pe ae 1h ees Sse 7 a irat | i Ote-— ee , Pek WOls em ge ae bet: oa Ca se ba ' he ee 4 vpae 4 ‘ iy nh aE cy AdAts Oi i eaig at Fees sure fh phd Pao ig SE Ab bee * ‘ Ve ee et. oo Games (96, 9b 833 EOLOU The person charging this material is re- sponsible for its return on or before the Latest Date stamped below. Theft, mutilation, and underlining of books are reasons for disciplinary action and may result in dismissal from the University. University of Illinois Library L161— O-1096 Digitized by the Internet Archive in 2010 with funding from University of Illinois Urbana-Champaign http://www.archive.org/details/oanamericangeolo151895desm iy th y iT os, THE AMERICAN: GEOLOGIST A MONTHLY JOURNAL OF GEOLOGY AND ALLIED SCIENCES. EDITORS AND PROPRIETORS: CHARLES E, BEECHER, Vew Haven, Conn, SAMUEL CALVIN, Jowa City, Lowa. JoHN M. CLARKE, Albany, N. Y. EDWARD W. CLAYPOLE, Akron, Ohio. PERSIFOR FRAZER, Philadelphia, Pa. FrANcIS W. CRAGIN, Colorado Springs, Colo. EDWARD O. ULRICH, Newfort, Ky. JOHN EYERMAN, LZaston, Pa. WARREN UPHAM, Cleveland, Ohio. MARSHMAN E, WApDswortTH, Houghton, Mich. ISRAEL C. WHITE, Morgantown, W. Va. NEWTON H. WINCHELL, Minneapolis, Minn. VOLUME XV. JANUARY TO JUNE, 1895. MINNEAPOLIS, MINN. Tue GEOLOGICAL PUBLISHING COMPANY. 1895. ALFRED ROPER PRINTING Co., Printers. BIC. m/s GONTENTS. JANUARY NUMBER. On a new Specimen of Cladodus clarki. FE. W. CLaypo.e. PERS LPOG) 50] A 1 The Columbia Formation in Northwestern Illinois. Oscar H. HERsHEY The Munuscong Islands. F. B. Tayror. [Illustrated.]. 24 The Age of the Galena Limestone. N.H. WincHELL.... 33 Acid Eruptives of Northeastern Maryland. CuHarLes sea aagW NM ROMA Si Soha ee Set cog ot aw 0 wo: niu oS eRe Raper Bien 39 Editorial Comment.—State Academies of Science, 46. Review of Recent Geological Literature.—The Thirteenth Annual Re- port of the U.S. Geological Survey, J. W. Powe, Director, 48.— Sulla serpentina d’Oira (Lago d’Orta) e sopra alcune roccii ad essa associate, FRANCESCO SaAnsI, 49.—The Geological History of Roch- ester, N. Y., H. Li. Farrcuiup, 50.—The Length of Geologic Time, H. L. Farrcuivp, 51.—Preliminary Report of Field Work during 1893 in Northeastern Minnesota, chiefly relating to the Glacial Drift, Warren Upnuam, 51.—The Lherzolite-serpentine and asso- ciated rocks of the Potrero, San Francisco, CHARLES PaLacHE, 52. —On a Rock from the vicinity of Berkeley containing a new Soda Amphibole, CHARLES PaLacuHE, 52.—The Great Ice Age and its Re- lation to the Antiquity of Man, James Gerkir, 52.—The Ore De- posits of the United States, James F. Kemp, 57.—The Geology of Angel Island, F. L. Ransome, 57.— Geological Survey of Missouri, Sheets Nos. 2 and 3, ArTHUR WrnsLow, 58.—Geological Map of Alabama, with an Explanatory Chart, Eucenr A. Smira, 58..—The Geological History of Harbors, N.S. SHauer, 59.—The Mechanics of Appalachian Structure, Bainry Wiuuis, 60.—The Average Ele- vation of the United States, Henry GannettT, 62. Correspondence.—Remarks on the Berner Oberland sections of Prof. H. Golliez in the Geological Handbook of Switzerland, 1894, A. Baurzer, 62.—Inequalities in the old Paleozoic Sea Bottom, J. E. Topp, 64. Personal and Scientific News.—Baltimore Meeting of the Geological Society of America, 64. FEBRUARY NUMBER. George Huntington Williams. Joun M. Crarke. [ Por- EPP UT ee eh He IG oc Aa vasa oes 69 The Geologie History of Missouri. ArrHur Winstow... 81 A new Cretaceous genus of Clypeastride. F.W.Cracin 90 Further observations on the Ventral Structure of Triar- thrus.-.C, K.Bercumr. [Plates IV.and V.]......: 91 The Second Lake Algonquin. F. B. Taytor. [Plate VI.| 100 Editorial Comment.—An amusing error, 120.—The fossil Fishes of Canon City, Colorado, 121. Oe IV Contents. Review of Recent Geological Literature.—Ueber Porocystis prunifor- mis Cragin, aus der unteren Kriede in Texas, Privz ERecH, 122.— The American Tertiary Aphide, with alist of the Known Species, and tables for their determination, S. H. Scuppmr, 123.—Gran- ites and Greenstones, a series of lables for students of Petrology, FrRanK Ruttey, 123.—On the Banded Structure of some Tertiary Gabbros in the Isle of Skye, ArcHiBaLD GBEIKIE and J. J. H. TEALL, 123. Recent Publications, 124. Correspondence.—“Cephalopod Beginnings,” Joon M. CuarKke, 125,— Erosion during the deposition of the Burlington Limestone, Francis M. Fuurz, 128.—Voleanic Ash-bed near Omaha, J. E. Topp, 130. Personal and Scientific News, 180. MARCH NUMBER. Development of the Corallum in Fuvosites forbesi var. occidentalis. GrorcGe H. Girty. [Plates VII and WAGE | Ssaegic Aart aprictorteet rn he rarsna cS. cae tetany eueete 131 Karly Protozoa.ckG.j Hp NEATnUE Ws cape chi Se oats ers eee 146 The Stratigraphic Base of the Taconic or Lower Cam- Dorset 2 IN So Le WW SUNG ERENT soe) «Perret el = es cn) eheliawaekechene tee 153 The Second Lake Algonquin. F. B. Taytor. [| Tlus- brate diy [beren eqtortal touch A ice tien Po Onaus ie eee Ae RO TE 162 Editorial Comment.—Glacial Geology of Great Britain and Ireland, 180. Review of Recent Geological Literature.—On new forms of marine Alge from the Trenton limestone, with Observations on Butho- graptus laxus Hall, R. P. Wuitrrevp, 183.— From the Greeks to Darwin,—an outline of the Development of the Evolution Idea, H. F. Ossorn, 184.—Preliminary Report on the Geology of South Dakota, J. EK. Topp, 186.—Summary of Progress in Mineralogy and Petrography in 1894, W.S. Bavney and W. H. Hosss, 186— Report of the Geological Survey of Ohio, Vol. VII, Epwarp Or- Ton, 187. Correspondence.—The Ups and Downs of Long Island, Jonn Bryson, 188.—The Name of the Copper-bearing Rocks of Lake Superior, U.S, Grant, 192.—Drumlin Accumulation, WARREN UpnHam, 194. Personal and Scientific News.—Personal items, Scientific meetings, etc., 195.—Pleistocene Papers at the Baltimore meeting of the Geolog- ical Society of America, 197. APRIL NUMBER. The Stratigraphy of Northwestern Louisiana. T. Way- LAND VAUGHAN; - || Plate’ DX joe Geren oct cesar 205 The Paleontologic Base of the Taconic or Lower Cam- brian.) NES WiINCHELL c/n ps ote eee eee 229 The Missouri Lead and Zine Deposits. JAmeEs D. Rops- BIBTSON: 5.5 oe ft toi aie eee Sea epee cute cath eee 235 On the Mud and Sand Dikes of the White River Miocene. tO Ore OF Via a oar AMERICAN GEOLOGIST, vol. XII, pp. 814-323. November, 1893. 8 The American Geologist. January, 1895 sheet, oxidation, leaching, soil production, and a general de- gradation of the surface of the drift, with a buried forest bed, which occurs only locally in Illinois but is more generally dis- tributed on the Iowa side of the Mississippi river. This pe- riod of subaérial erosion was followed, in northwestern Illi- nois, by a period of loess deposition. As it is held by some geologists* that the Columbia formation dates from the first ice invasion of eastern North America, with a continuance of its deposition somewhat later, and also that the loess of the central and southern Mississippi valley is a portion of this formation, some doubt has been expressed that the loess of northwestern Illinois is the chronologic equivalent of that of the lower Mississippi valley. It is the aim of the present paper to show that it is so equivalent: also that there is a re- markable parallelism between the several members of the Co- lumbia in the Mississippi embayment and in portions of northern IJ}linois. In the topographic basin of the Pecatonica river, in the north central portion of this district, there is a more complete and more easily deciphered record of the stratal succession than in any other portion, and my remarks will, therefore, re- late chiefly to that subdistrict. It is mostly comprised within the tract of early drift adjoining the southeastern part of the Wisconsin driftless area.t+ The Columbia formation in this part of Illinois is clearly differentiated into three distinct members, which, for conven- ience in discussion, are designated respectively as the Florence gravel or Fluvial member, the Valley loess, and the Upland loess. These will be described under their separate headings, with discussion of their mode of formation and significance, FLORENCE GRAVEL. This, the basal member of the Columbia deposits, is con- fined to the lowest levels of the principal valleys. and its out- *Twelfth Annual Report of the U.S. Geol. Survey, for 1890-'91, Part I, p. 402. ¢Consult Prof. T. C. Chamberlin’s map of the drift-bearing areas of the United States, forming plate virr in the Seventh An. Rep., U.S. Geol. Survey, for the relationship of the Pecatonica basin to the earlier and later drift and to the driftless area of Wisconsin and the north west- ern corner of Illinois. For maps of larger scale showing the basin, with the prominent moraines on the north and east and the driftless area on the northwest, see plates xxrx and xxxt in the Third An. Rep., and plate xxvir in the Sixth An. Rep., U.S. Geol. Survey. The Columbia Formation in N. W. Illinois — Hershey. 9 crops, although fairly numerous, never exceed more than a few feet in thickness. The typical localities are in the banks of Yellow and Crane’s creeks, a few miles west and south of the city of Freeport, but even here it can be examined only at low water. Wherever seen, it is in general a loose agglomer- ation of small gravel and sand of a blue gray color. The following section is typical of the deposit. It is commonly overlain by bluish gray loess with few shells. 1. Light blue-gray gravel and sand, with many shells. 6 inches 2. Dark blue-gray or bluish-brown fine sandy clay, full of black and light brown bits of wood..........-. 12 inches 3. Very loose light gray coarse gravel and sand, with shells anda little wood, exposed..............0...- 8 inches Usually the more sandy portions are full of shells of small size. A small collection of these has been submitted to Mr. C. T. Simpson, of the department of conchology, in the Na- tional Museum, who reports the presence of the following species, all of which are found living abundantly in the fresh waters of northern Illinois to-day: Pleurocera subulare Ba. Planorbis bicarinatus SAy. Physa heterostropha SAy. Spherium stamineum Con. Valvata tricarinata Say. Pisidium abditum Hap. 7 These all differ from the fossil shells generally reported from the loess along the Mississippi river. The fossil vegetable matter is in the form of (a) small black particles of carbon disseminated through the deposit, and giving it its blue-gray color; (>) long thin fibers, appar- ently rootlets, many of which seem to be /n situ in the dark sandy clays in which they now occur; (c) many black, semi- decayed pieces of tree branches, occasionally reaching a thiek- ness of several inches. Some of this wood, from the same lo- eality as the foregoing shells, was submitted to Prof. F. H. Knowlton, who reports that the interior is too much damaged by pressure to permit determination of the species, but that it is apparently coniferous. Branches have been found which certainly belong to deciduous species, but most of the woody matter from this horizon appears to be of cedar and pine. The material of which this deposit is composed throws much light on the manner of its formation. At least nine- tenths of the pebbles in the gravel are of local material, principally Galena limestone and white chert, derived proba- 10 The American Geologist. January, 1895 bly from neighboring bluffs. This local material is sometimes angular, but more generally is semi-rounded. Pebbles several inches in diameter have been found, and these are sharply angular. There also occurs among the gravel a great variety of drift pebbles. The sand is composed chiefly of well rounded grains of transparent colorless quartz. At one locality a gravelly stratum near the top of the deposit was lithified, by reddish brown oxide of iron, into asoft conglomerate. In the valley of Crane’s creek a considerable portion of the gravel consists of fossiliferous limestone of Cincinnati age, which could not have been derived from the drift in the immediate vicinity but must have been brought by strong currents of water from the outcrop of the Cincinnati strata, several miles up the valley. The composition, structure, and limited distribution of this member of the Columbia formation show it to be a river de- posit, such as is laid down by streams of a moderate gradient at the present day. Its surface maintains a nearly constant level relative to the present water level, presumably indicat- ing the flood-plain level of the Florence streams. ‘This opin- ion is further supported by local patches, apparently similar to the alluvial soil at the surface of our present flood-plains. Now, accepting the hypothesis that the surface of the deposit represents the ancient flood-plain level, we find that this level averages 10 feet or more below the alluvial plains of the pres- ent streams. It is generally conceded that the absolute ele- vation of a flood-plain in any given region is directly de- pendent on the relative altitude of the land above sea level, the flood-plain rising if the land is depressed, and, vice versa, disappearing and forming at lower levels or ceasing to be a flood-plain if the land is in process of elevation. As there is no evidence supporting the supposition that the relation be- tween altitude and water level was materially different, dur- ing the period of the growth of the Florence flood-plain, from what it is at the present day, we may safely assert that the land then stood at a slightly higher altitude than it does at present. This land was also then in process of depression. The Flor- ence flood-plain passes through the old interglacial rock gorges, which are quite numerous in the Pecatonica basin, and The Columbia Formation in N. W. Illinois.—Hershey. 11 in many cases fills their lower portions with a bed of blue gravel and driftwood to a depth of as much as ten feet. At the time of the excavation of these gorges the streams were more vigorous and flowed at a lower level, indicating a’ con- siderably more elevated condition of the region. But later, when the Florence gravel and alluvial sand and clay were ac- cumulating, not only the fact of the gradual silting of the val- leys, but the passage-of these flood-plains through the inter- glacial gorges, deeply burying their rock bottoms, indicates a lower altitude for the district than formerly. It is presumed that this depression, beginning long before the appearance of the first flood-plain deposits, continued at a comparatively even rate through the Florence subepoch, and was merely the first part of the great Columbia subsidence to which the loess owes its existence. Although this basal or fluvial member of the Columbia for- mation is, as yet, only known to the writer in the basin of the Pecatonica river, it is doubtless present in all the larger val- leys in this portion of the state. Lying at so lowa level and having such imperfect and inaccessible outcrops, it can easily escape observation. A few wells in northwestern Illinois pen- etrate a black mucky stratum, containing logs and other woody matter, under the loess.and over the drift sheet. This occupies the same stratigraphic position as the Florence gravel. but it is rather of the nature of an upland soil than a fluvial deposit. The buried forest bed of northeastern Lowa is also stratigraph- ically equivalent to the Florence gravel, and the fossil con- tents indicate a similar climate. Although the study of the fossils of our early Columbia fluvial member is yet very incomplete, I feel certain, from the great abundance of shells belonging to species now living in this region, that the climate was not arctic, nor even such as would be found within 100 or perhaps 200 miles from the edge of the great continental glacier. VALLEY Loess. The basal member of the Columbia formation in this district grades upward into a deposit which, in the Pecatonica valley, is a moderately fine stratified sand, followed above by a light bluish gray or brown loess; but in the smaller valleys, notably ithe valley of Yellow creek, the loess silt immediately overlies 12 The American Geologist. January, 1895 the Florence sand. The geographie distribution of the Val- ley loess is nearly c6extensive with that portion of the district which lies lower than a plane 100 feet above the river level at Freeport. In ascending the Pecatonica river, the deposit is first met with on the north side of the valley, near the mouth of Sugar river. Here it forms a nearly level though disecon- tinuous terrace, 50 feet above the river, and runs west along the foot of the bluffs to the Stephenson» county line, beyond which it is less distinet, though occuring at intervals on both sides of the valley. At Freeport its hight has decreased to 30 feet, and northwest from there it rarely forms any prominent terrace. Wells drilled into this terrace usually penetrate about 20 feet of fine silty loess, and then 80 feet of brown stratified sand. ‘This brown sand, or lower division of the Valley loess, is moderately coarse-grained at the base, where it often contains small pebbles and much ferruginous matter. The material gradually grows finer from the base upward, and from east to west in the valley. At the same time the strati- fication and lamination become less distinct as the material grows finer, and there is less evidence of wave and current ac- tion. The thickness of the deposit is something over 30 feet in the lower portion of the Pecatonica valley and decreases westward. It occurs only at the lower levels of the deeper valleys. In the vicinity of Freeport, and eastward down the valley, it has its greatest thickness below the level of 25 feet above the flood-plain of the river. Above this it thins out in passing up the sides of the valley, and it has not been recog- nized at hights more than 60 feet above the flood-plain level. Throughout the Pecatonica valley from the mouth of Sugar river to Winslow, near the state line, this division of the loess maintains a nearly uniform constitution, being everywhere an easily recognized bed of brown sand. But in passing up the valley of Yellow creek we find a change, sand deposits belong- ing to the loess occurring only in scattered patches. Instead, we find a few feet of highly ferruginous, indistinctly lami- nated clay, underlying the easily recognized upper division of the Valley loess. The iron oxide was probably derived from the old soil on the ridges near by, and in some places it is present in such amount as to give the deposit the appearance of an earthy iron ore. The Columbia Formation in N. W. Lllinois—Hershey. 13 Its constitution, distribution, stratification, and surface con- figuration, seem strongly to support the hypothesis that the brown sand division of the Valley loess was formed under flu- vio-lacustrine conditions, and that it consists of glacial silt derived from an ice-sheet somewhere to the east. The lower division of the Valley loess passes into the upper division by interstratification. This latter is essentially a stratified fine sandy clay or silt, having usually either a light or dark bluish gray color; but where it has been exposed to oxidation, it has a light buff color. The lamination is very distinct in the lower portion, but becomes less so upward; and finally it totally disappears at the top of the deposit. There is also a gradual decrease in the size of the particles from the base upward, and a general thinning of the strata to the west. A few fossil shells are sometimes found in this di- vision of the loess, apparently similar to those enclosed in the loess along the Mississippi river. Calcareous concretions are abundant in some localities, and the surface on exposure rap- idly becomes coated with a whitish efflorescence. When sub- ject to erosion, as in gutters and stream beds, the outcrop re- sembles laminated shales, sometimes having the appearance of being tilted at a high angle. At one place a small gully was found partially filled with rounded pebbles of a dark brown color, which, on examination, proved to be composed of loess belonging to this division, This upper or “blue clay” division of the Valley loess is found everywhere (unless it has been removed by erosion) in the main valley of the Pecatonica river and along its princi- pal branches in Stephenson county and in a portion of Winne- bago county; but it occurs only to a limited hight above the flood-plain of the river at Freeport. It attains its greatest thickness, which is 20 feet or more, at levels less than 50 feet above this flood-plain; and thence upward it rapidly thins out, totally disappearing before the 100-foot level is reached. Hence, although it has a rather wide distribution, it is essen- tially a valley loess. The phenomena connected with this division of the loess seem to indicate a formation under fluvio-lacustrine condi- tions similar to those of the lower division, but in a deeper and more extensive lake, with less powerful currents than that 14 The American Geologist. January, 1895 which preceded it. That the Valley loess of this region was not deposited like the ordinary flood-plains of great rivers, is evident from the way in which the strata dip down the sides of the valleys. It was formed by the sedimentation on the bottom of a long and narrow, branching lake. of current-car- ried glacial silt. But the lower portion of the Pecatonica valley received a very heavy deposit which, on completion, had a nearly flat surface. This has since been extensively eroded by the stream, and a system of terraces has thus been formed. Beyond the Pecatonica basin, along the bluffs of the lower portion of the Rock river, and at various places along the Mississippi river between Dunleith and Rock Island, quite extensive deposits of a valley loess, apparently synchronous and similar in mode of formation with that of the Pecatonica valley, have been observed. Here, also, this loess has been sarved into a rough terrace system. The immediate valley of the Mississippi was largely filled up with a thick deposit of’ loess which may have formed a nearly level plain 50, 100 or 150 feet above the present river level. It is more probable, however, that,as in the Pecatonica valley, the surface of this valley loess, when its deposition was completed, was a shallow trough, the deposits along the bluffs being considerably higher than along the center. The Mississippi loess consists basally of an irregularly stratified bed of brown sand, gradually growing finer upward and passing through a typical loess into the weathered clay of the upland loess, which the older geolo- gists scarcely recognized as loess. Uprianp Loess. This is a bed of light brown massive clay of glacial origin, which generally conformably overlies the Valley loess. The line between them is sometimes sharp and distinct, but often the one passes into the other by insensible gradations. In the city of Freeport there is a sudden change from the blue sandy clay and quicksand of the upper portion of the VaJley loess to the light brown, stiff, unweathered portion of the Upland loess. This is commonly known as “hard pan,” although this name belongs more properly to another formation. It con- tains numerous concretions of iron oxide or limonite in the form of balls and pipes, but has no calcareous nodules. The The Columbia Formation in N. W. Illinois — Hershey. 15 upper 3 to 5 feet of the Upland loess has been weathered to a loose porous clay of a buff color, which often breaks up into small cubical blocks. The distribution of this deposit is nearly coextensive with all that part of northwestern Illinois west of an irregular line entering the state at the northeast corner of Stephenson county, thence running east-southeast to the mouth of Sugar river, thence west-southwest along the Pecatonica river to the Stephenson county line near the village of Pecatonica, and thence eastward to near Rockford, from which point onward it is not yet traced but is supposed to extend in a very irreg- ular course southwestward along the valley of the Rock river to some point below Oregon, whence it probably trends off to the south, passing out of the district covered by this paper. Throughout the country between this line and the Mississippi river, the Upland loess must have originally existed asa man- tle of remarkably uniform thickness resting alike on the Val- ley loess in the deeper valleys and the old interglacial soil on the ridges. Its altitudinal limit has not yet been determined with certainty, as it has suffered great erosion and so has been removed from many of the steeper ridges. Beds of clay which are apparently Upland loess have been observed on some of the “mounds” of Jo Daviess and Stephenson counties, and it is probable that it was originally deposited on them all. It certainly attains a greater altitude than 1,000 feet above the sea, or more than 250 feet above the Pecatonica river at Freeport. Northwestern Illinois is a very hilly region, as compared with the central portion of the state. The range in altitude between the ‘“‘mounds” and the Mississippi river is as much as 600 feet, reached sometimes within a distance of a few miles. On these steep slopes the loess remains only in patches; but in Stephenson county, where the hills attain an elevation above the valleys of only a few hundred feet and the slopes are gentler, it occupies nearly the entire surface. Perhaps more than half of the formation has already been re- moved by erosion, but in favorable situations nearly the en- tire thickness remains and is found to be about as follows: In the northeast portion of Stephenson county, and in the northwest portion of Winnebago county, 7 or 8 feet, main- | 16 The American Geologist. January, 1895 taining also about the same thickness throughout all the northern half of Stephenson county. There was apparently 10 feet of Upland loess in Freeport and its vicinity ; and from here it thickens toward the west and southwest, so that it may have amounted to 20 feet in the southwest corner of the county. The thinning toward the east is in contrast with the Valley loess, and seems to indicate that the main source of the sediment lay beyond or up the Mississippi valley, instead of eastward as at the time of deposition of the Valley loess. The Upland loess is everywhere of greatest thickness in the vicinity of the Mississippi river. A few shells have been observed in this formation at a few localities, but they are rare and not of much importance. In- deed, the loess-depositing waters in the Pecatonica and Rock river valleys must have been nearly lifeless, in marked con- trast with the abundance of invertebrates in the streams of the preceding Florence subepoch. It has been concluded from a study of the phenomena con- nected with the Upland loess that it was deposited under al- most purely lacustrine conditions. The sediment gradually subsided to the bottom of the great lake where it was laid down with neither current nor wave action. The lake must have had a depth, over the lower portion of the Pecatonica valley, of at least 250 to 800 feet; over the Mississippi valley its depth was 600 feet or more; and throughout the greater part of northwestern Illinois it exceeded 100 feet. The different beds or divisions of the loess of this district were deposited one after the other without any stratigraphic break between them. Their phenomena indicate that they were formed in a lake, or series of lakes, at first long and nar- row, with many similarly shaped arms, and having strong currents capable of carrying coarse sand; but later gradually increasing in depth and width, with a consequent decrease in the sediment-carrying power, rising slowly along the valley slopes and over the upland ridges, until finally perhaps the highest land in northwestern Illinois was covered with water. This gradual increase in the size of the lake must have been brought on by a gradual subsidence of the land, which, as we have seen, began previous to the formation of the lowest por- tion of the loess. The Columbia Formation in N. W. Illinois —Hershey. 17 CORRELATION WITH ADJOINING GLACIAL Driv. The character of the Valley loess, as noted in the Pecaton- ica basin, points to an origin of its material from the lower part of the valley towards the east. As the material is un- doubtedly glacial silt, we naturally look in that direction for some evidence that an ice-sheet or continental glacier lay near to the loess-depositing waters. It is now believed that such evidence has been discovered, and I will endeavor to present such portion of it as is known to me. The irregular line mentioned as bounding the Upland loess on its eastern side very nearly coincides with the terminal line of a distinctive drift sheet.* This drift is distinguished from the very ancient sheet to the west of it by (a) a very much fresher appearance: (2) less oxidation and less depth of leaching; (c) a discordance between the gravel ridge (esker) systems of the two sheets; (d) a discordance in the direction of glacial movement, and, in the Pecatonica valley, in the trend of the terminal lines of the two ice-sheets when they oc- eupied the same relative positions; (e) a very much different topography, the country underlaid by the western or ancient drift having that of a slightly glaciated region, and the coun- try underlaid by the newer sheet having that of a more ad- vanced stage of glaciation; (/) the newer sheet is several times as heavy as the old, this difference being especially con- spicuous along the boundary; (y) the presence of slight but distinct morainie features east of the line, especially along the outer edge of the newer sheet; (h) very much less sub- aerial erosion on the drift east than on the ancient sheet west of the line; (7) the fact that the newer drift is near its edge overlaid by Upland loess, without any soil or. other evidence of land surface between, while the drift to the west shows de- cided manifestations of a long interval between the formation of the drift sheet and the overlying loess. The relations of the loess to this newer drift sheet are well shown in the Pecatonica valley. It has already been stated that the terrace formed by the Valley loess runs down the north side of the valley to about the mouth of Sugar river. *The existence of this drift sheet, as distinct from the older drift to the west, was first pointed out to the writer by Mr. I. M. Buell, of Be- loit, Wisconsin, who also noted the fact that it bounds the loess on its eastern side. 18 The American Geologist. January, 1895 This is twelve miles farther than the terrace on the south side of the river, which does not reach the Winnebago county line. This north side terrace in Winnebago county is a well-marked bench, 50 to 60 feet above the river, which has cut into it but hardly removed much of its bulk. Directly opposite, on the south side of the valley, instead of a similar terrace of 60 feet thickness of loess, we find no loess whatever; only the sloping rock surface overlaid with thin drift of the newer sheet. It is hence evident that the loess on the north side was deposited before the drift sheet was formed on the south side of the valley, else this side would have received a heavy deposit of loess also. Having found that the epoch of loess deposition was not subsequent to that of the newer drift sheet, we will next look into the probability of its having pre- ceded it. The newer drift in this vicinity (we use the term “newer drift” to distinguish this sheet from the very much older one to the west, and not as designating the latest formed drift sheet in America) was formed by a long and compara- tively narrow lobe of the ice which projected toward the west from the general front of the glacier. There is a ridged ac- cumulation of drift about its border, which is further distin- guished by a boulder belt. But the amount of material in this ridge, especially about its western end, is remarkably small, in comparison with the length of time it was occupied by the edge of the ice as indicated by other phenomena. Had a deposit of loess been found by the ice on the south side of the valley as great as now exists on the north side, and had it plowed up and entirely removed this loess as it must have done to produce the present configuration, the morainie ridge at its border, and especially at its westward end, should now be ten times as large as it really is. We naturally conclude that there never was any deposit of loess on the south side of the valley, and that the Valley loess and newer drift sheet in this vicinity were formed contemporaneously. This conelu- sion is further supported by internal discordance in the strat- ification of the loess of the terrace as though it were subject at times to external pressure from the direction of the ice. Moreover, while the main body of the ice lobe lay on the un- dulating country to the south of the river valley and the north edge of the ice rested in the valley, leaving a space between The Columbia Formation in N. W. Illinois.—Hershey. 19 it and the bluffs in which the loess was being deposited, near its western end it touched the bluff on the north side for'a few hundred yards, there accumulating its drift and boulder belt and cutting off the loess. The terrace is quite distinct east of this point, but up the valley to the west it is lower and otherwise much less prominent. This I interpret as indica- ting that while the loess was accumulating rapidly in the com- paratively small and narrow but deep trough between the ice and the bluff east of this point, westward it spread out over the entire valley and so is less strongly developed at any given point. Had the ice not occupied the position here supposed, this would not have been the case. The heavy deposits of Valley loess along the Mississippi river doubtless were derived largely from the ice-sheet which then stood not far back from the river in Iowa and Minnesota, and in smaller amount from its portion in Wisconsin—a northern prolongation of the ice-front here indicated in II- linois. Just beyond the extreme border of this newer drift sheet we find the ordinary Upland loess, originally 7 or 8 feet thick. Around the northern and western sides of the Pecatonica ice- lobe the loess terminates comparatively abruptly at the edge of the newer drift. Usually, however, it overlaps it for some distance. But while it is 7 feet thick beyond the newer drift, the overlapping portion is only from 2 to 8 feet in thickness, often gradually thinning until it totally disappears. This overlapping portion may extend one, two, or ten miles back upon the newer drift, but it is usually not present in any identifiable form more than a few miles. As already sug- gested, there is no stratigraphic break (if the term may be applied in a matter of this kind) between the newer drift and the Upland loess. ‘The one grades, sometimes quite insensi- bly, into the other. Around the edge of the newer drift we find the Upland loess quite sandy,a feature which is rare for it away from the bor- der, but just what we should expect near the source of the sediment. where the water rushed down from the ice-front, carrying sand as well as fine silt, and scattering it over the submerged hills near by. As a final argument, I will men- ‘tion that the loess-covered country lies higher than the 20 The American Geologist. January, 1895 country to the east, from which it is absent. This differ- ence along the border is so great that no differential subsi- dence theory will explain it. To suppose that the ice ad- vanced and plowed it up and removed it from the country where no loess is now found, is equally preposterous, for there certainly is no remnant of such a loess mantle any- where under the newer drift sheet, nor are the slight morainic ridges which bound it at all comparable in size with those that would have been produced by the plowing up of a loess deposit, a portion of which must have escaped being carried away by subglacial and extraglacial drainage. SEQUENCE OF THE GLACIAL History. The sequence of events here during the Ice age, as indicated by these observations, may be summarized as follows: 1. Northwestern Illinois, after having passed through one period of glaciation, had a prolonged period of subaérial ero- sion and soil formation, during which the climatal conditions were probably similar to what they are to-day. Near the end of this period, but while the surface was still covered with its temperate vegetation and the streams full of invertebrate ani- mals, we find the land in process of subsidence. The return- ing ice had certainly not yet reached the mouth of the Peca- tonica river, and perhaps was many miles away; but the streams had begun to silt up their valleys, forming low and gravelly flood-plains. 2. Next we find the ice moving up the Pecatonica valley, the land going down towards sea level and the water level rising, producing long lake-like rivers through which the gla- cier-born currents rushed, carrying coarse sediment. ‘The climate had grown cold, and the former flora and fauna had largely disappeared. 3. Still the subsidence continues; the lakes rise, and finer sediment is carried. The ice advance has, in the Pecatonica valley at least, reached its climax; and the front remains sta- tionary, or nearly so, while the Valley loess is being deposited. 4. The epeirogenic movement has now reached its culmina- tion; nearly the entire region, so far as not covered by the mer de glace, is submerged, and the Upland loess is laid down. The ice on the eastern side begins to retreat, and for a while the loess-depositing waters follow it up. But an elevatory - The Columbia Formation in N. W. Illinois —Hershey. 21 movement has set in, and the waters begin to subside. This movement must have been comparatively rapid, for no shore lines were formed and no considerable body of loess appears to have been laid down after the elevatory movement was well advanced. These coriclusions, although formed chiefly from a study of the loess deposits of the Pecatonica basin and surrounding re- gion, are, I believe, generally applicable to this portion of the upper Mississippi valley. It has been held by a number of glacialists that the loess of the driftless area in Wisconsin, Iowa, and Minnesota, was Jaid down in a large lake produced by the ponding up of the waters through the meeting of two lobes of the ice-sheet south of that area. But it does not yet appear that ice on the Illinois side came into contact with the Iowa ice at the time required. The Upland loess, once com- pletely mantling northwestern Illinois, west of the newer drift sheet mentioned in this paper, extends north into Wisconsin, where the waters depositing it seem to have been limited, at least for some distance in Green county, by a shore line of land instead of the border of a glacier. The same sheet of Upland loess reiippears on the Iowa side of the Mississippi, where Mr. W J McGee has shown it to be connected with a drift sheet similar to that with which it is connected in Illi- nois.* But on our own side of the river this drift sheet does not reach the Mississippi at the place assigned to it, if it does, indeed, at all. The earlier drift sheet of northwestern Illi- nois underlies all the country(except where removed by ero- sion) that the writer has been over between Freeport and Quiney. Furthermore, the Upland loess, which overlies the ancient drift sheet in the Pecatonica basin, is continuous (save as severed by erosion) over all the country west to the Mississippi river and south to the Rock river. It emerges from under deposits of a later age on the south side of the Green river basin, and thence continues over the country to the south as far as the writer’s studies have been carried.t *“The Pleistocene History of Northeastern Iowa,’’ Eleventh Annual Report of the U. S. Geol. Survey, for 1889-"90. +The relation between the loess of the Pecatonica basin and that of the central Mississippi valley was first pointed out to the writer by Mr. Frank Leverett. It has since been verified by personal observation. 22 The American Geologist. January, 1595 CORRELATION WITH THE CoLUMBIA FoRMATION IN THE LOWER Mississippr VALLEY. It is a well known fact that the loess of central Illinois is continuous with that of the extreme southern portion of the state, which is also known to be a continuation of the loess and loam, or upper member, of the Columbia formation in the Mississippi embayment. The absence of any known barrier across the Mississippi river below Savanna, IIl., the extension of loess from the driftless area to the lower Mississippi valley, the fact that the surface of the loess-depositing waters grad- ually rose (in relation to the land surface), at least in north- western Illinois, and that a subsidence of the land was al- ready in progress before the loess began to be deposited, seem to necessitate the rejection of the theory of an ice-dam to ac- count for the Upland loess of northwestern Illinois. We have been referring to the Upland loess as deposited in a great fresh-water lake; but it may not have been a true lake, for it seems quite probable that it had connection with the ocean waters in the Mississippi embayment. It may be assumed that a great submergence of the land in the upper Mississippi region and a similar submergence in the lower Mississippi valley, the deposits of each of which ap- pear to bear the same relation to the earliest drift sheet of Illinois both north and south, being apparently continuous with each other, afford sutticient evidence of the Columbia age of the loess and underlying alluvium of northwestern Illinois. Accordingly we will endeavor to show a parallelism between the various members of the Columbia formation in the Missis- sippi embayment and in the Pecatonica basin. McGee divides the Columbia formation in the lower Missis- sippi area into four members.* The lowest member, or the Port Hudson clays, is described as “a vast bed of blue, black, gray, or brown laminated clay, commonly clean, though some- times parted with sand, silt, or fine‘gravel, and often charged with calcareous or ferruginous nodules. * * * It is pre- eminently a low-level deposit, seldom rising far above the modern base-level. * * * This phase of the formation lines the broad ancient valley of the Mississippi from Cairo to *Pwelfth Annual Report of the U.S. Geol. Survey, for 1890-'91, pp. 392-407. The Columbia Formation in N. W. Illinois.—Hershey. 23 the Gulf.” These clays were deposited soon after the begin- ning of the Columbia submergence, the great river gradually silting up its lower valley. The Port Hudson clays seem to have been formed under very similar conditions as the basal fluvial member of the Columbia in northwestern Illinois; the general appearance and constitution of the former are similar to the finer portions of the latter; and they both apparently bear the same relation to the great Columbia submergence, and to the deposits over them. ~ Believing that the submergence of the upper Mississippi valley was contemporaneous with that of the Mississippi em- bayment and the Atlantic coastal plain, I think it very prob- able that this submergence had reached the stage of formation of flood-plain deposits in both regions at or about the same time; and that the Florence gravel, sand, and clay of the Pec- atonica basin, and presumably of all western Illinois, are the northern representative of the Port Hudson member of the Columbia formation; and that not improbably the two are continuous, as a single horizon, under the loess and modern alluvium, through the valley of the Mississippi. McGee next finds his second member of the Columbia for- mation in the Mississippi embayment to consist of a coarse stratified sand and gravel (Safford’s “Orange sand”). The submergence was greater and the region of the lower Missis- sippi had become an extensive bay, into which the great river brought vast quantities of sediment from the glaciers in the North and mixed it with the local material which makes up the great body of the sandy member in the Mississippi em- bayment. It certainly requires no great stretch of the imagi- nation to suppose that the sandy or lower division of the Valley loess in northwestern Illinois may be the northern ex- tension of this second member of the Columbia in the South. McGee also finds that at the time of greatest submergence in the Mississippi embayment a mantle of loess and loam, composed largely of glacial rock-flour from the north, was laid down on the bottom of the great bay. At the same time of maximum submergence in the upper Mississippi valley, a very similar bed of glacial silt was being deposited over nearly all the country which was not covered with ice. This is the so-called Upland loess of the Pecatonica basin and surround- 24 The American Geologist. January, 1895 ing region. As we have endeavored to show, there is every reason for believing it continuous along the Mississippi bluffs. and to some extent over the upland country to the Columbia in southern Illinois. In conclusion, there seems to me to be little doubt that the loess deposits of northwestern I[linois, including the Peca- tonica basin, are Columbia in age. Hence it seems to be rea- sonably inferred that the Columbia formation does not date from the time of the first glaciation of eastern North America represented by the ancient drift sheet adjoining the driftless area in northwestern Illinois and northeastern Iowa, but was contemporaneous with an intermediate stage of glacial ad- vance, which may probably have been closer to the end than to the beginning of the Pleistocene period. THE MUNUSCONG ISLANDS. By F. B. TAYLor, Fort Wayne, Ind. Since the autumn of 1891 excursions made in the vicinity of Mackinac island have added several new facts to those pre- sented in a previous paper relating to that region.