigenic or secondary origin of these limonites recognized by Rogers, but their mode of occurrence, that is—not as consecutive members of formations between which they outcrop and often appear to be imbedded, but as irregular accumulations comparatively shallow or altogether superficial. Sometimes lining, so as to occupy, enlarged fissures of stratification for a limited extent, they are still liable to be mistaken for regular or bedded depos- its. Others, occupying in like manner enlarged fissures of cleavage or jointing in limestone, are sometimes assumed to be of the nature of segregations or mineral lodes. But their most common occurrence is in what is often described as super- ficial basins or other depressions on imperfectly drained sur- faces and slopes upon a limestone floor, in proximity to lime stone, or within compass of its extended lines. This superficial association of limonite with the Silurian limestones themselves is ‘sometimes considered to be simply owing to the cavernous condi- tion of limestone, and to its liability to unequal erosion; whence the occurrence of local depressions, or sink-holes produced by subsidence, which -have eventually become repositories of iron- ores from purely adventitious precipitation of ferric hydrate from passing waters. Pre-existing caves and crevices are like- wise assumed to be so filled out with this deposit, or even by mechanical accumulations or ‘‘in-washes” of ferriferous material. * To the general, or even a wide, application of such a view to the occurrence of important deposits of iron-ores serious objections are opposed. First, caves and cavities of this kind have been produced by solvent action of circulating water. Second, what- ever insoluble products, including ferric hydrate, are separated from moving waters remain in suspension and finally escape. ‘Third, possession of superficial depressions by detritus, cale- schutt, etc., prevents them from becoming open receptacles of *Newberry; School of Mines Quarterly, Noy. 1880, Reprint p. 16. 562 The American Geologist. December, 189t unmixed chemical precipitates. Displacement of detritus must therefore precede separate deposition of homogeneous material, except by molecular replacement of limestone surfaces, calear- eous detritus and eale-sehutt. Physical displacement happens, if at all, by means of torrents, from which again no chemical deposition takes place except possibly by replacement, or at least only for a time. Important deposits of limonite free from de- trital admixture, even of clay, ordinarily, at least preclude an explanation of their mechanical accumulation in pre-existing cavities. Yet it is true that among the great variety of circumstances of environment and topography in which development of limonite has taken place on horizons of Lower Silurian limestones, instances there are where caves, cavities and enlarged crevices, once chan- nels of rapid transmission of waters, have eventually been ob- structed by falls of rock or otherwise, and, so cut off from drainage, have finally become quiescent reservoirs of mineral waters. In this way vacant spaces in caleareous beds may in some instances have become repositories of uninterrupted deposi- tion of ferric hydrate either by precipitation, or by indirect re- placement of limestone surfaces or calcareous contents. Limon- ite as sometimes occurring, and bearing evidence of having probably been formed in this way, has proved not uncommonly more enduring than the limestone itself, the destructive erosion of which it has survived in the form of outlying masses. Ordinary accumulations of limonite thrown down in caverns, sink-holes and other depressions along with detritus, within the limestone ore-belt of Pennsylvania, have been well characterized by Mr. d'Invilliers.* Some of the obstacles in the way of a be- lief that pre-existing cavities often afford lodgement to import- ant ore-deposits have been aptly stated by Emmons. t Unaltered siderite in irregular shaped masses, sometimes oc- curs in the midst of limonite in ore-banks upon horizons of the Lower Silurian limestones as in Columbia and Dutchess counties, N. Y.; at Richmond and West Stockbridge, Mass., and at a few points in Pennsylvania and Virginia. These occurrences af- ford whatever grounds be found for a theory of original deposition of concentrated ferrous carbonate, intermittent, that *Second Geol. Surv. of Penn. An. Rep. 1886, IV, p. 418. +Trans. Am. Inst. Min. Eng., 1886, Ex. p. 5. Genesis of [ron-Ores.—himball. 363 is, and even concurrent with sedimentation of the material of these massive limestone formations. Any change of sedimenta- tion, such as contemplated in this theory, even if chemically supposable, would have resulted in lenticular configuration of siderite, or of its derivatives, a feature as above pointed out, probably possessed by siderite only in the case of complete or pseudomorphous replacements of lenses of limestone. I have, in a previous paper, described lenticular occurrences of siderite at Burden, Columbia county, N. Y., on the horizon of a thin non-persistent and probably estuarine Lower Silurian lime- stone.* Whatever theory be entertained of their epigenesis, this must be perceived to be closely connected with overlying clastic ferruginous accumulations, the whole series occupying in-shore depressions in an undulating bottom overspread with calcareous material. In the paper referred to, these basin-like deposits, which in point of identification with Silurian members, are, I be- lieve, so far as known without parallel in this country, were sub- stantially explained as probably instances of physical replace- ment of limestone by ferriferous accumulations, graduating up- wards into ferro-calcareous grits. The transgressive character of these grits appears from the fact that their development is limited to the basins themselves. Their thickness in any given vertical section is proportional to the thickness of the ore. The grits as well as the siderite are distinctly lenticular. The siderite was considered as a metamorphic product from reduction of ferric hydrate in reaction with commingled organic matter. Having since come to the conclusion, through a critical exami- nation, in another place followed out, of the several theories of epigenesis of siderite to be found in treatises and text-books, that allare at variance with chemical observations, or opposed by objec- tions on physiographic grounds, [ am now forced to believe that these interesting occurrences require a different explanation. They seem, indeed, to present no exception to the explanation of epi- genesis of siderite by chemical replacement of alkaline mono- carbonates, but on the contrary to afford striking examples of complete or pseudomorphous replacement of limestone beds. Indirect replacement of limestone (IL) by limonite at the Hurst ore-bank, Wythe Co., Va., has been graphically described by *Am. Jour. of Sc. xx, 1890, 155. 364 The American Geologist. December, 1891 Mr. Benton.* A useful section of six feet by this observer shows. beneath the soil (1) limestone, with crevices filled with limonite; (2) limestone softened and decomposed, with crevices containing more limonite than No. 1; (3) meshwork of limonite almost com- pletely replacing the limestone, and including residual ochre and fine sand; (4) complete replacement of limestone by honeycomb: ore. Reticulation of limestone by limonite is seen to be pro- gressive downwards until no remnants of limestone are left except in the form of insoluble residues occupying druses. These afford some measure of the contraction incidental to replacement. Another striking example of the same kind given by Prof. Dana, has been referred to in the memoir, of which the present pages are by way of continuation, namely, in the Cone ore-bank at West Stockbridge, Mass.+ Its description by this observer is. as follows: ‘Several layers had become wholly replaced by pure limonite, and one of these so changed was a yard thick. Some surfaces. of the limestone were intersected by cracks, making areas three to six inches across, as represented in the figure; each crack hay- ing a border of limonite either side, an inch or so wide.’ The same authority is cited by Mr. Prime for direct replace-* ment of limestone by siderite ultimately weathered to limonite, namely, at Richmond, Mass.2 This occurrence, like others ob- served by Prime at Balliet’s ore-bank near Allentown, Pa., and in another ore-bank near Hellertown, both in close relation to the Calciferous limestone and schists, is, as concluded by him, an in- stance of ‘-alteration of the limestone to carbonate of iron parti- cle by particle, or so to term it, a pseudomorph by replacement.” The same writer attributes the limonites of the Calciferous lime- stone and schists in a general way, to alteration of ferrous car- bonate produced by reaction of ferrous sulphate with calcie car- bonate, both diffused and massive, Remnants of notably pyritous material have been observed in many of the limonite workings of the Green mountain belt of Lower Silurian limestones and their southern extension, especially *Rep. Tenth Census xv, 1886, 275. +See Am. Jour. of Sc. xii, 1891, p. 234. tAm. Jour. of Sc. xiv, 1877, 136. Several excellent cuts illustrating: the transition of limestone into iron-ores have been given by Mr. Chauvenet, Rep. Tenth Census xv, 1886, 292, 296, 297, 299. SAm. Jour. Sc. rx, 1875, 140. Genesis of Iron-Ores.—himball. 365 in intercalated or adjacent schists. Numerous analyses by the Second Geological Survey of Pennsylvania indicate the presence of sulphur in almost all of the ores of the same belt in that State. The dissemination of visible pyrite throughout unde- composed parts of both limestone and schists is also noteworthy. This seems to be in about the same minute proportion that fer- rous carbonate is often similarly represented. The epigenesis of the latter is probably from pyrite. But hitherto the most remark- able evidence of pyritous material in the development of limon- ites associated with the same limestone series has been found in Alabama. In that region concentrically weathered or foliated masses of limonite isolated on the hill-tops by erosion of enclos- ing clay, the residuum of decomposed schists, sometimes retain nuclei or cores of undecomposed and highly pyritous rock. Cen- tral portions of other masses of limonite consist of siderite. Hence the not uncommon occurrence in limonite workings in limestone of ribs, masses and nuclei of siderite, ferro-calcite or limestone, from incomplete replacement, or incomplete subsequent alteration. Hence also similar occurrences of pyritous residuums in limonite developments in adjacent or transition schists. In given instances, be the mode of replacement of limestone by ferrous carbonate what it may, whether from styptic or chaly- bic solutions, or whether originally or eventually introduced into Siluro-Cambrian limestones, in the lower member of which series (Calciferous) limonites have been so extensively brought to light in Appalachian valleys, there seems much reason to conclude, as sometimes held, that in the course of chemical erosion of the limestone and of decay of reiated schists, very considerable accumulations of residual limonite have resulted from alteration of diffused ferrous carbonate or pyrite, not exceeding two and one- half per cent., to stable ferric hydrate. Parts of the same series expose(l to weathering or erosive action, and commonly below the full thickness, seem, in certain instances at least, to bear some proportion to the thickness of related accumulations of limonite. That is, the vertical range of the residual limonite seems to be in proportion to the thickness of limestone eroded, or rather to the measure of its shrinkage. Yet along with the es- ape of dissolved lime and magnesia salts in measure of chemi- cal erosion, there is also dissipation of iron salts. According to Lesley, limonite or pipe-ore, so-called, has a 366 The American Geologist. December, 1891 stratigraphic range in Huntingdon County, Pennsylvania, near Warrior's Mark, of at least 1,250 feet. The whole thickness of the Calciferous—Chazy—Trenton series of limestones to the bot- tom of the Hudson River group, there attaining its maximum de- velopment in that State, is estimated by the same authority at 7,750 feet. A thickness of 6,000 feet of this series, as esti- mated by Prof. A. L. Ewing, has been removed from the Nit- tany Valley anticlinorium to form that valley, or at least 1,000 feet in vertical range, mainly by chemical erosion. * McCreath’s analyses have showa ferrous carbonate up to 24 per cent. to be widely distributed in Lower Silurian limestones. The question arises when this was introduced—whether before deposi- tion of succeeding schists or afterwards? That this anhydrous salt was not directly deposited seems on chemical grounds almost certain. Is it then exclusively a product of replacement of calcic carbonate through solutions of iron salts from extraneous sources, and introduced subsequently to envelopment with ferro-siliceous sediments? Or, is it, in part at least, the product, practically in /oco original’, of reactions be- tween calcic carbonate in place and vitriolizing particles of pyrite, originally reduced from ferrous sulphate in sea-water through remnants of animal matter in accumulating calcareous sands? The researches of Dr. A. A. Julien into variation of decom- position in the iron-pyrites series, led him to the conclusion that the original condition of iron sulphides along the Appalachian belt was that of pyrrhotite. To whatever degree, in that case, this mineral may have survived sub-aérial rock-decay, and been accumulated along with Lower Silurian sediments, would it serve as an extremely productive source of iron’ salts, through decom- position by carbonated waters, including alteration into marcasite and pyrite. Even this initial transformation, as indicated by Bischof,t is attended by elimination of 25.54 per cent. of iron, and by con- traction of volume not less than 382 percent. as estimated from relative densities. Hence promotion of permeability in the con- taining rock through development of cavities. From surplus iron extracted by carbonated waters is doubtless developed fer- rous carbonate, by reaction with calcie carbonate, or else ferric *See Geol. Surv., Pa. T,, pp. 422, 424, 454. +Cavendish Edt. IIT, 455. a Genesis of Tron-Ores.—himball. 367 hydrate—as determined by atmospheric environment. This re- action may be assumed to be common both to limestone and ad- jacent transition schists, and even less closely related siliceous schists. Tron sulphides, sometimes visible in sound Lower Silurian limestones, seem to be developed in about the same minute pro- portion that ferrous carbonate is often revealed by analysis. Limonite developed by epigenesis on horizons of these limestones and of adjacent schists commonly affords traces of sulphur, as pointed out by Mr. Prime. Much larger proportions of iron sul- . phide are notably developed in the schists. It may therefore be concluded that both immediate and ex- traneous sources have contributed to fixation of ferrous carbon- ate as now found in parts of these limestones and associated schists: and that iron was received by these sediments in a car- bonated atmosphere before or during their consolidation as well as afterwards. This conclusion seems to be in line with Dana’s* numerous ob- servations in western New England and eastern New York, as well as with those of the Second Geological Survey of Pennsylvania, and to fall in with certain general deductions of Mr. Prime? and of Dr. Julien. + Besides limestones of the Siluro-Cambrian series, other lime- stones of the Silurian and Devonian periods give identification to occurrences of epigenic limonitic iron-ores. These are irregular shaped masses often described as lenticular (but in an opposite sense of that term as applied in this memoir) between limestone and adjacent ferruginous strata. Thus occupying bordering divisions of strata, they not infrequently assume to partial view semblance of interstratified deposits with which they have some- times been confounded. * Such relations, however, point more or less distinctly to re- placement of calcareous material through essentially superficial agencies, and to circumstances of attitude and environment favorable to epigenesis of limonite. These circumstances are ordinarily less obscure and complex than, those which govern the *Besides the several papers by Prof. Dana already cited, touching the present subject, may especially be mentioned one on Berkshire Geology, (Berkshire [Hist. and Sc. Soc., Pittsfield, 1886.) +Am. Journal of Sc. Lx, 1875, 482. tAn. New York Acad. Se. ITI, 1886, 393, 399. 