* But these fragments have not found a suitable place of record in other papers recently published, and they are therefore gathered to- gether and presented here. Following this article will be an- other in which the Nipissing beach will be traced in its south- yard extension, as far as now known, and the probable limits of the lake of that time will be defined. The accompanying map is made to cover the entire width of the ancient strait of Mackinae at the time of maximum submergence. It shows details which will be referred to in the next article as well as this, and shows also the principal shore lines described in the first paper on Mackinac. The large ancient island north of Little Traverse bay is here named Traverse island. THe Munuscone Isianps. From the lookout on the top of Mackinac island a long line of hills broken in two parts may be seen toward the north on the northern peninsula of Michigan. Without closer examin- * Aacient STRAIT H OF MACKINAC By F.B.TAYLOR. SCALE OF MILE pease u REFERENCE HIGHEST BEACH qt ae Oascaved JY cawwsen (mmm) WIP/SRING BEACH me mn k MACKINAC nee XD ROUND | oS — STRAITS of M. a ° ME.GULPINS PT Akin, oS ACKINAC CX eS See Te cece B ~ ° CROSS VILLAG, Fiaton Fic. 1. Map of the Munuscong islands and the surrounding country. to the hills mentioned and we found that there had been at least three islands and possibly more. While these ancient islands were somewhat nearer to Mackinac, they were, on the other hand, much smaller in area than I had supposed. We visited the middle or nearest one of the three. Its distance ! 26 The American Geologist. January, 1995 northward from Mackinae is about 14 miles. This island was nearly three miles long, east and west, and perhaps half that width at its widest. It is irregular in outline and has a blunt spur projecting towards the north from its east end. Its longer axis extends from the east a little to the north of west and its highest point appeared to be at the west end. Another much smaller island lies about a mile and a half to the north- east and on its west and north sides has precipitous cliffs of limestone 75 to 100 feet in hight. The third island lies to the west-northwest of the middle one and on the east side of Pine river. It appeared to rise to about the same hight, but it is heavily wooded and was not visited. The middle and eastern islands form the water-shed between the nearer shore of lake Huron and the sources of the Munuscong river, which flows northeast to Mud lake, an expanded portion of the lower St. Mary’s river. The high western end of the middle island is divided between the properties of Mr. Webb on the south and Mr. Brown on the north, and both slopes are cleared, al- though the summit is still in timber. Both sides are of steep drift, that on the north being most gradual, but reaching to a lower level. The view from the top is well worth the trip Toward the northeast are the picturesque cliffs of the eastern ancient island: and beyond in the distance, a bit of the St. Mary’s river, and above that the high crest of St. Joseph island. Toward the north, stretching away from the foot of the hill is the wide, flat valley of the Munuscong and the plain of the northern peninsula. Seen from this hight, the entire sweep of low ground has the appearance of a recently deserted lake bottom. The day was clear and we could see quite plainly the hights north of Sault Ste. Marie, upwards of 35 miles to the north. St. Ignace was seen from the south bluff, and Mackinac island and the open water of lake Huron were screened only by the forest. At the foot of the hill on the south the highest beach is strongly developed. It is the upper edge of a sandy plain sloping gradually away to the southwest. The ridges at this point are not very distinct, but there are a few low ones near Webb’s house and better ones at the Italian settlement about three-fourths of a mile south. Measured by aneroid from lake Huron at Hessel, about seven miles distant, the altitude The Munuscong Islands.— Taylor. bo = ‘ of the highest beach is about 280 feet above lake level, and the top of the hill nearly 400 feet. At the time of our visit, Mr. Webb had just dug a new well. The earth thrown out was composed of sand, gravel and peb- bles, with a few small boulders, all very clean and nearly all well rounded. The well was sunk into the sandy plain to a depth of 32 feet, and tough stony clay was penetrated two feet at the bottom. The depth of this characteristic beach deposit is rather surprising in such a situation. It must have been entirely the work of waves that sorted the sediments out of the glacial drift and deposited them there. For when the water stood at that level there was no stream which could have been a contributor of sediments. The hill above the beach is of stony drift with a large portion of tough yellow clay. Apparently the whole mass of the beach has been gath- ered from drift cut out of the hill. This necessarily implies along period of wave action. The highest beach was crossed again as we returned at the base of the hill about a mile and a quarter east of the Italian settlement. After passing nearly two miles over the top of the ancient island, first east and then south, the road descends and once more crosses the highest beach in an open wood. There are several low sandy ridges at that place, faint and broken, but lying in parallel lines on a broad gentle slope toward the south. This is the first point reached on the ancient island on going from Hessel and is a little less than four miles from that place. The road extend- ing farther north crosses the island at a place where it was comparatively low. Between Hessel and the middle Munuscong the marks of submergence are very plain. There are three broad terraces, two with high bluffs comparatively fresh and abrupt and each facing over a swamp on the back part of the terrace next below. Going north from Hessel there is first a moderate rise from the shore to about 20 feet within a hundred yards. The sur- face is very stony and soon becomes swampy, with many fair sized boulders, apparently all glacial erratics. The ground continues with this character for nearly two miles to the foot of the first bluff, rising gradually to its base, where the hight is about 100 feet above the lake. The swamp is broken in 28 The American Geologist, January, 1895 several places by slightly higher patches of ground, and near Hessel it is bounded by low, broken, stony ridges which have more of the appearance of glacial than littoral forms. The first bluff rises about 40 feet at its edge and 20 feet more a hundred yards back. It is composed of sandy clay with many pebbles and small boulders, except at the top, where the clay is replaced by sand. From this the second terrace rises gradually for about a mile to the foot of another steep bluff, where its altitude is about 200 feet above the lake. It is swampy, like the back of the first terrace. The second bluff is slightly higher than the first one, and shows two feet or less of rounded gravel and small boulders overlying sandy clay with subangular stones. Back of the edge above there are signs of wave action in half formed gravelly ridges and small, low terraces. From this place the surface rises gradually northward, with some un- even features, to the last mentioned locality of the highest beach. At another time we visited the Cheneaux islands, which lie along the shore to the east of Hessel. None of them rise higher than 50. to 60 feet above the lake. Their surfaces are generally stony. In some places erratic boulders are very abundant. Many such may be seen along the path east of the Elliott House. It may therefore be regarded as a fixed fact that at the maximum of submergence the stretch of water between Mack- inac and the Canadian highlands back of Sault Ste. Marie was broken only by the Munuscong islands. The importance of the presence of ancient islands in the area of submergence san hardly be overestimated, especially if they are situated well out from the mainland. Each one furnishes a new point of support for the restoration of the former water plane, and must prove valuable in the ultimate study of the earth’s his- tory as disclosed in the deformation of former water levels. There are many more of these ancient islands still unexplored within the basins of the upper lakes. Gros Cap. Two days before the Munuscong excursion, we made a visit to the high Gros Cap region which lies west of St. Ignace and borders the shore of lake Michigan. It is a flat topped, ele- The Munuscong Islands —Taylor. 29 vated mass of Silurian limestone, in many respects like Mack- inac, only it is not so high and is not now an island. On the hill back of St. Ignace near the public school building we found a large bed of beach gravel at an altitude of about 75 feet above the lake. About a mile out of town there is a great curved beach ridge which extends around the edge of a flat tract forming a parapet in the shape of a horseshoe. The apex of the curve points toward the north over low ground and the road crosses the ridge twice and also the enclosed hollow only a little back of the point. One can seldom find as perfect a beach ridge as this, showing so clearly by its shape and place the nature of its origin. The southward ex- tension of the ridge on the two sides could not be seen beyond 30 or 40 rods on account of the timber. The west ridge ap- peared to extend south-southeast in a straight line. The al- titude of this beach above the lake is about 115 feet. Its_ formation undoubtedly took place substantially in the follow- ing way. In the rising stage of the water the flat-topped area was covered by the waves with gravel derived from ad- jacent limestone cliffs which rise to a higher level. Then the whole was submerged and remained for a time as a gravelly shoal. Finally as the water fell away again the waves re- newed their action, and when they began to break along the outer edge they heaped up the shifting gravel into a ridge at that place. After crossing a swampy tract the road comes out upon the shore of lake Michigan and continues to the northwest close to the lake. For about six miles it follows a great bank of beach gravel and pebbles which lies against the base of a high limestone cliff. At several places this cliff is vertical for 50 to 80 feet and there are several picturesque outlying remnants like the “Sugar loaf” on Mackinac island. The up- per limit of the littoral bank where best developed is about 45 feet above the lake, but the talus of the cliff rests upon it and obscures it in many places. Its composition, like the other beaches of this vicinity, is almost entirely of rounded pebbles of the local limestone. The quantity of beach mate- rial here is very great. The width of the bank varies from about 800 to 600 or 800 feet. The surface generally shows a 30 The American Geologist. January, 1895 series of parallel beach ridges, in some places very distinct. This is especially the case where the bank is narrow. The high tract of Gros Cap is divided in two parts by an east-west valley, and the shore near the lake falls away to a low, sandy flat along its front. Towards the north the high ground ends near Obeshaw’s corner, and the coast beyond is lower and sandy. A road across the hill eastward from the corner affords a short cut back to St. Ignace. Buta mile or more of dangerous corduroy over a swamp to the east has the effect of lengthening rather than shortening the distance. The swamp was cut off from the lake by littoral drift near St. Ignace. The top of the high ground is substantially flat and its altitude is about 160 feet. On the west edge there is a beach ridge much like that at 115 feet near St. Ignace, but not so well formed where we saw it. Much of the top is still in timber. But so far as we could see or learn by inquiry no part of it rises higher than that which we saw. Towards the southeast, Gros Cap is substantially continuous with the high irregular ground south of St. Ignace. On the northeast it is separated from high ground by a low trough one to two miles wide and occupied by swamps and ponds. The island of St. Helene, which lies about three miles off this shore in lake Michigan, is said to be a series of concentric gravel ridges. It is low, however, and probably does not attain a hight of more than 30 feet. There are many evidences of submergence along the line of the railroad northward from St. Ignace to and _ be- yond Trout lake. But none of them appear to record the up- per limit. The highest points observed were not over 260 feet above lake Huron. Gros Cap and the other high parts near St. Ignace appear to have undergone the same severe wave action as Mackinac. They are all composed of a friable limestone which was an easy prey to the waves. On Mackinac the weakness of the rock is greatly increased by softer layers which weather into a fine fire-clay, as may be seen in the cliff south of Arch rock. When the lake stood at a higher level, this clay collected in the rock crevices of the bottom along the shore and appears there to-day as a tough, buttery deposit, perfectly smooth in the fingers, and with two colors, red and greenish gray. The The Munuscong Islands.—Taylor. 31 formation of the cliffs in this region has been largely influ- enced in some places by these weaker layers. é Mackinac Isianp. Recent excursions to the low ground of the north end of the island have revealed the existence of a strong shore line there corresponding to that in the village at the south end. Its upper limit in the village is rather irregular, but the hight of the continuous beach is not far from 45 feet above the lake. The altitudes of the cut terrace and beach ridge at the north end of the island were not measured by barometer, but by an eye estimate only. In the woods near British landing, near the north end of the island, the road crosses some narrow beach ridges at nearly the same level. The road to Scott’s cave branches off to the right just below this point and passes thence about a mile on the wide flat of the terrace just men- tioned. At its back the flat ends against the foot of a steep bluff, which, for much of the distance, is a rock cliff 30 to 40 feet in hight. Its strength and altitude prove it to be the same shore line as that in the village. The littoral origin of this terrace and cliff is fully proven by Pulpit rock, which stands on the terrace a few rods out from the foot of the cliff. It is a tall and very slender outlier of fragile limestone which happened to be left standing when the waves finally with- drew. Its feeble structure, on the one hand, suggests an ulti- mate limit to the time since it was left standing, and its dis- tance from the cliff, on the other hand, suggests the relatively long duration at one plane of the wave action which made the cliff and a large part of the terrace. The marshy little valley back of British landing was probably shut in by a spit made at the same time, and with material derived mainly from the Scott’s cave cliffs. Modern wave action has removed all that may have existed of this shore line along the east and west sides of the island. This strong shore line on the north and south ends of Mackinac island, at St. Ignace, and Gros Cap, appears again at MeGulpin’s point across the straits. A similar beach at half its hight appears also on the shores of Little Traverse bay. The character and position of this shore line agree in all respects with the Nipissing beach as identified at points farther north, and it has been so named on the map. The 32 The American Geologist. January, 1895 features shown on the shores south of the straits were most of them described in the earlier paper om Mackinac referred to above, and those at Wellsburg and Sault Ste. Marie were also described in a previous paper.* At the maximum of submer- gence the ancient strait was 75 to 80 miles wide between the beach at Root river in Canada and the mainland on the south. Since the publication of the first paper on Mackinae new measurements of the hight of its upper beaches had led me to suspect that I had made them a little too high. But I have learned that recent instrumental leveling by the military au- thorities makes the beach back of the parade ground 175 feet above the Jake. This is five feet higher than I had made it, and substantially confirms my first measurement. The same authorities make the top of the big gravel ridge behind the village 60 feet above the lake. This is about 15 feet higher than the Nipissing beach near the Grand Hotel and the Mis- sion House, and can hardly be considered as a part of it. The northward rise of the highest beach from Mackinac to the middle Munuscong island is at the rate of a little more than five feet per mile, while the rise from the latter place to the Root river beach north of Sault Ste. Marie is a little more than four feet per mile. This is a good illustration of the value of ancient islands in disclosing terrestrial deformations which could not be detected otherwise. A wider experience inthe study of deltas has led me to suspect that my early estimate of the altitude of the highest beach at Traverse City was probably placed a little too high. The estimate of 80 feet was based on the hight of the old delta of Boardman river. I have not had an opportunity, however, to re-examine it. CoMPARISON OF SHORE LINEs. The following is a tabular statement of the hights in feet of the principal shore lines within the area of the map: Hicnuest Brac. Above sea level. Root river, near Sault Ste. Marie (Lawson).......... 1,014 Wrelisb une aie ch. teamcssiane alcceneeetene Seuciereiieneve te cpetens tore bts 910-++-? Middle Minis comess) aim cle crrctotsaer-ce cele ele) ieytein pete 860 Mackinacrislande ss) Sacco iene eyokeeioes citesers 785 c**A Reconnaissance of the Abandoned Shore Lines of the South Coast of Lake Superior,’? AMERICAN GEOLOGIST, vol. x1, June, 1894. The Age of the Galena Limestone.-— Winchell, 33 sWeguetousing and Petoskey............2.deuecec:s+ 680 BOAT SO MOTE NIN lettres sis -.- probably a little less than 660 NipisstnG BEACH. . Above lake Huron.* Saeialhs Sivas ABW OIS SY Ae OR ice ee oe Aire i tre 70 Mackinac, St. Ignace, Gros Cap. and McGulpin’s point.. 45 DMeametomsing And sPelOSKeY. fi. eee ce ae elecece oe 25 Besides these, there are isolated ridges and terraces at in- termediate levels, but as yet no certain correlation of these at different places has been made out. These notes make the record of observations so far made by me in the basin of the upper Great lakes substantially com- plete; and this is the sixth of a series of papers in which they have been published. On each of the principal excursions from twenty to sixty photographs were taken of the features observed. The plates used were 64 by 84 inches. Many of the pictures are good, although few views of the best sort could be obtained on account of the rough and uncultivated condition of the country. THE AGE OF THE GALENA LIMESTONE. By N. H. WINCHELL, Minneapolis, Minn. [Read at the Brooklyn meeting of the American Association for the Advancement of Science, August, 1894. | From the time of Schooleraft, who, in 1820, assigned the lead-bearing beds of the upper Mississippi to the Subcarbon- iferous, until now, the Galena formation has been a subject of much difference of opinion. W.H. Keating thought all the magnesian limestones of the upper Mississippi valley belonged above the Coal Measures, and made them the parallel of the Lias of Europe. Owen showed that they pass below the Coal Measures, and at first (1839) classified the lead-bearing beds with the Cliff limestone of Ohio, which was admitted to be of the same age as rocks which in New York state were of the Upper Silurian. Locke went further, and made out a fair case by placing the underlying beds, which now are generally admitted to be of Trenton age, as the equivalent of the Blue limestone of Ohio, which was then also supposed to be of the *Add 581 feet, the mean hight of lake Huron, for hights above the sea. Bes The American Geologist. January, 1895 age of the Trenton. The intervening strata as known to exist in New York, i. e., the shales and limestones of Pulaski and Lorraine, ete., were not found. James Hall at first accepted . the opinion that the Galena should be put in the Upper Silu- rian, as an equivalent, or a part of, the Niagara limestone. In 1848 T. A. Conrad stated, on the evidence of fossils furnished him by Mr. J. N. Nicollet, that the Galena belonged in the upper part of the Trenton. In 1852, however, Dr. D. D. Owen, in his final tabulation of his results of the survey of the region, same to the conclusion that the Galena limestone is the west- ern representative of the Uticaslate and the Hudson River for- mations of New York, the strata immediately underlying being named “St. Peter shell limestone,” or Formation No. 3, and supposed to represent the Trenton. This was nearly in aceord with Prof. Hall’s later view that the underlying strata, with greater or less distinctness, represent, largely by paleon- tological resemblance, the Birdseye and Black River limestones. While the terms Blue and Buff, which have had varying for- tunes, and questionable value, have remained, in one form or another, as designations for the underlying limestones, there has been no disturbance of Mr. Conrad’s general conclusion that the Galena is of the age of the Trenton, indorsed as it was by Hall and Whitney in 1870, until 1879, when C. D. Walcott revived the idea of its representing the Utica slate,* and fortified it with evidence drawn froma comparison of the fauna of the Utica slate with that of the Galena. He also shows the extension of the fossils of the Utica into the Hud- son River above and the Trenton below. Until now there has been no published investigation into the paleontology of the Galena since that of Mr. Waleott. It is the purpose of this paper to show that Mr. Waleott’s con- clusion can hardly be accepted. Mr. Walcott surveys the question both stratigraphically and paleontologically. In the former survey he reaches the result that a general, widespread change in the nature of the sediments took place at the close of the Trenton, extending from New York to Tennessee and further southward. In Illi- * The Utica slate and related formations. Fossils of the Utica slate, and metamorphoses of Triarthus becki, C. D. Waucorr. 1879, Albany. Printed in advance of vol. x, of the Transactions of the Albany Institute, June, 1879. The Age of the Galena Limestone.—Winchell. 35 _ nois this change is shown by the sudden transition from the Trenton limestone to the Thebes sandstone. There might be added to this general truth a further general law which per- tains to the Lower Silurian in North America, viz., that the Utica slate is followed by the Hudson River by a very gentle change, or is merged into the Hudson River so closely that the two formations cannot be separately identified in numer- ous places. Thus, Safford shows that in Tennessee the Nash- ville (Hudson River) involves the Utica slate. Although the slate is lithologically a dark shale, 100-150 feet thick, the characteristic graptolites are not confined to this stratum, but run up into the main body of the shale, and are found at numerous localities. Lithologically the Utica slate and the Hudson River formations usually are lost in each other, being linked together in all descriptions, their fossils even being put into the same chapter by James Hall in 1847. There is hardly an exception to this close union of the Utica slate with the Hudson River; indeed, as Mr. Walcott truly remarks, at the opening of his paper, the term Hudson River, with the Utica slate as a subdivision, has been generally received into geo- logical literature. In summarizing the paleontological data the following table is given by Mr. Walcott: Utica Galena. A ballon DE MNOte SPECIES! .202s e,..lses sc eos tyelsiee -fene tere 100 78 Species limited tothe formation......3.......0.. 54 19 Species limited to the formation and the Trenton (AMON) te bs Ae tors BROIL, CORO TG. 8 NOI a OC en OT Ian 1] 29 Species limited to the formations and the Hudson AEM OM IMGT OM, of a large and a small species, enhances the resemblance. Prof. J. D. Whitney, in reporting on the lead mines of Wis- econsint in 1862, dwells at length on the carbonaceous charac- ter of the Hudson River shales, which are said to show some- times ‘‘faint graptolitic markings.” “The presence of carbon in the shales of the Hudson River group over so extensive an area, and in such large quantity, is a matter of considerable interest, both practically and_= scientifically; it seems hardly possible that a material existing in such abundance and con- taining from one-tenth to one-fifth its weight of bituminous and carbon- aceous substances, should not at some future time be utilized for light- ing or heating purposes. in a region where coal does not occur,” p. 184. The suggestion that the Utica slate horizon is to be sought for in the beds overlying the Galena is confirmed by later de- velopments in the oil regions of Indiana and Ohio where the Utica slate is recognized at the bottom of the Hudson River formation, and yet where the underlying “Trenton” is a_ po- rous dolomite, not unlike the Galena limestone. In fact it -has been found that in many cases the fossils which in the upper Mississippi valley are found in the Galena, in Kentucky and Tennessee are said to come from the Trenton limestone. It may therefore be considered that the Galena limestone is only a phase of the Trenton, intensified in the typical region, and fading out in all directions. It is a convenient designa- tion in Iowa and some parts of Wisconsin and Illinois, but in Minnesota its convenience hardly warrants its continued use. The physical break and the faunal change which follow it, in the Northwest, are the probable parallels of those which mark the transition from the Trenton to the Hudson River (Utica slate) horizon to which Mr. Walcott has called attention. May 5, 1894. ACIDIC ERUPTIVES OF NORTHEASTERN MARYLAND. By CHARLES ROLLIN KEYES, Jefferson City, Mo. For several years prior to his peculiarly sad and untimely death, a few months ago, the late professor George H. Wil- *Geology of Iowa, vol. 1, part I, p. 67, 1858. tReport on the Geological Survey of Wisconsin, vol. 1, James Hall and J. D. Whitney, 1862. 40 The American Geologist. January, 1895 liams had been rapidly gathering materials for a systematic work on the massive rock types of North America. Prepara- tory to this special attention had been given to the eruptives. of the Piedmont plateau, particularly in Maryland. Care- fully made field and petrographical studies were instituted in different areas. Some of the results had already been pub- lished.* Two other memoirs were in press, both by the U. 8. Geological Survey; one on the old volcanics of South Moun- tain (which, however, is out of the district just named) by Dr. F. Bascom, and the other on the granitic rocks of Mary- land by professor Williams and the writer. Still other results were pearly ready for presentation. As a part of the work outlined there has recently appeared the Granites of Cecil County in Northeastern Maryland,t by Dr. George P. Grimsley. It is to some points brought out in this contribution to Maryland geology that attention is di- rected. The rocks. under consideration are the granite-gneisses which are widely known as the Port Deposit granites. They are regarded as igneous in origin, though now more or less squeezed, but the proofs of their eruptive character need not be reiterated here. The area is an extensive one and takes its name from the town of Port Deposit, in the neighborhood of which are large quarries. From them a large amount of stone has been shipped to nearly every part of the United States. The rock itself is admirably exposed for a distance of fully ten miles on both sides of the stream. The stone is a light colored, somewhat gneissoid, biotite granite, which is rather coarse grained but seldom shows a porphyritic facies. A more or less distinct banding of the light and dark constituents is quite characteristic. Both observations in the field and microscopical examinations of thin sections indicate clearly that the parallel arrangement of the components has been secondarily acquired through enormous pressure. The area is bordered on the north by trappean gabbro, on the east and west by the Piedmont gneisses. The area is di- vided medially by the Susquehanna river, which has cut a *Williams: U.S. Geol. Sur., Bul. 28. Washington, 1886. Also AmMERtI- CAN GEOLOGIST, vol. VI, pp. 35-49. Minneapolis, 1890. tJour. Cincinnati Soc. Nat. Hist., vol. xvu, pp. 59-67 and 78-114. Cincinnati, 1894. / Acidic Eruptives of Northeastern Maryland.—Keyes. 41 wide, deep gorge into the massive crystallines of the region, extending from beyond the state boundary nearly to the mouth of the stream. For the greater part of the distance the river flows in a canyon-like course from 250 to 300 feet below the general level of the Piedmont plain. The high cliffs and salients of granite stand out prominently on either side of the water course and form conspicuous features of the picturesque valley. Under the microscope thin sections of the granite from Port Deposit show a more or less distinct parallel arrange- ment of the minerals. The quartz is broken and granulated, the biotite is not so abundant as in some of the other Mary- land granites; microcline is of common occurrence; epidote and muscovite are developed in many places from the feld- spar; while small dark colored garnets are not of unfrequent occurrence. The granite is cut through in a number of places by dioritie dikes which vary in width from a few inches to 400 or 500 feet. Contrary to what has been commonly supposed to be the case, the southern part of the area is more gneissic than the northern. Consequently the Port Deposit rocks, which may be properly regarded as gneiss, pass by gradual transi- tions into the massive granite of Rowlandville, which lies to the north. Another feature which has been observed is that as the granite approaches the gabbro area there is a greater and greater development of the ferro-magnesian minerals, until at the contact it often becomes exceedingly difficult to determine whether the rock is really a granite or a gabbro. Another notable characteristic of the granite is the presence of numerons basie secretions, which often have the appear- ance of rounded inclusions. Two types of granitie rocks have been mentioned. The one is near Rowlandville and the other in the neighborhood of Port Deposit, the latter being the more gneissic. In the for- mer the rocks have been not sufliciently squeezed to entirely obliterate the original characters. They do, however, show in a remarkable manner the effects of orographiec pressure which has changed both the constituents and the structures in a very interesting way. One of the most prominent meta- morphie changes in the rock, as fully emphasized by Dr. 492 The American Geologist. January, 1895 Grimsley, has been the extensive development of epidote. As stated by him, the physical conditions particularly have been exceptionally favorable to the formation of this mineral. It oceurs everywhere in the Rowlandville area as a prominent metamorphic product, assuming variety of forms, sharply outlined crystals, rounded grains and hair-like needles, and developing in all of the original constituents alike. The pro- duction of epidote to such an unusual degree is manifestly one of the chief results of the metamorphic action, and hence the consideration of the mineral has been given in full detail. Now, the original Rowlandville rock was evidently a normal granitite or biotite granite having the common hypidiomor- phic. structure and carrying unusually large proportions of plagioclase. In places it is thought that it may have also contained some original muscovite. As already stated, epi- dotization has been carried on on an extensive scale. It is most marked in the feldspars. In the perfectly fresh rocks, those which have suffered no effects through meteoric changes, the formation of the mineral, it must be admitted, must cer- tainly be metamorphic rather than the result of weathering, as has been stated from time to time. All degrees of replace- ment of the feldspar by epidote occur, from crystals in which only an occasional grain of the latter mineral has originated to those in which almost complete pseudomorphism has taken place. Whenever there is a small amount of epidote, crystals of this mineral, with sharp outlines and of the usual mono- clinie habit, are of frequent occurrence; but as the amount increases the different crystals unite into larger masses with irregular boundaries. Another interesting observation which was made concerning the Rowlandville granite was that the epidote had no special tendency to develop in or near cracks in the feldspars, but that whenever the latter crystals showed pressure effects little or no epidote was formed. Another suggestive observation is that the epidote frequently devel- oped in certain zones in the feldspar crystals, in many cases both the interior and exterior of the feldspars remaining un- changed. Considering the well known fact of zonal variations in the chemical composition of feldspar crystals which has so well been worked out both by Hépfner* and by Beecke,+ who *Neues Jahrbuch, Geol., Min. u. Pal., 1881, 2 Haft, p. 182. +Tschermak’s min. und petro Mitth., xm, Band, p. 414, 1895. Acidic Eruptives of Northeastern Maryland.—HKeyes. 438 have proved that zonal feldspars, as a rule, grow more basic towards the center and that there is sometimes a recurrence of a more basic zone within the more acid layers, and remem- bering that the plagioclase feldspars in the Rowlandville granites are made up of different mixtures of the albite and anorthite molecules, the formation of the epidote may be at- tributed to a particular chemical composition of a portion of the feldspar which has been brought under favorable physical conditions. It may thus be concluded that under certain con- ditions and with certain combinations of the albite and an- orthite molecules there was a special tendency towards epi- dotization, when the rock underwent metamorphic changes arising from great pressure. It is an excellent illustration of one of those nicely balanced or delicately poised cases which are met with occasionally in the petrographical study of rocks which have been influenced by crustal movements, and of a change which is to be expected in a region which perhaps represents a part of the denuded base of anold mountain range. Itis but the expression of the universal law that in stony aggregates the whole mineral- ogical composition and structure are being modified contin- ually; in some places slowly, and others more rapidly accord- ing to the attendant circumstances. The ever changing physical conditions invariably set up continuous molecular shiftings in every rock, whatever may be its composition or its relations. Of recent years it has come to be more and more clearly understood that the changes undergone by rock masses have been occasioned by the natural tendencies of minerals to assume combinations more stable from those less stable. Wadsworth* in particular has emphasized this point. But the statement has not carried with them its full import and meaning. For, in any particular case while there is an at- tempt towards adjustment to satisfy a certain set of condi- tions, the conditions themselves continually change, sometimes in one direction, sometimes in another. In the production of these alterations in rock-masses time does not enter necessa- rily as a factor, although ordinarily the older a rock is the greater is the chance for disguising its primitive character. Thus in attempting to determine the original condition under *Nature, vol. xxxv, p. 417, 1887. 44 The American Geologist. January, 1895 which, for instance, an eruptive rock has solidified, the prob- lem becomes more and more difficult in proportion to the amount of change, until finally a point is reached where it is absolutely impossible to say with certainty what the real na- ture of the stony mass was in the beginning. In the consideration of the wide-spread effects of regional metamorphism the agency of tangential pressure as the result of orographiec movements is by no means the least important. Since the appearance of the classic work of Heim+ the influ- ence exerted by this one factor has become more and more clearly understood, as may be inferred from the writings of Bonney,+ Hatch,§ Lehmann, Reusch,4{ Térnebohm,** Schmidt,¢+ Teall,}} Williams§§ and others. But to return to the epidote belts in the plagioclase crystals. Dr. Grimsley also remarks that the undoubted causal relation which exists between the zonal structure of the feldspars and their alteration whereby those zones richest in lime have been most completely changed to epidote, greatly favors the opin- ion advanced. This view also finds substantiation in other granitic areas and probably furnishes a key to the problem of why similar rocks through metamorphism and under appar- ently the same physical conditions change to very different masses. It is probably a principle of very wide application and one which will doubtless furnish a clew to many ques- tions concerning metamorphism which have been long re garded enigmatical. With the Port Deposit rock, which, like the Rowlandville variety, is in all probability of the eruptive origin, there is a very distinct foliated structure that has been produced sec_ ondarily through pressure. The result of more intense dy- namie action has been to crush the minerals, thus giving rise to cataclastic rather than mineralogical changes, as epidotiza- +Untersuch. tiber den Mech. der Geb. u. s. w., Band II, 1878. tQuar. Jour. Geol. Soc., London, vol. xLu, 1886, STschermak’s min. und petrog. Mitth., Bd. VII, 1885. |Undersuch. uber die Ent. der altkry. Schiefergesteine, u. s. w. 1884. *|Neues Jahrbuch, BB. V, 1887. **Geol. For. Stockholm Borhandl., V, 1880. ++Neues Jahrbuch, BB. IV, 1886. tt{Geological Magazine, Novy., 1886. SSU.S. Geol. Sur. Bul., No. 28, 1886; also ibid., No. 62, 1890. Acidic Eruptives of Northeastern Maryland.—Heyes. 45 tion. The feldspars of this rock are both alkaline and lime- soda varieties, with a marked development of potash feldspar in the form of microcline. The feldspars show conspicuously the effects of great squeezing and crushing, which, combined with the same chemical alteration, have given rise to a con- siderable development of the albite mosaic. + The Port Deposit granite-gneiss carries a considerable amount of allanite which is invariably mantled by epidote, the two forming isomorphous intergrowths. The epidote thus formed is regarded as original, as has been thought probable in the case of similar occurrences in the granites farther south in the vicinity of Baltimore. In regard to the staurolitic mica schist which forms a long narrow belt separating the Rowlandville and Port Deposit areas, Dr. Grimsley is inclined to the view that it was origi- nally a sedimentary deposit, more ancient than the granites and that it probably owes its highly crystalline character to contracting metamorphism produced by them at the same time of their eruption. Attention is called in the memoir to the economic value of the Port Deposit rocks, but more on this point might have been said. The quarries furnish about one-half of the entire amount of granite obtained in the state of Maryland. The stone has been taken out in commercial quantities for more than three-quarters of a century. The output of the Port De- posit quarries alone during 1892 was nearly eighty thousand tons, valued at almost half a million of dollars. Asa building stone it is very durable, and according to the test made by the United States engineers it withstands a crushing strain of over eighteen thousand pounds per square inch. Among the structures built of this rock, as may be gleaned from the Maryland hand-book, may be mentioned fortress Monroe and the artificial island opposite it on which was erected fort Wood, forts Carrol and McHenry, near Baltimore; fort Delaware, the sea-wall at St. Augustine, Florida; the navy yard and dry dock at Portsmouth, Virginia; the Naval Acad- emy at Annapolis, Maryland; the foundation of the Treasury building, the Philadelphia, Washington and Baltimore rail- road stations and Saint Dominick’s church at Washington; also the bridges over the Susquehanna at Havre de Grace. 46 The American Geologist. January, 1825 Maryland; the Chestnut street, Girard avenue, Callowhill and South street bridges over the Schuylkill at Philadelphia; the principal bridges of Baltimore, and the new water works crib at Chicago. It has also been used in construction of the entire plant of the Maryland Steel Company’s works at Spar- row Point, Maryland, and of Harveford college; besides a large number of private dwellings and public buildings in Baltimore and Philadelphia. EDEPTOREAL COMM EN ®: STATE ACADEMIES OF SCIENCE. The fact that the general governinent lends substantial aid in furthering scientific research is very generally acknowl- edged to be simply a wise provision for promoting the general welfare and happiness of the entire people. From this point of view the maintenance of organizations for the investiga- tion of problems relating to astronomy, geology, mineral re- sources, coast and geodetic surveys, irrigation of the great arid wastes, chemical and lithological phenomena relating to agriculture, sanitation and public health, and other matters that affect more or less the entire public, is recognized as nothing more than the discharge of an imperative duty. That the individual States also have duties in relation to similar problems has not been so generally recognized. Most of the States support universities where, in addition to the work of teaching, a greater or less amount of scientific work is done. Many have technical schools under one name or another, but these, like the universities, are founded not so much for re- search as for purposes of instruction. In a few states geologi- cal surveys are supported; but, as a general rule, States, as such, have rarely done much in encouraging scientific work. Notwithstanding the indifference of the public to scientific work as expressed by the local state governments, nearly every State in the Union contains a number of capable men devoted to scientific research. The recognized advantages of organ- ization and codperation, as compared with the results of dis- connected individual effort, have led to the formation of State Editorial Comment. 47 Academies of Science; so that now there is scarcely a State in the Union which has not its organized band of enthusiastic laborers in the various scientific fields. These State Acade- mies have some advantages over the larger national associa- tions, not the least important of whieh is the fact that at- tendance upon their meetings involves less expense of time and money: two commodities which the unselfish scientific worker can usually illy afford to spare. Some of the best work done anywhere is presented at these meetings. Like all other truly scientific work it enlarges the domain of human knowledge, brings the forces and phenomena of nature more directly under human control, and ameliorates in some degree the conditions of human existence. The public, which, with- out effort on its own part, immediately becomes possessed of all the benefits of scientific investigation, owes something to these scientific workers. A few States discharge, in part, their obligation to the peo- ple on the one hand and the scientists on the other by publish- ing and distributing the reports of the local Academy. The reports of the Kansas Academy have for some years been published by the State. Three years ago Iowa began the pub- lication of the reports of her Academy. It is to be hoped that the same relation between the state organization that embodies the highest scientific attainments and the state gov- ernment will be established in more and more of the intelligent commonwealths of the Union. In this connection it is a matter for congratulation to find that the members of the Indiana Academy and the more pro- gressive members of the recently elected legislature of the same State are planning to effect an arrangement whereby the work of the Academy may become available for the informa- tion of the people at the trifling expense of publication and distribution. The Indiana Academy has now been in exist- ence some nine years, and in that time has enrolled among its members many workers of more than national prominence. Amony these the reader will easily recall Jordan, Coulter, Branner, Mendenhall, Arthur, Noyes, and others no less emi- nent. While the Academy, as such, has published little di- rectly, its papers have embraced the results of some of the best work covered by the period of its existence. Quite re- 48 The American Geologist. January, 1895 cently it has undertaken a thorough Natural History Survey of the state, a task which, by reason of its numerous well scattered and thoroughly competent observers, it is able to accomplish much more cheaply than any other organization. Let us hope that the coming legislature of this wealthy and intelligent State will recognize its opportunity. 8.30: REVIEW OPT RE CENT GEOLOGIC ait LE POAC LER. Thirteenth Annual Report of the United States Geological Survey, for the year 1891-92, J, W. Powe, Director. Partl, Report of the Director; pp. vii, 240, with two maps: 1892. Part Il, Geology, accompanying pa- pers; pp. x, 372, with plates mm—cvit, and 41 figures in the text; 1893.— Part IT, Irrigation; pp. xi, 486, with plates evii-cx, and figures 42-63 in the text; 1893. Hach of the three parts of this report, which was published a few months ago, forms a separate volume, and each has its own index. While some delay is unavoidable in the issuance of these important reports, it certainly seems very desirable and practicable to diminish considerably the interval between the work and its publica- tion. It is very gratifying in this connection to note that only half a year intervened between the times of distribution of the twelfth and thirteenth annual reports of this survey. In the first part Maj. Powell and the heads of the thirty-two divis- ions of the survey present their administrative reports, briefly stating the areas of exploration, special subjects under investigation, and the progress of topographic and geologic mapping. During the fiscal year of this report, topographical surveys were being made in twenty-three states; and previously these surveys had been finished in Massachusetts, Rhode Island, Connecticut, New Jersey, and the Appalachian moun- tain belt from Maryland to Alabama. The geological mapping up to the date of this report had included the western two-thirds of Massachu- setts; a large area from Baltimore south to Richmond; another in the Appalachian region of eastern Tennessee, northwestern Georgia, and northeastern Alabama: small tracts about Madison, Wis., in eastern Iowa, the northwest part of South Dakota, in Florida, about New Or- leans, in central Texas, and about Denver and Leadville in Colorado; larger areas in New Mexico, northern Arizona and southern Utah, the Yellowstone National Park, and a contiguous region reaching north and northwest in Montana; small districts in Washington and about Eureka and Virginia in Nevada; and a large region of the Sierra Nevada belt through the northern two-fifths of California. Final geologica purveys, of greater or less extent, had been completed in thirty-two states and Review of Recent Geological Literature. 49 territories, covering an aggregate of 110,000 square miles, and repre- sented by a hundred atlas sheets. Among the special papers forming Part IJ, those of Mr. T. Nelson Dale, on the Rensselaer grit plateau in New York, and of Prof. I. C. Russell, on his second expedition to Mt. St. Elias, have been already re- viewed in the last volume of the Am. GEOLOGIST (pages 54 and 190, July and Sept., 1894); and the four other papers are noticed in the following pages of this volume. Part III, on the surveys for plans of irrigation in the arid region com- prising the greater part of the western half of the national domain, con- sists of the report on Water Supply, by Mr. F. H. Newetn, noting the rainfall and gauge measurements of streams, with maps of irrigated and irrigable lands, and of pasture and timber lands, in the Missouri, Yel- lowstone, and Platte river basins; two reports by HERBERT M. Winson, one being on American Irrigation Engineering, considering its eco- nomic and financial aspects, different kinds of canals, weirs, dams, and reservoirs, and the other on Engineering Results of the Irrigation Sur- vey, as developed in the basin of the Arkansas river, Colorado, of the Sun river, Montana, of the Truckee and Carson rivers, Nevada, in the High Sierra reservoirs, California, the El Paso reservoir on the Rio Grande, Texas, and the Pocatello canal in Idaho; and two reports by A. H. THompson upon the construction of topographical maps and the se- lection and survey of reservoir sites in the hydrographic basin of the Arkansas river, Colorado, and upon the location and survey of reservoir sites in Utah and Idaho during the fiscal year ending June 30, 1892. A most important element in the plans of irrigation for many districts is found to be the fluctuations in the rainfall, with occasional deficiency or entire failure of streams during seasons of exceptional drought. Ww: U. Sulla Serpentina W@ Oira (Lago d-Orta) e sopra aleune roccit ad essa asso- ciate. FRANCESCO SANsr. (Rendiconti Reale Inst. Lombardo di Sci. e Lit., (2), vol. xxv, pp. 681-688. Milano, 1892.) In this paper are des- cribed the rocks of a small but very interesting petrographical province lying in the north of Italy. The rocks include stratified amphibolites, serpentine, amphibole gneiss, altered granite and quartzite. More spe- cifically they are: (1) Altered granite of the Val Pellino. This is a dusky white rock flecked with greenish spots. Its principal constituent is quartz vari- ously orientated. The feldspars present include both orthoclase and plagioclase. Biotite, altering to chlorite, aud pyrite are present, as are also zircon and apatite as inclusions. The orthoclase occurs as large turbid individuals, having crystalline form in part, and being in part altered to kaolin. The plagioclase shows a zonal structure, with altera- tion setting in from the periphery. Among the alteration products are calcite and epidote. (2) Bodies of quartzite compressed in the granite. These are com- pact masses of scaly fracture and dusky gray to translucent glassy 50 The American Geologist. January, 1895 color. They are holocrystalline with bipyramidal quartz, microcline, muscovite, chlorite, pyrite, and zircon having pleochroic¢ aureoles. (8) Gneiss without amphibole of the Val Pellino. This is distinetly stratified, has a granular structure, and is composed of quartz predom- inantly, orthoclase and plagioclase, biotite with inclusions of magnetite, and associated chlorite and muscovite, apparently alteration products. Zircon occurs as an inclusion in quartz, with a mineral doubtfully ree- ognized as cordierite. Andalusite is also present. (4) Amphibole gneiss stratified with amphibolite. This rock shows slightly different phases, but is always schistose. It is made up of quartz, orthoclase, plagioclase, and amphibole. The latter is of intense green color and characteristic pleochroism. (5) Amphibolite. This has a uniform dark green color and. is made up of a network of acicular crystals of amphibole traversed by rare veins of quartz or feldspar, the latter mainly plagioclase. (6) Serpentine. This is represented by a considerable mass of dark green mineral, traversed by small and more or less sinuous veins. Un- der the microscope, the mass is seen to be individualized, the green mineral breaking up into small intricate bands. Dispersed granules of high relief and without crystalline form are noticed. These granules are surrounded by serpentine. A mineral giving high interference col- ors and with fresh aspect is referred to actinolite. Muscovite and chlo- rite as alteration products, and granules of magnetite, are noticed. An undetermined mineral,;undoubtedly represented in the granules of high relief, is present. Since, however, the crystalline form, and for the most part even the cleavage lines, are lacking, diagnostic characters are not present. This mineral has been considered to be olivine because of the high colors of polarization; but the author considers this refer- ence incorrect. Where the granules are separated by serpentine, a web structure is seen, the strings being serpentine, and the intervening spaces being filled with the mineral in question. These lines meet at an angle of about 90.° Such a structure has been described by Hussack as ‘“‘balkenstructur,’’ and is characteristic of pyroxenite serpentine. The mineral here shows kinship to both orthorhombic pyroxene (ensta- tite 7) and to monoclinic (salite 7). The observations exclude the belief that the serpentine is derived di- rectly from the amphibole, and confirm rather the opinion of Cossa that it comes from pyroxene. He KB. The geological history of Rochester, N. Y.. By H. L. Fatroniip. (Proc. Rochester Acad. Sci., vol. 11, pp. 215-2238, June, 1894.) In this paper Prof. Fairchild has given a sketch of that part of geologic history which can be read from the rocks at Rochester. ‘The strata below the upper part of the Medina are known only from drill records which go down over 83,000 feet. The lowest rocks. mentioned are a siliceous limestone and a ferruginous quartz rock, whose exact age is uncertain; they im- mediately underly the Calciferous. A large part of the section is com- posed. of 954 feet of Trenton dark limestone and 1,075 feet of Medina red ‘ Review of Recent Geological Literature. 51 sandstone and shale. The strata from the top of the Medina up to and including the Niagara limestone, can be studied in: the Genesee rayine. From the Niagara to the present no deposits, except those of glacial or- igin, are known. UW. 8. Ge The length of geologic time. By H. L. Farronmp. (Proc. Rochester Acad. Sci., vol. 1, pp. 263-266, July, 1894.) This article will be of value for reference, as it gives a Concise statement of the various estimates, from that of Charles Lyell to the recent ones of King, Upham, Walcott and others, of the time required for the deposition of the sedimentary rocksof the globe. Nineteen different estimates, with complete biblio- graphic references, are presented. U. S..G. Preliminary report of field work during 1893 in northeastern Minnesota, chiefly relating to the glacial drift. By WARREN Upnam. (Geol. and Nat. Hist. Survey of Minnesota, 22d [1893] Ann. Rept., pt. m1, pp. 18-66, pls. land 2, 1894.) The first partof this paper is devoted to a brief outline of the topography of the northeastern part of the state, and the altitudes of a large number of points are given; these are taken from railroad pro- files and from recent determinations made by members of the Minnesota Survey. Following this are descriptions of the only rock outcrops known in Aitkin and Cass counties. The most important and interesting part of this report is that treating of the glacial drift; an outline of the glacial geology is given and special attention is called to certain points, the chief of which are mentioned below. A map is presented, which, among other features, shows the results of the most recent work as to the location of the moraines in the northern part of the state, and the area occupied by Beltrami island of the glacial lake Agassiz; this island lies just to the northwest of Red lake. A very complete list of glacial striw is given, and attention is called to the divergent directions of these striw at certain points, the most marked being ia the vicinity of Duluth. Drift from three princi- pal sources is recognized: (1) on the west, from the north and north- west; (2) east of the Big fork, from the north and northeast; and (8) in the same region, from the east. Drift from the last direction is easily recognized by its boulders, which are characteristic of the rock of the Keweenawan areas on the north shore of lake Superior. Several sec- tions from cuts on the Mesabi range show alternations of layers of till from the last two directions. The locations of four moraines north of lake Superior are indicated much more accurately than has heretofore been possible, and the most northerly, named the Vermilion or Twelfth moraine, is here described for the first time. Several pages are devoted to a discussion of the raised beaches on the north shore of lake Superior, and a brief accouut is given of the history of the ice-dammed lakes that made these beaches. Three beaches are referred to the Western Superior glacial lake, eight to the glacial lake Warren, and one to the glacial lake Algonquin. The last beach is united with the present beach at Duluth, but it gradually ascends east- ward, reaching a hight of 49 feet above lake Superior at Sault Ste. The American Geologist. January, 1895 o bo Marie. Nine distinet deltas are mentioned at Duluth as having been made by Chester creek at different stages of these lakes. U. 8..G. The lherzolite-serpentine and associated rocks of the Potrero, San Pran- cisco. By CHarnes Panacnue. (Bull. Dept. of Geol., Univ. of Califor- nia, vol. 1, no. 5. pp. 161-180, Aug., 1894.) A rather detailed account of this serpentine is given in order to disprove the supposition that there are no serpentines of igneous origin in the Coast ranges. It is shown that the rock was originally a lherzolite, i. e., was composed chiefly of an aggregate of enstatite, diallage and olivine, unaltered portions of which minerals are still to be seen. Cutting this lherzolite-serpentine are masses of hypersthene diabase and epidiorite, the hornblende of the latter being probably secondary after pyroxene. U. §..G. Onu rock from the vicinity of Berkeley containing a new soda amphibole, By CHarnes Panacné. (Bull. Dept. of Geol., Univ. of California, vol. 1, no. 6, pp. 181-192, pls. 10-11, Aug., 1894.) The material studied comes from alarge boulder, which is probably near its parent ledge, about three miles north of Berkeley. The rock has a white matrix of saccha- roidal albite, in which matrix are prisms of a blue amphibole. An in- vestigation shows that this mineral is intermediate in chemical compo- sition between glaucophane and riebeckite, that it is similar to the latter mineral in the relation of the axes of optical elasticity to the crystallo- graphic axes, but that the extinetion angele is about twice that of riebeckite; the pleochroism is also a little different from that of riebeck- ite. Since an almost exactly similar amphibole, as far as optical prop- erties are concerned, has been reported from Colorado by Dr. Whitman Cross (Amer. Jour. Sci., III, xxxrx, 359-370, 1890), the author proposes the name crossite for the mineral here deseribed. The Coast ranges of California have long been known to contain schists with a blue amphib- ole, which has been referred to glaucophane, but which it is believed will be found to be largely crossite. U.S. G. The Great Jee Age and its relation to the Antiquity of Man. By JAMES GeIKIE. Third edition, largely rewritten. Pages xxviii, 850, with 18 maps and charts, a frontispiece, and 78 woodeuts, including numerous full page illustrations, in the text. (London: Edward Stanford, 26 & 27 Cockspur street, Charing Cross, S. W., 1894.) First published in 1874, about a.year before the closely related treatise by Dr. James Croll, Climate and Time, this work was largely extended in its second edition (1877), and the same author four years later presented a continuation of his studies of the Glacial and Postglacial periods, in his almost equally notable volume, Prehistoric Europe. During the thirteen years which have passed since then, be has been industriously adding to his data for the present new edition, which has 225 pages more than the second. Its most regrettable omission is the appendix, appearing in the first and second editions but not in this, entitled ‘‘List of the fossil organic re- mains of the glacial deposits of Scotland,’’ by Robert Etheridge, Jr., with bibliographic references and concise descriptive notes of most of Review of Recent Geological Literature. 53 the localities yielding these fossils. As here newly edited and for the greater part rewritten, with two chapters by Prof. T. C. CHAMBERLIN, on the “Glacial Phenomena of North America,’’ this volume well sus- tains its author’s eminence as the foremost of living glacialists. It seems not too much to say that this work, in its successive editions, and Dr. Croll’s volume before mentioned, have done more than any other contributions among the very extensive mass of glacial literature, since the early grand work of Agassiz, to stimulate many eager students in fruitful investigations of the evidence and history of glaciation and in classification of the glacial and glacio-fluvial formations of Europe, North America and other regions. Like the writings of the author’s brother, Sir Archibald Geikie, this account of the Ice age is presented ina very clear and attractive style, commendably adapted to the under- standing of ordinary unscientific readers, while yet carefully stating the latest discoveries and theories in this increasingly debated. division of geology. Twenty of the forty-three chapters relate to Scotland, describing its glacial, glacio-fluvial, interglacial and postglacial deposits, striation, rock-basins, ice-sheets, and local glaciers; four chapters relate to Eng- land; one to Ireland; three to northern Europe: one to the Urals and the mountains of central Germany; two to the Alps: one to other parts of Europe, as France, Spain, Corsica, the Apennines, Iceland, the Frée islands, the Azores, and Gibraltar; a chapter of nine pages reviews the glacial succession in Europe; two chapters describe cave-deposits, ‘‘val- ley-drifts,’’ and loess; a chapter of eleven pages summarizes the climatic changes of Europe during the Glacial period, and the evidence of con- temporaneous Paleolithic man; the fortieth chapter discusses the gla- cial phenomena of. Asia, Australia, etc., and South America; the next two, by Prof. Chamberlin, relate to North America; and the final chap- ter treats of the cause of the climatic and geographic changes of the Glacial period. Six epochs of glaciation, with five interglacial epochs, are recognized, being nearly the same as in the author’s paper published in the Trans- actions of the Royal Society of Edinburgh (vol. xxxvu, pp. 127-149, with map) in 1892, excepting that one more glacial epoch, the latest, with the corresponding interglacial epoch, is here added. 1. The first glacial epoch is represented by the Weybourn crag and Chillesford clay, followed by the interglacial forest bed of Cromer. 2. For the second and maximum epoch of glaciation, an ice-sheet is mapped as stretching from Scandinavia east across the northern two- thirds of Russia to the Urals, the river Obi in Siberia, and Novaia Zem- lia; southward to latitude 50° in Russia, Poland, and eastern Germany; and southwest to central Belgium, to the Thames, beyond the southern and western coasts of Ireland, and across the Hebrides and Shetland islands. At the same time the Iwerées and Iceland were entirely ice- enveloped. With the Irish. North, Baltic and White seas, the area of this ice-sheet exceeded 2,000,000 square miles. Its limits have been greatly extended eastward since the similar map was prepared for D4 The American Geologist. January, 1895 Prehistoric Burope. This also was the time of greatest extension of the glaciers in the Alps, Pyrenees, and Caucasus. The ensuing interglacial beds of northern Germany contain remains of a temperate flora and fauna, indicating even milder conditions than those of the present day, and the rivers eroded deep valleys. 3. For the third glacial epoch, ice-sheets covering Ireland, Scotland, northern England, and Wales. are represented as confluent with the Seandinavian ice-sheet, which reached south to Hamburg, Berlin and Warsaw, and east to the Valdai hills and White sea. During the next epoch of interglacial conditions, the Baltic sea is shown to have had a temperate marine fauna, while the adjacent lands of northern Germany had a corresponding terrestrial fauna and flora. 4. In the fourth glacial epoch, or that of the Great Baltic glacier, de- limited by conspicuous moraines, the ice-sheet covered nearly all of Scandinavia, excepting a considerable tract of southern Sweden; it reached east over a large part of Finland, and south along the Baltic trough to the lowlands of northern Germany and eastern Denmark; but the North sea existed as now, and the British Isles had only local or dis- trict ice-sheets of comparatively small extent. The next interglacial epoch had forests of deciduous trees farther north than they now flour- ish; and the Baltic was for a time converted into a fresh-water lake, named the Ancylus lake from its most Characteristic fossil shells, as made known by the studies of Baron de Geer and others, but later it was con- nected with the sea by straits across southern Sweden, admitting a ma- rine molluscan fauna of somewhat more temperate character than now. While the Baltic was a lake, the bed of the North sea, the English channel, and large tracts which are now shallow sea surrounding the British Isles, and a belt thence to the Ferées and Iceland, are mapped as land, whereby the European flora was extended to Iceland and Green- land. That migration may, however, as the reviewer thinks, be better explained otherwise, as stated farther on. 5. The fifth glacial epoch is represented only by local or valley mo- raines in the British Isles, the snow-line in Scotland having been at an average hight of 2,500 feet. 6. After aninterval of forest growth in the mountain valleys, another and the final epoch of local glaciers, occurring only on the highest mountains in Scotland, had its snow-line at the hight of 3,500 feet. Prof. R. D. Salisbury, reviewing this volume in the Journal of Geol- ogy (vol. 11, pp. 780-747, Oct-Nov., 1894), well notes the remarkable par- allelism of the European and North American glacial history, ‘‘that the outermost border of the drift in Europe, as in America, is not character- ized by terminal moraines; that the limit of the drift deposited during the second advance of the ice [Prof. Geikie’s third glacial epoch] in Europe, as in America, is not commonly marked by well-defined mo- raines. though moraines are not altogether wanting: that the great body of loess in Europe, as in America, seems to be connected with the ice advance which succeeded the greatest; and that the ice during the next succeeding advance (the second after the greatest), both in Europe and Review of Recent Geological Literature. 55 America, developed the great terminal moraines, and that these mo- raines are bordered on the outside by plains and valley trains of sand and gravel, denoting more vigorous drainage than during the earlier stages of the ice.”’ Commenting on this, the present reviewer would inquire, May not the close agreement in the glacial succession on the two continents be more probably in each case the expression of varying physical conditions of the increase, culmination, and especially the de- cline, of a single cycle of glaciation, rather than the records of several independent epochs of ice accumulation and departure 7 Applying the interpretation of these series of glacial and interglacial deposits which seems to find warrant in Russell’s observations of the Malaspina ice-sheet in Alaska, covered on its border for a width of sev- eral miles with drift on which forests, thickets, and abundant herba- ceous flowering plants of temperate species grow luxuriantly, we may attribute all the complex sequence of drift formations in Europe, as in North America, according to the opinion of the reviewer, to moderate fluctuations of the boundaries of the ice-sheet and of its waning rem- nants, during a continuous Glacial period of probably no longer dura- tion than 20,000 or 30,000 years. While the ice-sheets were being accu- mulated, doubtless a severely boreal and arctic climate prevailed in these regions; but when the formerly greatly elevated lands had sunk under their ice burden to their present altitude or lower, a warm tem- perate climate was restored, similar to that which now characterizes the low latitudes from which the ice was being melted away. Any re- fidvance of the ice-border would then cover remains of a faunaand flora consisting wholly or chiefly of temperate species. Under this view, the time divisions which Prof. Geikie calls epochs seem more properly to be considered as episodes or stages in a single epoch or period of con- tinuous though fluctuating elaciation. Professor Chamberlin’s two chapters contain, in 52 pages with two maps, a very comprehensive and valuable statement of the chief fea- tures of North American glacial geology. In all the grand outlines and most of the conclusions, as the explanation of practically all our drift phenomena by land-ice, the reviewer is in hearty accord, so that it is almost trivial to refer principally, as in this notice, to the following points where he would differ in the inferences from recorded observa- tions. The Laurentide and Cordilleran ice-sheets should probably be shown as confluent across ‘the low portion of the Roeksy mountains in the region of the Peace river and northward: during the maximum stage of glaciation, the greatest thickness of the Laurentide ice-sheet may have extended along an east to west belt somewhat south of the Labradorian and Hndsonian centers of later radiating striation and drift transportation; the northward elacial flow from northern New Eneland toward the St. Lawrence, as suggested by Chalmers, appears to have belonged only to a very late stage when the melting of the ice in the St. Lawrence valley, proceeding faster than on the mountainous area at the south, left there a large isolated remnant of the departing ice-sheet; the imbrication or overlapping of the drift series, well illus- 56 The American Geologist. January, 1895 trated in the frontispiece and text descriptions, may be due, in some places where it is most complex, to changes in the directions of currents in one and the same ice-sheet on the same area at different times, such as are found to have prevailed in eastern and northeastern Minnesota, being there comprised wholly within Prof. Chamberlin’s latest or Hast- Wisconsin division of the declining part of the Ice age; and the inter- glacial fossiliferous beds of Toronto and Scarboro, Ont., seem referable to a stage in the glacial retreat when lake Iroquois, the glacial represen- tative of lake Ontario, had begun to outflow by Rome, N. Y., to the Mo- hawk and Hudson rivers, after which the epeirogenic uplifting of the Rome outlet caused the lake level at Toronto to rise to the high Iroquois beach, the glacial readvance that covered the fossiliferous delta beds having been probably only a moderate fluctuation of the ive-front, till this time lingering on the highland between Toronto and Georgian bay. Nearly half of North America, or an area of 4,000,000 square miles, was ice-covered. It will be very interesting to learn, from Prof. Cham- berlin’s observations in northwestern Greenland and from future explo- rations of the Arctic archipelago, whether this continental ice-sheet was confluent over Grinnell land and Smith sound with the Greenland ice. The terminal or retreatal moraines of the Laurentide portion of the North American ice-sheet, traced across the northern United States to the northwestern plains of Manitoba and Assiniboia by Chamberlin, Smock, Lewis and Wright, Todd, Leverett, Salisbury, Upham, and others, af- ford most impressive proof of the land-ice origin of our drift; and these twelve to twenty or more moraines, Marking pauses in the glacial re- cession, are accepted as all belonging to the closing part of the whole history of the Ice age. The distinction of the successive portions of the North American gla- cial drift in the order of their age by geographic names, as the Kansan, Hast-lowan, and Hast- Wisconsin formations, here proposed by Prof. Chamberlin, seems to be clearly a step of progress. It would perhaps be better, however, for reasons of euphony, to shorten the two latter names simply to lowan and Wisconsin, which, with their definitions, will be sufficiently understood. This system of nomenclature is elastic, permit- ting interpolation and elimination, and it leaves the question open for further investigation and discussion, whether the Glacial period was dual, threefold or more complex, with one, two or more interglacial ep- ochs, or, on the other hand, was essentially continuous, with compara- tively small oscillations of the ice boundaries during both the growth and decline of the ice-sheet. Concerning the causes of glaciation, Profs. Geikie and Chamberlin doubt the adequacy of Dr. Croll’s astronomic theory, which a few years ago obtained more general assent; but they fail thus far to approve the alternative epeirogenic theory of Dana. Le Conte, Wright, Upham, Jamieson, Falsan and others, which attributes the ice accumulation to ereat uplifts of the land bringing a snowy climate throughout the year. This view, however, will explain how the Frée islands, Iceland and Greenland, may have received their largely Huropean floras; for if the Review of Recent Geological Literature. 57 high elevation which Prof. Geikie places after his fourth glacial epoch were instead during preglacial time, bringing on the ice-sheets, low shore tracts of the land bridge to Greenland may never have been covered by the ice and so would preserve the flora for Iceland and Greenland when this part of the earth’s crust subsided and the Ice age ended. The duration since the departure of the ice from the temperate portions of Europe and America is thought to have been less than Dr. Croll’s theory would require. For our continent Prof. Geikie presents Dr. J. W. Spencer’s discussion of the age of Niagara falls, regarding this time as about 32,000 years. Evidence now in hand, however, seems to prove that no outflow passed from lakes Superior, Michigan and Huron to the Mattawa and Ottawa, on which the greater part of Dr, Spencer's esti- mate is founded. Probably 7,000 years is as close an approximation to the duration of Niagaraand the Postglacial period as we can attain. Twenty years ago the present writer derived his earliest interest in our glacial and modified drift from a perusal of the first edition of The Great Ice Age. This third edition will be read by all glacialists with much renewal and increase of enthusiasm for the many Pleistocene questions which still remain debatable. Every page is richly suggestive, and the theory of alternating glacial and interglacial epochs has served well for the collection and orderly arrangement of a vast mass of infor- mation as to the Ice age and its complicated history. W. U. The Ore Deposits of the United States. By JAMES F. Kemp. (S8vo. pp. i- xvii, 1-343, with 94 illustrations: revised and enlarged; Scientific Pub- lishing Co., New York and London, 1895.) This work has already been reviewed in THE AMERICAN GEOLOGIST (vol. xii, pp. 268-269, Oct., 1893), and it is only necessary here to call attention tothe revised and enlarged edition. ‘In the second edition many pages have been rewritten and expanded. The endeavor has been to introduce into the body of the work the new materials that have become available in the last year This is especially true of iron ores, of the geology of the Sierras and of nickel and cobalt. In all some fifty pages of new matter have been added, and fifteen cuts.’ The publication of a second edition of this book within less than two years after the first edition was issued is suf- ficient evidence of its usefulness and value. Wns Ge The geology of Angel island. By F.. Ransome. With a note on the radiolarian chert from Angel island and from Buri-buri ridge, San Mateo county, California. By J. G. Hrxvr. (Bull. Dept. of Geol. Uniy. of Cal- ifornia, vol. 1, No. 7, pp. 198-240, pls. 12-14, Oct., 1894.) Angel island is three and a half miles north of San Francisco and is composed largely of San Francisco sandstone and a jaspery rock (radiolarian chert). The chief geological interest centers in the phenomena connected with the igneous rocks of the island, which are chiefly a large dike of serpentine and an intrusive sill. The rock of the sill varies considerably, but its characters seem to ally it more closely with the fourchites described by J. F. Williams from Arkansas than with any other class of rocks. In 58 The American Geologist. January, 1895 the serpentine the only original mineral now distinguishable is diallage. A narrow belt of glaucophane schist frequently occurs at the contact of the country rock with both the serpentine and fourchite. As this schist is clearly a product of contact action, all of the glaucophane sehists of the Coast ranges can not be referred to regional metamorphism, as has heretofore been done. The glaucophane is developed in the cherts as well as in the sandstones. ; The chert (phthanite of Becker) is found to contain abundant remains of radiolarians, So poorly preserved, however, that specific determina- tion is out of the question. Several figures of these fossils are given, and Dr. Hinde is able to refer some of them to certain genera: he calls attention to the number and variety of the forms of the genus Dictyomi- tra which are present. UeaS-1G: Geological Survey of Missouri, Sheets Nos. 2 and 3, the Bevier sheet and the Iron Mountain sheet. ARTHUR WiINsLow, state geologist. Jefferson City. Published by the Geological Survey. Each of these ‘‘sheets’’ is accompanied, the former by three, and the latter by two, other sheets of the same size as the sheets themselves, and they are included separately in two paper covers or folios. Each sheet has a description sheet, giving briefly an account of the geology of the area of the sheet, while on the other accompanying sheets are perpen- dicular and cross-sections illustrating the geological structure. Hach sheet covers an area fifteen minutes of latitude by fifteen minutes of longitude, making approximately a rectangular parallelogram of con- venient proportions. The seale is ae of nature, or approximately one inch to the mile. Based upon latitude and longitude they do not agree with the boundaries of townsand counties, although the town and county lines are expressed on them, as well as the section lines of the land survey. They are both marked in detail by contour lines, the in- terval being 20 feet. The Bevier sheet was done under the charge of C. H. Gordon, with C. F. Marbut and M. C. Shelton as assistants. The Iron Mountain sheet is by the state geologist, who had the aid of Kras- mus Haworth on the crystalline rocks, and E. H. Lonsdale and ©. F. Marbut as topographers and geological assistants. The Bevier sheet was engraved in Washington, D. C., by Evans and Bartle, and is dated Octo- ber, 1893. The Iron Mountain sheet was engraved by George S. Harris and Son, at Philadelphia, and is dated January, 1894. One other simi- lar sheet has been issued—the Higginsville sheet, noticed in the GEOL- ogist, vol. x, p. 317. No other state survey has attempted so detailed topographical work nor so costly and elaborate a system of mapping. These sheets compare, to their advantage, with those of the United States Geological Survey; and if the State of Missouri persists in this en- terprise to the completion of the survey, on this scale of excellence, she will not only be far in advance of her neighbors, but will rank with the States of central Kurope. N. H. W. Geological Map of Alabama, with an explanatory chart. KUGENE A. Smirn, state geologist, Montgomery, 1894. Review of Recent Geological Literature. 59 Greatly in contrast with the foregoing is this excellent map of Ala- bama and its synoptical companion sheet. It covers the whole state but has no topographical contours. It is published with the well-known excellence of engraving of Julius Bien and Company, of New York. Its size is about twice that of one of the Missouri sheets, and its publica- tion with its companion sheet probably cost about the same sum as one of the Missouri sheets. The great contrast to which we refer is not in the degree of excellence of the geological work, for they both illustrate the best of geological work. It is rather in the plan, the history and the utilitarian results achieved by the two surveys, for, after all, the practical good that comes to society from such enterprises is the final arbiter which determines their existence or decrees their death. The highest flights of technical science, whether in physics or in geology are amenable to this arbiter, and probably more certainly so in the demo- cratic communities of the United States than elsewhere in civilized countries. Dr. Smith seems to have realized this, and has moved slowly toward his contemplated result, making as much haste as was safe; every step has had its utilitarian aspect foremost, while the additions that he has made to science have not been few. His survey is probably more firmly grounded in the good will and appreciation of the intelli- gent citizens af Alabama than ever before. This map of Alabama is the best ever published of that state, and certainly will subserve all the uses for which such a map is wanted for many years. The Alabama survey has not been wrecked on either of the alluring reefs of paleontol- ogy or topography. While avoiding them both, it still has fathomed and outlined them both for future explorers to work out in detail. The Missouri survey struck the topographical reef at the outset, and has spent much time and money in making a detailed examination. It is not wrecked, but is damaged badly. If it survives the shock and reaches safe sailing again, it will illustrate the recuperative strength of geological science in the esteem of the Missouri legislature. The Geological Iistory of Harbors. By N.S. SHauEr. (Thirteenth An. Rep., U.S. Geol. Survey, Part II, pp. 93-209, with plates xxlI-xLv, and figures 7-15 in the text.) This paper treats of the influence of har- bors on the settlement and development of the country; the diverse ge- ologic conditions by which the harbors have been formed, with a sys- tem of classification: geologic processes tending to preserve or to destroy them, with suggestions as to the means whereby these processes may be favored or hindered through the agency of man; and the special fea- tures of the ports on our Atlantic. and Pacifie coasts, and of those on the great Laurentian lakes, which are now or may become of importance to our foreign or domestic commerce. In the classification of harbors, their several genetic kinds are named delta, reéntrant delta, glacial or fjord, mountain range, glacial moraine, lagoon and sand bar, sand spit, volcanic crater, and coral reef harbors. The work for the improvement of our harbors by the U. S. Engineer Corps, and the very accurate hy- 60 The American Geolog/st. January, 1895 drographic surveys of all our coast lines, and especially in the vicinity of the principal harbors, by the U.S. Coast Survey, have been freely used by the author, making a very instructive and valuable memoir of exceptional popular interest. Concerning oscillations of the land, which contribute very largely to the formation and changes of harbors, Prof. Shaler says: ‘Although there is much evidence to show a process of de- pression along the Atlantic coast line, recently operative, and probably still in progress at certain points, and the known facts of the Pacifie coast point to similar movements there, and although there is, further- more, evidence tending to show a very modern uprising along the coast from New York northward, the shores of our continent may fairly be considered as in a tolerably stable condition.” WwW: U, The Mechanics of Appalachian Structure. By BatLEy Winuts. (Thir- teenth An. Rep., U. S. Geol. Survey, Part II, pp. 211-281, with plates xLvi-xcvi, and figures 16 and 17.) The most common types of moun- tain ranges, and the causes and conditions of their formation, are no- where better displayed than in the Appalaehian mountain belt, stretch- ing 900 miles from New York to Alabama, witha width from 50 to 125 miles. Great thicknesses of Paleozoic sediments, which were there de- posited on the western border of a continental area, are compressed into long and narrow parallel folds, sometimes overturned and over- thrust. From the early work of H. D. and W. B, Rogers to the recent studies of the long overthrust faults by Hayes and Campbell, this belt has held a prominent place in the growing literature on the structure and.origin of mountain ranges, to which the present work is probably the most important contribution yet made by American authors. Four districts in the Appalachian province are each distinguished by a pre- vailing structural type, namely, the district of open folding in the Alle- ehany region of Pennsylvania and West Virginia; the district of close folding along the Appalachian valley; the district of folding and fault-° ing in the Southern Appalachian region of Virginia, Tennessee, and Georgia; and the district of folding with schistosity in the Smoky mountain region. Attempting in the laboratory an experimental reproduction of folds and faults in alternating hard and soft strata, as had before been done by Sir James Hall, Favre, Schardt, and Cadell, the author used bees- wax to represent the rock formations, mixed in varying proportions with plaster of Paris to harden it, and with Venice turpentine to soften it, so obtaining a range in quality from brittle solid to semi-fluid. Plas- ticity in the earth’s crust being a result of pressure due to load, this condition was imitated by placing a body of shot, heavy, but yielding and convenient to handle, above the strata. A maximum weight of 1,000 pounds was used, evenly distributed over the models, giving a pressure of five pounds per square inch. The machine for imitating the lateral pressure by which the mountain strata were folded. and up- heaved was a strong oak box with a piston which could be advanced by a screw. Review of Recent Geological Literature. 61 The models and experiments were designed in accordance with the accepted conception of the earth’s crust as ‘ta superficial shell 5 to 7 miles thick, which rests upon and grades in substance aud physical condition into a subjacent shell. The under is only differentiated from the upper by its relative position in consequence of which it supports a crushing load and forms a latently plastic foundation.”’ More tersely stated, the geologic condition to be imitated was that *‘the strata which have suffered folding and faulting floated upon and graded downward into a latently plastic mass.”’ It was further required that the thick- ness and extent of the strata should be so related that as a whole they should be flexible rather than rigid. The principles which had been Stated by Heim. Gilbert and others, that deformation by fracture, with shearing and overthrnst, occurs under moderate Joad, and that deform- ation by flexure, with open or closed and finally overturned folds, takes place under great load, are well proved by these experiments. In the very extensive and admirable series of illustrative plates we are shown the gradual development of every stage and phase in the formation of mountain folds and faults. Mr. Willis concludes that the vast lateral pressure producing the Ap- palachian and other mountain belts can not have been due wholly to the contraction and shrinking of the earth’s interior. He would there- fore add to that partial explanation the theories of Dutton and Reade. The resulting composite theory is advocated as follows: ‘To every hy- pothesis brought forward to account for the folding of the stratified rocks there is one objection made by its opponents: The cause is not quantitatively equal to the task required of it. For argument’s sake, admitting for each and every one that the criticism is sound, I do not understand that it disposes of any which are based on good inferences from observed facts. The process of deformation was exceedingly com- plex and thus afforded opportunity for the action of more than one cause. As the work performed was stupendous, it required the com- bined power of all available forces.” Referring to the vet more difficult question of the causes of the par- tially concomitant but (according to the opinion of Mr. Willis) unre- lated epeirogenic uplifts and growth of this.continent, he writes: ‘‘The Paleozoic continent and sea of North America had their origin in un- known causes of pre-Cambrian time. After Paleozoic deposition and deformation the rise of the whole continent lifted alike the Blue Ridge belt of crystallines, the folded zone of the Appalachian province, and the undisturbed strata of the Mississippi basin. The uplift bore no re- lation in area or time to the fact of compression, and it has gone on through geologic periods after folding ceased, as is shown by the an- cient base levels and revived drainage of the whole region east of the Mississippi valley.’ To the reviewer it seems more likely that an inti- mate genetic relationship existed between the Appalachian revolution of mountain folding and the accompanying rise of the interior of North America from the previously very long enduring Paleozoic sea; and the 62 The American Geologist. January, 1895 later epeirogenic movements of this region may well have been similarly related, in Common Causation, with orogenic folding and faulting of our Cordilleran mountain belt. w. U. The Average Elevation of the United States. By Henry GANNETT. (Thirteenth An. Rep., U. S. Geol. Survey, Part II, pp. 283-289, with plate cvu.) Erom the compilations of altitudes which are published in Bulletins 5, 72 and 76 of this survey, and from all other available hyp- sometric data, a contoured map of the United States on a scale of x500000-: OF about 40 miles to an inch, has been published, from which the map forming plate cvir, folded in the pocket of the volume, has been produced by reduction. This map is on the seale of about 105 miles to an inch, and is colored to display the areas between the suc- cessive contour lines of the seashore and 100 feet, 500 feet, 1,000, 2,000, 5,000, 8,000 and 11,000 feet above the sea. In his paper Mr. Gannett states the mean altitude of each state and its respective areas between these and other intercalated contour lines. The mean altitude of the whole United States is found to be approximately 2,500 feet. Delaware, with a mean hight of about 60 feet, and Florida, about 100 feet, are the lowest states, while Wyoming, at 6,700 feet, and Colorado, at 6,800 feet, are the highest. Since the publication of this paper, a careful determi- nation of the mean altitude of Minnesota, from the contoured maps prepared by the geological survey of that state, has giyen it as approxi- mately 1,224 feet, quite well agreeing with Mr. Gannett’s estimate, which is 1,200 feet. W. U. CORRESPONDENCE: REMARKS ON THE BERNER OBERLAND SECTIONS OF PROF. H. GOLLIEZ IN THE GEOLOGICAL HANDBOOK OF SWITZERLAND, 1894.* Mr. Golliez has published in the *Livret Guide’ two sections of the Bernese Oberland which vary so materially from all previous results that I feel myself compelled to a reply, all the more because this book 1s cer- tain of a wide distribution and I see that the new theory has created surprise among Swiss geologists. : 1. Section Meiringen-Innertkirchen by Mr. Golliez p. 207. Mr. Golliez assumes it is true a great flat fold, but puts instead of Malm, Trias! in contradiction to all previous observers. The trough nucleus of Lias and Dogger rises according to him theoret- ically towards the middle of the Pfatfenkopf wedge, Dogger and Lias are assumed as doubled in the Unterwasser section; at the entrance to the gorge of the Aar at Meiringen they bend back upwards. There must be weighty reasons which induce Mr. Golliez to place himself in contradiction to all the geologists who have hitherto studied this region. *Translated by Dr. Persifor Frazer from a circular distributed at Zurich at the late meeting of the International Congress of Geologists. Correspondence. 63 One reads with astonishment of ‘*poor fossils absolutely incompetent fo inform us with certainty’? (by this the Triassic Diploplora are meant), whereas I refer to the extended Belemnites, which I know in the east- ern continuation of the chain, for the view held till now. Mr. G. de- pends more on petrographic ‘‘habitus’ and an insecure analogy with the ‘“‘Briangonnais;” he thinks there are occurrences of ‘‘intercalations”’ of quartz, sandy Dolomite. and Gypsum. Up to this time only Lime- stone and secondary segregations have been seen as they occur in every limestone: possibly Mr. G. has allowed himself to be deceived by Réthidolomite folded from below upwards. (Compare my section Sheet ix, fig. 1, right hand side.) But how any one can make Triassic dolo- mite on such a basis out of our high mountain limestone is undiscover- able. In the Unterwasser section (compare my figure 4) I know of no repe- tition of the beds. In the nucleus of the Pfaffenkopf wedge there is no Lias; on the other hand it occurs on the boundary towards the Gneiss at Ahorni, where according to G.’s hypothesis it ought not tooccur, and where besides the wedge is wrongly drawn. Mr. G. opposes or finds fault with the presence of Eocene on sheet xiii in Reichenbachthal, ete. Inexplicably the important Eocene trough of this valley corroborated by myself and Mosch, which has been abso- lutely established by Nummulites, largely developed Taveyannaz sand- stone, and Flysch, seems to have escaped him. : The statement on p. 209 that I assume Flysch on my older chart along the foot of Bernese Oberland mountain wall, where Dogger exists, is in- correct as my legend proves. Provisionally Dogger, Oxfordian, and Eocene were indicated there in the same color, because their bounda- ries were not at that time settled. This *‘pretended Flysch”’ exists only in the fancy of Mr. Golliez. In fine, the section by Mr. Golliez of Meiringen to Innertkirchen so far as it is correct has long been known, and where it would offer sur- prising novelties it is wrong. 2. Transverse section of the Bernese Oberland, by H. Golliez: page 212. Under this pompous title a section from the Ménch tothe Habkehren valley is given, in regard to the northern part of which Mr. Golliez will have to explain himself to Mésch: only the southern half concerns me. The discovery which Mr. Golliez made in the gorge of the Aar recurs here again, but he is more sare of his affair; the flanks (Absttrze) of the Monch are said to be Triassic-marble according to the section. Who- ever, at the little Scheidege. sees only occurrences of marble may im- agine that the Monch is marble up toitsgneiss cap. In fact, the marble is a very small factor compared to the ordinary high mountain lime- stone. Dolomite has nowhere been observed, and as little has the Opal- inien bounded by marble. Mr. Golliez’s Trias hypothesis (or better, illusion) is wrong for the M6nch also, and has not a trace of holding ground. Were it correct, for consistency’s sake, on many of the Dufour sheets Malm would have to 64 The American Geologist. January, 1895 be transformed into Trias, even where it is paleontologically well sup- ported by the presence of Tenuilobatus beds and Tithon. To designate the non-fossiliferous part as Trias is indefensible from petrographic and tektonie considerations, Mr. G.’s section is wrong. The Malm nucleus sinking into the valley near Lauterbrunnen is to be united with the Oxfordian between Ménn- lichen and Tschuggen above: and further away, with the Malm of the slopes of Liitsechenthatl. The relations are here relatively simple and by their help the other- wise unintelligible Wetterhorn section, p. 208, is easier to comprehend with the quite abnormally placed Eocene. This section is besides wrongly printed, since on the right band of the Wetterhorn summit fossiliferous Upper Dogger should have been placed instead of marble. It is true this occurrence is not consistent with Mr. Golliez’s Trias hy- pothesis. The cut of the “Glissement”’ on the gneiss, of which further explana- tions are wanting, is original. In a word, Mr. Golliez’s sections are very well adapted to create con- fusion in the minds of those who are not acquainted with the facets: they do not belong in a ‘‘Livret-guide, whose purpose is not to dissemi- nate undigested hypotheses, and I consider myself under the cireum- stances justified in opposing these geological improvements of the Ober- land. (Signed) A. BALTZER, Professor in Bern. INEQUALITIES TN THE OLD PALEOZOIC SEA BOTTOM. You will be inter- ested to learn that gray granite, similar to that found at LeMars, was struck at Sioux City at the depth of 1,515 ft., or 355 feet below the sea level. It was penetrated about 500 feet and showed characters similar to those found in the LeMars well. At the latter point granite was struck at 1,000 ft., about 150 feet above the sea, a difference of 500 feet in a distance of 25 miles. Crystalline schist was brought up by a dia- mond drill from 560 feet at Pawnee City, Pawnee Co., Neb.. as I believe Prof. L. E. Hicks has published. That, I estimate, to be not less than 620 feet above the sea. Yet at Brownsville, 85 miles northeast, a drill was sent down 1,000 feet, probably 100 feet below the sea, without pass- ing through the Carboniferous. At Omaha a boring to the depth of 1,752 feet, 785 below the sea, failed to clearly reach the Silurian. This gives us a glimpse of the irregularity of the old Paleozoic sea bottom, and shows that the Carboniferous is considerably thicker than estimated by Dr. White in his report on Towa. J. KE. Topp. Tabor, Towa, May 12, 1890. PERSONAL AND SCIENTIFIC NEWS: THe GEoLoGIcAL DEPARTMENT AT JoHNS Horpkrns UNIVERSITY. Sinee the death of Prof. George H. Williams the courses of Personal and Scientific News. 65 instruction in geology at the Johns Hopkins University have been somewhat changed. The department of geology is now under the direction of Dr. Wm. B. Clark, Professor of Organic Geology, assisted by Dr. E. B. Mathews, Instructor in Miner- alogy and Petrography. In addition to the instruction given by these two gentlemen, Mr. G. K. Gilbert and Mr. Bailey Willis, both of the United States Geological Survey, will give courses of lectures on physiographic geology and on strati- graphic and structural geology respectively. _Barrimore Meeting or tHE GEOLOGICAL Socrery. The seventh annual meeting of the Geological Society of America was held, under the presidency of Prof. T. C. Cham- berlin, in the geological laboratory of the Johns Hopkins University, Baltimore, Md., from Thursday to Saturday, De- cember 27th to the 29th. Sixty or more fellows of the society were in attendance, and fifty papers were presented. Pres. D. C. Gilman, speaking in behalf of the university and city, gave a cordial address of welcome. In selecting Baltimore as the place for its winter meeting, the society had counted es- pecially on the presence of Prof. George H. Williams of this university, the second vice-president of the society, as one of those extending to it greetings and hospitality; but his la- mented death last summer left to his associate, Prof. William B. Clark, double duty on the local committee and the pre- sentation of an address in memorial of Prof. Williams. A memorial of Mr, Amos Bowman was also given by H. M. Ami. Three other societies of national extent also held meetings at the same time at the Johns Hopkins University, namely, the American Society of Naturalists, the American Morpho- logical Society, and the American Physiological Society. Many affiliated workers in all departments of the natural sciences, convening from widely different parts of the coun- try, were thus afforded opportunities for most pleasant re- newals of old acquaintance; and the several meetings. occu- pying different rooms of the university at the same time, reminded one of the yet more numerous sections in the annual summer meetings of the American Association. During a part of Friday the Geological Society, on account of its fairs number of papers, met in two sections, petrographic papers being read in one section, and glacial papers in the other. Professor Chamberlin, in his address Friday evening as the retiring president, spoke of his observations during the past summer on the glaciers and ice-sheet of Greenland, especially of Inglefield gulf and of Bowdoin bay, a fjord extending from that gulf northward to Lieut. Peary’s winter station. ae series of very instructive lantern views of these glaciers was exhib- ited after the address, of which, and of the other glacial and 66 The American Geologist. January, 1895 Pleistocene papers, concise abstracts will be given in the February AMERICAN GEOLOGIST. After this address about forty fellows of the society had an informal supper, followed by toasts to which Mr. W J Me- Gee, Profs. W. H. Nilesand I. C. Russell, and Maj. Jed. Hoteh- kiss responded. The toast-master, as at the society's former meetings, was Prof. B. K. Emerson, who will be gratefully and laughingly remembered by all present on this and other such oceasions, for his felicitous manner of stirring up ripples and waves of merriment where usually there are only calm reflee- tion, profound investigation, and earnest eee The officers elect for the year 1895 are: Prof. N.S. Shaler, president; Prof. Joseph Le Conte, first vice Sete Prof. C. H. Hitcheock, second vice president; Prof. H. L. Fairchild, secretary; Prof. I.C. White, treasurer; J. Stanley-Brown, ed- itor; R. W. Ells and C. R. Van Hise, members of the council. Five new fellows were elected. With this addition, the total membership is 284. It is announced, in the report of the council, that the soci- ety’s library is to be deposited in the Case Library at Cleve- land, Ohio, with facilities for loans to fellows during periods not exceeding two months. The next meeting of the society will be in connection with that of the American Association, at San Francisco, Cal., in August; but the place of the next winter meeting is not yet determined. Appended is a list of the papers read at the Baltimore meet- ing. Many of them were followed with important discussion. On certain features in the jointing and veining of the Lower Silurian limestones near Cumberland Gap, Tennessee. N.S. SHALER. The Appalachian type of folding in the White mountain range of Inyo county, California, C.D. Wancorr. New structural features in the Appalachians. ARTHUR KErrn. The faults of Chazy township, Clinton county, New York, UH. P. Cusx- ING. Detailed mapping shows that the nearly horizontal Paleozoic strata are cut by many intersecting faults, the faulted blocks being consequently of small size. The subject is of special interest from its bearing on the probable structure of the adjoining Adirondack moun- tain area of crystalline rocks. The formation of lake basins by wind, G, K. GILBERT. Observations of lakelets on sterile Cretaceous shale of the plains crossed by the Ar- kansas river in southeastern Colorado. The Tepee buttes. G.K. Graupert and F. P. Guiiiver. Knolls 10 to 30 feet high, left by subaérial denudation where Lucina colonies existed in the Ft. Pierre shales, on a belt extending northward and eastward from near Pueblo, Colorado. Remarks on the geology of Arizonaand Sonora, W J McGrr. Geology of the Highwood mountains, Montana. Water H. WEED and Louts V. Prrsson. Genesis and structure of the Ozark uplift. CHARLES R. Keyes. The geographical evolution of Cuba. J. W. SPENCER. Recent glacial studies in Greenland, T.C. CHAMBERLIN. (Presidential address. ) Fu Personal and Scientific News. 67 Observations on the glucial phenomena of Newfoundland, Labrador, and southern Greenland. G, FREDERICK WRIGHT. Highland level gravels in northern New Hngland. C. H. Hrrencock. Variations of glaciers. Harry Firuptne ReEIp. Discrimination of glacial accumulation and invasion. WARREN UPHAM. Climatic conditions shown by North American interglacial deposits. War- REN UPHAM. Glacial lakes in western New York. UH. L. Farrcurp. Lake Newberry, the successor of lake Warren. WH. Va. PArRCHILD. Notes on the glaciation of Newfoundland. T. ©. CHAMBERLIN. The pre-Cambrian floor in the Northwestern states. C. W. Haun. From the records of deep and artesian well borings a series of sections and maps shows the extension of the pre-Cambrian rocks from their outerop- ping areas downward under the later formations to the successive depths of contours atthe present sea level, and at 500 feet and 1,000 feet below that level. A further contribution to our knowledge of the Laurentian. FRANK D. ApaAms. Description of an area of anorthosite and surrounding crystal- line rocks of the Grenville series extending from the island of Montreal about 50 miles northward. The crystalline limestones, ophiolites, and associated schists, of the eastern Adirondacks, J. ¥. Kemp. These limestones and schists, occurring in small areas, usually less than a square mile, are regarded as older than the gabbros and anorthosites of the Norian series, being probably the remnants of an extended formation which was cut up by the gabbro in- trusions, metamorphosed largely by them, and afterward eroded. The crystalline limestones and associated rocks of the northwest Adirondack region. C. H. SMytu, JR. Lower Cambrian rocks in eastern California... C. D. Waxcorr. The White mountain range, whose structural features were noted in the second paper of this list. Devonian fossils in Carboniferous strata. HH. S. Wiuutams. In north- ern Arkansas, at Spring Creek, near Batesville. The Pottsville series along New river, West Virginia. Davin WHITr. Stratigraphic measurement of Cretaceous time. G. K. GILBERT. Describ- ing regular alternations of shale and limestone. in pairs of strata to- gether mostly from one to three feet thick, occurrmg commonly through- out a great thickness of the Ft. Benton, Niobrara and Ft. Pierre shales in the Arkansas river basin, The hypothesis suggested for these alter- nations is dependence upon the astronomic cycles of precession of the equinoxes, which would require some 20,000,000 years for the deposi- tion of this portion of the Cretaceous series. representing perhaps half of the Cretaceous period. Notes on the Cretaceous of western Teras and: Coahuila, Mexico, Ke. T. DUMBLE. The Cretaceous deposits of the northern half of the Atlantic coastal plain, WiuiaM B. CLark. The marginal development of the Miocene in eastern New Jersey, \WU1AM B. CLARK. Sedimentary geology of the Baltimore region. N. UW. Darvon. The surface formations of southern New Jersey. RouLin D. SALISBURY. On new forms of marine alge from the Trenton limestone, with observa- tions on Buthograptus laxus Hall, R. P. Warrrrenp. Spherulitic volcanics at North Haven, Maine. W.S. BAYLEY. The peripheral phases of the great gabbro mass of northeastern Minnesota, W.S. Bayney. On the northern boundary of this great gabbro area are basic and granulitic rocks whose composition indicates their relation- ships with the gabbro. The basic rocks are aggregates of the basic con- stituents of the gabbro, and they are characterized especially by their abundance of titanic iron. The granulitic rocks differ from the minerals 68 The American Geologist. January, 1895 of the gabbro mainly in structure. They consist of aggregates of rounded diallage, hypersthene, and plagioclase, all of which minerals are present also inthe normal rocks. The basic rocks are regarded as probably dif- ferentiated phases of the gabbro, of earlier age than the great mass of the normal rock, while the granulitie phases are simply structural peri- pheral phases. The contact phenomena at Pigeon point, Minnesota. W.S. BAYLEY. An exhibition of specimens. The relation of grain to distance from margin tn certain rocks. ALERED ©. LANw. Description of the variation in texture and grain of some quartz diabase dikes of the northern peninsula of Michigan. and com- parison with effusive flows of similar mineral composition. Interstitial micropegmatite is primary or pneumatolytic, and the feldspar crystal- lization began before that of the augite, continuing until later. The main object of the paper was to elicit, by discussion, the best methods of measuring the coarseness of grain of a rock. Crystallized slays from copper-smelting. ALKRED ©. LANE. Describing (with exhibition of specimens) some slag from the cupola furnaces used in copper-smelting, with large melilite crystals, between one and two centimeters square, interesting optically and in mode of occurrence, Crystallized hematite is also noted. On the honeycombed limestones in the bottom of lake Huron, RoBerr Breti. The limestones over a certain region in the bottom of this lake are ascertained by the fishermen to be extensively eroded in a peculiar manner which the writer calls honeycombing and pitting. This condi- tion is ascribed to a differential solubility of the rock in the presence of slightly acidulated water. On the nomenclature of the fine-grained siliccoux rocks, LEON S. GRIs- WOLD. On some dikes containing “huronite.’ AtRRED KE. Bartow. A petro- graphical notice of certain dikes of diabase north and northeast of lake Huron, containing ‘huronite,’’ as the mineral was named by Dr. Thom- son in 1836. It is found to be an impure or altered form of anorthite, which has undergone either partial or complete ‘‘saussuritization,”’ owing to metamorphic action. The characteristic features of the California gold quartz veins. WALDE- MAR LINDGREN. On the quartz-keratophyre and its associated rocks of the Baraboo bluffs, Wisconsin. SAMUEL WEIDMAN (introduced by W. H. Hobbs). In the vicinity of Baraboo, Wis., acid porphyritic rocks occur of pre-Cambrian age, which correspond chemically with quartz-keratophyres. They ex- hibit under the microscope fluxion, spherulitic, poikilitic, and other structures of voleanic rocks, and are associated with volcanic breccias which show them to have their origin in asurface flow. The granites of Pike's Peak, Colorado, Epwarp B. MATTHEW (intro- duced by W. B. Clark). An areal and petrographical description of the granites composing the southern end of the Rampart or Colorado range, showing that great macroscopic variation may result while the micro- scopic characters remain monotonously uniform, A new intrusive rock near Syracuse, New York. N, H. Darron and J. F. Kemp. On the decomposition of the granite rocks of the District of Columbia, GEORGE P. MERRILL. Ancient physiography as represented in sediments, BAtEY WILLIS. Serpentine pseudomorphs after olivine, formerly called quartz-pseudomorphs, Middlefield, Mass. B. K. EMERSON. Skeleton erystals of salt which have been called chiastolite and later spinel, from the Trias, Westfield, Mass, B. K. EMERSON. Radiating puckering of corundum crystals around allanite, Pelham, Mass, B. K. EMERSON. THE AMERICAN GEOLOGIST, Vol. XV., Plate III. (iis Ua AMERICAN GEOLOGIST. VoL. XV. FEBRUARY, 1895. No. 2. GEORGE HUNTINGTON WILLIAMS. 1856-1894. { Portrait. ] Itaque adolescentes mihi mori sic videntur, ut cum aquae multitudine flammue vis opprimitur.—-Caro. The student of organic nature, busied with the various forms under which life has manifested itself, frequently meets with phases of individual growth, among the living or in the earth’s catacombs, which show that one creature may pass through its developmental changes more rapidly than its fellows, span- ning structural chasms, leaping vales and sealing hights which others of its race must plod slowly and traverse with weary effort. In intellectual growth is the faithful parallel of such physical acceleration of development which the Greeks idealized in their concept of Athene, full-grown and accoutered at her marvelous birth; equipped for war, not robed for peace. The geniuses of science, “standing on the mountain-top and catching the first rays of the rising sun,” pregnant with new views of nature, have realized that the path to success must be hewn out with labor demanding the utmost of their equip- ment. Experience has written nothing more indelible than that for the loiterer, the dreamer, the man of leisure there is mo niche in science. In the death of professor Williams, who was a man of gen- ius, of intellectual prowess and an unremitting laborer, it is difficult to fully apprehend the loss which has fallen to geo- 70 The American Geologist. February, 1865 logical science in America. As the aged Cato is made to say, this life has been quenched, not permitted to burn out. At the very threshold of his prime, with all his powers symmet- rically ripening, and in the promise of a future glorious to himself and the sciences he loved, he is stopped. The pang is such as rent the heart at the too early departure of Roland D. Irving and H. Carvill Lewis. American geology is now called to mourn not simply be- ‘ause one of its workers has fallen by the way, but in that it has lost that rare product among its devotees, a well-rounded man of broad culture, wide ‘interests and generous instincts, an investigator of astuteness and notable success, a teacher of magnetic fervor, a speaker of polished fluency and trenchant aptness. It is a loss we could ill afford, for which there seems now no compensation, from which none can reap a benefit and all suffer only bereavement. The key to the mystery is in the keeping of heaven. Professor Williams died of typhoid fever on the twelfth of July last, at his childhood’s home in Utiea, N.Y. During the scorching days of early summer, while in the field upon the Piedmont plateau of Maryland, he drank freely of a germ- poisoned well. His system, tired and exhausted by the labors of the academic year, gave way to the attack which followed. He was born at Utica, January 28th, 1856, and was, hence, in his thirty-ninth year. His father, Robert S. Williams, a prominent citizen of that city, a man of substantial and en- nobling tastes, surrounded his three children, of whom our lamented friend was the eldest, with the refining influence of such interests, coupled with sturdy virtues drawn from a long line of Puritan heritage. As the writer knew it fifteen years ago. it was a home whence emanated only inspirations of the good, the beautiful and the true, where gentler influences reigned and where a mighty and well-selected library cast an irresistible charm. No one could have held a livelier appreciation of such early advantages than did Williams himself, and while he accounted the lack of them in another no fault or necessary obstacle to success, he was quick to see that it was not without signifi- ‘ance. Circumstances which would have left many another less keenly alive to the need of an active, vigorous employ- George Huntington Williams.—Clarke. 71 ment, were to him a wholesome stimulus toward the best which life could afford. He was of a fine nervous temperament, which, if it prevent- ed a high degree of physical robustness, nevertheless infused both body and mind with activity. To many who knew him well it was a source of surprise that he endured so sturdily the often arduous strain of geological field work, and that it ever became to him a means of bodily repair and refreshment. Yet it was his mind that was normally and by nature more richly endowed than his body. During his early training in the public schools of Utica, terminating with his graduation from the Utica Free Acad- emy, he left traces all along of the first degree of excellence. In the autumn of 1874 he entered Amherst college. Here he showed the same proficiency in all lines of academie¢ work, loving and excellent in the languages and their clas- sics, stout in mathematics; the two essential ingredients of the first half of sueh a course. The former kindled a flame which was never allowed to die, and to these accomplishments must be due in no small degree, his broader and more delight- ful tastes. T am not aware that Mr. Williams had manifested any es- pecial aptitude for natural science during his boyhood; a re- spect ip which he was like many who have attained eminence as investigators and philosophers in this field of knowledge. The rigors of his preliminary training and earlier college course may have afforded no opportunity for the development of such tastes, and the scientific instinct was dormant until he came into contact, in his junior year, with that devoted teacher, professor B. K. Emerson. I recall his enthusiastic devotion to zoology (asubject which at that time came within the scope of professor Emerson's work); which seemed for him a door opening into a new world of interest. And when he touched the living rock and had become thoroughly enamored of geology, his fondness for its zoological side long clung to him. Being graduated in 1878, a portion of the following year was spent at Amherst in post-graduate work. Petrography was then a virtually new science in this country. Zirkel, of Leipzig, had aroused an interest in the microscopical study 12 The American Geologist. February, 1895 of rock-masses by his work for the United States Geological Survey when under the direction of Clarence King (1876), but there were then few American students in Germany im- bibing this new knowledge, and as few at home to whom Zir- kel’s work appealed. In 1879 there were probably not a dozen men here who were making serious efforts in this new depart- ure, but of these professor Emerson, alive to every phase of his science, was one. Mr. Williams’ interest was enlisted un- der these influences, and he was led to seek, the following year, the well-springs of such knowledge at G6ttingen and Heidelberg. Meanwhile, however, he returned for a_ brief period during the spring of 1879, to Utica and taught vari- ous sciences in the academy which he had left five years be- fore. Though in this capacity but for two or three months, he infused such a degree of enthusiasm in his pupils for every subject he touched upon as to render the writer’s task as his successor a difficult one. Emerson had graduated at Gottin- gen during the life-time of that versatile geologist, von See- bach, and to G6ttingen he naturally sent his pupil. There Ehrenberg, thirty years before, had turned the microscope upon the rocks, searching for their minutest organisms; von Waltershausen had done his immortal work on voleanoes, and Klein, now of Berlin and the foremost of physical mineralo- gists, was then lecturing. Here in the winter and summer semesters of 1879-80 Williams heard these lectures by Klein and those by Hubner in chemistry. The next year he changed to Heidelberg, where was and is Rosenbusch, a name which in- creasing numbers of Americans delight to honor, and there was begun a friendship between instructor and pupil which death alone could interrupt. After two years of work, prin- cipally with this inspiring man, he went up for his examina- tion in December, 1882, achieving his degree with honor. Upon too many of the young Americans who throng the German universities the glamor of the doctorate exerts a pal- pably unwholesome influence. The title here passes for more than its face value and, unhappily, it matters little whence it comes. When a well-directed public sentiment shall have re- stored to its proper dignity the now disordered and cheapened title, professor, the doctorate may resume its appropriate sub- sidiary place. With Williams the attainment of this degree George Huntington Williams.—Clarke. 73 was but the terminating incident of his course and the title was never unduly paraded. Returning to his home directly upon its accomplishment, he found himself situated as many others have been, with abun- dant opportunity to find something to do. At this critical period in the life of every young man, when the first serious step in his career has to be taken, Dr. Williams did not find his way laid open for him by outside influences; the writer recalls his disappointment at the failure of anattempt to con- nect himself with the work of the Smithsonian Institution. Soon, however (March, 1883), he obtained a fellowship-by- courtesy at the Johns Hopkins University, at Baltimore. It was not such a position as a young man not without supple- mentary resources could afford to accept, nor was it, of itself, quite to the level of Dr. Williams’ hopes, although it was to prove the stepping-stone to his most successful career in that institution ; for in 1884 he was advanced to the title of Asso- ciate, becoming thereby a member of the academic staff; in 1885 he became Associate Professor, and in 1892, ordinary Professor of Inorganic Geology. When Dr. Williams entered upon his work at this institu- tion there had been no department of geology and the instrue- tion given had been of the most desultory sort, a little in mineralogy and lithology having been attempted in connexion with the department of chemistry. Upon him devolved the organization of the department, and the high efficiency which it has now attained is due almost solely to the vigorous pros- ecution of his conception of what such a department in such a university should be. He was quick to acknowledge the warm espousal of all his efforts by president Gilman. The out- put of his academic work as embodied: in his students has stamped a value upon it which cannot now, probably never can be estimated, but its success in the eyes of those who were watching him from positions of close association is expressed in the memorial minute adopted by the board of trustees and the academic staff of the university, in which they bear testi- mony to “his alert, inquisitive observation, the close judg- ment and sound reasoning which he brought to the interpre- tation of what he saw, his excellent power of statement, whether with voice or pen; his cultivated appreciation of lit- 74 The American Geologist. February, 1895 erature; the energy, hopefulness, enthusiasm which he carried into his work and imparted to his associates; his genuine in- dividual interest in his students; the friendliness and help- fulness of his relations to his colleagues and his readiness to coéperate in every worthy undertaking.” He who trains students insures his own immortality, Tbe young geologists, quick with the inspiration caught from in- tercourse with this man, will be his best and perpetual memo- rial. They are not many, his career was too short; but through them his elevating ideas and clear purposes for his science will not be lost. There is one phase of this career, the best of it, he himself would have said, that in which lay the poetry of his life,which must not be overlooked. This was his total and unreserved devotion to his home. It is the more fitting to mention this here as many of the readers of these pages have shared the hospitality and known the loveliness of that home. It was a spot where every geological worker was welcomed, whose en- tire resources were at the command of the scientific comer ; and, to the students, the point where they came into closest touch with the personality of the teacher. In 1886, Mr. Williams married Mary Wood, a daughter of the late Hon. Daniel P.=Wood, of Syracuse, N. Y., a man widely known for his accomplishments in law and statecraft, and whose appreciation of science was evinced, during his long career in the legislature of his state, by the generous and unflinching support which he accorded to the work of its geo- logical survey under professor James Hall. The marriage brought about one of those rare relationships in which the work of the man found at once its most appreciative codper- ation and support, and its most rigorous vritic, in the intel- lectual intuitions of the woman. The value of such compan- ionship, not alone to the worker, but to his work, is not often overestimated. In his peripatetic work she was often his companion, accompanying him among the hills of Maryland and upon his Norwegian trip with Prof. Rosenbuseh and Dr. Reusch; and in the study she was his first and acutest auditor. Three sons were born into this home, two of whom still live, one of them bearing his father’s name. It is not possible in this place to give an extended analysis George Huntington Williams.—Clarke. (6S) of professor Williams's published work; that may be reserved for another occasion and writer. Here its results and condi- tions are briefly summarized. During his university life in Germany, in the interval be- tween his semesters at Gottingen and Heidelberg, Mr. Wil- liams made a tour of southern and southeastern Europe, bringing back with him the materials for his first scientific publication, “Glaukophangesteine aus Norditalien,” which was printed in the Neues Jahrbuch fiir Mineralogie in 1882. This was followed in 1883 by his inaugural dissertation, pub- lished in the same journal, on the Eruptive Rocks of the vi- cinity of Tryberg in the Black Forest, an elaborate investiga- tion which elicited the applause of geologists best able to appreciate it. The work of a geologist is preéminently what his environ- ment makes it; henee with Dr. Williams’ return to America and the commencement of his work at the Johns Hopkins University his attention was directed to geological problems presented by the region about him. In 1884 he began a series of papers pertaining to the petrography of the vicinity of Baltimore, publishing two in that year and continuing them for nearly ten years. Twenty papers and maps published during this period may be regarded as pertaining to this sub- ject, and the outcome of his geographical location. Many of the briefer of these papers appeared in the University Circu- lars, a mode of publication in which the author evinced his patriotism for his patron institution, even at the risk of hid- ing his work from a great part of the interested world. But under the auspices of the United States Geological Survey, with which he became connected soon after his appointment at Johns Hopkins, he was enabled to elaborate his results in“ detail, publishing in 1886 an important bulletin (No. 28) on the Gabbros and associated Hornblende Rocks occurring in the neighborhood of Baltimore. In his Guide to the Crystal- line Rocks of Baltimore and vicinity, prepared for the meet- ing of the American Institute of Mining Engineers in that city in 1892, the geological map of Baltimore and vicinity, published by the University in 1892, the Baltimore sheet pre- pared in collaboration with Nelson H. Darton, for the Geo- logie Atlas of the United States, professor Williams was ena- 76 The American Geologist. February, 1895 bled to summarize the main results of his labors in that region. Immediately connected with this work was the series of highly important investigations upon the voleanie rocks of the South Mountain, published in 1892 and 18938, which demonstrated the existence in that region of eruptives in all respects like those of recent origin. Another valuable series of papers embraces those which pertain to the petrography, mineralogy and crystallography of his native state, New York, the materials for which were largely gathered during the intervals of his academie work. We find fourteen of these extending over a period of six years (1884-1890), among the more important of which are those relating to the petrography and contact-effects in professor Dana’s “Cortlandt Series” on the lower Hudson; and four papers on the serpentine dike at Syracuse, discovered by Van- uxem about 1840, but lost sight of for nearly a half-century after. The vacation periods of 1884 and 1885 were spent in northern Michigan and the results of his work there were ex- pressed in an exhaustive treatise on the Greenstone-schist areas of the Menominee and Marquette regions, published as bulletin No. 62 of the United States Geological Survey (1890). Among his other special papers we find one bearing on the geology of the island of Fernando de Noronha, two on the rocks of the Sudbury District, Canada, one on rocks from Alaska and another on the ecrystallines of the Andes. At the close of the London meeting of the International Congress of Geologists, in 1888, professor Williams joined his instructor, Rosenbusch, in a visit to the crystalline regions of Norway, under the guidance of Dr. Hans Reusch, whose in- vestigations upon areal metamorphism have made those re- gions famous. Though he produced but a single brief paper upon the results of this trip, yet its effects were undoubtedly far reaching upon his subsequent work. In all these papers his writing is characterized by its lucid- ity and incisiveness, its freedom from contentiousness and its generous tolerance of adverse opinion. ‘There was nothing bellicose in his composition and he never penned a polemic. The value of his services to his science cannot be estimated alone from these technical papers in his special field of activ- =~] Sas | George Huntington Williams.—Clarke. ity. He brought himself into contact with the intelligent public in several general expositions of the broader bearings of his interests, such as his two articles on the relation of the microscope to the study of the rocks, published in “Science,” and a more extended presentation of Some Modern Aspects of Geology, in the “Popular Science Monthly.” And of wider in- fluence as well as of standard importance is his ‘‘Modern Pet- rography,” published in 1886, as the first of a series of ‘““Mon- ographs on Edueation,” issued by Heath, of Boston. His “Klements of Crystallography” (1890), written to supply the needs of his own pupils, has become widely adopted in insti- tutions of higher education in America and is understood to have already passed through several editions. His mechanical ingenuity and adeptness were shown in his design for the petrographical microscope constructed by the Bausch-Lomb company and which has long been hatched upon the cover-page of this journal; and also in the inven- tion of a machine for cutting and grinding thin rock-sections, of which the motive power is electricity. Of this useful con- trivance he published a description in the American Journal of Science for February, 1893. Even to this young man the honors which beautify and crown success were beginning to come. He had been made a vice-president of the Geological Society of America, a corre- sponding member of the Geological Society of London and a member of the Mineralogical Society of France. Under the auspices of the Maryland board of managers of the World’s Fair Commission he was given charge of the preparation of the state book, and in conjunction with his associate, pro- fessor W. B. Clark, prepared the geological part of that work. Under similar auspices he served as one of the judges of award in the Department of Mines and Mining at the World’s Fair, and the last paper but one published by him was an account of the exhibits in mineralogy and petrography, which ap- peared in the GroLoaisr for May, 1894. Professor Williams’s early departure has terminated one of those truest lives which Dr. Holmes characterized as like a rose-cut diamond, with many facets answering to the many- planed aspects of the world about it; its influence elevating, its memory sweet. JoHN M. CLARKE. 78 The American Geologist, February, 1895 List oF THE PuBLISHED WorKsS OF PRor. GroRGE H. WiILLTAMs. (The main portion of this list is taken from the Bibliographia Hopkins- Zensis, issued in 1893. Glaukophangesteine aus Nord-Italien. Neues Jahrbuch fir Min., ete., 1882, I; p: 202! Die Kruptivgesteine der Gegend von Tryberg im Schwartzwald. Inau- gural dissertation. Ib., Beilage-Band II: pp. 585-654, 1885. The synthesis of minerals and rocks. Review of Fouqué et Michel- Lévy’s ‘Synthese des minéraux et des roches.’’ Am. Chem. Jour., V, p. 127. Relations of crystallography to chemistry. Am. Chem. Jour., V, p. 461. Barite crystals from DeKalb, N. Y. Univ. Cire., 29, March, 1884, p. 61. Preliminary notice of the gabbros and associated hornblende rocks in the vicinity of Baltimore. Ib., 80, April, 1884, p. 79. Note on the so-called quartz-porphyry of Hollins Station, north of Baltimore. Ib., 32; July, 1884, p. 131. On the paramorphosis of pyroxene to hornblende in rocks. Am. Jour. Sci., XXVIII, pp. 259-268, October, 1884. Noticeof J. Lehmann’s work on the origin of the crystalline sehists. Proc. Am. Assoc, Adv. Sci., XX XIII, p. 405. Review of J. Lehmann’s *‘Entstehung der altkrystallinen Schieferge- steine.”’ Am. Jour. Sci., XXVIII, p. 392. November, 188+. Dykes of apparently eruptive granite in the neighborhood of Balti- more. Univ. Cire., 38, March, 1885, p. 65. The microscope in geology. Science, V, March, 1885. Hornblende aus St. Lawrence Co., N. Y.; Amphibol-anthophyllit aus der gegend von Baltimore: Ueber das Vorkommen des yon Cohen als “Hudsonit’? bezeichneten Gesteins am Hudson Fluss. Neues Jahrbuch Hur Vi etce LSSo yn les ps allay Cause of the apparently perfect cleavage in American sphene. Am. Jour. Sci., XXIX, pp. 486 490, June, 1885. A summary of the progress in mineralogy and petrography in 1855. Reprinted from the Am. Naturalist for 1885. The peridotites of the “Cortlandt Series’ near Peekskill on the Hud- sonriver, N. Y. Am. Jour. Sci., XNXXI, pp. 26-41, January, 1886. The gabbros and associated hornblende rocks occurring in the neigh- borhood of Baltimore, Md. Bulletin U. S. Geol. Survey, No. 28, Wash- ington, 1886; 78 pp. and 4 colored plates. Modern petrography. Tleath’s Monographs on Education, No. 1, 35 pp., Boston, 1886. On a remarkable crystal of pyrite from Baltimore Co., Md. Univ. Cire, 53, November, 1886, p. 30. The norites of the *‘Cortlandt Series’? on the Hudson river, near Peeks- kill, N. Y. Am. Jour. Sci., 3, XXNIII, pp. 135-144 and 191-199, Febru- ary and March, 1887. On the chemical composition of the orthoclase in the Cortlandt norite. Ib. ‘p. 243: George Huntington Williams.—Clarke. 79 On the serpentine of Syracuse, N. Y. Science, LX, p. 232, March 11, 1887. . On the serpentine (peridotite) occurring in the Onondaga salt-group at Syracuse. N. Y. Am. Jour, Sci., XXIV, pp. 187-145; August, 1887. Holocrystalline granite structure in eruptive rocks of tertiary age. (Retiew of Stelzner’s ‘‘Beitrage zur. Geologie der Argentinischen Repub- Hikee)e Tbs. SOONG ps Slo; Avril, 1887. Notes on the minerals occurring in the neighborhood of Baltimore. Baltimore, 1887, 18 pp. Note on some remarkable crystals of pyroxene from Orange Co., N. Y. Am. Jour. Sci. XXXIV, p. 275, October. 