368 The American Geologist. December, 189% distribution of accumulations of iron-ore connected with the lower series of limestones, mainly on account of the distinct configura- ? tion and undisturbed relations of the accumulations themselves. VIL, Replacement of Crystalline iron-ores. According to Lesley and (Invillers the famous magnetite de- posits at Cornwall, Pennsylvania, like the developments of brown hematite on the same horizon throughout the Great Valley, were originally a formation of Lower Silurian magnesian limestone beds. “It may safely be said,” as remarked by these observers, “that the Cornwall ore-mass has experienced three stages of development; being originally a formation of lime-shales; then becoming a great brown hematite formation; and finally a mag- netic ore-formation, ’’* The advanced metamorphism of the original ore-replacement from limonite, or perhaps from siderite, to magnetite, is a phenomenon which there is much reason to believe, is connected with local doleritic intrusions along the edge of the Pennsylvania Mesozoic, as also in the case of other occurrences of magnetite on the same horizonat Boyerstown, Dillsburg and elsewhere in the same State. Replacements of metamorphic limestone by other types of crystalline iron-ores have recently been observed by me in St. Lawrence County, N. Y. Here the Calciferous limestone has become crystalline, and its ore-replacements have become meta- morphosed into red hematites or anhydrous ores of the specular type. At Pierrepont, highly crystalline specular ore, of splen- dent lustre, occurs in white metamorphic limestone of Calcif- erous age. Taken in connection with my previous memoir on the present subject, the foregoing facts, here very briefly considered, tend to prove that replacement of Paleozoic limestones, and other cal- eareous material, including calcic carbonate from decay of siliceous schists, has been wrought indifferently from both in- filtrating chalybie and styptic waters, through surrender in each case of a weak base like ferrous oxide for a strong base like lime. | have also sought to indicate some of the circumstances of at- mospheric environment, topography or vicissitudes governing alteration of the product of preservation, or-—on the other hand *An, Rep. of the Geol. Surv. of Penn., for 1885, 1886, p. 539. Genesis of Tron-Ores.—himball. 369 direct replacement; and to attach what is conceived to be due significance and importance to such circumstances. Chemical replacement of limestone by ferrous carbonate, it is hardly necessary to remark in review, proceeds from surfaces of cleavage and stratification, wherever penetrated by infiltration of atmospheric waters from neighboring permeable ferruginous rocks like schists and shales; or, again, from surfaces and interstices of rocks, wherever calcic carbonate is produced by decomposition of silicates. Or, still again, solutions of lime and iron salts from one or the other source, give scope to similar and successive re- actions. Hence transmutations within compass of both limestone and adjacent schists. Mixed detritus from both kinds of strata, and overspreading considerable surfaces below the level of de- velopment or outcrops of such strata, also give place to like re- actions. Hence numerous shallow deposits of limonite at the base and on slopes of Appalachian ridges. Much of the ferric hydrate which appears due to tardy precipitation at considerable distance from sources of iron-salts is doubtless from indirect re- placement of limestone schutt. VII. Replacement of Cambrian Limestones, Late Superior region, and Missourt. The notable occurrences of crystalline iron-ores at Tron Mount- ain, Shepherd Mountain, and Pilot Knob in Missouri, within developments of stratiform porphyritic petrosilex (hillaflinta) was ascribed by Pumpelly, in the year 1872, to replacement of limestone.* Development of the petrosilex was also supposed to have resulted from chemical processes of replacement. How- ever this may be, it is not difficult to imagine development of petrosilex from a siliceous limestone, or from a limestone inter- calated with siliceous matter, concurrently with replacement of the calcareous material by iron-ores. Developments of this kind may be regarded as akin to the jaspery foliations of petrosilex along with crystalline ores in the Lake Superior region, the genesis of which by replacement of calcic carbonate has recently been traced by other geologists. The relations of specular or hematite schists in the Lake Su- perior region to siderite, and the phenomena of its original de- velopment and distribution have recently been treated, first, by *Geol. Surv. of Missouri, 1875; lron Ores, 26. 370 The American Geologist. December, 1891 the lamented Prof. R. D. Irving, and later by Mr. D. H. Browne, and by Mr. C. R. Van Hise.* The conclusions of the present memoir seem, as may be claimed, to strengthen the probability that occurrences of siderite and ferro-calcite, like those described by these authors as the im- mediate source of hematite in the Penokee-Gogebic range of Wis- consin and Michigan, are of the nature of chemical replacements of limestone, and calcareous shales and grits more or less car- bonaceous. Such developments are doubtless remnants of sider- itic material, of which the greater part has been further altered into brown and red hematite successively. As indicated by these writers themselves, from solutions of ferrous salts, replacement of calcareous material has been effected according to local conditions determining circulation and inter- ception of these infiltrations. That this was once, or at least in part, direct, is shown by the development of siderite. Products of indirect replacement like ferric oxide proceed as in other in- stances either from spontaneous oxidationof the replacing carbon- ate, or from its tardy alteration. The part taken by dykes in the interception of drainage has particularly been shown by Van Hise. Replacement of limestone by siderite, and subsequent altera- tion of this epigene product are opposite phenomena incidental to essentially ditferent atmospheric environment. Carbonic anhy- dride, or reducing gases, or a mixture of both, which may be assumed to have prevailed concurrently with the first process, or rather wherever this was set up, eventually must have given way to an ordinary oxidizing atmosphere. The association of car- bonaceous strata sufficiently attests this point. FOREIGN EXAMPLES OF REPLACEMENT OF LIMESTONE BY IRON-ORES. I close the present memoir with a few brief illustrations of re- placement of limestone by iron-ores in well known and important developments in several parts of Europe. As such most of these have been distinctly recognized. IX. Replacement of Carboniferous limestone, England. ah ‘ . ° . ° lhe Carboniferous or Mountain-limestone series of the north- ern and north-midland counties of England, as in other parts of that island—especially in South Wales,consists of alternations of *Am. Jour. Sc. xxxu, 1886, 255; xxxvir, 1889, 32, 299. Genesis of Lron-Ores.—himball, 371 thick limestones with thin shales and sandstones. The limestones are horizons of siderite and hematite, of which the larger de- velopments are irregularly distributed within compass of the cal- careous strata. Phillips* has given a selection of cuts which well serve to illustrate the phenomena of indirect replacement of limestone by hematite through alterable ferrous carbonate, as pointed out by Smyth,f and as attested by the presen¢e of fossils, identical with those of the limestone, partially converted into brown oxide. NX. Replacement of Mesozoic limestones, England. The iron-ore occupying horizons of estuarine limestone of the Lower or Bath oolites at the top of the Upper Lias series in Northamptonshire abounds with shells and corals converted into ferric hydrate. As animal life could not possibly have existed in waters charged with iron salts to the degree apparently indicated by the ore, Mr. Samuel Sharp concludes that the iron must have been introduced by infiltration after the deposition of the sedi- mentary material. { From a microscopic examination, Sorby concluded that Cleve- Jand ironstone of the Middle Lias of Yorkshire has been derived partly from mechanical deposition, and partly from subsequent chemical replacement of originally deposited calcie carbonate, ‘which probably thus served to collect together from associated ferruginous non-calcareous beds a large part.of the iron” contained in this ore. This is particularly proved by pseudomorphous siderite after aragonite penetrating molluscus shells originally composed of that form of calcic carbonate. 2 Lower Liassi¢ beds of calcareous siderite or ferro-calcite oceur in North Lincolnshire as upper members of a series of limestones and shales, and characterized by a great abundance of Gryphaeu arcuatau. The ore-series consists of alternations of unaltered ironstone with thin limestones, together aggregating, according to a section by Mr. George Dove, 16 feet in thickness. The ore, as described by Mr. D. Adamson, is intercalated with ferriferous limestone carrying from 8 to 16 per cent. of iron. || *Ore-deposits, 1884, 164. +Memoirs Geol. Surv. of Gr. Britain, Parts I-IV, pp. 18, 19, 25. A See Jour. Geol. Soc. 1870, 376; Judd, Mem. Geol. Surv. Gr. Br., 1875, 36. SAn. Jour. Geol. Soc. 1879, 84. |Jour. Iron and Steel Inst. 1876, 327, 372 The American Geologist. December, 1891 Lower Cretaceous, Wealden or Middle Neocomian calcareous strata in the same county, give place to oolitic brown ironstone which is described as highly fossiliferous as well as calcareous. The same strata are overlain conformably by the Lower Green- sand series of arenaceous shales, with which is imbedded lime- stone passing into ironstone. * NI. Replacement of Liassic limestone Luxemburg and Lorraine. The oolitic limonites of Luxemburg and Lorraine, equivalent with the ores of the Cleveland district of Yorkshire, and of the same gen- eral character, bear likewise evidence of replacement of limestone. Highly calcareous, as practically shown by their self-fluxing prop- erty, they contain remnants or nuclei of unaltered limestone, as well as numerous molluscus shells transformed into limonite. + NII. Replacement of Mesozoic limestones, central France. Some very striking exhibitions of the class of phenomena which it is here sought to illustrate, are afforded on a large scale by well known deposits of limonite and hematite within the develop- ment of Jurassic and Cretaceous limestones in the ancient prov- ince of Berry, now included in the Department of the Cher, in central France. I refer to occurrences recently studied by M. de Grossouyre.{ A graphic description by this engineer leaves scarcely room for doubt of the origin of these deposits by in- direct replacement. In the elaborate memoir now referred to, no attempt is made to trace the process of epigenesis beyond the action of solvent chalybic waters in excavation of limestone, and in deposition of ferric hydrate in its place. So far from being the simplest statement of the process of indirect replacement, this explanation is upon the assumption of chemical erosion of the limestone as a distinct act antecedent to precipitation of ferric hydrate, or, however insupposable, of anhydrous ferrous carbonate. Hence, as imagined, the formation of caves, cavi- ties, basins, ete., in limestone, followed by the filling of such receptacles with products of chemical precipitation. The same reasoning has often been applied to similar occurrences in this country and elsewhere. Reasons in general against such an assumption have already been given. The theory of molecular *Bauerman, Met. of iron, 1872, 91. +M. A. Habets, Jour. Iron & St. Inst. 1873, 285. tAnn. des Mines x, 1886, 311-416. Genesis of Iron-Oves.—himball. 373 replacement precludes any such intermittent action on the part of a single agency. NII, Replacement of Tertiary Limestone, Hesse. Epigenesis of oolitic iron-ores in Tertiary limestone of Rhenish Hesse has substantially been described by Tecklenburg as _ re- placement of an oolitic limestone, the source of infiltrations of iron salts being an upper ferriferous limestone of the same series. * —ALV. Replacement of Pre-palwozoic crystalline limestones, Banat. Some striking ¢xamples of replacement of crystalline limestone at Russkberg (Banat) by siderite passing into hematite on the one hand, and into magnetite on the other, were in other terms de- seribed by Mr. Rafael Hofmann, in the year 1854.7 Like the other more important iron-ore developments of the Carpathians, these are upon horizons of pre-paleozoic lime- stones. t Among other well-known developments of siderite and its de- rivatives in continental Europe within limestone strata, suftice it in passing to mention those of Carinthia and Carniola; and not- ably those of the Styrian Erzberg near Eisenerz in Austria; also those of the Rhenish province of Coblentz and Siegen in Ger- many. 4% Commonly regarded as epigene products, these have usually been described by German authorities in various terms as Sticke, || Lagerstécke, Gangsticke, and Flétze, sometimes of direct deposi- tion successive in relation to enclosing strata, sometimes as me- chanical fillings or ‘‘in-washes” of pre-existing spaces; and, again, as chemical segregations. In most of the conspicuous instances named, circumstances of environment and topography are such as to indicate more or less clearly molecular replacement of lime- stone or dolomite. ‘ M. Sibertzy, of the Geological Survey of Russia, considers cer- *Zeitsch, Berg—Hiitten—und Saliaen Wesen xxrx 1881, 210. tGangstudien, I1, 468. {Von Hauer—Geol. Oest._-Ungar. Monarchie, 1875, 194. SSenft. Geognosie 1876, 451; Von Hauer loc. cit. 223. |Dr. E. Reyer truthfully says that Geology and the miner call that form, as to whose form nothing is known, a Stick. (Berg-u-Huetten- mannische Jahrbuch xxtx, 1881, 26.) B74 The . Linerican Geologist. December, 1891 tain iron-ores of that empire as products of replacement of Per- mian and Carboniferous limestones. Another Russian authority, M. P. Zemiatschensky, entertains similar views in respect to iron- ores of central Russia. * NV. Mediterranean iron-ores as replacements of limestones. 1—Iron-ores of Bilbao, Spain. No more remarkable developments of iron-ores can be in- stanced than those of the Biscayan province of Spain. These ores, known far and wide under designations of localities of numerous workings on the flanks of Mt. Triano, include those of Somorrostro, Triano, and Matamoras, from which immediate lo- calities, according to Mr. Gill, over 25 millions of tons was pro- duced in 1882, or 93 per cent. of the whole product shipped from the port of Bilbao during that year. These ores are of several amorphous types and gradations, in- cluding limonites, turgites and hematites, some of the latter verging upon thespecular variety. They areof different degrees of purity, inversely proportional to their tenor of earthy silicates; and ac- cording to the degree, first, of replacement of limestone, and, second, of alteration from the condition of ferrous carbonate, from which all types and gradations have evidently been de- rived. These important 1ron-ore deposits occupy the horizon of lime- stone, especially of a formation interposed between overlying fossiliferous argillaceous limestone, and a lower limestone under- lain by variegated and micaceous grits, containing nodular spheerosiderite, the whole series, of Middle Cretaceous age, being much disrupted and dislocated. The ore, wrought in places to depths of over 100 feet, greatly fluctuates in thickness, owing to inequality in vertical range of replacement, whence obviously the uneven or billowy surface of the limestone floor, as described by Gill and others. In other places the limestone is fully developed, no replacement having been effected. Again, the whole vertical range of the limestone is represented by ore, while at still other localities a lenticular bed of unaltered limestone separates the so- called campanil, clearly a hematitic or transition product of alteration of siderite—more or less incompletely transformed, ———— ee ee *Cited in Bibl. of iron-ores. Geol. Nat. Hist. Surv. of Minnesota, Bull. No. 6, pp. 320, 334. Genes. s of lvon- Oves.