1887. Rutil nach Ilmenit in verandertem Diabas. Pleonast (Hereynit) in Norit vom Hudson-Fluss. Perowskit in Serpentin (Peridotite) von Syra- cuse, N. Y. Neues Jahrbuch fur Min., ete., 1887, LH, pp. 265-267, On a new petrographical microscope of American manufacture. Univ. Circ., 62, p. 22, January, 1888; Am. Jour. Sci., XX XV, p.114, February, 1888. On a plan proposed for future work upon the geological map of the Baltimore region. Univ. Cire., 59, p. 122, August, 1887. Progress of the work on the Archean geology of Maryland. Ib, No. 65, p. 61, April, 1888. The gabbros and diorites of the ‘‘Cortlandt Series’? on the Hudson river near Peekskill, N. Y. Am. Jour. Sci., XNXNXY, p. 438-448, June, 18838. The contact-metamorphism produced in the adjoining micaschists and limestones by the massive rocks of the ‘Cortlandt Series’* near Peekskill, N. Y. Ib., XXXVI, pp. 254-269, plate VI, October, 1888. Geology of Fernando de Noronha. Part HI. Petrography. Ib., XXXVI, pp. 178-189, March, 1889. On the possibility of hemihedrism in the monoclinic crystal system, with especial reference to the hemihedrism of pyroxene. Ib.,. NNXVIII, pp. 115-120, August, 1889. Contributions to the mineralogy of Maryland. Univ. Cire., 75, p. 98, September, 1889. Some modern aspects of geology. Popular Science Monthly, Septem- ber, 1889. Note on the eruptive origin of the Syracuse serpentine. Bulletin Geol. Soc. Amer., I, p. 533. Geological and Petrographical observations in southern and western Norway. Ib., pp. 541-553. Celestite from Mineral Co., West Virginia. Am. Jour. Sci. NNXIX, pp. 183-188, March, 1890. Same reprinted in German in Zeitschr. Kryst. u. Min., XVIII, p. 1, 1890. On the hornblende of St. Lawrence Co., N. Y., and its gliding planes. Am. Jour. Sci., XX XIX, pp. 352-358, May, 1890. The non-feldspathic intrusive rocks of Maryland and the course of 80 The American Geologist. February, 1895 theiralteration. First paper. The original rocks. Am Grouoerst, July, 1890, VI, p. 35. Elements of crystallography for students of chemistry, physics and mineralogy. New York, H. Holt & Co.; 8vo, 250 pp., 383 figures and 2 plates. The greenstone-schist areas of the Menominee and Marquette regions in Michigan. Bull. U.S. Geol. Survey, No. 62, 241 pp., 29 figures and 16: plates. Washington, 1890. The silicified glass-brecciaof Vermilion River, Sudbury district. Bull. Geol. Soc. Amer., IT. p. 138. The petrography and structure of the Piedmont plateau in Maryland. Ib., pp., 801-318. Anglesite, cerussite and sulphur from the Mountain View lead mine, near Union Bridge, Carroll Co., Md. Univ. Circ., 87, April, 1891. Octavo, reprint. Anatase from the Arvon slate quarries, Buckingham Co., Va. Am. Jour. Sci., NUIT, p.431, November, 1891. Notes on the microscopical character of rocks from the Sudbury min- ing district, Canada. Appendix I to Dr. R. Bell’s paper on the Sudbury mining district. Rep. Geol. and Nat. Hist. Survey of Canada, 1888-1890, IF, pp. 55-82. Notes on some eruptive rocks from Alaska. Appendix to Prof. H. F. Reid’s paper on the Muir glacier. Nat. Geog. Mag.. IV, pp. 63-74. Geological excursion by University students across the Appalachians in May, 1891. Univ. Circ., 94, December, 1891. A university and its natural environment. Address before the Johns Hopkins University. Ib., 96, March, 1892. Crystals of metallic cadmium. Am. Chem. Jour., XIV, p. 274. Geology of Baltimore and vicinity. Part]. Crystalline rocks. Guide- book for Am. Inst. Min. Engineers, Baltimore, February, 1892, pp. 77-124. Geological map of Baltimore and vicinity. Published by the Johns Hopkins University, G. H. Williams, Editor, October, L892. The voleanie rocks of South Mountain in Pennsylvania and Maryland. Am. Jour. Sci... NLIV, pp. 482-496, December, 1892. Reprinted in ‘‘Sci- entific American,’’ January 14, 1893, and abstract Univ. Cire., 108. The microscope and the study of the crystalline schists. Science, Jan- uary 6, 1893. A new machine for cutting and grinding thin sections of rocks and minerals. Am. Jour Sci., XLY, p. 102, February, 1893, and Univ. Circ., 103. Maps of the territory included within the state of Maryland, especially the vicinity of Baltimore. Univ. Cire., 108, February, 1893. On the use of the terms poikilitic and micropoikilitic in petrography: Jour. of Geology, I, No. 2, p. 176, February, 1893. Piedmontite in the acid voleanie rocks of South Mountain, Pennsyl- vania. Am. Jour. Sci., NUVI, p. 50, July, 1893. Crystalline rocks from the Andes. Jour. of Geology, I, No. 4, p. 141, 1893. The Geologic History of Missour’.—Winslow. 81 Johann David Schoepff and his contributions to North American geo- logy. Bull. Geol. Soc. Amer., 1893, pp. 591-594. Mines and minerals of Maryland. Maryland World's Fair Book, 1893. Piedmontite and Scheelite from the ancient Rhyolite of South Mount- ain, Pa. Am. Jour. Sci., July, 1893, vol. XLVI, p. 50 Recent contributions to the subject of dynamo-metamorphism. Jour. of Geology, vol I, p. 580. 1893; review. The distributiou of ancient volcanic rocks along the eastern border of North America. Jour. of Geology, vol. Il, No. 1, pp. 1-31, pl. 1, 1894. Sixth annual excursion of the Geological Department. Uniy. Circ., 109, p. 26, February, 1894. The Columbian Exposition. Notes on various exhibits relative to mineralogy and petrography. Am. GEoLoGtst, vol. XIII, No.8, pp. 345- 353, May, 1894. On the natural occurrence of Lapis-Lazuli. Univ. Cire., 114, p. 111, July, 1894. Sixty-eight reviews of American geological and petrographical liter- ature, published in the Neues Jahrbuch fiir Mineralogie, Geologie und Palaeontologie, between 1884 and 1890. The Williams family, tracing the descendants of Thomas Williams, of Roxbury, Mass. N. Eng. Hist. Reg., 1880. Reprinted for private dis- tribution. and \W. M. Burton. On the crystal form of metallic zinc. Am. Chem. Jour., XI, No. 4. and Wm. B. Clark. Geology and mineral resources of Maryland, with geological map. In the book ‘‘Maryland,’’ published by the State Board of Managers for the World’s Fair Commission, July, 18938, and N. H. Darton. Baltimore Atlas Sheet. Geologic Atlas of the United States, U.S. Geol. Survey. THE GEOLOGIC HISTORY OF MISSOURI.* By ARTHUR WINSLOW, St. Louis. Mo. Introduction.—Yhe geology of Missouri has now been studied for a period of half a century. Though much detail yet remains to be worked out, its general features are known; the periods to which the formations belong have, in the main, been determined and their structure is understood. We are, therefore, in a position to narrate with some confidence many facts of the geologic history of the state. In the pres- ent state of our knowledge of such a complicated subject, it is, however, not always possible to make positive statements. But, in such eases, much can be said which is at least sug- *Read by title at the Brooklyn meeting of the Geological Society of America, Aug., 1894. 82 The American Geologist. February, 1895 gestive and which may be profitable in directing future inquiry. Before proceeding to the subject proper a few xemarks will be in place concerning the classification of the rocks and the distribution of formations. In the following table is present- ed a scheme which is the outcome of recent work by the writer and associates of the State Geological Survey. The names and the divisions of this scheme differ in several respects from those previously published. We will not attempt here to give the reasons for these changes. They will appear in the forthcoming report of the Geological Survey on the lead and zine deposits of the state, now being printed. We shall use this classification and nomenclature in the following discussion. Distribution.—The Archean rocks of Missouri oceur exelu- sively in the southeastern part of the state. They are confined principally to an area of about 2,000 square miles, situated less than 80 miles south of St. Louis and less than 50 miles west of the Mississippi river. They consist essentially of porphyries and granites, composing a group of hills named the St. Francois mountains. The Lower Silurian (and possible Cambrian) rocks of the Ozark stage surround these Archean crystallines on all sides. They extend eastward nearly to the Mississippi river, north- ward to the Missouri, excepting in the vicinity of St. Louis, westward to within 50 milesof the Kansas line, and southward beyond the border of the state. They consist principally of magnesian limestones and sandstones. The Trenton and higher Lower Silurian formations are seen to overlie the Ozark formation only over a small area south of St. Louis and along the Mississippi river. Over the whole western portion of the state they are absent. They consist mainly of magnesian limestones. Upper Silurian strata are absent in the state, with the ex- ception of a few exposures in the east, adjacent to the Missis- sippl. Devonian rocks are sparsely represented in the eastern and northeastern portions of the state. Neither the thickness or area is anywhere great. A few isolated patches are found along the Missouri river, on the north side. In the west the The Geologic History of Missouri.— Winslow. CLASSIFICATION OF Mrssourt Rocks. 85 SOUTHWEST | SOUTHEAST CENTRAL MIssourRl. MISSOURI. MISSOURI. Upper. Coal Middle, Measures.| J] ower. Carbon- Kaskaskia. i , Lower St. Louis. Cala 3 |) ——$——— ——— iferous. Augusta. Kinderhook. | Hetilton. = | Onondaga Devonian. Eureka shale.| ~|imestone. Absent. Oriskany sandstone. Lower Helderberg. peer Absent. Niagara. Absent. Cape Girard- eau limestone. Hudson River shale. Tr Absent. Receptaculites Trenton. limestone. Absent. Trenton lime- stone. Joachim lime- stone. Roubidoux or ee sD accharoidal SiJurian. Crystal City sandstone. limestone. S Jefferson % | Potosi So) reine: nls = : = | limestone. | 5 “! White River |-= e Moreau ower : limestone, in- | , ~| = | sandstone Silurian. Ozark. cluding sev- ‘3 |= Ean ee eral beds of | 2 o | Osage sandstone. # | St. Joseph) 3 | limestone. cel MICS TONES) | ies | eee ates oe es 5 Cole Camp D | g | sandstone. La Motte lalproctor sandstone, limestone. Tron Mountain conglomerate. Cambrian. Doubtfully present. Algonkian. Pilot Knob beds. Archean. Porphyries and Granites of the St. Francois mountains. By Southwest Missouri is meant the western half of the state south of the Missouri. By Southeast Missouri is meant the eastern border of the state, south of the Mis- souri river, astrip about 50 miles broad. By Central Missouri is meant a strip about 50 miles broad, extending south from the Missouri river and lying between the southeastern and southweste rn districts. 84 The American Geologist. February, 1895 only Devonian rock (and this is doubtfully assigned to that age) is the Eureka shale, which is a stratum of black shale, varying fron 10 to 60 feet in thickness. It is found only in the extreme southwestern corner and there lies between the magnesian limestones of the Ozark stage and the Lower Car- boniferous rocks. Lower Carboniferous limestones and shales in great thick- ness are exposed over wide areas in the northeastern, central and western sections. They are generally in direct contact with beds of the Ozark stage. Sometimes, Devonian and higher Silurian strata intervene. The Coal Measures cover the whole northwestern, and broad strip in the southwestern portions of the state. They rest unconformably upon the Lower Carboniferous and extend beyond the limits of the latter formation. From this brief description it will be seen that the rocks of the different formations surround the Archean nucleus in a somewhat concentric form, though the sequence is broken in many places. This center is geologically a quaquaversal arch which has been raised and depressed several times. It is well known as the Ozark uplift. With these explanatory remarks we will now proceed to de- scribe the conditions which prevailed and the noteworthy events which took place during the different geologic eras or periods, beginning with the oldest. The Archean Era.—The Archean land surface of this por- tion of the globe must have been a very extensive one. At the beginning, at least, it probably spread well beyond the state limits. Its original outlines are at present undefinable, but, from the fact that the rocks of the present land must origi- nally have been derived in large part from these pre-existing Archean rocks, the mass exposed to denudation must have been very great. The Algonkian Era.—Before the end of the Algonkian era the Archean land surface of Missouri was entirely submerged. Whether this condition was reached during the late Algon- kian or during the early Algonkian we are unable to say. Probably there was a gradual lowering, such that complete submergence was not accomplished till towards the end. The extent of the Algonkian deposition is unknown and undeter- The Geologic History of Missouri.—Winslow. 85 minable. The only considerable exposure at present is the small patch on Pilot Knob. Possibly, rocks of the same for- mation are represented under the surrounding Paleozoic beds ; of this, however, there is no positive evidence, excepting, per- haps, in the record of a deep drill hole put down at Raytown, south of Kansas City. Here the base of the Paleozoic rocks was reached at a depth of 2,480 ft., and below this 36 ft. of crystalline rocks were penetrated. A specimen of this core examined by the writer, is a highly micacious schist, com- posed almost entirely of black mica. It is different from any rocks found in the Archean of the southeast and is more like rock referred to the Algonkian elsewhere. A drill hole at the St. Louis insane asylum 3,600 ft. deep, one at Carthage about 2,000 ft. deep and one near Sullivan, Franklin county, about 1,200 ft. deep, all reached crystalline rock. In the first, the rock is reported by Prof. Broadhead to have been granite ; in the second, Mr. J. D. Robertson determined the specimens to be porphyry; in the third, drillings examined by the writer consisted of pink feldspar and quartz like those of the Ar- chean granites. These last results, therefore, are opposed to the existence of Algonkian rocks at the respective localities, though such may have existed there in the past and have since been removed. The Cambrian Period.—During the Cambrian period, Mis- souri was probably a land surface, at least in large part. This conclusion is reached: first, because there are either only a very limited thickness or no rocks of this age in the state; and second, because there is evidence of a very great erosion between the Algonkian era and the Silurian period. During this interval all but the small Pilot Knob patch of Algonkian beds were entirely removed and the underlying Archean gran- ites and porphyries were deeply trenched. It is to this date that we must assign the original seulpturing of the hills and valleys of southeastern Missouri, around and between which the Silurian limestones are now spread. To have eroded this great massof resistant Algonkian and Archean rocks must cer- tainly have taken a long period, even geologically considered. Possibly, thiselevation and erosion may have begun well back in the Algonkian time and have continued through the Cam- brian. This would make the maintenance of the conditions 86 The American Geologist. February, 1895 of emergence still longer and would make the almost com- plete removal of the Algonkian beds more readily understood. It is, however, possible that this land surface was only about the St. Francois mountains, and that Cambrian beds now exist in the deep basins away from here, especially to the northeast. Of this we have no local evidence to present, how- ever. The Silurian Period.—Karly in the Silurian, or possibly before the end of the Cambrian, well nigh the whole of Mis- souri must have been submerged and the deposition of the rocks of the Ozark stage was begun. Before the end of the Lower Silurian epoch it is probable that a re-elevation took place, exposing a large land surface to erosion. We conclude this because we are of the opinion that the Trenton and- higher Silurian strata never covered the whole Ozark area. There is no positive evidence of their former existence there. The absence of any remnant or outlier, and also the absence of these rocks between the Devonian and Lower Silurian for- mations of the extreme southwest are both facts opposed to the idea of this extension. The same applies to the Crystal City sandstone, though to a less degree. Lithologically this formation has more the character of a fluvial or estuary de- posit than of a wide spread sandy stratum. ‘The flow struc- ture or false bedding frequently exhibited is in harmony with this idea. The unconformity with underlying rocks, exhib- ited at many localities, shows that an erosion period preceded its deposition. At the end of the Silurian period most of southern Missouri or of the Ozark uplift was, without much doubt, well above water level. The Devonian Period—appears to have been essentially one of emergence in southern Missouri and to have remained so throughout. As with the Trenton and Upper SiJurian strata, there is no positive evidence, in the nature of outliers or re- siduary products, of the former presence of Devonian rocks over the Ozarks. Along the western border of the uplift the formation is also absent between the Ozark stage of the Lower Silurian and the overlying Lower Carboniferous strata, with the exception of where the Eureka shale comes in, in Me- Donald county. Similarly, they are absent along most of the The Geologic History of Missouri.m—Winslow. 87 eastern border, while along the northern border they oceur in limited patches, as if filling estuary-like depressions in the margin of an old land mass. This, therefore, we also class as a long erosion period, during which the Ozark rocks were ex- tensively denuded and perhaps even base leveled. During this interval the inequalities of the surface were produced which caused the oft observed unconformity of contact with the later deposited Lower Carboniferous beds. The Lower Carboniferous Epoch—At the beginning, and possibly before, the waters crept in over the uplift, seizing hold of the insoluble products of sub-aérial decay of the Silu- rian rocks to make shales, sandstones and chert conglomer- ates, filling in great erosion depressions with these and dis- solving the lime to assist in the formation of the Lower Car- boniferous limestones. This movement continued doubtless for a long time, though at a very slow rate. From the fact that fragments of Lower Carboniferous chert are found over the surface so far into the interior as Howell and Crawford counties, the waters must have reached that far. Whether they extended beyond this, to the Archean area, is doubtful No remains of these rocks are found there. It is probable however, that estuary-like arms from the Illinois Carbonif- erous reached westward into Missouri. It is further probable that the submergence of the central portion of the Ozarks did not last long, that only a thin stratum or somewhat isolated patches of rock were formed which were quickly and readily removed later. The mass of the rocks were doubtless deposited around the flanks and ran out to a feather edge toward the interior. Well before the end of the Lower Carboniferous the uprise began and continued, probably, until almost all of southern Missouri became a land surface. Ter eee s pe Otek ee 2 ; ‘ » pe 7 . ‘ f ‘ ie 4 he a haa The Second Lake Algonquin.—Taylor. ELT. , actly on astraight line. A straight line was therefore drawn through Mackinae and Houghton and this line was taken as the first or fundamental isobase. On a comparison of the re- maining points of observation off CC it was found that they could not be better represented than by straight lines parallel to CC. In this way BB and DD were constructed. The main part of the Nipissing plane so determined lies mostly between the isobases BB and DD, and it extends from Mackinae to Houghton. ‘This area is 250 miles long and about 100 miles wide, if we count the distance to Gladstone and Fayette which lie south of BB. From the points observed in this principal area the place of the node line AA was calculated and its place so determined, is approximately parallel with the other lines. From this principal area, which comprises carefully measured parts of the Nipissing beach in each of the three upper lake basins, the Nipissing plane was produced in all di- rections and its relation to the various littoral features of the remaining parts of the lake basins were noted. Some of these will be described in detail later on. The mean rate of rise in the Nipissing plane from Petoskey to Sault Ste. Marie is little more than 64 inches per mile. It will thus be seen that a differ- ence of five feet in altitude is equivalent to nearly ten miles difference in the place of an isobasal line. Almost any of the measurements may be in error as much as five feet either way. It follows that the isobases may be ten miles in error either way atany place. But the extension of the measured plane over so wide a space, and especially its very close agreement with facts which point to its extension over several times that space in other parts, reduces the probable error very much and increases the value of the isobases. Facts in widely sep- arated places prove that these lines are certainly not far out of place. Points of observation not situated on a line gener- ally show an altitude which agrees with an extension of the plane between or beyond thelines. There are a few points that appear to be exceptions. All but one, however, are within the limit of error. Marquette and L’Anse seem a little too high and Midland a little low. North Bay alone is wide of the mark, being 40 feet higher than the main plane pro- duced to that point. The rate of rise from Sault Ste. Marie to North Bay (transferred to M on the line EE) is nearly ‘ 118 The American Geologist. February, 1895 one foot per mile. In this case it must be assumed that the plane actually changes its attitude in that direction. The distances between the isobases, and the rise in feet from each to the next, are presented below in tabular form. Intervals. Miles Distance. Feet Rise. AVAU BON ISIBY, oo. eeucutaia estates coavet ei eles oder ole 45 25 BBE O GE, os tuiue mrauccr cleats pike Cisne cyclorernces 36 20 COR DID ER Cea ace see ee Oe ee en 45 25 ID) OB anS)) Oe ear ee vege Oe Geary oy 4 95 "490 RGA ES SIDE Fe sot elie ae ToC gt eg tS eg 126 70 (AGA So UH) Seo ee Cae ee See tee Rate ewe. 221 160 The apparent discrepance from a true plane between AA and DD are all entirely within the limit of error. There is no reason to infer, for instance, that the 25 feet in 45 miles from CC to DD represents a real increase in the rate of rise. Prof. Lawson’s levelling makes the beach at Sault Ste. Marie 49 feet above lake Superior, while that at Mackinac may be a little more than 45 feet above lake Huron, in which case the appar- ent extra rise would vanish. It is a fortunate circumstance that three of the best points of observation, viz.: Sault Ste. Marie, Mackinac, and Petoskey, are almost exactly on LM, the line of maximum rise of the main plane. Even after allowing lib- erally for such deviations as appear to be present, the fact still remains that the most remarkable feature of the Nipis- sing plane is its very close approach to uniformity over an extent of more than 700 miles or from Duluth to Buffalo. Following is a table of the altitudes of the Nipissing beach at the principal points of observation, all measured in feet from the Huron plane: Pievlslamads Gawsomyepvacescersem cree eee erere oki cee ete 64 ? INothiendRortacemakescanaleecnceem see eerie cere 50 | oka M0) | eric der Re ae Cian Bike nein oa Omitcosaie ta dca Gass i 45 Havel CHELAR DOL a cighia'a is hate, ale alae cde totem re keene teretete aeiceaiee sae (0) IDE WCRI WE) Ball ier nia pee MrnA A im niAC a oak OU niga pepo £ 60 AT PASTS Os Seatiix's oresda ts ss ver Su5h a/ she Sue loenere sites ke eRe eter rar aeroeetor: 37 SIE W XO Db Ve Ke cee ieee Seer Pranic orn eAPHG A Go DIBA Ob Ge 45 OG Mtn Stier tevsrteys ieccastie acetone ate stares ener omer Tea 45 Salt SteseMari ene cet va creer ils, ora oe clatorevsve eicearaes enotorotene ake nena aed 70 MachkinackandsGrosi@aipyrciciis sii cretckesa cre tereeterteielecerraiereret 45 Hayette anduGiladstomes saci. ccieverct cite se rcisteiereerecicr 20 Petoske yi ieociscrne leev-ts sucisy ns? ses ohersho el sreatae nletenemoheteretens tercteds topeiel 25 Worthington, Ont. eipprox.a. sce eee nite eieer ci OU North Bay eicacieaeme nc ase cle teeie ie stoner eet iereeetetsic teletrs 160 AY DUCES WY0 ie re Seis SO ein year Sate it bd Sob lA praia ieio GO ORG 50 The Second Lake Algonquin.—Taylor. 119 Wwebridge (Spencer)............ 5 SES NILES PCMGEN) sncye%s, vies 2. blaceei tig nae cee ee Ae The node line passes a little south of Buffalo and a little north of Duluth. Near the center of the map its direction is N. 63° W. and the direction of maximum rise of the deformed plane at right angles to this is therefore about N.27° E. But at the sides the meridians converge slightly northward. This agrees closely with the direction of the conjectural isobases for the region of Georgian bay as shown in De Geer’s map of recent changes of levelin Eastern North America.* Lake Su- perior is 20 feet higher than lake Michigan, and the node of the Nipissing plane should therefore be on a line about ten miles south of the isobase BB. This node is shown by the short line FF which passes through the outer Apostle islands and strikes the north shore at Beaver Bay. In his article on the Algonquin beach, Dr. Spencer says that Minnesota point at Duluth shows that the water there has been backed up to a higher level recently.t This view is undoubtedly correct, and the opinion expressed by me in discussing this feature in the fourth paper of the above list needs to be modified accord- ingly. The long Chaquamegon point near Ashland, Wiscon- sin, is another recent littoral bar of the same kind, and it is curious to note that both of these lie on the south side of the caleulated nodal line of the Nipissing and Superior planes and that there are no other great littoral bars like them on the shores of thislake. This correction points to the conclusion that the Nipissing plane rises from Duluth to North Bay about 165 feet, instead of 125 or 1380 as stated in the fourth paper. The isobase DD crosses Isle Royale and strikes the north coast of lake Superior about at Portage river, Isle Roy- ale has many shore lakes like Lac la Belle, cut off by littoral bars. There is good reason to believe that the Nipissing beach _is in its normal place on the north shore, as indicated by the projection of its plane from the southeast. And if it is there we cannot avoid the conclusion that the change which de- formed it also carried all the other higher beaches up with it. Yet professor Lawson, as pointed out in the latter part of the fourth peper, infers that there has been no deformation of the *Op. cil. 4*‘Deformation of the Algonquin Beach,”’ ete., page 19. 120 The American Geologist. February, 1895. lower beaches of that coast. But the methods which he used prevented the discovery of such deformation as may exist. By the projection of its plane from the south shore the Nipis- sing beach should be expected on the extreme northern shore at an altitude of 100 or 110 feet. | Zo be concluded. EDITORIAL COMMENT: An AmusInGc HRRoR. Our able and esteemed contemporary, Nature, has fallen into a rather amusing error in quoting an illustration from the first volume of the reports of the geological survey of Iowa. Prof. Calvin, in an illustration opposite p. 61, has represented the overhanging limestone at “the Cascade,” Burlington, 7 winter. The cascade is frozen and the ice hangs from the edge as long stalactites with a mass of stalagmitie ice at the bottom. Perhaps from want of familiarity with so wintry ¢ scene the writer in Nafwre has mistaken the ice for the lime- stone and adds words to that effect. Prof. Calvin says, “The limestone often stands out in overhanging cliffs over the softer Kinderhook beds,” but in Nature we read, ‘The lime- stone often stands out in overhanging cliffs over the softer shale beds beneath and gives the appearance of a cascade, as shown in the accompanying illustration, which is reduced from a plate in the report.” Regarding the report itself our contemporary adds the fol- lowing remarks, which from such a source are highly complhi- mentary : “The volume referred to in the foregoing note showed us that the publications of the Iowa survey were to be of a high character. The second volume goes to confirm this view. It is a description of the coal deposits of Iowa, by Dr. C. R. Keyes, and is a model of what such a report should be. With text running into more than 500 quarto pages, 18 full page plates of a high quality, representing interesting formations in connection with the Coal Measures, and over 200 figures in the text, the volume is an attractive handbook for the coal Editorial Comment. 1A miners of lowa. * * * We offer our congratulations to Dr. Keyes and the geological corps with which he is associ- ated.” E. W. C. THe Fossir FrsHes or Canon Crry, CoLorapo. A little more than two years ago, announcement was made by Mr. Walcott of the discovery of fish remains in a red sand- stone of lower Silurian age, near Canon City, Colorado. The specimens were widely exhibited to the paleontologists of this country and, at the meeting of the International Con- gress at Washington, were not only generously displayed, but the opportunity of examining the locality of their occurrence afforded to, and accepted by many of the visiting geologists. Dr. Otto Jaekel, of Berlin, who had done some refined work in the microscopic study of fossil fishes, was invited to make a close analysis of these remains, and in a recent review of Walcott’s paper entitled ‘“ Preliminary notes on the discovery of a vertebrate faunain Silurian (Ordovician) strata” (1892), he has made some interesting observations (Neues Jahrbuch, 1895, p. 162) thereupon. ‘The first glance at the remains in question,” he writes, “‘at once conveys the impression that they are much more closely related to Devonian than to any Silurian fishes as yet known.” Some of the scales are stated to undoubtedly belong to the //oloptychiida, other fragments are to be ascribed to the placoderms. ‘ The question is now this; whether these remains are really of lower Silurian age. Upon visiting the locality in 1892, many European geologists were, like myself, convinced that the stratigraphic relations at this place are not simple and readily made out, as the strata have been greatly dislocated by faults. So there seems to be at least a possibility that Devonian sandstones are lying be- tween those of lower Silurian age, although the immediate proximity of lower Silurian fossils in a petrographically sim- ilar sandstone and the absence of other Devonian fossils in the fish-bearing strata does not support such a suggestion, Still its possibility is strengthened by the fact that, if I am correctly informed, there are red Devonian sandstones in the neighborhood of Canon City, and its probability shown by the character of the fossils themselves.” Ti Me 122, The American Geologist February, 1895 REVIEW OFP\RECENT, GEOLOGICAL Wa EwA I Oeds: ¢ Ueber Porocystis pruniformis Cragin (? Araucarites wardi Hill) aus der unteren Kreide in Tevas; by HERMANN RAUFF (Neues Jahrbuch fiir Min- eral, etc,, 1895, Bnd I, pp. 1-15, pl. I.) Robert T. Hill was the first to notice, under the name Goniolina (1889) these peculiar spherical or ovoid bodies which, in 1893, he described in some detail as the cones of an araucarian, designating them as Arau- carites ? wardi. In the latter year also, Prof. F. W. Cragin, regarding the fossils as bryozoan, described them under the name Porocystis pru- niformis. Dr. Rautff’s analysis, based upon a few internal casts, sub- stantiates neither of these opinions, but indicates certain superficial similarities between the surfaces of such internal casts and representa- tives of the genus Receptaculites. ‘On the spherical form and mosaic structure of the surface we cannot place much weight. They are un- essential similarities, for Porocystis shares them with other and wholly distinct organisms. But we may ascribe some little value thereto, from the fact that bodies like the Receptuculitide are constructed of humerous homomorphic elements (Merones), each of which consists of a thiek- ened summit expanded into a plate and a longer or shorter radial, per- forated by an axial canal, and that these radials (So far as our observa- tions permit us to judge) swell at their proximal ends until they rest against and crowd one another. WRadials of quite similar form we have found in Receptaculites, as well asin some of the Ischadites.”’ The au- thor ventures no further opinion in regard to the structural portion of these fossils, leaving this determination contingent upon the acquisi- tion of more complete Material. Als ilo! (Se Ueber das Oberdevon der Ostalpen, IIT; Die Fauna des unterderonischen Ritfkatkes, 1. By rrrz Frecnu, with the assistance of I. LOESCHMANN. (Zeitschr.der deutsch. geol Gesellsch., vol. 46, pp. 446-479, pls. 80-87, 1894.) This is the first instalment of descriptions of the Devonian faunas of the Corinthian Alps, whose geology has already been carefully expounded by Prof. Frech in various numbers of these proceedings, and, more recently in book form; ‘Die Karnischen Alpen.’’ The species here described are largely gasteropods of various genera, out of 51 species, 37 belonging to this group. Their variety is interesting, if not remarkable, evincing, first, an abundant representation of the capulids (Platyceras and Platy- ostoma= Diaphorostoma, Fischer, 10 species and varieties) in harmony faunas; five examples of the , with other lower Devonian or ‘‘capulian’ Silurian genus Zremanotus (better Zrematonotus); typical forms of Bel- lerophon, of Bucanella and Oxrydiscus, with representatives of the genera, Pleurotomaria, Murchisonia, Triangularia (a new genus having the form ofa triangularly pyramidal Solarium) Huomphatus, Polytropis, Trochus, Loxvonema, Polytropis, Macrochilus, Philhedra, Horiostoma and Turbonit- ella. J. M. C. Review of Recent Geological Literature. 123 The American Tertiary Aphide, with «a list of the known species and ta- bles for their determination. By Samus. H. Scupper. (Thirteenth An. Rep., U.S. Geol Sury, Part II, pp. 341-866, with plates cr-cvr.) Thirty- two species of plant-lice. representing fifteen genera, all regarded as distinct from any now living, are found in Tertiary strata at Florissant in Colorado, Green River in Wyoming, and Quesnel in British Colum- bia. Though one might suppose, as the author remarks, that the deli- cate, gauzy texture of the wings and the softness of the bodies of these insects would scarcely permit their preservation in the rocks, they are so plentiful at the locality first named that it has yielded more than a hundred specimens which have been examined by the author. As a whole, these Tertiary genera and species differ most remarkably from those of the present day in the great length and slenderness of the stig- matic cell of the wings. In the plates the fore wings of all our known fossil species are figured on an identical scale, reversed when necessary to represent all of them as left wings. and with deficiencies in the out- lines and neuration supplied by conjectural dotted lines. Besides Ter- tiary Aphidie in Europe, two or three specimens of Mesozoic age have been found in England: but these mostly are allied to present genera, not haying the extraordinary features of the American fossil forms. W. U. Granites and greenstones: a series of tables for students of petrology. By FRANK RutieEy. (8vo, 48 pp.: London, Thomas Murby, 1894.) The first of the tables is a tabular classification of eruptive rocks, in which the essential minerals of each rock are placed with the name. Following this the various rock structures are defined, and a short description of each rock species is given, the description including not much more than its place in the scheme of classification, the structure and the essential, accessory aud secondary constituents. The last tables are determina- tive mineralogical ones; they differ from cther tables of this nature in that chemical formule and specific gravities are omitted, and the ta- bles are cleared of other matter which does not relate to simple micro- scopic investigation. This little book will prove useful to students and teachers; one of the features which especially commends it is its easil) accessible and concise descriptions of the various rock species. WU. SiG. On the banded structure of some Tertiary gabbros in the Isle of Skye. By ARCHIBALD GEIKIE and J. J.H Train. (Quart. Jour. Geol. Soc., vol. 50, pp. 645-659, pls. 26-28, Nov., 1894.) Banded structures are known in basic igneous rocks from several localities, perhaps the best developed instances being in the gabbros and anorthosites of the Adirondacks, of Canada, and of the Lake Superior region. In the gabbros of the Isle of Skye this structure, as shown by the descriptions and photographs which accompany the paper, attains a remarkable degree of perfection. These banded gabbros are coarse-grained rocks composed of pyroxene, plagio- clase, olivine and titano-magnetite; the banding is due to a variation in the relative proportions of these four essential constituents, the lighter 124 The American Geologist. February, 1895 colored bands being rich in feldspar, and the darker rich in the ferro- magnesian constituents and magnetite. There is noessential difference between the different bands as regards coarseness of grain, and*the in- dividual minerals interlock with each other across a junction line just as they do inthe central portions of the bands. It therefore seems im- possible to account for the banding by the successive injection of mag- mas of varying composition, and, as cataclastic phenomena have not been observed, the authors conclude that the cause which produced the banding must have operated before the crystallization of the minerals. They consider the banding as the result of a heterogeneous magma. The analogy between these banded structures in the deep-seated basic rocks and some of the bandings in the ancient gneisses, especially the Lewis- ian gneiss of northwestern Scotland, is clearly pointed out, and it is shown that the causes which produced the former may justly be con- sidered as applicable to the latter. ‘‘In view, however, of the undoubted evidence of secondary dynamic action in many regions, and in the ab- sence at present of any well established criteria by which we can in all cases discriminate between original and secondary structures, we are not yet in a position to define the exact limits within which the hypoth- esis of the intrusion of heterogeneous magmas is applicable to the ex- planation of the Lewisian gneiss.” This paper presents one of the many facts which, in recent years, have led most geologists to conclude that many of the parallel structures in the ancient gneisses are not necessarily due to original sedimentary deposition, but can be explained equally well, or better, on other hy- potheses; still, there remain some who find it difficult to consider band- ing in gneisses as anything but good evidence of a sedimentary origin for these rocks. U. S. G. RECEN®Y PUBLICATION: I. Government and State Reports. Proc. U. S. Nat. Mus., vol..17, No. 1002. Discovery of the genus Old- hamia in America, C. D, Walcott. Geol. Sur. of Alabama, Eugene A. Smith, State Geologist. Geological map of Alabama, with explanatory chart, 1894. Bull. No. 5, Illinois State Mus. Nat. Hist. New genera and species of Echinodermata, S. A. Miller and Wm. IF. E. Gurley, 53 pp., 5 pls., Dec. 20, 1894. Il. Proceedings of Scientifie Societies. Proc. Boston Soc. Nat. Hist., vol. 26, pts, 2-8, 1894, contains: Facetted pebbles on Cape Cod, Mass., W. M. Davis: Some typical eskers of south- ern New England, J. B. Woodworth: On the distribution of earthquakes in the United States since the close of the Glacial period, N. 8S. Shaler; The geographical development of alluvial river terraces, Rh. KE. Dodge; The preglacial channel of the Genesee river, A. W. Grabau; A speci- Correspondence. 125 men of Ceratiocaris acuminata Hall from the Waterlime of Buffalo, N. Y., G. W. Stone. TIl. Papers in Scientific Journals. Jour. of Geol., Sept.-Oct., 1894, contains: The Cenozoic deposits of Texas, E. T. Dumble; Outline of Cenozoic history of a portion of the middle Atlantig slope, N. H. Darton; The Metamorphic series of Shasta county, California, J. P. Smith; Superglacial drift, R. D. Salisbury. Amer. Naturalist, Oct., 1894, contains: The duration of Niagara falls, J. W. Spencer. Ottawa Naturalist, vol. 8, No. 6, Sept., 1894, contains: Notes on the “Quebec group,’ T. C. Weston; Notes on fossils from Quebee City, Can- ada, H. M. Ami. Canadian Record of Science, vol. 5, No. 8, contains: Description of two species of ammonites from the Cretaceous rocks of the Queen Char- lotte Islands, J. If. Whiteaves; The World's Geological Congress, H. M. Ami. Amer. Jour. Sci., Noy., 1894, contains: Origin of bitumens—a_ retro- spect, S. F. Peckham; Study of the cherts of Missouri, EK. O. Hovey; Jopper crystals in aventurine glass, H. 8. Washington. IV. Kuwcerpts and Individual Publications. Fossil Salvinias, including description of a new species, by Arthur Hollick. Bull. Torrey Botanical Club, vol. 21, pp. 253-257, pl. 205, June, 1894. The Preglacial channel of the Genesee river, by A. M. Grabau. Proce. Boston Soc. Nat. Hist., vol. 26, pp. 859-869, Sept. 8, 1894. Ore deposits of Camp Floyd district, Tooele county, Utah, by R. C. Hills. Proc. Colorado Sci. Soc., 12 pp. V. Proeeedings of Scientific Laboratories, ete. Bulletin, Dept. of Geol., Univ. of California, vol. 1, No. 5, contains: The lherzolite-serpentine and associated rocks of the Potrero, San Fran- cisco, Charles Palache. No. 6 contains: On a rock from the vicinity of Berkeley containing a new soda amphibole, Charles Palache. No.7 contains: The geology of Angel island, F. lL. Ransome; A note on the radiolarian chert from Angel island and from Buri-buri ridge, San Mateo county, California, G. J. Hinde. CORRESPONDENCE “CEPHALOPOD BEGINNINGS.”’ In the December (1894) number of ‘*Nat- ural Science,’’ Dr. F. A. Bather has generously devoted considerable space to a critical review of some of my recent papers pertaining to early stages of cephalopod shells, all of which have been published in the AMERICAN GEOLOGIST.* So important do the primitive shell-characters in this group of beings appear, that such a review from so well-equipped *The Protoconch:of Orthoceras, XII, PP. 112-115. 1893; The Early Stages of Bactrites, XIV, pp. 37-43, 1894; Nanno, a new Cephalopodan type, XIV, pp. 205-208, 1894. 126 The American Geologist. February, 18¢5 a writer is very welcome to me, the more as my observations of facts are not called into question. If My. Bather’s interpretation of these facts differs from my own, it may enable us the sooner to get at the full sig- nificance of these structures. Bather’s paper, entitled “Cephalopod Beginnings,’ and covering some seventeen pages of the magazine referred to, is bright, logical and in- cisive. Lam fully alive to the force of his arguments, which, for such readers as may care to follow this subject, may be briefly summarized thus: From the primitive cephalopod ancestor of ‘far pre-Cambrian times”? have been derived along divergent lines the three orders, Nautil- oidea, Ammonoidea and Coleoidea (Bather’s term for the Dibranchiata). These three may be divided into two groups, one in which the proto- conch was always fragile and is altogther lost; these are the Nautiloidea. The others had a stronger and calcareous protoconch and have retained it, either with the shell coiled about it, or enclosed within secondary depositions; these are the Ammonoidea and Coleoidea. The observa- tions which I haye made in the first two of my papers militate against this proposition, and have, hence, invited attack; but | cannot help feeling that Dr. Bather’s argument is rather procrustean inasmuch as his division of the Cephalopoda based upon the destructibility of the protoconch was proposed some years before this later evidence was ad- duced. It has been argued by me that the protoconch described in the first of my papers is that of Orthoceras and that the structure of Bactrites as recounted in my second paper and eyinced both in its protoconch and the position of its septal funnels distinetly shows its orthoceran affini- ties. There are some side lights upon the evidence adduced by me in regard to these protoconchs which it will be pertinent now to direct upon the subject. The orthoceran character which, in confirmation of the views of some of the older palzeontologists who knew nothing of its protoconch, I ascribe to Bactrites, hinges to some degree upon the generic character of the protoconch-bearing shell regarded by me as Orthoceras., It Nas been already explained that this little protoconch with the first two septa attached, was found in a Devonian limestone (Styliola layer of the Genesee shales), that its general aspect, the circular conch, the central position of the sipho on the last septum (I have shown that it is lateral in Bactrites from the very beginning) and the absence of any deflection of the conch as in the Ammonoidea, including even JMmoceras and Agonia- tites, all make for Orthoceras, When my description of this fossil was first prepared I ventured to ask Prof. Hyatt to examine my observations and drawings. feeling that in so doing I took the case directly to the court of last resort. It was not the Orthoceras of his observations and he certainly expressed himself at first as doubting the pertinence of that generic reference, still conceding many of the orthoceran characters of the specimen. His position in regard to it then was similar to that of Bather now, involving even the suggestion that, as it was quite palpably not the protoconch of a goniatite, it might be that of some otherwise unknown ammonoid genus. This argument is a good one either from Correspondence. 