— himball. y from the underlying vena dulce. This is a soft limonite passing into turgite and also graduating in places into a harder variety known as vena dura, in which abound pseudomorphous rhombo- hedrons of hematite, after siderite. The shaly blue limestone, containing reqguicnia lerigata, and giving place to ore-bodies on the north side of the divide between the Nervion and the Somorrostro rivers (Mt. Triano), presents a continuous outcrop on the south side, and forms the crest of the mountain. The vena dulce, or gallery ore, is described as the character of ore deep under cover; campanil, the choice or ship- ping ore of the region, under moderate cover; and rubro, a worthless variety in exposed ledges, The latter is a sideritic, cellular, cherty limonite, forming outliers or crags, evidently cor- responding to the upper edge of disrupted and highly tilted masses of the reguienia limestone, weathered and leached by at- mospherie action without the aid of underground moisture, and without protection of cover, but passing into rena on attaining cover. In both brown and red-ore mines siderite occurs in blocks as cores or nuclei of altered products. The source of ferrous salts yielding more or less alterable fer- rous carbonate in contact with limestone, appears to have been overlying, now mostly obliterated, ferriferous and pyritous sedi- ments, of which remnants are preserved. Unequal conditions, perhaps in original composition of the ore-limestone, but cer- tainly as to attitude and environment, have led to unequal de- velopment of ore-masses, some of which, according to Gill, hav- ing the semblance of mountains of ore, proving mere shells of good ore with nothing but siliceous material behind them. Changes of volume, as unequal replacement and chemical altera- tion have advanced, may be believed to have been adequate to produce no small part,if not the whole, of the disruptions and dis- locations, so marked a feature in the stratigraphy of the region. Though some of the phenomena here referred to have been differently interpreted by M. Barson* and M. Baills,+ the deserip- tions given by Gill} furnish abundant evidence of sideritic replace- ment of Cretaceous limestone strata, and of subsequent altera- tion into limonite and hematite more or less advanced as condi- *Rev. Univ. des Mines, rv, 1878, 648. +tAnnales des Mines, xv, 1879, 209. {Jour. Iron and Steel Inst. 1882, 63. 6 The American Geologist. December, 1891 tions for weathering action have been more or less favorable, especially as regards the intervention of moisture. . 2. Lron-ores of Elba. The specular iron-ores of the island of Elba, which have often been instanced in text-books as an example of eruptive or sub- limation deposits, a conclusion questioned by G. Vom Rath in the year 1870,* have since been described by Lotti of the Geological Survey of Italy, as in part altered products of replacementof cal- careous rocks with which a chemical interchange of materials has taken place, in conformity with the law that the more easily solu- ble minerals are replaced by the less soluble. + 3. Algerian tron-ores (Tafna), Among well-known Algerian iron-ores are those of the Tlemcen district, near the western border of the province of Oran. These ores, commercially known as Tafna ores, are, as described by M. Pouyanne, } hematites occupying the horizon of Liassie limestone, which rests unconformably on ancient crystalline schists. While masses, large and small, of unaltered limestone and siderite are unequally distributed inall of the workings, these masses all furn- ish evidence of gradual and progressive transition into hematite, while specular and magnetic oxides occur as products of further alteration. Other deposits imbedded with Tertiary strata are made up of detritus from the Liassic ores first mentioned. Washington, D. C., March 21, 1891. CRITERIA OF ENGLACIAL AND SUBGLACIAL DRIFT. By WarneN UrxHam, Somerville, Mass. The purpose of this short paper is to call the attention of gla- cialists to the means of discrimination of the portion of the drift which, at the time of final melting of the ice-sheet, was enclosed within the ice and therefore is called englacial drift by Pres. Chamberlin, and the portion which was subglacial, lying under the ice. It is hoped that the availability of the criteria here men- tioned will be discussed by others, and that we may attain the most useful methods of observation and determination, in all parts of our drift-bearing area, concerning the question whether a large *Jahrb. fiir Min. 1870, 786. +Emmons, Trans. Am. Inst. Min. Eng. 1886. Ext. 8. tAnn. des Mines 1x, 1876, p. 81. ~] ~| Criteria of Dri ft.— Upham ; 3 fraction of the drift, or only a small amount, was contained within the ice-sheet, becoming superglacial by ablation, at the time of its departure. Englacial Till. The following characters have seemed to me, in examination of the drift deposits of New Hampshire and other New England states, and of Minnesota, Lowa, the Dakotas, and Manitoba, to distinguish the englacial till, reaching from the sur- face to a variable depth,as compared with the lower subglacial till. 1. More plentiful and larger boulders are usually enclosed in the portion of the till that was englacial. Sometimes many of them are only partially embedded at the surface. 2. These boulders and the smaller pieces of rock are mostly angular or subangular. While being carried along in the ice- sheet, the englacial drift was not subjected to attrition, which ac- counts for the large size and unworn character of its rock frag- ments. 3. The englacial till has commonly a somewhat more gravelly and sandy and less clayey composition, owing to the washing away of much of its finer material by the drainage of the glacial melting. 4. It has a looser texture and is much more easily excavated This portion of the englacial drift was allowed to fall loosely when the ice disappeared. The subglacial till, on the other hand, be ing compressed by the vast weight of the ice-sheet, became very hard and compact, whence comes its popular name, ‘* hard pan.’ 5. The effect of weathering, by which the small ingredient of iron in the till has become changed next to the surface from pro- toxide combinations to the hydrous sesquioxide, giving a’yellow- ish color, strongly in contrast with the darker gray and bluish color of the unweathered portion below, often is limited at the plane that separates the readily permeable, loose englacial till from the comparatively impervious subglacial till. 6. Between the two, there is frequently a layer of subglacial stratified gravel and sand, from a few inches to a few feet thick. Subglacial Till. Characteristic features of till accumulated be- neath the ice are, conversely, the prevailingly smaller size and glaciated shapes of the enclosed boulders and fragments, its larger proportion of clay or very fine rock flour, its remarkable hardness, and in many sections the cessation at its top of the coloration due to weathering. Another criterion of subglacial till is the position of its oblong 378 The American (reologist. December, 1891 stones, generally with their major axes approximately parallel with contiguous glacial striz and with the course of movement of the ice sheet, and the embedding of flat stones with their flat sides nearly horizontal, or, where the accumulation rises in a prominent mass, as in drumlins, taking a parallelism with the slopes of the surface. In the englacial till stones of these shapes are less abundant, because of their exemption from glacial wearing, and they have no observable order of arrangement. Furthermore, the subglacial till often exhibits, especially in sections of drumlins, a peculiarly bedded structure, in parallelism with the surface. Though boulders, gravel, sand, and clay are thoroughly commingled, the deposit is imperfectly laminated and tends to separate and crumble into thin flakes. This is frequently noticeable in a fresh excavation, but is most distinctly seen after a few weeks of exposure, Mr. Hugh Miller has observed similar structural features of the subglacial till over large tracts of northern England ;* and the dis- crimination of the englacial and subglacial till, relying on most of the characters here noted, was probably earliest pointed out by Dr. Otto Torell, of Sweden. + A partial stratification by water within the till, producing some- times thin layers of gravel, sand, or clay, inconstant in character and thickness and usually of short extent, or often only a distinct approach toward the formation of such layers, is occasionally ob- served in both the englacial and the subglacial till, probably more frequently in the former; but veins of gravel and sand, of such extent as to yield a sufficient supply of water for wells, are more common in the latter, or, as before noted, at the plane between these deposits. The obscure stratification seems attributable to seeping water during the deposition of the till, whether subglacial or englacial and superglacial, while the definite and larger gravel veins were formed. in small and temporary subglacial water courses, Both deposits contain boulders and other drift derived from near and from remote rock outcrops. Local topography deter- mined the relative abundance of these portions, and probably also whether the ratio of far travelled material is greater in the en *Report of the British Assoc. for Adv. of Science, Montreal, 1854, pp- (20, 721. +Am. Jour, Sci., ILI, vol. xiil, pp. 76-79, Jan., 1877. Criteria of Dri ft.— Upham. 