127 the point of view taken then by professor Hyatt or now by Dr. Bather: but, though appreciating its premises, Iam nevertheless impressed by its serious improbability. The possession of this fossil was not a mere incident. By assiduous effort and by every mechanical and chemical contrivance known to me, I have for many years endeavored to wring the fossil contents from this heretofore little studied formation of the Genesee shales. This is one of the results, and while, among the others, cephalopod protoconchs and protoconch-bearing shells abound, it would, I submit, after this protracted effort, be somewhat less than likely that a genus of cephalopods in these faunas should still be known by its pro- toconch alone. There are here Manticoceras, Gephyroceras, Tornoceras, and perhaps some other forms of the goniatites, Clymenia, Bactrites, Gomphoceras and Orthoceras. The possible variations in the form of the protoconch within the limits of a group of allied genera or even of a given genus are not yet satisfactorily established. From our present knowledge and presumably, they are not great. This protoconech is assuredly not that of any of the goniatitine genera mentioned, nor of Clymenia, which T have fully described, nor that of Bactrites, unless these primitive shells vary in all essential particulars with the species. One may readily admit the suggestion of Bather that many of the things termed Orthoceras may prove to be something else than typical orthocerans: I may, however, remark from my knowledge of the ortho- cerans of this fauna that they have not evinced any dissimilarity from such typical forms. A recent expression from Prof. Hyatt conveys the impression that the facts above stated and the evidence from the fossil itself which he has since examined has somewhat modified his opinion. In his latest and very remarkable paper, the “Phylogeny of an Acquired Characteristic,” he writes (p. 361): ‘Clarke has recently shown that a straight, Ortho- ceras-like shell may have a complete egg-shaped protoconch like that of Bactrites. His form certainly has the characters of an Orthoceras, but the protoconch is large and like that of the Ammonoidea. The shell may be transitional from Orthoceras to Bactrites but is probably not a typical form of Orthoceras.’* At this writing I believe that Prof. Hyatt did not have before him my accountof the ‘‘Early Stages of Bactrites,”’ and I must here rehearse the fact, the force of which Bather himself seems not fully to have recognized, that the whole and entire argument for regarding Bactrites as a straight ammonoid shell rests upon Branco’s determination of a Mimoceras-like protoconch in shells which /e believed to be Bactrites, but whose mature characters were unknown. Herein the material described by me has a decided advantage: if was abundant and its characters at every growth-stage from inception to maturity are known, its later phases showing it to be in full agreement with the species upon which the genus was founded. Disavowing any intention of casting doubt upon the observations of Dr. Branco, | think it clear that the Bactrites which have been described by me are a step further away from the Goniatitinw and nearer the nautiloids than the Mimoceras- like shell described by him. The New York specimens of Bactrites 128 The American Geologist. February, 1895 seem to me to very substantially strengthen Hyatt’s conception of the common straight orthoceran ancestor of both nautiloids and ammonoids, and there is no closer approximation to, or expression of, this radicle than in the nautiloid shells of the Lower Silurian which IT have recently termed Nanno. In regard to this genus, Vanno, | may venture to say on my own be- half to my various kindly reviewers that in the brief and preliminary description of the Minneapolis shells I did not believe myself to be ig- noring the work of Holm upon similar shells which he referred to Hn- doceras, knowing that the opportunity would soon be afforded of do- ing it fuller justice in a more lengthy account of the Minnesota Silurian cephalopods, and | am sorry if offense has been given by my apparent omission. Nanno aulema; none will, at least, deny its euphony, and to the suggestion in the December number of this journal that the name is inappropriate to a genus of cephalopods, it may be remarked that the good old terms Loligo and Sepia are pleasingly discordant with the recent spondaic terminology of these creatures. No one familiar with the structure of typical Hndoceras will long stand out for the generic identity of the two. But what place is there for Nanno in Dr. Bather’s two-fold division of the Cephalopoda; the *‘Lipo-protoconchia™’ and the * Sosi-protoconchia;’”’ the former ‘‘ practically coextensive with the Nautiloidea,’’ ‘‘which, starting with a very fragile protoconch, soon lost it altogether,’ the latter, “starting with a stouter protoconch”™ and preserving it as in the Ammonoidea and Dibranchiata? Would Bather have Nanno with its immense protoconch not a nautiloid, and its close allies, Hndoceras, Cameroceras Vaginoceras, Piloceras, all not nautiloids? Or would he, by leaving it outside the pale of both of his divisions, regard it as a near expression of the ancestral form of both? The latter seems, as already observed, nearer the correct interpretation of the structure: but it does appear to coincide with Bather’s view which is stated thus: ‘‘We are therefore not entitled to say that the Ammonoidea were derived from the Nautiloidea, although we may not doubt that all three orders sprung from a Common ancestral stock first evolved in far pre-Cambrian times.” J. M. CLARKE. EROSION DURING THE DEPOSITION OF THE BURLINGTON LIMESTONES. In the October number of the Gronogisr (1894), I put forward some evi- dence to show that there had been a cessation of deposit during the building up of the Burlington limestones, and that erosion took place, followed by a renewal of deposition. T will now describe strata lying in an inclined position with all surroundings going to show that they were thus deposited and that the inclination is the result of previous erosion, The locality is about three miles north of the city of Burlington in the bluffs along the valley of Flint river. This is rather a small stream which traverses the country diagonally from the northwest to the south- east. The blutfs are quite prominent and in some places very abrupt, although deeply covered with loess and drift. The north bluff is fre- quently broken by deep ravines in which, at a number of places, rock » Correspondence. 129 / exposures are displayed. However, the mantle of drift is so heavy— being from 20 to 50 feet—that it is difficult to find exposures of any great length. One of those in evidence is the longest within a radius of a mile. One of the ravines spoken of comes into the valley through the blutt from a due northerly direction. It is very broad for about a quarter of a mile back from the face of the bluff. It then forks, being formed by two smaller ravines which come together. one from the northeast and the other from the northwest. The bottom of the main ravine is but little above the levelof the Flint valley, while the tributaries are much higher and descend yery rapidly, thus showing their comparatively re- centorigin. In the fork between the smaller ravines the rock is exposed on both sides at some distance back from the junction. The exposure in the northwest tributary is much the better one and is that which ap- pears in the cut. This shows about 60 ft., which is not more than half the length in view. The depth is 10 ft. It will be seen from the cut that the strata dip quite rapidly. The angle is from 10° to 12°.) This is uniform for the full length of the exposure and probably extends to the extreme end of the point, which is not more than 50 yards away, but it is hidden by the loess and drift. The angle of dip would bring the inclined strata to the level of the bottom of the main ravine just below the junction of the tributaries. This inclination of the strata is purely a local feature, for, 250r 30 rods farther up the ravine, the same rock appears in a perfeetly horizontal position, although of course ata higher level. Also at several other places Within a radius of a mile I have seen the same rock and always without 130 The American Geologist. February, 1895 any perceptible dip. There is nothing to show that the strata have ever been tilted or distorted in any way. They seem to lie just as they were deposited. he inference is that there must have been erosion preceding their deposition. It would also indicate that the Flint valley and the main ravine must have already had an existence. It seems like presumption to try to place the origin of the drainage system at so early a date as the middle of the Upper Burlington epoch, but the eyi- dence points too strongly to ignore it. | called attention to this facet in my previous article on this subject. As determined by fossils, this rock lies but a few feet above the bed at the Cascade quarries whieh fur- nished such conclusive evidence of erosion. The two localities are only about 6 miles apart and it seems quite certain that the time of erosion was the same for both. rancis M. Funrz. Burlington, Towa, VOLCANIC ASH BED NEAR OMAMA. | believe [ have never informed you of the discovery of a voleanic ash-stratum in the bluffs of the Missouri 74 miles north of Omaha. It is 18 inches thick, with clearly defined up- per and lower limits, about 40 feet above low water in the river. It lies in the lower clayey portion of the loess, about 6 feet above its well marked base, where it rests on the horizontal surface of drift gravel at least 20 feet in thickness, and, judging from other exposures near by, underlaid by till. The loess rises 30-40 feet above the ash layer, and there is no sign of disturbance since the deposition of any of the forma- tions. The ashes are more tinted with iron oxide than in other localities I have seen, but Mr. J. S. Diller, of the United States Geological Survey, pronounces it clearly identical in character with that before submitted to him from Knox, Cumming and Seward counties of Nebraska. I have not yet found the laver on the Iowa side of the river, though I have ex- amined several similar localities. I hope sometime to find time to work up some of these subjects into shape suitable for publication. J. Kk. opp. Tabor, Towa, May 12, 1890, PERSONAL AND: SCLENTIEIC NE VV: Prof. W. W. Clendenin has been appointed state geologist of Louisiana, at the same time holding the place of professor of geology and mineralogy in the State University. He will conduct the survey on the plan of Prof. Smith in Alabama. Proressor JAMES HALL HAS RECEIVED a medal and diploma of foreign membership from the “ Regia Lyneei Academia,” of Rome, in recognition of his services to geological science. This Academy was instituted in the year 291 A. D. and is by far the oldest of existing learned associations. [ Nore.—The report of the Pleistocene papers of the Baltimore meeting, G. S$, A., is deferred till the March No. ] Testa fee Tur AMERICAN GEOLOGIST, VOL. XV. Puate VII. 13 rs DEVELOPMENT OF FAVOSITES. TE, AMERICAN GEOLOGIST. Wior.. © V. MARCH, 1895. No. 3. DEVELOPMENT OF THE CORALLUM IN FAVO- SITES FORBESI. VAR. OCCIDENTALIS. By GEorGE H. Girty, New Haven, Ct. One American representative of Favos/tes forbes’ from the Wenlock limestone of England is the variety oce/dentalis. The type specimen described by Prof. Hall in 1879,7 as wellas the material on which the present paper is based, were found in the Niagara shales of Waldron, Indiana. The varietal differences in these two formsare considerable. In the American species the corallum is small, usually not over 6 em. in diameter, and the shape pyriform or hemispher- ical, thus differing slightly from #. forbes’. The individual cells, moreover, vary from 1 to 8 mm. in diameter, while, in the English variety, they range from 5 to 2 mm.{ In the original description of F'. forbes’, Edwards and Haime do not mention the character of the mural pores, yet the figures in- dicate that these are small and closely set, with ten or twelve rows to a corallite. In the variety occ/dentalis, however, they are of large size and widely separated, both laterally and lon- gitudinally. It is rare to find more than one row between any two corallites, and occasionally none appear to be present. The strongly pustulose character of the cell walls seen in British specimens has not been observed in American forms.§ *Acknowledgements are due Dr. C. E. Beecher forthe use of material, as well as for valuable suggestions in the preparation of this paper. +Hall, 1879. Geology of Indiana, If Annual Report, p. 229. tEdwards and Haime, 1850-54. British Fossil Corals, p. 259, SHall. 1879. Geology of Indiana, IT Annual Report, p. 280, 132 The American Geologist. March, 1895 THE CoRALLUM. The corallum of Favosites forbest var, occidentalis begins with a single corallite, as in Plewrodictyum,* and attains a maximum size of 6 or 7 em., having in general a globose or pyriform shape. Increase takes place by lateral and intersti- tial growth. Although the two modes of growth are really identical, for convenience the development of each will be treated separately, and for the same reason the regular in- crease of the colony has been separated into different stages. In all representatives of this genus, and in F. forbes/ no less, new buds are introduced regularly in the angles between older corallites. The practice is only a little less determined when the buds are introduced about the periphery instead of in the body of the corallum. This habit, nearly as much as the examination of specimens, has led the writer to distin- guish different stages in the growth of young coralla and to assign to each stage later than the second a definite number of cells. These particulars are at present minor details, and have little or no bearing on the main points of this paper. SraGE I.—The first stage consists of the initial cell alone. This at first is conical, but later becomes pyramidal or pris- matic in form through the pressure of adjacent corallites. During this stage it is also slightly curved, so that a dorsal and a ventral side may be distinguished. Subsequent growth appears to be straight. The initial cell is usually procumbent and attached firmly to some object of support. The side of attachment is most commonly the dorsal, more rarely the lateral. but never the ventral side. This upturning of the corallite is probably due to an attempt of the polyp to rise into a position favorable for food and growth. . Only two specimens belonging to this stage have been ob- served. In many young colonies, however, the initial coral- lite, together with the point of attachment, show plainly through the epitheca, thus rendering it possible to determine with some certainty the relative ages of many of the periphe- ral cells. Srace II].—When the initial corallite has attained the length of from .5 to 1 mm., it gives off four buds (6). This Corallum im EF. forbes’, var occidentalis.—Girly. 133 constitutes the second step toward the completion of the ma- ture corallum. These buds spring invariably from the dorsal or attached side, for, at this stage, the corallite has bent up- ward in its growth sufficiently to allow budding on that side. The appearance of the buds is rarely simultaneous, but usu- ally successive, and a regular alternation seems to be the rule. Occasionally in a very robust individual, the interval between the appearance of the first and second buds was much re- duced. Asa result 0, and 4, appeared simultaneously, and a little later b, and 6,. Each bud is connected with its pa- rent by a pore, and the connection is maintained and con- tinued upward by a row of pores. Srace III.—The next step in the growth of the corallum is the introduction of five new buds (¢) in the peripheral spaces between those already existing. Srace [V.—During the fourth stage, ten buds (d) are given off on the periphery between each of the older cells. Srace V.—This stage consists of nineteen buds situated at before. At this point the original corallite is completely sur- rounded, while further growth takes place regularly along lines already indicated. THe INTERSTITIAL CELLS. As interstitial buds can appear only when divergence of the older corallites permits, the order of their appearance is sub- ject to great irregularity, but, in a general way, they may be said to arise, like the peripheral buds, in the angles where the older corallites (in this case three in number) meet. The subjoined table gives the number of interstitial and peripher- al eells regularly produced at each stage :— Stage. Peripheral. Interstitial. Total Periph. Total Interst. Total of all. eae The initial cell. l WAR hetere ee 4 QO dl 0 5 1 Cit) eee ene nes ) 3 9 3 13 Diep sy 10 4 19 17 37 Ver iccicre: 19 52 38 69 108 The first set of interstitial buds consists of three cells, and is nearly contemporary with the third series of peripheral buds, only slightly preceding it. The central bud of the three is often much older, appzaring nearly simultaneously with the second generation. 134 The American Geologist. March, 1895 The diagram on Plate II, -figures 1, 2, 3, 4, 5, represent stages in the development of Favros/tes forbes’, symmetrically considered. Two groups may be distinguished among the colonies just discussed. In one, the initial cell is strongly upright, with but a slight surface of attachment. From this there results a corallum elongated in form, and much resembling a Cyatho- phylloid in appearance. No specimen with this characteristic has been observed still attached. The other form occurs in greater numbers. Individuals representing it are found attached to crinoid columns where they ultimately form a ring about the stem. They have also been observed upon ramose forms of Bryozoa. The initial cell, as well as the five or six corallites next produced, are prostrate upon the surface of support, becoming resurgent only when the first bud is formed. This variation seems to be the direct result of conditions which surround the coralla. As the acute-conical shapes were presumably in a place less favorable for growth, they assumed an upright position and direction. The other form, the explanate almost incrusting one, being thrown by chance upon an advantageous place, as- sumed temporarily a resupinate mode, of growth. Thirty-eight coralla have been found nearly entire, and ina state of good preservation. The development from the initial corallite through two or more generations of buds can thus be traced out with considerable certainty. Of these coralla, three were younger than the completed second stage. Of the remaining thirty-five, four produced three, and thirty-one produced four peripheral buds as the second stage, and in ev- ery instance, these buds appeared onthe dorsal side. Those features, therefore, which constitute perhaps the only new and important points brought out in this paper seem to be well established. Irregularities in the development just outlined are not so great as to preclude reduction of the whole to a general sys- tem. By comparing irregular colonies with more symmetri- cal ones, an ideal law may be detected toward which all are tending. And so the word law may be used in connection with the development of coralla, but only in this sense, that certain buds habitually appear in certain symmetrical posi- Corallum in F. forbesi, var, occidentalis —Girly. 1385 tions, while others sometimes accompany them, but without system or order. In the development of these coralla, two elements can be readily distinguished, viz.: the initial cell with the four buds which it produces, making a well-defined group: and the true peripheral and interstitial buds, whose number and _ position are largely dependent on the number and position of the first. The character of the former group may vary in different spe- cies of Favosites. The secondary corallites may be more or less than four, and may be differently disposed about the initial cell, but the law governing the introduction of the other buds is both obvious in its nature and apparently the same throughout the genus. In Favosites forbesé the four secondary buds seem to form a constant increment of aug- mentation which each individual in the colony tends to per- petuate. Several instances have been noticed, one of which is figured on plate vu, figure 24, where a polyp, separated for some reason from the rest of the corallum, has produced four buds from its dorsal side in the same manner as the prim- itive corallite. All the so-called irregularities have been man- ifestations of the same tendency. ‘That this number is in most instances reduced to one or two in crowded colonies seems to be due to the rapidity with which one generation suc- ceeds and closes over another. In the appearance of the first four buds, no one order pre- dominates. The four possible arrangements have all been observed, and in nearly equal proportions. A few instances have been met where the initial corallite developed but three buds in the second series. After a careful inspection of all undoubted examples of this occurrence (plate vu, figure 26) it is evident that the two outer buds are the oldest, and that all three are of unusual size. The space available for growth having been thus defined and partially occupied by the two outer cells, and the inner bud, the first to appear, having usurped the rest, the remaining bud was forced either not to be developed, i. e., to appear as a pore, or tocome in as an in- terstitial cell. In regard to the parentage of the peripheral buds as a whole, there can be no question, inasmuch as they are by definition external, and their origin and growth can be made out on any 136 The American Geologist. March, 1895 well-preserved specimen. It might be asked, however, whether the buds which ultimately surround the initial cell are not immediately given off by it. This does not appear to be the ease, both from the long interval which separates their ap- pearance from that of the first four, as well as from the gen- eral law which governs the introduction of new cells. More- over, a partially developed corallum was dissected by the writer, by means of acids, and the basal pores of such buds as were developed were found to pass into cells of the series } and ¢, and not into the initial cell. The number of interstitial cells has already been seen to vary considerably, depending as they do upon the position and development of the other corallites. Their own position seems to be due to the general crowding of the colony. Those cells which are interstitial between the first and second gen- eration, spring from the first, those between the second and the third from the second, and so on. Not only has this been observed in the single specimen dissected, but it also agrees with the strong unilateral tendency which is exhibited in other ways. In general, it may be asserted that the oldest cell buds first, and that the cells of other generations send _ off buds in the order of their ages. Thus the order of the whole corallum is in a measure predetermined by the order of the four buds constituting the second generation. The period at which the initial cell is completely surrounded varies slightly in different coralla. It is evidently dependent on the rapidity with which the enveloping buds, especially the final pair, in- crease in size. Specimens showing stages in the growth of /avos/fes Jorbes/ are figured on plate vi, figures 1-26; plate vim, figures May wat Raa l a) Favosites spinigerus Hall. This species is less abundant, and less satisfactory for study than Favosites forbes’, although obtained from the same lo- ality and in the same preservation. In its development, it is closely allied to the species above discussed. The initial cell produces four buds from the dorsal side, as in /. forbes’, but, through prolific budding, these are generally separated by a large number of interstitial cells. Subsequent growth is more dorsal than in /’. forbes/, so that, in all the specimens ex- VCorallum in FE. forbesi, var. occidentalis.—Girty. 137 amined,the initial corallite retains a peripheral position. This peculiarity in the development of F. sp/nigerus is illustrated on plate vin, figures 6-15. Favosites conicus Hall. Only three specimens have been secured which atford any evidence as to the earlier stages in the development of this species. They were obtained from the Delthyris Shaly lime- stone of the Lower Helderberg group in Albany county, New York. Figures 17, 18 and 19 of plate vi represent the lower or epithecal surface of these specimens, which seem to show the initial cell of the corallum, together with the cells next produced. The initial cell may be determined not alone by its larger size, for that character proves to be sometimes misleading when employed as a sole criterion for estimating the relative ages of corallites, but also by the shape of the theca. Where the corallites are all of the same age, or all mature, mutual pressure causes them to yield equally from their naturally cylindrical form, one not more than another. When different ages are represented, crowding causes the younger cells to be more distorted than those older. Consequently, in a section taken across the corallum at a point before the secondary cells had reached maturity it will appear that the initial cell is comparatively round, but the four secondary cells, while rounded on the outer side, are laterally compressed, and abut squarely on the initial cell. A third consideration to be en- tertained in orienting young colonies, in default of a better way, is that of symmetry, which appears to be a constant fac- tor in the development of coralla. Thus, when the character of the material does not permit of determining the initial cell and the relative ages of other cells by observing the point at which each makes its appearance, these essential facts can be ascertained with a fair amount of accuracy in other ways. No examples of Favosites con:cus have been obtained which represent only the younger periods of growth. Specimens, as usually found, are unattached, but in each case on the under surface a group of cells occupying a central and apical posi- tion are broken. ‘These cells represent the cementing portion of the corallum, broken when the latter was detached, and in- dicate the number and position of the primitive corallites. 138 The American Geologist. March, 1895 This consideration, together with those above enumerated, afford a fairly accurate determination of the younger cells and their grouping about the initial cell. The development of the corallum in this species seems to be essentially the same as that of Favosites forbesi. This is most apparent from figure 19, plate vii. The initial cell pro- duces four buds from the dorsal] side, as the second generation, and ultimately becomes surrounded by individuals, which are not, presumably, sprung directly from itself. In figure 17 the normal number of buds belonging to the second genera- tion is apparently increased to five, but the extra cell, that on the extreme left, is so small in the comparison with the others that it seems justifiable to refer it to the third series. In fig- ure 18, on the contrary, the second generation seems to be one short of the usual number. A large but unbroken individual on the left may represent the missing cell. Favusites hemisphericus. The specimens here under discussion, from the the Cornif- erous limestone, are referred doubtfully to the species /. hemisphericus. Their small size precludes the possibility of comparing them definitively with the large coral masses which are classified largely on the form of the corallum. In this spe- cies the development in its early stages proves to be identical with /’. forbes’ (plate vin, figure 16). The growth of the co- rallum has not been followed to the stage where the initial cell is inclosed. OBSERVATIONS. Perhaps the most noticeable features in the development of the corallum in Favosites is that the initial corallite gives rise to buds which are (7) four in number, and (2) all on one side (dorsal) of the corallite. Moreover, this tendency toward unilaterality is persistent and results in the fact that not until the fourth or fifth generation does the original individ- ual attain an inseribed or subeentral position. | Four species of Favosites have been discussed, all belonging to the globose or pyriform variety. They come, moreover, from four dis- tinct horizons, yet the essential feature of their development appears to characterize the pyriform type of growth. The conclusion seems warranted that this feature remains constant throughout the genus in the hemispherical forms. The fol- Corallum in EF, forbesi, var. occidentalis. —Girty. 139 lowing explanation of these two elements (/ and 2) and their origin is suggested : An initial corallite which gives off in succession six buds equally distributed around its perimeter is taken as an arche- typal form. Then, following the mode of growth observed in Favosites forbesi, before the secondary corallites are large enough to bud, the divergence of these cells allows six inter- stitial buds in the six corners, thus decussating with the sec- ond generation. 5 In the third generation, the inherited tendency would be for the six members of the second generation each to produce six buds. The diagram (plate vu, figure 21) represents the con- dition of the corallum at this period. It will be seen that, owing to the interstitial buds, one side of the corallite (>) is appressed to the corallum. Asa result but four buds can be developed normally by each individual, the two others exist- ing (n potentia as pores, since pores and buds are fundamen- tally homologous. This process is repeated by each member of the corallum (except the, initial cell) and at each act of gemmation. By accelerated heredity there would finally re- sult an initial cell giving off four buds on one side of the polyp. In the suppositious corallum above suggested, the initial cell was assumed to put forth six buds, constituting the sec- ond generation of the corallum. A little later six others are produced, alternating with the first series and forming the first set of interstitial cells. The third whorl of buds would be above the first, the fourth above the second and so on, forming in this way twelve vertical rows of buds or pores. This fact shows a striking and significant identity in number with the almost invariable number of septa, and therefore of interseptal loculi observed in Mavos/tes. Moreover, in I’. forbes’ the initial corallite at the first generation gives off regu- larly four buds, then three others alternating with these and soon. This development, however, is on one side only, and if continued completely around the circle would give twelve radii of gemmation (see diagram 22, plate vim). In this set of coincidences rests the defense for choosing precisely six secondary buds rather than any other number. That the regular hexagonal form of the corallite rules 140 The American Geologist. March, 1895 throughout the coralline is apparent, while the mechanical cause and geometric necessity are equally obvious. It may be that the hexagonal symmetry (in septa and buds) of the individual in a favositoid colony is due to the hexagonal form, together with the habit of prolific budding in the earlier stages, especially in the ancestral type suggested in this paper. The constitution of the corallum is such as to force the buds of each individual to fall into 6 or 6x vertical rows, and this in turn might affect the development of septa. On the other hand, it may be objected that for the same reason hexagonal symmetry must prevail in colonies of rugose corals, whereas tetrameral symmetry is found to be the rule. Among the Rugosa, however, budding is either calycinal, where the life of the parent is terminated by the act of gemmation, or, when lateral, is not usually prolific. In Favosites one of the most noticeable features of the co- rallites is the mural pores, which extend in one or more verti- cal rows along each face, and, apparently, served to connect the visceral cavities of adjacent polyps. If a marginal row be observed it will be found to run parallel with the edge for a short distance, then, approaching it, to pass to the other side. There is usually an enlarged pore upon the angle from which a bud is produced, truncating in its growth the edge of the prism.* For a short distance, the original row remains solitary upon the new face, when suddenly one or more rows are initiated, apparently by the young bud. In other words, the pores extend upward in parallel series, in an irregular and extended spiral. The bend in the line of pores apparently indicates a slight twisting on the part of the corallites, which may be due to the tension of the bud in its effort to acquire an upright position. To this cause is very likely due the in- termediate and alternating position of all the young cells. It would thus follow that the calcified and consequently immovy- able portion of the corallite did not extend as high as the hinge-point of the pore line when the bud was given off. It is not supposed that the spiral movement of the pores was produced by a continued and slow revolution of the corallite. The introduction of new series with new buds and the disap- *Beecher, 1891. Trans. Conn. Acad., vol. vim, p. 215, et. séq. Corallum tn FE. forbes’, var, oceidentalis.—Girty, SL pearance of the old ones might give this impression, while the yielding due to tension may be only Joeal. The existence of rows of pores on all sides of each cell has no bearing on the question of the unilaterality of that cell, nor is the number of rows a key to the number of radii of gemmation. Any or all of the pores may be developed from adjacent corallites. It is not assumed, however, that buds are necessarily produced on but one side of each cell through- out the corallum, although no instances to the contrary have been observed. If a complete gemmation does occur in Pavo- sites, it may be regarded asa reversional manifestation, and is to be looked for in senile or pathologic individuals. How far the development observed in Favosites forbest holds good for Favos/tes as a genus it is difficult to determine. It seems probable however, that in all the globose forms, the development is one-sided, and that the four cells, which may be termed the increment of generation, characterize the de- velopment of coralla of this form. Variety may occur in the order in which these cells are given off, and in the persistence with which they are reproduced. On the basis of their mode of growth, Favosite colonies may be roughly divided into den- droid, explanate, and globular or hemispherical forms. The growth of the globular forms is essentially radial. The interstices which consequently arise are filled, as fast as they appear, by new buds, so that at any given point in its growth the corallum abounds in small, immature ealices. It is con- eeivable, however, that the divergences might be so distribu- ted that all the young cells matured simultaneously, before any new ones appeared, or even that this might occur period- ically. In this form the number of peripheral buds is com- paratively small, and after attaining a certain point, the cor- allum depends for its increase almost exclusively on intersti- tial germination. This point is reached at an early period, and is determined by the form of the object of support. When the peripheral cells rest on the surface, further increase by the introduction of new ones is clearly impossible except, perhaps, laterally between the old cells. In that case their character is uncertain and their number small. With the incrusting forms, it is far different, as the growth of the corallum is peripheral and the introduction of inter- 142 The American Geologist. March, 1895 stitial buds fortuitous. Instead of being divergent, the cor- allites here are parallel and contiguous. In the branching varieties, however, the growth, as deter- mined by mature specimens, is exclusively by interstitial germination. As can readily be seen, this, joined to a limi- tation in the length of each corallite, would produce a trunk- like corallum, the branching being effected by the outgrowth and prolongation of a number of corallites in a body. There is no permanent apical bud, but one assumes a central position fora time, and then swerves outward, terminating at the perimeter, while another takes its place. Possibly bifurcation of a stem may result from the deflection or divergence of two cells of nearly equal size, having a central position. The hemispherical forms, therefore, seem, in their mode of growth, to stand midway between the explanate and the branching forms. These coralla have no proper limit of growth, and the size which they attain depends largely upon external physical conditions. As the dendroid shape seems to be a subsequent specialization of the pyriform variety, its earlier development would probably agree with J”. forbes?, while both forms, the globose and the dendroid, pass through a more or less explanate stage. The explanate and arborescent varieties, however, have not been investigated by the writer in their earlier stages. The affinities of Mavosi/es as deter- mined by its mode of growth would seem to be with Awlopora and Romingeria rather than with any other genera of the Perforata excepting Michelinia and Pleurodictyum. Like Pleurodictyum, Favosites passes through an auloporoid stage* represented by the initial cell. When one or two sec- ondary cells have been added, the corallum can still be likened to two auloporoid cells, where, the stolon being reduced to a mere pore, the corallites themselves are brought into close apposition. Even a large favositoid colony can, in the same way, be compared with a colony of Au/opora, although in the Jatter, as far as known, so many as four cells are not budded from one individual. A further point of similarity is estab- lished by the fact, that, in both genera, the individual cells produce buds on one side only. Corallum in FE. forbesi, var. occidentalis. Crirty. 143 relationship of Awlopora, although Syringopora is referred to the Perforata, and Syringopora likewise passes through an Aulopora stage in which the whole colony is prostrate and at- tached. On the other hand, although the genus Awlopora bears an outward resemblance to certain forms among the Alcyonaria with which group it has been customary to place it, the cell walls in such colonies are characteristically formed of consolidated spicules, while Av/opora shows no trace of such structure. ! ‘Taconic. The Canadian geologists are agreed on the question of the age of these voleanics, and compare them directly with the Keweenawan rocks of the lake Superior region.+ In the Cambrian of Newfoundland the sections which are given by Murray show such rocks as diorites, porphyries and amygda- loids. These he puts, with their associated beds, into his b>] “intermediate system,’ which he supposes is the parallel of the original Huronian as described by himself and Logan in the Canadian reports. } It is evident, from a survey of the facts from both sides of the Atlantic that the Taconic period was liable, from its com- mencement to its close, to widespread volcanic action, and its strata seem to manifest this fact in the constant interming- ling of voleanic rock-material with the ordinary products of sedimentation. Where these events were most frequent the strata are less fossiliferous. Where they are not legible from the strata the sea was more fit for life, and in such places fos- sils have been found. It is also apparent that the oldest sediments which may properly be included in the Taconic, above the great plane of *Text-Book of Geology, 3d edition, 1893, p. 710. {Logan. Geology of Canada, 1863, pp. 241-244. Seuwyn. Rep. Prog. Can. Geol. Sur, 1877-78, A, pp. 3-15. Eis. Rep. Prog. Can. Geol. Sur., 1886, J, p. 28: 1887, K, p. 85. tMurray. Geol. Sur. Newfoundland, 1868, pp. 145-147. Republica- tion of 1881. 162 The American Geologist. March, 1895 non-conformity that separates the Taconie from the Archean have not been identified with certainty. and that whatever may be the horizon at which such contacts happen to be ob- served, they can be considered the base only for those several points of observation. That the conformable strata of the Taconic extend for many hundred feet, if not thousands of feet, below the zone with Olenellus is well authenticated in America. In Newfoundland, according to Mr. Howley, the present Government geologist, and in the opinion of Mr. Mur- ray earlier, the Signal Hill quartzyte, and the underlying slates with Asp/del/a are not separable from the strata carry- ing Olenellus, though the Olenellus strata are much higher in the formation. Not including the Signal Hill beds, there is still a thickness of 1,800 feet below the Manuel's brook econ- glomerate containing Olenellus. In New Brunswick, accord- ing to Matthew, the Etcheminian series, reaching a thickness of 1,200 feet, lies below the St. John group proper, the base of which is thought to be at the Olenellus zone, and is hardly separable from the St. John group. Lately Mr. Walcott has reported the existence of a great thickness of conformable clastic strata below the Olenellus zone in the eastern slopes of the Appalachians, from Vermont to Alabama.* If then we accept the great structural break which seems to be of wide extension in Ameriea, referred to above, as a datum from which to reckon the continuance of Taconic time, which would also be in accord with the views of Irving on the significance of non-conformities, the Taconie system would have a definite basal plane determined by the physical history of the earth, which has always been the governing element in the great faunal changes of geology. THE SECOND LAKE ALGONQUIN. 3y FRANK BuRSLEY TAYLOR, Fort Wayne, Ind. (Concluded.) The Attitude of the Deformed Plane. The remarkable uni- formity of the main Nipissing plane does not appear to ex- tend far toward the east from Sault Ste. Marie. For, as already stated, its projection in that direction passes about 40 feet below the Nipissing beach at North Bay. Its position seems *Van Hise. Correlation Papers: Bull. 86, p. 469. The Second Lake Algonquin.—Taylor. 163 to suggest that the plane rises northeastward to an anticline ora fault. This, in turn, suggests that the inclination of the plane probably dies out toward the southwest somewhere be- yond the node line and passes into a dead level; that is, into ground that was not affected by the change which produced the deformation. The attitude of the main plane is substan- tially such as it would be if it were the foot-plane of a simple northeastward uplift, and had been dragged up incidentally with a more sharply raised region lying farther to the north- east. Reasoning solely from the attitude of the main plane, the ratio of the northward component of elevation to the eastward component is about 19 to 8, or a little less than 5 to 2. But there are certain facts which show that the change was not so simple as this. If we examine Nipissing beach closely we find that its structure proves that for at least 25 feet from its upper level the water must have fallen away with extreme slowness and apparently at a perfectly uniform rate. This is shown at Au Train. Sand River, Marquette. and other places on the Superior shore, where the beach ridges of a numerous series are strong and very regular.