379 glacial or in the subglacial till, for it seems to vary in this respect in different districts. During the progress of the accumulation of the subglacial till, it was supplied mainly from the lower part of englacial material, in which boulders and fine drift of near origin were more abundant than higher upintheice. Hence, asa whole, doubtless the subglacial till has more local material, though dif- fering little in this respect from the basal part of the drift within the ice-sheet. The streams depositing kames and osars, as I be- lieve, brought these sediments largely from the upper and more remotely derived portion of the englacial drift, and also trans- ported them for the greater part long distances, thus wearing the boulders and gravel to subangular and rounded forms. There- fore, in the order of their percentages of distances of transporta- tion, the subglacial till is generally lowest, and the englacial till next, while the stratified gravels, sands, and clays brought by streams from the ice were successively deposited, each mostly beyond the preceding and farther from their sources. Perched Blocks. When the ice-sheet was melted away, its en- closed boulders were dropped, and sume of them, lying as con- spicuous objects upon the surface, are strown sparsely over the prairies or are perched, apparently where they might be easily dislodged, on the slopes and crests of hills and mountains. Oc- “asionally these perched blocks are of great size. Two found by Dr. G. M. Dawson on the eastern foot-slope of the Rocky mount- ains, about 3,300 feet above the sea, measure respectively 42 by 40 by 20 feet and 40 by 30 by 20 feet. Other blocks in the same region extend up to the height of 5,280 feet, and they all were derived from the Archean area east and north of lake Winnipeg, some 700 miles distant. * President Chamberlin has deseribed remarkable belts of abun- dant superficial boulders associated with terminal moraines in Hlinois, Indiana, and Ohio.+ These boulders are almost exclu- sively crystalline Archeean rocks, and are thus known to have been transported across a distance of at least 300 to 500 miles from the north. They show that here and there in the ice-sheet rock musses, derived from remote hilly or mountainous tracts, were borne forward high above the land; and that on the approxi- mately level country of these states only the lower portion of the ice contained much drift derived from local rock formations. *(teo]. Survey of Canada, Report of Progress for 1882-83-84, pp. 147-149 C +Bulletin, G. S. A., vol. i, 1890, pp. 27-31. S80 The r | merican Geologist. December, 1891 Most of the very plentiful boulders usually present in the hills and ridges of the terminal moraines were doubtless brought as the highest part of the englacial drift. Kames, Osars, and Valley Drift. That a large amount of drift was carried along in the ice-sheet and became exposed on its sur- face during its final melting, seems to me clearly proved, not only by the thickness of englacial till according to the criteria be- fore noted, but also by the various deposits of assorted or modi- fied drift. Perhaps the most interesting class of these deposits is that which consists of prolonged ridges of irregularly bedded gravel and sand, often extending in a series many miles, sometimes 20, 50 or even 100 miles or more in length. These ridges usually have steep sides and a narrow arched crest of variable hight. Associated with them, and especially with the terminal and mar- ginal moraines of the ice-sheet, are mounds, hillocks, and short ridges likewise composed of gravel and sand having a confused stratification, often somewhat anticlinal in conformity with the slopes of the surface. Both the very long gravel ridges or series of ridges, and the very short ridges, hillocks, and knolls, were formerly classed together, and were called kames, eskers, or osars, but a useful discrimination has been proposed by MeGee and Chamberlin, in accordance with which the term /ames is now restricted to the gravel hillocks, knolls, and ridges of slight ex- tent, while the long ridges are named osars or eskers.* Precisely the same explanation of the mode of formation of the osars was reached independently fifteen years ago by Dr. N. O. Holst in Swedent and by the present writer in New Hampshire. t Four years earlier, as I afterward learned, nearly the same view had been first published by Prof. N. H. Winchell, in Minnesota. |! *W J McGee, in the Report of the International Geological ‘Congress, second session, ‘Boulogne, 18815 p.G21.7 YU: Chamberlin, in the Third Annual Report of the U.S. Geol. Survey for 1881-82, p. 299; and Am. Jour. of Science, II, vol. xxvii, pp. 378-390, May, 1884. The article last cited presents many bibliographic Seba eee and shows that the term osar (pl. osars), in this Avglicized form, has long been in common use by Jackson, Hitchcock, Desor, Mure hison, and other authors. +*Om de glaciala rullstensasarne,” Geologiska Foreningens i Steck- holm Foérhandlingar, vol. iii, 1876, pp. 97-112. This paper is reviewed by Dr. Josua Lindahl] in the American Naturalist, vol. xxii, pp. 589-591 and 711-715, July and Aug., 1888. t“ On the Origin of Kames or Eskers in New Hamshire,” Proc, A. A. A. sed vol. Xxv, 1876, pp. 216-225. Geology of N. H., vol. iii, 1878, chapter i. Proceedings, Boston Society of Natural History, vol. xxv, 1891, pp. 228-242. Geol. and Nat. Hist. Survey of Minn., First Annual Report for 1872, p. 62, etc.; Second An. Rep. for 1873, p. 194. Proe. A. A. A.S., vol. xxi, tor 1872, p. 165. Criteria of Dri ft.— Upham. 38 During the Champlain epoch, as the time of disappearance of the last ice-sheet has been named by Dana, its superficial melting was rapid throughout the warm portion of each year, while the sub- elacial melting went on at a very slow rate through both winter and summer, the same as it had been during the entire epoch of glaciation. Owing to the rapidity of the melting on the ice sur- face, and to the amount of englacial drift thus exposed and = sub- jected to erosion and transportation, we believe that the subglacial stream courses already existing were inadequate for the drainage, and that they were mostly obstructed and closed by the transpor- tation and deposition of modified drift. The waning ice-fields were then deeply incised by brooks and rivers pouring over them in the descent to their border and to the adjacent land lately un- covered by the glacial retreat. © Hydrographic basins of the ice- sheet probably extended 50 to 200 miles or more from its margin, resembling those of a belt of country along a sea coast; but the glacial rivers, and their large and small branches, had much steeper gradients than those of the present river systems on the land surface, and often or generally they flowed in deep ice- walled channels, more like canons than ordinary river valleys. Much englacial drift, which had become superglacial, was washed away by the rains, rills, and small and large streams from the ice surface; and the osar gravel ridges are the coarsest sediments progressively deposited near the ice-front in such channels which were cut backward into the retreating edge of the ice by the su- perglacial streams. The best development of osars on this continent, scarcely in- ferior to that of Sweden, is found in Maine and has been thor- oughly explored and studied by Prof. George H. Stone, who con- eludes that the material forming these long ridges, also the short ridges and knolls called kames, and the valley drift, or stratified gravel, sand, clay, and fine silt, spread along the river courses and on the lowlands, were all supplied chiefly from the englacial drift.* This origin seems to me also true for the kames, osars, and valley drift which have come under my observation in New Hampshire, Vermont and Massachusetts, and in Minnesota, Mani- toba, and adjacent portions of the Northwest. In a paper read * Proceedings of the Boston Society of Natural History, vol. xx, 1880, pp. 480-469. Proc., A. A. A.S., vol. xxix, 1880, pp. 510-519. Am. Jour. Sci., III, vol. xl, 1890, pp. 122-144. 