* Spencer, as quoted above, reports much the same appearance on the shore of Georgian bay, and Lawson describes several such places on the north Superior shore. Considering the difference in the materials of the beaches, the case is almost as good at Macki- nae and Gros Cap. These features exclude—certain supposi- tions that might be made as to the character and order of the changes producing deformation. And among others they exclude the supposition of a simple northeastward uplift as given above. That idea seems fair enough at a glance, but it is based solely on a consideration of the attitude of the plane, without any reference to other evidences which may require a different explanation. The Order of Changes. The order of events appears to have been about as follows: For a long period of time the upper lakes were in open connection with the ocean through several straits, the deepest being the one over Nipissing pass. This strait had a minimum width of 25 miles and a maximum depth of nearly 500 feet. Not until the waters had fallen away from this high level to that of the Nipissing pass, did *Fourth paper, pp. 866-371, 164 The American Geologist. March, 1895 lake Algonquin come into existence. There probably was some elevation at its outlet in the earlier days of lake Algon- quin. But it is almost certain that there was none, or at least exceedingly little, in its closing days. For, as was pointed out above, an elevation of the outlet would cause all the shores of the lake to be submerged. The character of the beaches on the Superior shore, however, shows very clearly that no such change occurred during, nor for a long time after, the formation of the Nipissing beach and that at least in its later days the shores of lake Algonquin were not disturbed by any noticeable eastward deformation. But the Nipissing beach rises eastward and there is the old outlet to-day 160 feet above lake Huron and 40 feet above the main Nipissing plane. The only explanation which is entirely consonant with all the facts requires us to suppose that the eastward factor of de- formation began at some time after the North Bay outlet, and the whole Nipissing beach, with all those for 25 feet or more below it, had been abandoned and left high and dry in conse- quence of simple northward differential elevation. And this northward elevation must have been very gradual and very uniform in its rate, if the present appearance of the Superior beaches goes for anything. On this line of evidence I am driven to conclude that it was not an eastward elevation that caused the change of outlet but a northward one, This points in turn to the more important conclusion that lake Algonquin, as defined by the Nipissing beach, was probably in a geolog- ical sense a very short-lived affair. For if there had been much northward differential elevation while the North Bay outlet was active and without causing it to go dry, the plane of lake Algonquin would have changed its attitude by swing- ing on an east-west axis through the outlet. The upper aban- doned beach of Nipissing age north of that axis would then appear to rise northward more rapidly than that south of it. But no evidence of such a change of plane was found; on the contrary there is conclusive proof against it. For the main plane of the Nipissing beach passes right across the east-west axis apparently without the slightest sign of a break. This shows that the level of lake Algonquin from the beginning of the Nipissing beach must have been very close to the level of the St. Clair outlet: so close that only a very slight north- The Second Lake Algonquin. —Taylor. 165 ward elevation was required to cause the change of outlet.* From a consideration of the plane as above, we may argue that, since the Nipissing beach south of the North Bay axis was formed when both outlets were active at once, and since there is no extra rise of the plane north of that axis,it fol- lows that all the lower beaches of lake Algonquin have been made since the St. Clair outlet opened. That being the case, it follows that very nearly all of the deformation which has affected the Nipissing plane must have taken place after the abandonment of the North Bay outlet. And further, since the last 40 feet of elevation at North Bay did not carry the water plane up with it, we may be sure that the St. Clair out- let was active at the time it occurred. These facts indicate that the level of the sea in the Mattawa and Ottawa valleys east of North Bay had probably fallen only a few feet below the level of lake Algonquin before the outlet was changed and the outflow at North Bay ceased. This agrees with the re- ported fact that the lower valley of the Mattawa shows no certain evidence of having been recently occupied by a great river.t While these considerations do not locate the main eastward uplift exactly in time, the character of the beaches, however, seem to show that none occurred until! after a simple north- ward rise of at least 25 or 30 feet had taken place on the south Superior shore. But there is good evidence to show that the simple northward rise was considerably more than this. The Pictured rocks, Grand and Au Train islands and the north end of Presque Isle are sheer cliffs, standing with their bases submerged. They show that no eastward component of ele- vation affected lake Superior until a considerable time after *It is possible that a considerable part of the time of lake Algonquin passed before the time of the Nipissing beach. That period may have been closed by an uplift at North Bay raising the water in the whole basin to the level of the Nipissing beach which then began to be formed, But if there was such an uplift it was probably slight, and no certain evidence of it has yet been found. tin his paper referred to above, Prof. Wright describes a great boul- der terrace 80 feet above the river at Mattawa, and attributes it to the action of the old outlet river. It seems probable, however, that Dr. Bellis right in supposing this particular terrace to be morainic. Tt does not appear that the declivity of the Mattawa immediately above the village is sufficiently steep to account for such an accumulation as the result of river action. 166 The American Geologist. March, 1895 that lake had become independent; ,4 that is, after the water had fallen a © Z from the Nipissing to, or a little § & below, the present Superior level at % Sault Ste. Marie. Forif that were the case, there would be a sharply accentuated beach passing west- ward from Sault Ste. Marie and sloping downward in that direc- tion under the lake so as to pass about 25 feet below it at the Pic- +. tured rocks and Presque Isle, and the cutting of that shore would ac- count for the present partly sub- merged cliffs. This probable sig- nificance of the cliffs of the south /00 Plane (692 Ft A.T) 50 Hu ron Sault Ste, Marte shore was long ago recognized by others. There are so many features of this kind on the south shore and about the western end of the lake, all pointing to a recent stage of the lake at alower level, that the exist- ence of this submerged beach seems certain. I propose to call it the Superior Plane (602 FLAT) Sault beach, for its place was de- termined by the barrier at Sault Ste. Marie. It was the last beach made by lake Superior before the i I beginning of the great eastward 3! uplift and ought to appear above et present lake level on all the Su- 1Z\ perior shore north of the isobase a \ DD. The overhanging rocks, cliffs \2 \ and caves of the Apostle islands show extreme littoral erosion, and this may be attributed to the fact that the present wave line strikes there a little above the same level that was so heavily cut by the waves of lake Algonquin. The ile Iie. The Second Lake Algonquin.—Taylor. 167 Palisades of the Minnesota shore are probably due to the same cause.* The Nipissing beach is now submerged 25 feet at Duluth. But before the eastward uplift began lake Superior had be- come independent and its level had fallen 50 feet, or to the level of the Sault beach. It follows that when this last beach was formed the levelof lake Superior at Duluth was relatively 75 feet lower than it is to-day. The submerged channel of the St. Louis river eroded 40 to 50 feet in glacial drift from Fond du Lae to the harbor of Duluth, and probably more or less refilled since, points strongly to a period of the lake at the supposed Sault beach level.t+ Niagara and Lake Algonquin. But far away from lake Superior and the Sault there is another chronometer of the time since lake Algonquin lost its northern outlet. Itis a part of the gorge of Niagara river. During the comparatively short life of lake Algonquin, and through all that much longer time while the sea filled the ancient Nipissing strait, the great cataract of to-day did not exist. During that time the chan- nel of the Niagara river was occupied by a small stream which drained only lake Erie. The cataract of that stream was a small thing compared with that of to-day. Dr. Spencer has ealled this the Erigan river, and we may appropriately call its cataract the Erigan fall. Its volume was about the same as that of the present American fall, or about three-elevenths of the whole stream. The great difference in the magnitude of the Erigan and Niagara rivers leads one to expect that there would be at least some degree of difference of a corres- ponding kind between the gorges which their cataracts would make. And such a difference is there plainly enough. From the Horseshoe fall to a point a few rods above the cantilever railroad bridge there is a wide deep pool. The water in it is somewhat turbulent, but that is evidently not due to any fea- ture of the pool itself so much as to the powerful currents that invade its depths from the foot of the present cataract. At the cantilever bridge, however, the gorge becomes percep- tibly narrower and undoubtedly shallower, and the wild fury *Lawson, op. cit.. pages 197-8. +Mr. Warren Upham, in Twenty-second Ann. Rept. Geol. and Nat, Hist. Survey of Minn., for 1893, Part IIT, p. 64. ™ strengthened when we take into ac- 165 The American Geologist. March, 1895 of the water as it rushes toward the Whirlpool is plainly due entirely to the character of that part of the gorge. In short, the head of the old gorge of the Erigan river was a little above the cantilever bridge when the St. Clair outlet first opened, and it was there that the greater cataract of Niagara began its work. The distance from the falls to this point is a little less than two miles, and this represents the work of modern Niagara since it replaced the Erigan river. The facts seem to show that probably about half of this work was done dur- ing the progress of the simple northward uplift and before the great eastward elevation had begun. In his recent admirable paper on the “Duration of Niagara Falls,’ Dr. Spencer has presented a more elaborate discussion of the development of the Niagara gorge than has ever been made before.* His cross-sections of the gorge are particularly instructive. With some slight omissions and additions I re- produce three of them here in fig. 2. It seems to me that there ran be no mistaking seetion ©, which represents the Erigan gorge, as the product of a much smaller stream than the greater Niagara which made sections D and E. This conclusion is still further count the obvious fact that the river in the Erigan gorge is much shallower than in the wider part above, probably not more than one- third as deep. But Prof. Spencer er oe . r Seesssaeees, me, the only true explanation o Nidgare == the Erigan gorge—the only expla- @*°™ "555 nation which is perfectly correlated with the lake history as revealed in the deserted beaches. He explains the Erigan gorge by supposing it to have been made by the great cataract at a time when there was a sheer fall of 420 *Duration of Niagara Falls,’ by J. W. Spencer, Am. Jour. Sei., 11, vol. xLvit, Dec., 1894. The Second Lake Algonquin.—Taylor. 169 feet, and the greater hight of the fall is taken to account for the narrowness of the gorge.” The depth of the river is assumed to be as great as in the parts above. A little consid- eration shows, however. that neither of these ideas is defens- ible on sound principles. On the depth of the gorge of the rapids Dr. Spencer’s con- clusion seems to me to be contrary to conclusive facts. I re- gard it as a matter of simple demonstration that the river is much shallower there than in the wider gorge above the rail- road bridges. If we know the volume of a river from meas- urement at some place where its velocity is moderate we may readily calculate its mean depth in any other place if we know its width and velocity. For its velocity is inversely propor- tional to the area of its cross seetion, and if we know the width and velocity then we can easily find the mean depth. I regret that I have no accurate data on this point. But after standing beside the rushing, roaring torrent of the narrow Whirlpool rapids and then being rowed in a skiff across the river at the American fall, one is fully convinced that the ve- locity of the water in the Whirlpool rapids can hardly be less than five or six times that in the wider gorge above. But ae- cording to Dr. Spencer’s idea of a substantially uniform depth for the whole gorge, the water cross-section of the Erigan gorge is about half of that at Jolhnson’s ridge. This allows for a velocity only twice as great. In order to find a cross- section to suit the observed velocity we must reduce the mean depth of the Erigan gorge to 75, 60, or perhaps only 50 feet. It is impossible to supply the conditions of high veloe- ity for the rapids in any other way. In support of the first point Dr. Spencer appeals to the law of erosion, viz., the steeper the declivity of a stream the more it cuts vertically and the less horizontal. This law is true for streams flowing without cataracts, but it does not apply to cataracts or vertical falls of different hights, and the ex- ception is still more pronounced where the strata are horizon- tal and the weaker Jayers below are capped by a harder ledge above, as is the case with Niagara. The magnitude of the gorge in such a case depends mainly upon the stream’s power of excavation at the bottom of the cataract where the water falls with greatest force upon the softer, lower rocks, under- 170 The American Geologist. March, 1895 g mining those above, and this depends, other things being equal, upon the hight of the fall. It is true that the higher the fall the greater its power to cut downward. But by the resist- anee of the rocks at the bottom and the consequent deflection = - € ‘6 wage: Sea ast ‘Mia rare (eon ‘Gorgest Erigan Qorge re ae kore Sins FELT I alt I = I : a = I — i T oa eae stealaenT, esses oes al — ——S a ae x =e —_ =x River Ere. 3: of forces in strong currents the power to cut laterally is also increased. For a cataract cirecumstanced like Niagara the law is the very reverse of that for rivers flowing without sataracts, namely, the volume of the river and the geological structure remaining the same, the higher the cataract the wider the gorge. It is interesting to compare the gorge of the present period of Niagara with the channel of the rapids at Sault Ste. Marie. Since the abandonment of the Nipissing outlet, Niagara has cut back its gorge nearly two miles. But the Sault, which has probably been open half as long, has no visible recent rock gorge, or, if there is any, it is submerged. Of course there are many different elements to take into account. But even when a liberal allowance is made for all cireumstances which might cause Niagara to cut back more rapidly and the Sault less rapidly, it still remains a fact that the difference between their amounts of cutting is so great that it demonstrates the younger age of the Sault. The inference from this fact should be put alongside of that drawn from the character of the Superior beaches. The beaches prove that the northward uplift was extremely gradual and even in its action, while the Sault without a gorge suggests that the barrier which holds up lake Superior was not uncovered until a considerable time after Niagara had replaced the Erigan river. But on the other hand, the submerged Sault beach in the Superior basin proves that the barrier had been uncovered some time before The Second Lake Algonquin.—Taylor. 171 the eastward uplift, and that until after its independence lake Superior was affected only by a northward element of defor- mation. The eastward uplift occurred, therefore, at a con- siderable time after the abandonment of the North Bay out- let. By these facts relating to lake Superior and the Niagara gorge we are enabled to put the date of the eastward uplift, or rather of its beginning, at a considerable period of time after the extinction of lake Algonquin. The water must have fallen away from the Nipissing beach at Sault Ste. Marie more than 50 feet before lake Superior became independent. But a fall of 35 feet at North Bay closed the outlet, and it follows, therefore, that the closure took place before the Sault began its career. It is probable that the water at the Sault fell away even farther—more than 50 feet—before the beginning of the eastward uplift, because the submerged Sault beach necessarily required a considerable time to attain the pronounced development which the Pictured rocks and other products of its action show. In a word, the eastward uplift began only at a considerable time after the independence of lake Superior had been completed by the simple northward uplift. This is as far, however, as the order of changes can be made out at present on evidence which traces forward from the time of lake Algonquin. But over against this there are facts of another kind which enable us to put the beginning of the eastward uplift well back from the present time. The St. Clair Flats. Not the least important of the many things that find an explanation in this study of lake Algon- quin is that curious formation called the St. Clair flats. It is in reality a great modern delta of pure sand. But the waters of the St. Clair river, coming directly from lake Huron, are almost as clear as crystal. No other stream in that region, not even the muddy streams that empty into lake Erie, have any deltas, but all have open estuaries instead. Dr. Spencer, as quoted above, describes the heavy cutting of the waves along the present sandy shore of the east side of lake Huron. By their predominant run toward the south the waves are constantly carrying the sand in that direction, and the same is the case in a less degree on the west side. There is on this account a constant tendency for sand to collect at the south 172 The American Geologist. March, 1895 end of the lake, just as it has actually collected in enormous quantities at the south end of lake Michigan. But the head of the St. Clair river opens just at the southern apex of lake Huron, and the result is that the drifting sand constantly passes into the river and tends to build out spits across its head. ‘This process has actually contracted the entrance to one-half the average width of the river below. The spit on the east side is well developed and its point has been turned down stream by the current of the river. The predominance of drift from the east shore has crowded the river over against its west bluff and filled in the old channel for a mile and a halfon the east side. This crowding process has made the rapids at the head of the river. Asthe sand is swept into the opening it is caught by the current which sets in strongly at the start (four and a half miles per hour) and is carried down stream, Once in the current the sand is kept rolling along the bottom until lake St. Clair is reached. Here the river strikes still water, spreads out, and slackens its flow. At this place, therefore, the sand comes to rest and the great delta of the clear river has gradually grown to immense proportions, and ata place about 25 miles from lake Huron. The delta has filled in nearly a quarter of lake St. Clair, and it covers nearly 130 square miles. The average thickness of that part of the delta which has been built since the beginning of the eastward uplift, supposing the level of the lake at that time to have been about 35 feet lower, must be 25 to 30 feet. It there- fore probably contains not far froma cubic mile of sand, not counting submerged extensions, which would probably nearly double its area, but which are mostly thinner and would not add greatly to the whole mass. It seems clear that the great eastward uplift did not occur until Niagara had consumed a large part, perhaps half, of the time which it has taken to cut the gorge back two miles. The rate of the recession of a cataract is liable to many irregular- ities. But if the rate for Niagara has been substantially uni- form, then we might say that the St. Clair delta has been built in approximately the time that Niagara has been cut- ting back its last mile. Presumably the current of the St. Clair river was stronger in the past, before drowning by the eastward uplift had progressed so far as now. The power of The Second Lake Algonquin.—Taylor. 173 the river to carry sand therefore has probably been gradually decreasing as drowning progressed. The Nipissing plane projected southward to the mouth of St. Clair river, passes about 35 feet below its present level and below the bottom of the shallow lake. It follows that the delta above that level has been built since the eastward uplift began, and this im- plies a considerable lapse of time. It therefore puts the be- ginning of the eastward uplift relatively a long way back from the present day. But that is probably all it does. It reveals very little as to the present or very recent status of deformation, unless the one to three feet of water which now covers most of the delta may be taken to show a very recent drowning. As to the probable character of the most recent change, however, good evidence of another kind is close at hand. It was pointed out above that a northward differen- tial elevation affecting the whole basin of the lakes as a rigid vessel would cause their plane to swing on an east-west axis passing through Port Huron. It follows that if there has been a very recent predominance of northward over eastward uplift, it ought to be recorded on the Jake shores north of the Port Huron axis and south of the node line A A. The long- est shore comprised between these lines is the west shore of lake Michigan. It is much the most favorable, and I have ex- amined part of it closely. The appearance of that shore be- tween Sheboygan and Two Rivers is described in the third paper of the above list. It shows no sign of a recently aban- doned northward-rising beach, but affords instead positive evidence of present or very recent encroachment of the lake upon the land, showing apparently that the very latest phase of deformation has been eastward more than northward ele- vation, raising the outlet at Buffalo and consequently the level of all the waters west of it.* At Mackinae and in the vicinity of the straits there is ap- parently an old water plane now submerged five to ten feet. It is seen in the wide submerged rock shelves and in numer- ous gravelly shoals in the adjacent parts of the lakes. But not enough is known of its character to be of much use in *This fact may require a considerable modification of Dr. Andrews’ estimate of postglacial time based on the erosion of this shore. (Quoted by various writers from the paper mentioned above. 7A: The American Geologist. March, 1895 this discussion. It is possible, however, that it is the correl- ative of the Sault beach in the Superior basin and indicates a partial resubmergence, which may include the region of Sault Ste. Marie. This, then, is the history of the second lake Algonquin and of the subsequent deformation of its ancient water plane, so far as relates to the area which was actually occupied by the lake itself. There are, however, other outlying regions, which were surely affected by the same deformations. Some of these are near and others that were less certainly involved are far away. Buta full discussion of the evidences from such regions would lengthen this paper unduly. Evidence of Recent Elevation and Tilting in Contiguous Regions. Lake Erie, however, became so closely concerned with all the changes after the opening of the St. Clair outlet that it can hardly be omitted. It lies entirely on the lower side of the node line AA, and all its shores were therefore drowned when the eastward component of deformation began to act; and they were affected to a less degree in the same way by the northward component also. The Nipissing plane produced southward under lake Erie would pass about 60 feet beneath the present level at the mouth of the Detroit river and about 80 feet below Sandusky and Toledo on the south shore. But it may be that the plane decreases its declivity oradually southward and does not pass so deeply under as these figures suggest. All the rivers of lake Erie, including even the muddy, silt-bearing Maumee, are without deltas, and have open estuaries, many of which are navigable. It is undoubt- edly the reeent drowning of its shores that has made these harbors. Before that change took place, the Maumee must have had a fall of considerable hight over the rock ledges above Maumee City. The recent backing up of the water is plainly shown by many spits and bars, like the points of Maumee bay, Sandusky and Erie, and those at Pointe Pelee, Rondeau and Long point on the Canadian shore. Upwards of a thousand square miles of the former lower valley of the Maumee were submerged by the eastward uplift. The deepest place in lake St. Clair is 80 to 385 feet at the extreme lower end of the lake, almost within the bead of the Detroit river. The mean depth of the St. Clair river is about The Second Lake Algonquin.—Taylor. eis 30 feet, and it is the same for the Detroit river, except where it spreads out between islands and becomes somewhat shal- lower. There is one point in each river which is nine fath- oms or 54 feet deep, and for considerable distances the depth is seven to eight fathoms. The soundings in lake St. Clair show that the bottom slopes off gradually southwestward from the front of the delta to three or four fathoms and seems to show no submerged channels except near the outlet. It ap- pears from these figures that the lake is shallower than the river above and below it, except at one point near the head of the Detroit river, and that there are parts of each river that are 25 feet deeper than the deepest point in the lake. But with so much sand passing through the St. Clair river, there must have been a considerable tendency to fill up the bed of the river itself. No doubt some filling has actually taken place. But it has probably been mainly by the coarser sand particles which were able te resist the current that swept the finer grains along to the delta. The delta has dam- med the stream to a small extent and so deadened the current slightly. Although it passes through only one plane of observation, the line EE has been put upon the map to show where that isobase would be, supposing the deformation at that distance to preserve a parallel relation to the other lines. It is not to be supposed, however, that the rise, or its acceleration, nec- essarily passes on indefinitely toward the northeast. It must come somewhere either to a fault or an anticline. he sounded no uncertain note upon the vexed question of the ‘‘great submergence.’ At the same time he expounded views of ereat, nay, entire, novelty, regarding the demarcation by great terminal moraines of the limits of a series of huge glaciers whose courses he traced in England and Wales. He also recognized a system of extra- morainic lakes of great size, in which he thought the whole of the low-level driftof England south of the Trent and the Humber to have been deposited, These opinions took English geologists completely by surprise. Not- withstanding that the winning graciousness of Lewis’ manner, his elo- quence, perfect mastery of detail, and wealth of illustration, made the exposition of his views one of the richest treats of the sectional disecus- sions, he yet failed to entirely convince his hearers. The late Dr. H. W. Crosskey, who was secretary of the Erratic Blocks Committee of the British Association, met him with fact pitted against fact; but it must be said that Lewis showed himself as adroit in defence as in attack. During the summer of 1888, Lewis returned to England full of large schemes of work, but bringing with him the seeds of that malady to 182 The American Geologist. March, 1895 which in a few days after his arrival he succumbed. mals and plants. Higher forms, he claimed, were produced from lower ones through an internal perfecting principle. It is astonishing to find him, twenty-two centuries ago, stating but rejecting the doctrine of the survival of the fittest. With the death of Aristotle came a rapid decline in the study of phi- losophy. His doctrines were later taken up by the Arabs and carried into Spain: but the doctrines were placed under the ban of the church early in the thirteenth century, and hence the further study of Aris- totle in Hurope was checked. With the awakening of science the natural philosophers again came to the front. sacon (1561-1626) was perhaps the first to raise the ques- tion of the mutability of species. Descartes, a contemporary of Bacon, expressed the opinion that the universe is a mechanism which could be explained on a physical basis. Leibnitz in part revived Aristotle, and * directed investigation to the gradations between species. The celebra- ted German philosopher, Kant, traced back all higher forms of life to simple organisms: referred to man’s former quadrupedal attitude: ap- 186 The American Geologist. March, 1895 preciated the effects of environment, accidental variation, and artificial selection. Oken, for reasons stated, is ranked much lower by Osborn than he has been by Haeckel. His philosophy is a curious mingling of science and myths. Among the evolutionists of the eighteenth century, Buffon isaccorded a high place. Yet his views varied greatly at different periods of his career. First he was a special creationist, then an extreme transmuta- tionist, and finally concluded that species are neither fixed nor mutable. Perhaps his greatest service lay in his suggestiveness. Erasmus Darwin (1731-1802) believed in the spontaneous origin of the lowest forms of life. Yet he was a thorough evolutionist. The modifications of form, he thought, arose from reactions within the organism,—thus he antici- pated Lamarck. He believed in the inheritance of acquired charac- ters and made it a factor in evolution. The author gives an interesting sketch of Lamarck whom he pronounces ‘‘the founder of the complete modern school of descent and the most prominent figure between Aris- totle and Darwin.’’ He also takes up the parallelism between the writ- ings of EK. Darwin and Lamarck, and exouerates the latter from the charge of borrowing. Perhaps a criticism may be made here that La- marck’s views are not brought into sufficient relief, though they are stated at some length. The final chapter is devoted to Darwin and his contemporaries. The work will be of great service to the general reader as well as to the men of science. Jt should be widely read. JA Ace A Preliminary Report on the Geology of South Dakota. By J. E. Topp. State Geologist. (South Dakota Geol. Sur., Bulletin No. 1, pp., 5 plates and a geological map of the state, 1895.) This is the first re- Vili and 172 port issued by the recently inaugurated survey. It gives a detailed ac- count of the present state of Knowledge concerning the geology of the state, and as such will form a convenient starting point for further in- vestigations. The Pre-Cambrian of South Dakota consists of (1) the granitic rocks of the eastern edge of the state, (2) the Sioux quartzite in the southeastern corner of the state, and (3) the slates, schists and gran- ites of the nucleus of the Black hills. The Paleozoic strata are not ex- tensively developed, occurring only in the Black hills. The Mesozoic rocks are the most extensive in thickness(with perhaps the exception of the Pre-Cambrian) and area, and of these the Colorado and Laramie di- visions of the Cretaceous cover half of the state. Tertiary and Quater- nary deposits are well represented, the Miocene covering a large area on the central southern side of the state, while the drift is confined to the eastern half of the state. After the discussion of the stratified rocks a chapter is devoted to the eruptive rocks. and one to a sketch of the geo- logical history of South Dakota. The report closes with an account of the economic geology. Wis ish (Ck A Summury of Progress in Mineralogy und Petrography in 1894, Petrog- raphy and Mineralogy, by W.S. BAyLey. Mineralogy by W. H. Hopes. (From the Amer. Nat. Price 50 cents.) The monthly notes on miner Review of Recent Geological Literature. 187 alogy and petrography in the American Naturalist for 1894 have been reprinted and bound together in pamphlet form. An index of authors and a partial index of subjects have been added, and the whole makes a convenient and useful summary of progress in these two lines. U.S. G&G. Report of the Geological Survey of Ohio, Vol. VII. By Epwarp Orton, State Geologist. Roy. oct., pp. xvi + 700; plans and figures, 56 plates of fossils, and a case of ten maps showing the outcrop boundaries of the principal coal seams. The volume is divided into four main parts, viz: Economic geology, Archeology, Botany and Paleontology. There is also a general chapter by Prof. Orton, explaining the whole geological scale and structure of the state, and another by the same, on the clays of Ohio, their origin, composition and varieties. . Khussuk group, or Neobolus beds. 4, Khewra group, or purple sandstone.* Olenellus here occurs near the top of No. 3, the Kussak group. Below it are found Neobolus warthi, Hyolithes wynni, with annelids and bivalves. According to the limitation that has assumed Olenellus as in the basal zone of the Cambrian, the whole of No. 4 and the most of No. 8 would be exeluded from it. In America the Paradoxides horizon was believed for several years to be at the bottom, even when Olenellus had been dis- covered, because the structural relations were not evident, and beeause both in Bohemia and in Britain Paradoxides only had, at that time, been found in the lowest fossiliferous strata. When this error was corrected for America, by Mr. Walcott, who visited Newfoundland and verified the Seandi- navian order of faunal succession, the idea was at once as- sumed that the Seandinavian basal plane of the Cambrian should be taken generally as the Cambrian base line. This as- sumption has been popular with paleontologists. It gives a definite plane, from a biological point of view, but it ignores greater and more significant physical events which have > and the separated the history of the globe into “times, rocks into systems. It also curtails the original definition of Cambrian, in the country of its nativity, forit has already led to the attempted assignment of a large part of the basal Cam- brian to the pre-Cambrian, which is, in other words, Archean, although such beds are strikingly unlike any known Archean. Reference is here made to the Torridonian and to the Long- myndian. The Taconie of New Brunswick has been very fully inves- tigated by Matthew. In his summary conclusionst+ it appears that the Taconie is there divisible into four parts, the low- est being the Eteheminian, separable from the overlying por- tions by some kind of physical disturbance which left traces *On the Cambrian formation of the eastern Salt range, Records Geol. Sur. India, vol. xxvi, pt. 3, pp. 71-86, 1894. tTransactions of the Royal Society of Canada, 1595. Base of the Taconic or Lower Cambrian.— Winchell. 233 of a non-conformity at its summit. That part which first succeeds this plane is strongly paradoxidean, while the upper- most portion is broadly equivalent, paleontologiecally, to the Olenus horizon of Britain, or to the lower part of the St. Croix series of the upper Mississippi valley. In the whole series in New Brunswick no species of Olenellus is reported by Matthew, who is rather inclined to believe its position is hela by the species of Paradoxides and other trilobites found in his “Division 1.” It is possible, however, and perhaps probable that the horizon for Olenellus is to be sought for in the Etcheminian, and that the trace of non-conformity at the top of that group indicates, as in Europe, the cause of the change from Olenellus to Paradoxides, viz., voleanie disturb- ance. Whether Olenellus ever existed in New Brunswick or not, itis plain that a great series of clastic strata, nearly non- fossiliferous, there extends downward below the lowest trilo- bitie fossils, and that the whole has been included by Matthew in the Lower Cambrian. The thickness of this lowest part is 1,200 feet. The Cambrian of Wales is the Taconic of America, even in the errors at first committed by the respective authors of these terms. The Taconic, however, has never been limited at the bottom except at the great plane of non-conformity which, as Sir Archibald Giekie shows, extends through the northern parts of Europe and North America, and which sud- denly separates the crystalline Archean from the nearly hori- zontal elastics which lie upon it with “violent” non-conformity. As the histories of these formations are developed in geolog- ical literature they are shown to have a wonderful similarity. This is true not only as to the nature of the roeks of which they are composed, the fossils which they contain and the succession of events which make up the epochs of time repre- sented, but in the progress of the investigations which have been carried on on opposite sides of the Atlantic. But the Taconic, from the first, has extended down to the ‘sedimentary base” which coincides with this great plane of non-conform- ity. It embraces, therefore, all the eruptive rocks which have their dates within Taconic time, whether they be ash-bed frag- mentals or injected or eruptive traps. If it be in general the 234 The American Geologist. April, 1895 parallel of the European Cambrian, it is highly probable that some of the eruptive rocks which have been found closely as- sociated with the Cambrian in Wales and England are of so late a date that they fall within Cambrian time. These seem to be represented in the Taconic in America. The exact re- lation that they bear to the Olenellus horizon has been an American question with different views, as in Europe, but in America the earliest principal disturbance apparently followed this fauna, as will appear later. The position of the Olenellus zone has been thus summarily defined by Van Hise: Placed in the Algonkian, under this definition [i. e. assuming the Olenellus zone as the base of the Cambrian. N.H. W.] are 11,000 feet of quartzytes conformably below the Olenellus in the Wasatch; 10,000 feet of argillytes, sandstones, quartzy tes, and conglomerates conforma- bly beneath the Olenellus in British Columbia; 12,000 feet of sandstones, shales and limestones uncomformably beneath the lowest known Cam- brian in the Grand canyon of the Colorado: a similar series of rocks unconformably beneath the Cambrian in Llano county, Texas, a series unconformably beneath the upper Cambrian in the Adirondacks, and the rocks of St. Mary’s and Placentia bays, Newfoundland, which are unconformably below Lower Cambrian strata. Van Hise, Correlation Papers, p. 469. It is only intended by this brief review to call attention to the stratigraphic position of the Olenellus fauna in those por- tions of the globe where it has been most carefully deter- mined. It certainly is a convenience from a_ paleontological standpoint to recognize definite faunal planes. It may be, therefore, an aid to the progress of geological research to refer to the plane of the Olenellus fauna as a marked and well established datum; and in the present state of stratigraphic paleontology such an assumption may serve a good purpose fora trial hypothesis; but it should be remembered that there are many lines yet to be followed out and many regions yet unexamined. The Paradoxides and the Olenellus faunas may be found to be closely related, and perhaps to blend, as sug- gested by Matthew. It should also be remembered that if it become agreed to limit the Cambrian at the Olenellus zone the underlying conformable clastic strata, down to the great non-conformity, are not excluded from the Taconic. The Missouri Lead and Zine Deposits —Robertson, 285 THE MISSOURI LEAD AND ZINC DEPOSITS. By JAMEs D. RoBerTSON, E. M., St. Louis, Mo. Nore. Inthe recently published transactions of the Bridgeport meeting of the Amer- ican Institute of Mining Engineers is a paper by Mr. Arthur Winslow having the above title. This paper is itself based upon an exhaustive report on the lead and zinc depos- its of Missouri prepared by Mr. Winslow, while state geologist, from work prosecuted during the last five years. In this work the writer assisted. The original report is very broad in scope, the design being to make it a work of reference on lead and zinc, with Missouri as a center; a work which would be of general utility to this important indus- try of the state. It thus contains brief descriptions of lead and zinc deposits in other countries, general statistical tables, descriptions of processes and other matter of wide bearing. The general geology of the mining areas is described in great fullness and their history and problems are treated. Interest is centered, however, in the ore depos- its of the state, detailed descriptions of the numerous ore bodies are given and their structure, composition and origin are discussed in a comprehensive way. The recent papers of Posepny, Jenney and others have awakened renewed interest in these topics in general, and especially as affecting the deposits of the Mississippi vailey; and the ap- pearance of the report is hence very timely. The following paper is essentially an ab- stract of the general discussion of the lead and zinc deposits of Missouri as set forth in the report. The lead and zine deposits of Missouri have of recent years become of such importance as to cause that state to rank first in the production of zine and lead ores. In the year ending June 30, 1893, there was produced 40,300 tons of lead ore and 108,600 tons of zine ore. The year ending June 380, 1894, showed a production of 52,000 tons of lead ore and 89,150 tons of zine ore, a decrease in the latter item but a decided increase in the former, in spite of hard times. All of the deposits of lead and zine are found in that por- tion of the state south of the Missouri river. Geographically and categorically the deposits fall into three districts. These are: 1. The southwestern district, comprising Jasper, Newton, MeDonald, Barry, Lawrence, Dade, Greene, Webster, Christian, Taney, Stone and portions of Wright, Douglas and Ozark counties, 2. The southeastern district, comprising Franklin, Jeftfer- son, St. Francois, Perry, Ste. Genevieve, Madison, Iron, Wash- ington and portions of Crawford, Reynolds and Cape Girar- deau counties. 3. The central distriet, composed of Cole, Moniteau, Mor- gan, Benton, Hickory, Camden, Miller and parts of Pulaski, Laclede, Maries, Osage and Pettis counties. In the central and southeastern districts the rocks are mainly of the Ozark stage of the Lower Silurian, and in these rocks occur the ore deposits. In the southwestern district the 236 The American Geologist. April, 1895 Lower Carboniferous rocks are the most abundant, and in these the principal ore deposits are to be found. In the east- ern portion of this district, however, there are a number of deposits in the Ozark rocks. The age of the rocks of the Ozark stage has long been a mooted question. They were originally classed as the equivalent of the Calciferous rocks of the New York section and recent investigation goes to prove the correctness of this view.*, The rocks consist in the main of magnesian limestones of varying texture, with inter- calated beds of sandstone. Considerable chert is associated with them. ‘The rocks of the Lower Carboniferous belong to what is generally known as the Burlington group, including, however, patches of Keokuk and rocks of the Kinderhook group. The ore deposits, however, are confined principally to the Burlington rocks. These consist mainly of fine, coarsely crystallized limestones, associated in places with beds of light colored, brittle chert, which are sometimes lo- ‘ally greatly developed, and occupy a large part of the section. Structurally, the geology is quite simple. There is one master flexure expressed in the quaquaversal dip of the rocks from the Archean center. Beyond this there are a few minor flexures and also a few well marked faults. There are also a large number of minor faults and crevices unaccompanied by movement. In the southwestern district the ore deposits are found al- most wholly in the Lower Carboniferous rocks. In the central and southeastern districts they are confined entirely to the Lower Silurian. ‘The deposits of the southwest are largely of zine ore, while in the southeast lead is the principal ore mined. The different districts are characterized by special forms of deposits. Thus, in the southwest the usual type is the mas- sive. The ore body is frequently several hundred feet in diameter, consisting of ore and gangue and surrounded by a more or less barren limestone or chert bars. Stringers or sheets of ore may run out into the country rock, but these are not of sufficient size to affect the general form. In the east- ern part of this district, tabular deposits in vertical crevices *Por the details of this investigation, the reader is referred to the Re- port on Lead and Zine. Mo. Geol. Surv., Pt. I, pp. 878-385. The Missouri Lead and Zine Deposits.—Robertson. 