5S Pe be The y | erica (eologist. December, 1891 last August before the Geological Society of America, I show that the volume of the drift contained in the last ice-sheet when it was melted from these states and province appears to have ranged from very little on some tracts to the thickness of at least forty feet on other tracts. On the average, [ believe that it was not less, but probably considerably more, than my estimate of its amount in New Hampshire, namely, the equivalent of a uniform sheet of drift six or seven feet thick. In Great Britain, however, the material of the kames and other modified drift is thought by Prof. James Geikie to have been de- rived almost wholly from subglacial drift through the action of streams flowing beneath the ice-sheet; and he believes that there was very little englacial drift, quite too little to permit the en- glacial derivation of the stratified drift which is affirmed by Torell, Holst. and others in Sweden, and by Dana and many others who have studied the drift of North America. But another eminent British glacialist, Mr. G. W. Lamplugh, ina very complete and valuable discussion of the drift deposits of Flamborough Head and other parts of England, published this year, thinks that the ice-sheet which moved outward from Scandinavia and the high- lands of Scotland and northern England, sweeping across the low area that is now the bed of the North Sea, and then encroaching on the Flamborough coast, was charged with a large amount of englacial drift, not only Norwegian and Scottish boulders, but also marine débris with fossils, gathered up into the ice from ground that had been previously and is again now the sea bottom. * In this country, we owe to Prof. James D. Dana the earliest enun- ciation, more than twenty years ago, of the doctrine that the ice- sheet contained abundant drift and deposited it during the final melting, partly as unstratified and partly as stratified drift:+ and only a few years later this opinion was also published by Prof. N. H. Winehell, with especial emphasis on the effect of the superfi- cial melting to cause this drift to become superglacial.t Both these authors appear to claim that a larger proportion of the whole yolume of the drift was englacial at the close of the Glacial *Quart. Jour. Geol, Society, London, vol. xlyii, 1891, pp. 384-451, with maps and sections. +Trans., Connecticut Academy of Arts and Sciences, vol. ii, 1870, pp. 66-86. Manual of Geology, editions of 1874 and 1880. *Geological and Natural History Survey of Minnesota, First Annual Report, for 1872, p. 62. Pop. Sci. Monthly, vol. ili, 1873, pp. 293, 294. Criteria of Dri ft.— Upham. 380 period than I should be able, on the basis of my observations and the foregoing criteria, to adimit. There were surely, as I think, extensive and thick deposits of subglacial till, besides some scanty subglacial beds of stratified gravel, sand, and clay; and the aggregate mass of the subglacial drift appears to me without doubt to exceed, and perhaps two or three times over, the mass of the ice-held drift. Testimony of Ewisting Ice-sheets, Dr. N. O. Holst in his ex- amination of portions of the margin of the Greenland ice-sheet, found extensive deposits of both englacial and subglacial drift, respectively characterized by angular and by glaciated stones and boulders. The largest accumulation of superglacial drift, which had been englacial, was observed on the southern edge of a lobe of the ice near Frederikshaab. The drift covering the ice surface here extends along a distance of nearly twelve miles, and reaches a half mile to one anda half miles upon the ice. According to Holst’s Swedish report of his observations, summarized in transla- tion by Dr. Josua Lindahl,* the quantity and upper limit of the superglacial drift at this locality are as follows: Its thickness is always greatest near land, but here it is often quite difficult to estimate its actual thickness, as it sometimes forms a compact covering, only in some fissures showing the underlying ice. This un- even thickness of the moraine-cover offers to the ice a proportionally vatying protection against the sun. It thus happens that the unequal thawing moulds the underlying surface of the ice into valleys and hills, the latter sometimes rising toa hight of fifty feet above the ad- jacent valley, and being so densely covered with moraine material that this completely hides the ice core, which, however, often forms the main part of the hill. Farther in on the ice, the moraine gradually thins out. At the local- ity just referred to, the moraine-cover, 3,000 feet from land, measured several inches in depth; still the ice was seen in some bare spots. Be- yond 4,000 feet from land, the moraine formed no continuous cover, and at 8,300 feet it ceased entirely, with a perceptible limit against the clear ice. Only some scattered spots of sand and gravel were met with even a few hundred feet farther in on theice. Dr. Holst estimated the aver- age thickness of the moraine taken across its entire width near its east- ern end at one to two feet. The limit between the moraine-cover and the pure ice is always located at a considerable though varying elevation above the edge of the inland ice. In the instance of the above-men- tioned moraine it varied between 200 feet and 500 feet. Terminal moraine Dages in proc ess of accumulation on the *Am, Naturalist vol. xxii, pp. 589- 598 cal 105-715, - July and rege ., 1838, 584 The American Geologist. December, 189% thinned border of the ice, were seen in several places, sometimes, as shown by the following quotation, consisting chiefly of sub- glacial drift, elsewhere of englacial drift. The border moraines north of the Arsuk fjord ice-river are visible far out on the sea off Ivigtut. Dr. Holst examined one that surrounds the southernmost strip of land at a distance from land of about 2,000 feet. It is not one continuous ridge, but consists of several disconnected por- tions arranged in a semi-circle. One of these portions was about 200 feet wide and thirty-five feet high. This moraine was mainly a ground- moraine, probably forced up by some elevation of the ledge under the ice. Another border moraine to the north of Kornok’s northern ice-river, was Of a different character. The stones, at least at the surface, were greatly in preponderance over the gravel. They were angular and of varying size. The moraine showed some arcuations, but taken as a whole it was parallel to the land. In some exceptional instances it ap- proached closely to the land, even so as to touch one of the projecting points, but generally it was located some distance away from land. Its width was estimated at 100 feet, and its hight at more than fifty feet; it should be remembered, however, that it might have had a core of ice. Its length was about one and a half mile. South of this moraine, and farther in on the ice, were seen three more moraines, the greatest one extending about 1,000 feet in length. Two of them were parallel, one inside the other. Still more impressive testimony of a large amount of englaciab and finally superglacialidrift is given by Mr. I. C. Russell in his description, as follows, of the Malaspina glacier or ice-sheet lying between the base of Mt. St. Elias and the ocean. This is a pleateau of ice having an area of between 500 and 600 square miles, and a surface elevation in the central part of between 1,500 and 1,600 feet. It is fed by the Agassiz, Seward, Marvine, and Hayden gla- ciers, and is of such volume that it has apparently displaced the sea and holds it back by a wall of débris deposited about its margin. All of its central portion is of clear white ice, and around all its margins, excepting where the Agassiz and Seward glaciers come in, itis bounded bya fringe of débris and by moraines resting on the ice. Along the seaward bor- der the belt of fringing moraines is about five miles broad. The inner margin of the moraine belt is composed of rocks and dirt, without vege- tation, and separated more or less completely into belts by strips of clear ice. On going from the clear ice toward the margin of the glacier one finds shrubs and flowers scattered here and there over the surface, Far- ther seaward the vegetation becomes more dense and the flowers cover the whole surface, giving it the appearance of a luxuriant meadow. Still farther toward the margin dense clumps of alder, with scattered spruce trees, become conspicuous, while on the outer margin spruce trees of larger size form a veritable forest. That this vegetation actually Katon. 385 The Winnebago Meteorite. grows on the moraines above a living glacier is proved beyond all ques- tion by holes and crevasses which reveal the ice beneath.* The abundance of superglacial drift on this small ice-sheet in Alaska, and its comparative scantiness on the greater part of the border of the extensive ice-sheet in Greenland, seem readily ex- plained by the recent and present rapid decrease of the Alaskan ice, while that of Greenland is probably now increasing and the climate growing somewhat colder. f Both these ice-sheets lie on or near very mountainous districts. It will be of the highest interest to glacialists to obtain similar ob- servations of the Antarctic ice-sheet, for most portions of its vast expanse seem to flow out into the sea from areas of low land, more nearly representing the basin of the North Sea, from which, according to Lamplugh, the confluent Scandinavian and Scottish ice moved upward over the eastern shores of England, bringing much englacial drift derived from that lower area. In like situa- tions, too, far from mountainous or even notably hilly country, are the localities which have afforded to me the greatest estimated thickness of the englacial drift, as about forty feet adjacent to the Altamont moraine on the Coteau des Prairies in southwestern Minnesota, { and about the same amount where currents of the ice- sheet converged from the northeast and northwest at Bird’s Hill near Winnipeg, Manitoba.% In each of these places the englacial drift is largely derived from the neighboring low region. THE WINNEBAGO METEORITE. By E. N. Eaton, Ames, Iowa. In the August number of the GroLoGisr professors Torrey and Barbour again publish their analysis of the Winnebago county meteorite. The analyses thus far published vary so greatly that I hesitatingly add a preliminary one made by myself *“An Expedition to Mount St. Elias, Alaska,” National Geographic Magazine, vol. iii, 1891, pp. 185, 186. +Am. GEOLOGIST, Vol. vili, pp. 145-152, Sept., 1891. tGeol. and Nat. Hist. Survey of Minnesota, Ninth Annual Report, for 1880, pp. 322-326; Final Report, vol. i, 1884, pp. 605, 604. S$Geol. and Nat. Hist. Survey of Canada, Annual Report, new series» vol. iv, for 1888-89, pp. 38-40 E. B86 The American Geologist. December, 1801 soon after the ‘‘fall” and published in the Awrora,* a magazine edited by the students of the Lowa Agricultural college. For comparison these analyses will be placed together. RECORDED ANALYSES OF THE WINNEBAGO METEORITE, +Eakins > rt Sige ater: ie matic Tere Nickeliferous iron 19 40 20.22 45.00 SiO, 35.71 23.88 47.03 25.86 FeO $15.12 26.71 €29.43 16 18 MgO 24 00 25.91 2.96 1.63 ATES 2.08 2.62 2.94 1.62 CaO 1.41 Styl 17.58 9.67 Ss 2.13 Alig KO 80 ar; Ni 13 dij CriO- 08 ir. | 100.86 {| 99.3 | 99 94 99.96 In their last article professors Torrey and Barbour do not give the percentage of metal, but in a former article under the same analysis of matrix it is stated to be 459 .** In the fourth column the analysis is calculated on this basis. It will be observed that Torrey and Barbour’s analysis contains over twice as much metal, almost seven times as much lime and less than one-fourteenth as much magnesia as that reported by Eakins. Do the sections of the aerolite show such diversity in chemical composition? That it is not altogether homogeneous is evident from a microscopical examination. The nickeliferous iron oceurs in nodules of varying size while there is no regu- larity in the distribution of olivine, triolite, ferrous oxide or other constituents. Also in the fragments the surface is oxidized in an extremely thin layer while on the larger masses it is somewhat thicker. That this variability is not conspicuous in dealing with larger masses is indicated by Torrey and Barbour obtaining the identical specific gravity as that reported by Kunz (3.608)+7 while my own (3.67) is nearly a medium between Kunz and Eakins (3.804 at 28.5C.).¢i 9 My chemical analysis corre- sponds quite closely with Eakins. tAllowing 45 per cent. for metal. SSome of the iron combined as FeS hence per cent. FeO too large. In original article estimated as Fe, O, (29.68 per cent.) © Ferric oxide. **Am. Jo. Se. Vol. 139, p. 521. ++Trans. N. Y. Acad. Sc. Vol. 1x, No. 8, May-June, also AMERICAN GroLocistr, Vol 6, p. 249. trAm. J. Sc. Vol. 140, p. 312. kdittorial Comment. 387 In reviewing the facts presented by the analyses, one is inclined to doubt the veracity of the specimens upon which professors Torrey and Barbour made their analyses. In view of the num- ber of counterfeit specimens that were exhibited soon after their value became known, some of which resembled the meteorite closely, a mistake of this nature might easily occur. The specimens upon which my analysis was made were sent by Mr. Eugene Secor, of Forest City, a trustee of the Towa Agricult- ural College, to Prof. Herbert Osborn, and are now under his care in the college museum. Other specimens were sent to me by parties in Forest City, and [ think there can be no doubt as to the genuineness of the samples analyzed. On the whole it would appear advisable that there be a careful revision of the work for such variability im chemical composition is unparalleled in the history of meteorites, and if true should have clear confirmatory evidence. EDITORIAL COMMENT. RECENT STUDIES IN SPHERULITIC CRYSTALLIZATION. Constitution und origin of spherulites in acid eruptive rocks. WAYtMAN Cross. (Phil. Soc. Wash. Vol. 1x, pp. 411-444.) Spherulitic crystallization. Jos. P. Ipprnes. (Phil. Soc. Washington, Vol. rx, pp. 445-464.) Mr. Cross found, in the investigation of spherulites and litho- phys of Colorado that the views both of the German and the French and of the English petrographers were inapplicable and the schemes of classification were unsatisfactory. Ile sketches German opinion, from Vogelsang to Zirkel and Rosenbusch, with critical observations. In particular, the term ‘‘microfelsite ~ proposed by Zirkel and considered by Rosenbusch to signify a distinct mineral species occurring in scales and fibres and having a characteristic radiating spherulitic strueture, Mr. Cross con- siders with Iddings, Teall and Brégger to be improperly defined. He rather inclines to the opinion that these substances consist of a ‘“submicroscopic’ intergrowth of orthoclase and quartz, and BSS The American Geologist. December, 1891 that the fibers and seales in the ground mass of porphyries and rhyolites may be minute particles of feldspar indeterminable by existing means of research, In a similar manner the term ‘‘petrosilex” is employed by the French petrographers, under the lead of Michel-Levy, in a loose way, as is admirably illustrated by the definition, ‘‘a partially amorphous magma impregnated with silica already individualized in astate of opal or chalcedony.” | Spherulites are supposed, by the same authority, not to consist of known minerals, unless they be quartz and feldspar, intergrown in the manner of pegmatite. The result of the author's study of the Colorado material seems to show that indefinite substances, such as crystallites, petrosilex and microfelsite, have been assumed to be present unnecessarily in many cases heretofore, under the influence of preconceived ideas. The chemical constitution of the pitchstone containing the Col- orado spherulites shows, that on complete crystallization the rock resulting would be composed nearly two-thirds of alkali feldspar and a little more than one-third of free silica. The author coin- cides with Iddings in the description of Obsidian cliff, that, in- stead of being due to anarrest of crystallizing consolidation (sup- posed by all European authors) spherulites of the smallest size as well as the larger spherulitic masses, are due to the crystallization of some definite minerals from a magma, under special conditions. There are a few older crystals in these rhyolites which, at a period prior to the spherulitic, were formed from the magma and by their arrangement bring out the fluidal structure. These took up the small percentages of lime, magnesia and iron oxides which analysis shows to exist in the pitchstone, forming phenocrysts of plagioclase, leaves of biotite, microlites of augite and trichites of magnetite. Mr. Cross examines specially the larger spherulitic masses, but he considers even the smallest to consist of definite and often identifiable minerals. As to the origin of these spherulites, Mr. Cross supposes that amorphous silica plays an important role. — First a colloidal sub- stance, embracing the elements of silica and of feldspar, is sup- posed to be separated from the magma, this being ‘‘a local change in the character of the magma,” but whose cause and attendant conditions Mr. Cross does not attempt to state. From this pri- mary colloidal globule are generated amorphous silica in one di- kditorial Comment. 389 rection and feldspar in another, the latter taking radiated and branching forms under varying tension and viscosity in the mag- matic mass.