237 occur more frequently, although massive or cavern deposits are also found. In the southeastern district we also have massive deposits, but the structure of the ore body is totally dissimilar to those just referred to. These consist of great masses of magnesian limestone in which the lead ore is disseminated in grains of varying size. As in the southwest, so in this district are found the tabular or sheet deposits, as well as lenticular and pipe deposits and stockwerke. These occur mainly in Jeffer- son, Washington and Franklin counties. The ore body is composed of a mixture of gangue, ores and accessory minerals. The gangues consist of country rock, clays, sands and shales, secondary cherts and limestones, dol- omite and barite. The country rock is generally limestone, either pure or dol- omitic, or chert. It occurs both massive and fragmental. The former is seen in the southeastern district, where the ore is disseminated through large bodies of massive magnesian lime- stone. In the southwest, the country rock is mainly frag- mental and consists largely of chert breccia, although frag- ments of Coal Measure sandstone, shale and coal are met with in this breccia. The chert is angular, sometimes pitted, and while some blende or galena may occur in the crevices or cavi- ties, these minerals are never found in any quantity through the rock. In the southeastern district, where the deposit oc- curs in portions of the Lower Silurian rocks close to the Archean floor, water-worn boulders of granite are met with. Clays of many varieties are found in these deposits. They are generally dark red in color, but also occur in all tints of red and yellow to pure white. Some of these lighter colored varieties are called “tallow clays,” from their resemblance to tallow, and often contain a notable quantity of zine. Sands resulting from the decomposition of cherts and quartzite oc- cur in Jasper county and the adjoining Cherokee county, Kas. The shales consist of earthy sands and plastic and non- plastic clays which grade into sands on the one side and clays on the other. They are sometimes partly consolidated and sometimes soft and of the consistency of mud. Secondary cherts consisting mainly of an amorphous chalcedonie silica are abundant as gangues in Jasper and Newton counties and 238 The American Geologist, April, 1895 at Galena, Kas., to which districts they are practically con- fined. They vary in color from white through all shades of drab and brown to black, They exhibit an equally wide range of texture, varying from a soft shale on the one hand, to a rock as hard and considerably tougher than quartz on the other. They frequently form the matrix of a breccia of angu- lar chert fragments, which they hold with such tenacity that, in breaking, the line of fracture will pass through the chert fragment without even loosening it. At times the siliceous solutions appear to have partially dissolved the original chert fragments, thus causing the two to grade into one another. This silicification was evidently later than the deposition of the ores, as well-formed crystals of the galena and blende are frequently found enclosed in this matrix, and on being dis- solved out leave perfect exteriorcasts. Secondary limestones occur in some deposits, but, so far as noticed, do not appear to becommon. In specimens of such, the limestone forms the ma- trix of the chert breccia and often encloses crystals of blende. Dolomite, other than the magnesian limestones of the Ozark stage and of the pink erystals which are merely of mineralogi- cal interest, is principally found in the southwestern district. It is usually composed of a dense though incoherent mass of gray, grayish white or drab dolomite crystals. It appears to have been formed by magnesian solutions acting on the lime- stones into which it often grades. Barite occurs as a gangue mineral in the southeastern and central districts. It is gen- erally of the opaque white variety, tinged with iron on ex- posed surfaces. Vuggs occur in it lined with tabular ecrys- tals. It also occurs in some localities in limited quantities in large tabular, semi-transparent crystals, colorless or of a blu- ish tint. The minerals include the zine and lead compounds and the accessory minerals. The zine minerals are sphalerite, calamine, smithsonite and, rarely, hydrozincite. Sphalerite is found crystallized through- out the ore body and encrusting cavities. It isseen deposited on chert, limestone and dolomite. It is generally of a dark red color with a resinous luster, but is also found of a bright yellow color and often in small crystals of cinnamon and gar- net colors. Calamine, locally known as ‘silicate,’ is found The Missouri Lead and Zine Deposits.—Robertson. 239 mainly at Granby, Newton county, and at Aurora, Lawrence county. It isin the usual forms and there is little uncom- mon in its occurrence. It results from the decomposition of blende and coats crystals of that mineral as well as of calcite, and frequently forms pseudomorphs of the latter mineral. Smithsonite is likewise found in the usual forms and colors. It is the principal ore of zine found in the southeastern dis- trict. In the trade it is known as “silicate” and is not dis- tinguished from calamine. Of the lead minerals, galenite is the most abundant and important. It occurs in cubes and cube-octohedrons in aggre- gates sometimes of large dimensions. In the southeast it is found in crystalline and crystallized aggregates associated with barite in the tabular and crevice deposits and in granu- lar disseminated form in the magnesian limestones in the massive deposits. When deposited on calcite, barite, second- ary chert or other gangue, the crystals are usually well devel- oped; when found in the disseminated deposits the ecrys- tals are generally imperfect. All of the galena of this state contains a small quantity of silver, varying from 3 to 4 ounces per ton. Cerussite is found in all the districts, generally near the surface. It is nowhere abundant now, al- though it was previously mined in considerable quantities. Anglesite and pyromorphite are comparatively rare, and are of no commercial importance. Calcite is found ina variety of forms, generally crystallized in the usual scalenohedral forms. Sometimes these crystals are found with the alternate angles rounded in a very pecul- iar way. Barite has been referred to before. It mainly occurs in the southeastern and central districts; only little is found in the southwestern district. It replaces fossils in the Lower Carboniferous limestone in Pettis county. Dolomite is abun- dant in the southwest but occurs sparingly as a mineral in the southeast. It is found in aggregates of small crystals, sometimes so incoherent as to forma sand. It also occurs in curved erystals of the usual shape, of a beautiful peach pink color. Pyrite and marcasite are found inall districts although the former is rather rare. Marcasite is comparatively com- mon in the southwest. Chaleopyrite in small tetrahedrons is also frequently found. Quartz in the crystallized state is rare. 240 The American Geologist. April, 1895 It has been seen in the southwest as a coating on galena and cerussite and blende. Drusy quartz, or “mineral blossom” is quite common in the southeast. There are a number of other minerals found in greater or smaller quantities of little but mineralogic interest; such are bitumen, malachite, azurite, limonite, goslarite, ferrogoslarite and melanterite. The order of deposition of the minerals appears to be the following: dolomite, blende, galena, barite, pyrite, calcite. This order is not invariable, but is the one most commonly found. In the southwest the deposits are usually characterized by : brecciated structure. This sometimes grades off insensibly into the country rock. Some of the crevice deposits in the southeast and central distriets are brecciated in structure, as are also the circle deposits of the latter district. The mas- sive deposits of the southeast are, however, characterized by a granular or crystalline structure. The dense structure is applicable to certain vein deposits in the central and south- east. The general form of a southwestern massive ore deposit is a series of horizontal runs, which are ore bodies of an ill defined oblong shape, and which widen at places into large chambers, sometimes several hundred feet in diameter. The galena is almost invariably found over the zine and is frequently in a somewhat soft clayey gangue mixed with broken chert, al- though it occurs also on chert and limestone. In some mines the gangue is composed entirely of original and see- ondary chert, with small amounts of dolomite or dolomitie sand, no limestone being visible in the roof, but only found in the barren bars. In other mines the gangue is principally limestone or dolomite and little or no chert is found. Still other deposits, notably those of Webb City, are opened under massive roofs of solid, barren limestone of considerable thick- ness, under which the ore is found in large chambers, oceur- ring in the chert breccia and sometimes in Coal Measure shales. In the southeastern district, the massive deposits consist of: large bodies of the country rock which carry, in a more or less concentrated state, crystals or grains of galena. These rocks contain no chert, although a cherty limestone appears to overlie the ore-bearing limestone in some places. In some The Missouri Lead and Zine Deposits.—Robertson, 241 of the mines, the galena is concentrated to a greater or less extent in certain strata, while in other deposits there appears to be no regularity in the concentration of the ore. Asa rule there are no well defined limits to the ore body, but the min- eral contents of the rock gradually decrease until it is un- profitable to work. Only traces of zine have been found in these mines, but iron and copper pyrites are found in limited quantities and these contain small amounts of nickel and co- balt, which have hitherto been saved. Many small crevices are noticed in these mines, but they die out in depth and could consequently have played no part as carriers of ascend- ing solutions. Some faulting was noticed in one of the mines of this district. Though the ore deposits are frequently in proximity to such lines of disturbance, but little ore is found on the plane of the main fault and the others were of small throw and apparently of slight significance. The crevice deposits of this and of the central district are totally different in appearance from these massive deposits. They are often horizontal and consist of a network of small channels opening into larger or chimney-shaped bodies. The ore occurs usually ina gangue of clay or barite. Some of these deposits are of the vertical or vein type and show un- mistakable evidences of faulting. These are quite narrow and are filled with barite and clay in which the galena occurs. The Virginia minein Franklin county was followed to a depth of 480 feet, but the crevice was only + to 6 inches in width. There is one other variety of deposits, found in the central district and known as the circle type. In this the ore body is of a rudely conical shape, barren limestone being found on the exterior walls, and,in the interior, a circular mass of barren or nearly barren limestone debris. The galena is found in the breccia filling the circular space, attached to the limestone and associated with barite and calcite. In attempting to account for the origin of these deposits the first question to be disposed of is that of the formation of the cavities inwhich the minerals are found. These cavities are of two kinds: 1) vertical or transverse to the strata; 2) horizontal or between the strata. The various movements of the earth have, as already inti- mated, given rise to flexures and faults, generally small in 242 The American Geologist. April, 1895 size. Crevices have also been opened by the contraction of the sediments. These crevices and fault planes acted as chan- nels for meteoric waters, and were enlarged by them. The period succeeding the deposition of the Ozark rocks was one of great erosion. ‘This is indicated by the small representa- tion of the Upper Silurian and Devonian rocks, the country not being submerged during the greater portion of the time these rocks were being deposited elsewhere. The presence of organic acids in the meteoric waters would increase their sol- vent action.- There was, moreover, much erosion after the deposition of the Lower Carboniferous rocks, and also after the deposition of those of the Coal Measures. That there was a slight deposit of these latter rocks over a large portion of southern Missouri, is probable. The area was above water, however, from an early date, in the Coal Measure period, with a possible slight exception, to the present day. The cavities of the large southwestern deposits were formed by this solvent action of surface waters which enlarged joint planes and crevices. Their location on the margin of the Coal Measures afforded opportunity for the access of waters carrying large quantities of organic acids, derived from decaying vegetation, which increased their solvent power materially. Added to this, the structure of the rocks of the Lower Carboniferous, pure limestone with many intercalated chert beds, furnished material readily dissolved, as well as contact planes affording easy access to the material. It may be readily conceived that once the limestone supporting these beds of chert dissolved, that chert, on account of its extreme brittleness, would frae- ture and break into the materials which now forms the breccia that characterizes these deposits. Horizontal cavities, flat tabular-shaped spaces enlarging into chambers at times, such as are frequently met with in the southeast, had their origin in the same solvent action of water, here localized among certain stratification and joint planes where the rock yielded more readily to that action. Those cavities, the filling of which have given us the type known as “circle deposits,” are best explained by referring to certain caves which have their opening in the roof. One of these caves in Stone county was examined and surveyed by Dr. E. O. Hovey and the writer. The main feature was a The Missouri Lead and Zine Deposits.—Robertson, 2438 large, circular dome-shaped cavity with a small opening in the roof. In the center of this amphitheatre was a huge pile of debris which had loosened and fallen from the roof and sides. The cave had been formed by the solvent action of water and at this point had widened out, producing a large cavity, the interior of which was filled as described, by fragments of the roof and wails which had become detached and fallen in. The filling of the annular space thus left by limestone debris and the deposition of barite, calcite and galena in the interstices would give just such a circle deposit as seen at the Conlogue mine in Miller county, or the High Point in Morgan county. The disseminated deposits of the southeast are formed by a metasomatic interchange of minerals, no cavity existing prior to their deposit. The filling of the cavities is the next step. The gangue, as already stated, consists largely of country rock and of decom- position products derived therefrom. It may be readily con- ceived that fragments of rock, perhaps less soluble than the rest, becoming detached, would lodge in and assist in the fill- ing of the cavities. The clays and sands were undoubtedly the product of the immense surface erosion then in progress, and were transported. Someof the clays—such as the tallow clay—were probably deposited chemically. The minerals were undoubtedly deposited from solution sometimes by chem- ical interchange. and sometimes by evaporation and concen- tration of solutions. It now remains to consider the source of the mineral solutions. Many theories have been propounded regarding the source of the minerals forming ore bodies. So far as these refer to the subject under discussion, they may be expressed in three comprehensive hypotheses: 1. That the minerals were origi- nally deposited in a concentrated condition. 2. That the minerals were derived from great depths. 3. That the min- erals were widely diffused, but were gathered together and deposited by lateral secretion. The first of these theories in- sists that the minerals existed in the original oceanic waters in a considerable degree of concentration, and were deposited directly, or, in the case of disseminated deposits, by metaso- matic action. It is hard for us to conceive, however, how such circumstances could have obtained. Besides the fact that in 244 The American Geologist. April, 1895 waters carrying so high a proportion of mineral matter, ani- mal and vegetable life could not have existed, this theory does not explain why such deposits are not found over amore widely extended area, especially when there appears to be but little difference in the rocks of adjoining areas. Moreover, it would be necessary to extend these metalliferous ocean waters to cover both the Lower Silurian and the Lower Carboniferous epochs. Further, while disseminated deposits might possibly be explained by such an hypothesis, the large deposits of the southwest are not. The second theory is that the minerals came in solution from great depths. That this is true of many deposits of known true fissures is undoubtedly a fact, but in the present instance there are many obstacles in the way of this hypoth- esis. First, the crevices which have been found decrease in size as they descend. Some of them in immediate contact with ore bodies are entirely barren or carry but little ore. Again, underlying considerable portions of the ore-bearing rock is a large bed of sandstone, open, porous and water-bear- ing. No ore has been found in this rock, and it seems very strange that concentrated solutions could have passed through it and left no trace. In all well authenticated vein deposits where solutions have presumably come from great depths, lead ores carry a recognizable amount of silver, and accessory min- erals, such as rhodochrosite, rhodonite, arsenical, antimonial and bismutiferous minerals are found. In Missouri, however, the lead carries from a trace to three or four ounces of silver per ton, with the exception of that from one acknowledged true fissure deposit in the granite at Einstein mine, where the ore carried considerable silver and where some of these accessory minerals were found. The third hypothesis, that of the wide diffusion of the met- als, supplemented by Iateral secretion, has in it more local elements of evidence to support it than either of the others The widespread existence of the metals in rocks has been demonstrated by Emmons, Sandberger, Forschammer, Bischof, and others. The action of lateral secretion has, however, been condemned by many writers who narrowed its application to the leaching of the immediately adjacent rocks. The question has thus been raised as to the sufficiency of the metalliferous The Missouri Lead and Zine Deposits.—Robertson, 245 contents and as to whether the metals found in rocks were not introduced subsequently to the deposits of ore. In regard to the first point, it is not at all necessary to confine the area of supply to the immediately adjacent rocks; and in regard to the latter point, while it would be impossible to prove its falsity, itis in many cases highly probable that the minerals existed diffused in the rocks, from the fact that they are found in similar rocks in areas removed from ore deposits. The applications of this theory, heretofore, however, appear to be inadequate to explain these deposits. Prof. Chamberlin’s explanation of the Wisconsin deposits and,incidentally,of those of Missouri, introduced lateral secretion as a secondary cause, the primary one being concentration by oceanic currents in the Lower Silurian seas. This does not cover the case of the large Lower Carboniferous deposits of Missouri, and appears to be too theoretical to satisfy the demands of the case. Mr. F. C. Clere suggests that the deposits were derived by lateral secretion from the Coal Measure shales. For this he requires a Quaternary submergence during which these shales were leached and their metalliferous burden deposited in the Lower Carboniferous rocks below. These Coal Measure shales, how- ever, are very impervious to water and are not associated with all of the deposits, by any means. Moreover, no deposits of any importance are found in Coal Measure rocks, as would be expected. The hypothesis here advanced to account for the origin of these metalliferous solutions is that of concentration through surface decomposition. This hypothesis starts with the prop- osition that the metals existed originally in the Archean crystalline rocks either diffused or in veins. On the degrada- tion and decomposition of these rocks, the metalliferous min- erals were partly transferred to the Silurian rocks and from these in a like manner transferred to the rocks of the Lower Carboniferous stage. Here the surface decomposition, ex- tending through long periods, favored local concentration of the minerals in the meteoric waters and these, penetrating downward, deposited their load where conditions were favor- able. The widespread occurrence of lead and zine in nature is treated of in acomprehensive way in the report referred to.* *Mo. Geol. Sury. Report on Lead and Zine, Pt. 1, p. 30. 246 The American Geologist, April, 1895 In support of this hypothesis a series of analyses of the rocks of the state was undertaken by the writer to determine the presence and amount of the metals in question. In the report referred to the results of these analyses are given in full, as well as the method pursued. Here it will be sufficient to give an outline of the results. Metalliferous Contents of Missouri Rocks. Lead per cent. Zinc per cent. ARCHEAN Rocks. Range of S analyses of 4 specimens 0.00197 to 0.00680 0.00189 to 0.01760 SILURTAN ILAGNESIAN LIMESTONES. Range of 12 analysesof6 specimens ‘Trace to 0.00156 Trace to 0.015388 LOWER CARBONIFEROUS LIMESTONES. Range of 15 analyses of 7 specimens Trace to 0.00846 Trace to 0.00256. These analyses were made with great care and after much experimenting. While there are not a sufficient number of determinations to base many generalizations upon, they cer- tainly afford results of a very significant nature. Copper, manganese, and barium sulphate were also determined, al- though the results of these determinations are not given here. The presence of larger amounts of these metals in the im- pervious crystalline rocks certainly points to the conclusion that they existed there originally and were not introduced. subsequently from more recent sources. The average con- tents of the limestones are thus 0.001009 Y lead and 0.002399 zine, which is equivalent to 0.00198 tbs. galena and 0.00608 tbs. blende to the cubic foot of rock. This would give— 27°8 tons galena per square mile, 1 foot thick. or 13,900 tons galena per square mile, 500 feet thick, and $3.6 tons blende per square mile, 1 foot thick, or 41,500 tons blende per square mile, 500 feet thick. Thus we find, according to our hypothesis, which does not limit the action of lateral secretion to the immediate wall rocks of the deposit, that the metalliferous contents of the rocks are ample to supply the ore deposits. In support of this hypothesis we have evidence of great and prolonged erosion during different geological periods, as has been referred to before. This has occurred in Wisconsin as well and has been noticed by all the writers on the geology of that state. The hypothesis also accounts for the dolomization of the Lower Carboniferous limestones, the waters draining. the Lower Silurian areas carrying in solution sufficient mag- The Missouri Lead and Zine Deposits —Robertson. 247 nesium bicarbonate to effect this. Besides this, the crevice deposits, avhich diminish in size as depth is reached, indicate that they were filled from above. Finally, the decay of large quantities of rock would give rise to correspondingly large bodies of ore, thus explaining the association of bulky depos- its such as Jead and zine, with the comparatively soluble limestones. Coming down to evidences of a more local nature we note that the large deposits of the southwest occur on the border of the Coal Measures, On examining the geological map of the state a tongue of Lower Carboniferous rocks will be no- ticed, extending to the eastward. This was probably the site of an estuary, through which large quantities of water derived from the central and eastern parts of the area flowed, contain- ing the products of decomposition of the magnesian limestones of those sections. Thus was the material supplied. During the Coal Measure epoch an immense amount of decaying or- ganic matter supplied the most perfect means for the redue- tion of the mineral in solution. The ample drainage con- stantly kept up the supply of metalliferous solutions and the deposition probably took place rapidly. The crevice-shaped cavities were filled by similar solutions and were probably deposited in a similar manner by the aid of organic matter. The disseminated deposits of the southeast are more difficult to explain. In general they are found in an open porous rock, which is probably one of the chief causes of their for- mations. In addition to this, the occurrence of more or less organic matter in the rock has had some influence, and the presence of shale beds has restricted and directed the flow of solutions. The crevices frequently found in these mines have been, in all likelihood, the avenues through which the solu- tions traveled in reaching the shallower of these deposits. This is evidenced by the frequent occurrence of galena in them. The deeper deposits of Flat River, however, ‘cannot be readily referred to these crevices, on account of their narrowing and dying out in depth. There is, however, underlying these deposits a bed of sandstone, open, porous, and water-bearing, which might be suggested as a solution rarrier. ‘The water in this bed is under sufficient head to 248 The American Geologist. April, 1895 sause it to rise well into the limestone rocks in the valley where the texture and structural conditions allow. a This statement includes the more important evidence which favors the hypothesis advanced. It is thought that it ex- plains existing conditions better than does any other. Of course, there is much more additional work needed in the field and in the laboratory to supplement what has been done. There are many details of the chemistry of the processes of solution and deposition of these ores, the causes controlling the localization of deposits, ete., which need elucidation ; and it is hoped that this report may be the means, to some extent, of stimulating such work. ON THE MUD AND SAND DIKES OF THE WHITE RIVER MIOCENE. By BAC] CASES lithacaiNe ve During the past few years attention has been called by va- rious authors to the occurrence in widely separated localities of dikes of sandstone, which pierce for many feet the neighbor- ing strata. The most pronounced occurrence of these dikes was reported by Mr. J. S .Diller from northern California (Bull. Geol. Soc. Am., vol 1, p. 411). The article contains a full ac- count of the nature and occurrence of these dikes and the author's conclusion that they are intrusions of sand from below, along cracks determined by voleanie action (p. 487). In describing the dikes he says, ‘the dikes are nearly vertical, wall-like masses of sandstone, varying from a mere film to 8 feet in thickness. * * * The dikes are parallel: to the joints in the vicinity and so related to them as to indicate that the joints have not been produced by the dikes, but that on the contrary the position of the dikes has been determined by the joints.” From the occupancy of preexisting joints by the dikes and from the position of the mica grains in microscopic sections of the sandstone Mr. Diller reaches the above stated conelu- sion, that the dikes are intrusions from below. To account for this intrusion he calls attention to the fact that below a certain level the materials of the earth’s crust are saturated Dikes of the White River Miocene.—Cuase. 249 * with water, this water may be under hydrostatic pressure and certainly is under that of the overlying strata, so if any crack is opened from above to a saturated layer of loose sand the water will rush up and carry with it the sand. The subse- quent hardening of this sand will produce the sandstone dikes. In evidence of the voleanie origin of the cracks occupied by the sandstone, the author of the paper calls attention to the parallelism of the dikes as illustrated in fig. 2, p. 413 of his article (op. cit.). Later, an article appeared by Prof. Robt. Hay on the ‘“Sand- stone Dikesof Northwestern Nebraska” (Bull. Geol. Soc. Am., vol. 11, p. 50). The dikes here described are similar to those described by Diller but are fewer in number, only two being noted. They are in the vicinity of Chadron, Nebraska, and pierce the clays of the so-called Pine Ridge. Prof. Hay re- gards them as intrusive from below, as will be seen from the following quotation from his article: “It (the main dike) does not on either side reach the top of the ravine, and a bluff of much greater elevation a few hundred feet away shows no sign of its presence, so it may be definitely regarded as hav- ing been formed before the completion of the soft clays and marls. * * QOne of the evidences of intrusive character lies in the structure of the laminated sheets on either side of the dike. In these the lamine farthest from the dike are more argillaceous than inside and the inside lamin are decidedly grooved, with vertical ridges, and grooves to correspond on the sides of the wall itself.” Prof. Hay does not attempt to explain the origin of these dikes but suggests that “these dikes may be related to the phenomena of mud volcanoes, as they were certainly intruded from below, and they may be expressive of the closing period of the Black Hills uplift.’ He alsu speaks of the existence of other dikes in the “bad lands” of South Dakota. It is the aim of this article to describe these dikes and show how they dif- fer from those already described and possibly throw some light upon the formation of sandstone dikes in general. The “bad land” or White River Miocene region of South Dakota is the seat of the eroded remnants of a vast lacustrine deposit of lower Miocene or Oligocene age. The entire thick- ness, according to Hatcher (Am. Nat., March 1898, p. 218), is 250 The American Geolog?st. April, 1895 something over 600 feet. The beds are composed of alternat- ing layers of a very fine-grained clay and sandstone, the latter passing at times into a hard conglomerate. The deposits were divided by Hatcher (loc. cit.) into two sets of beds, the Oreo- don and the Titanotherium beds, named from their charaec- teristic fossils. Later (Bull. Am. Mus. Nat. Hist., vol. v, p. 101) Wortman subdivided the upper into the Protoceras and Oreodon beds, so we have now: The Protoceras beds, 180 feet, clays and coarse sandstones. The Oreodon beds, 270 feet, mostly clays. The Titanotherium beds, 175 feet, clays and sandstones. It is in the two lower of these beds that the dikes occur. There are associated with the sandstones, veins of chalcedony, which may be either in connection with the sandstone or en- tirely separate, and the sandstone may exist entirely free from the crystals of quartz. Speaking of these veins, Hatcher says (Am. Nat., March, 1898): “In various portions of the Titan- otherium beds there are numerous vertical veins of chalce- dony running through the beds in every direction. These veins vary in thickness from that of a sheet of paper to about two inches. * * * Occasionally other minerals, as ordi- nary calcite and its common variety known as Iceland spar, are found in small cavities in these veins. * * * These veins occur only in certain localities of limited area. Any single locality is never more than a few miles in extent.” These observations relate only to the lowest bed and to the veins of chalcedony. During the summer of 1894 the writer was able, while in the bad lands, to make some observation on the occurrence in both the lower beds of not only the chalce- dony veins but also the mud or sandstone dikes not mentioned by Hatcher. Let us consider first the dikes of soft sandstone or mud free from crystallized silica. The sandstone is not hard, but on the contrary is very soft and friable and seems in many cases to be little more than a mixture of sand and clay, sometimes | passing into almost pure clay. They stand up from the sur- rounding clays but a few inches, in the greatest instance ob- served not to exceed six, and in weathering no blocks are formed, the disintegration is complete in the dike. The color of the intruded sandstone in the Oreodon beds is a light green Dikes of the While River Miocene.—Cuase. 251 ~ and it is easily recognized as identical with a layer of green sandstone lying near the base of the same beds, the Metamyn- odon sandstone of Wortman. In some cases it may be darker and softer from a larger mixture of clay, but never loses its distinctive sandy character. In the dikes of these beds and those below, the Titanotherium beds, one fact is especially no- ticeable, the contents of a dike at any point is universally from a stratum below. ’ The dikes commonly traverse the clays perpendicularly to their stratification and in a straight line, but with no common direction or any parallelism. They extend at least through the two lower beds, having here a vertical range of 450 feet. Different dikes were traced continuously for over a mile and were uniformly about three inches thick; other dikes reached an observed thickness of a foot, and I was informed by Dr. Wortman of some 18 to 20 inches wide. The thickness seemed to be constant in vertical range. The strata on each side are undisturbed and only on the faces next the dike was there seen any evidence of motion. Here for perhaps a quarter of an inch in there was a ming- ling of the clays of different strata as if by water action, and a slight deflection upward. In some instances, at a point below the effect of surface wash, the sand had penetrated the clays for an inch or less on each side. There seems to be an entire lack of structure in the dikes such as is mentioned by Diller (Bull. Geol. Soc. Am., vol. 1, p. 425) and Hay (Bull. Geol. Soe. Am., vol. 1m, p. 53). In the cases where the dikes are connected with the chalce- dony erystals the veins may exist on one or both sides of the intruded material between it and the clay walls of the crack. The absence of the crystals from one side or the other is not a local accident, but seems constant for large areas. In every case where it occurs, on one or both sides of the core, the crystals have a perfect vein structure, presenting a flat sur- face to the core or dike and one to the clay wall, and meeting irregularly in the middle. There are inclusions in the veins identical with the substance of the dike and also of calcite. One noticeable fact is that the veins of chalcedony in many observed cases, and probably in all, thin out from above downward. 252 The American Geologist. April, 1895 Where the veins of chalcedony occur alone, they are so per- fectly analogous in form and position with the dikes as to make it evident that the joints and cracks they occupy are of the same origin as those of the dikes, and they may throw added light on the method of the formation of these cracks. The veins run not only vertical and in all directions, as de- scribed by Hatcher, but have also an inclined position, cross- ing the nearly horizontal layers of clay at angles varying from 90° to 45°: no smaller angles were observed. From their hardness they resist weathering a great deal longer than the soft clays and stand up in jagged lines above the surface. When the clay around is removed and the support fails, pieces are broken off from the thin seams and fall on the neighbor- ing clays; thus whole hills are covered with small sheets of quartz and are protected as by a shingle roof from the action of rain. Other local elevations are determined by the union of several veins in a common center, and from these centers run ridges, more or less pronounced, each determined by a vein and with a backbone of chaleedony. When a vein enters a hill obliquely to its stratification, it determines from its su- perior resistance to erosion the outer and upper edge of a cliff on the hillside. When the veins meet and cross they do not penetrate and destroy each other, but fuse, and perfect homogeneous crosses were obtained from localities of such intersection. Frequent inclusions of clay and calcite are found in the veins, and the clay is uniformly from a layer below where it is found. In seeking an explanation for these dikes it is evident we must seek for the cause of the cracks which they occupy, and in doing so we must consider the evidence furnished by the veins of chalcedony as well as the dikes proper. We find that the theory proposed by Diller to explain the dikes in Califor- nia is here only partially applicable. The conclusion reached by him that the sand was foreed up from below with water, receives conclusive confirmatory evidence from the dikes of the Miocene clays as shown above. On the other hand, the origin of the cracks receives no light from his explanation. The absolute lack of any parallelism in the cracks precludes the idea of their production by earth movements; nor were they produced by successive movements in different directions, as Dikes of the White River Miocene.—Cuse. — 253 is shown by the perfect fusion of the veins of chalcedony in crossing each other. They were formed all at the same time in cracks which crossed each other. Hatcher (Am. Nat., March, 1898, pp., 208, 209) says of these veins: “On first thought the writer was inclined to attribute their origin to mud cracks, any particular region where they now occur having been for short periods, during seasons of low water, above the water level, and subjected to the action of the atmosphere and the heat of the sun became baked and cracked ; just as we now so often see at low water along the mud flats of our streams and lakes. But it is obvious that if these veins owe their origin to mud cracks they would be filled, not with chalcedony, but with the same materials as the overlying beds; for when the waters again covered this region, the mud cracks would immediately be filled with the same materials that now compose the overlying beds.” This objection to the mud cracks, it seems to me, will hardly hold, as it is evident, in many cases at least, that the cracks were immediately filled by the intrusion of upward moving sand and water. Further, Hatcher says (loc. cit. p. 209): “It has since oc- curred to the writer that these cracks were not made while the particular strata in which they now appear occupied the immediate bottom of the lake, but after the overlying beds were deposited. ‘The extreme fineness of the particles form- ing the clays of the Titanotherium beds in those places where these veins occur is evidence that the clays were deposited by a slow process of sedimentation in still waters. The bottom of a lake where such materials were being laid down would consist for several feet of a very thin mud or ooze. This would gradually become firmér toward the bottom as deposi- tion continued, but would still mechanically retain a consid- erable per cent. of water. Later, when the entire overlying series of strata were deposited and the region brought perma- nently above the water level, this imprisoned water would gradually disappear by filtration or otherwise, aided perhaps by the pressure of the superincumbent beds. This loss of moisture in the clays would diminish their volume and bring about a readjustment of the particles composing them. The decrease in volume would be taken up in two ways: First, as 254 The American Geologist. April, 1895 in the case of mud cracks, the particles would tend to collect about certain centers in the beds, and these centers of adhe- sion would increase laterally by the attraction of adjacent par- ticles until cracks of varying thickness would form between the peripheries of adjacent centers cf adhesion. The pressure of the overlying beds would determine the vertical direction of these cracks, and would afford the means for the second way, by which the decrease in the volume of the clays would be taken up, viz., by a decrease in the vertical thickness of the beds. These cracks thus formed far beneath the surface were afterwards filled by chaleedony dissolved out of the over- lying beds by heated waters percolating through them.” This explanation would account most perfectly for the veins which cut the strata of the clays in a line oblique to their planes of deposition and also the gathering of the veins together in common centers, causing the regions to resemble, as mentioned by Hatcher, huge septaria. Conclusions: The dikes of mud and sand occupy pre-exist- ent cracks which were filled by intrusions from below of wa- ter and suspended material. The water was forced into the eracks from porous layers either by hydrostatic pressure or that of the superincumbent strata, probably both combined. The cracks are not the results of earth movements. .They are in all probability both mud cracks and cracks formed by segregation of the clays around local centers. The veins of chaleedony were formed by the entrance into cracks of similar origin as those containing the dikes, of sili- cated waters. The cracks were already filled more, or less completely with water and sand. The thinning out of the seams from above downward indicates that the silicated wa- ters filtered in from above. EDITORTEAL, COMME ING SECULAR CHANGES oF ARCTIC CLIMATE. The astronomic theory of the causes of the Ice age, as ad- vocated by Croll, Geikie, and Ball, is examined by Mr. E. P. Culverwell in the Geological Magazine for January and Feb- Editorial Comment. 255 ruary. Like Woeikof and others, he finds this theory insuf- ficient to account for the climatic conditions of the Glacial period and the accumulation of its continental ice-sheets. This conclusion, however, seems not to be inconsistent with the view presented in the last number of the AMEertcan GEoL- ocist (page 201), that the Kansan and Iowan stages of ex- tended growth of the North American ice-sheet, with the intervening considerable retreat of the ice border in the upper part of the Mississippi basin, were due to the last two cycles in the precession of the equinoxes, bringing the winters of the northern hemisphere in aphelion. Dr. G. F. Becker’s recent investigation of astronomie conditions favorable to glaciation lead him to conclude, altogether differently from the three British scientists first mentioned, that low eecen- tricity of the earth’s orbit and high obliquity of the ecliptic are likely to promote snow and ice accumulation in high lati- tudes and mountain distriets.* He thinks also that geographic conditions, as high land elevation and changes of marine currents, conduced toward the causation of the Glacial period. Granting that the Pleistocene ice-sheets were formed,as Dr. Becker indicates, by such concurrent geographic and astro- nomic conditions within the past 50,000 years, continuing until] some 8,000 years ago, it seems to me highly probable that even the small present eccentricity (0.0168) was adequate to cause the interglacial recession of the ice-sheet in the in- terior portion of our continent between the Kansan and Iowan glacial stages, of which we have abundant evidence in buried forests, peat, and other fossiliferous beds enclosed between deposits of till in Ohio and the other states west and north- west to Minnesota. When we compare even this small ratio of eccentricity with the great range from the earth’s mean surface temperature, produced entirely by the sun’s heat, to the absolute zero, which Dewar finds to be —461° Fahrenheitt (this being the temperature, or rather the total absence of heat, in the interstellar spaces and upon the earth if its sup- ply from the sun should cease), we may believe that so slight climatic effects as might result from the present eccentricity, in connection with equinoctial precession and nutation,’could *Am. Jour, Sci., III, vol xivriz, pp. 95-118, Aug., 1894. 4McClure’s Magazine, vol. m1, pp. 557-562, Nov., 1894. 256 The American Geologist. April, 1895 ‘ause important fluctuations of the ice-sheets in both Ameri- ‘a and Europe. Finding Croll’s theory unsound, Mr. Culverwell advances one of his own, which is stated as follows: Is it possible that there may have been any considerable interchanges of atmosphere between the earth and the regions of space through which it has passed’ It is certain that there must have been some such inter- change. Whether the atmospheric pressure is increasing or diminish- ing depends on whether, in the course of the carth’s motion through space, more of the interstellar molecules get entangled in the earth’s at- mosphere than, leaving that atmosphere, get entangled in the interstel- lar gases through which the earth happens to be passing, and are thus dragged away from the earth. If once we were allowed to assume the magnitude of these changes, the whole difficulty of explaining Glacial or genial ages, so far as temperature Changes are concerned, would van- ish. Tor instance, if due to some gascous conditions of space, or per- haps to the absorption into the atmosphere of the gaseous components of meteorites or shooting stars, there be an addition to the atmospheric pressure of one millimetre in three centuries, and if this process has been continued for 20,000 or 25,000 years, then it follows that some 25,- 000 years ago the atmospheric pressure would have been less by about one-tenth part than it is at present. This would be equivalent to rais- ing land and sea by about 2,500 feet, for the blanketing effect of the de- creased atmosphere would be about the same as that which now lies above a mountain 2,500 feet high. Thus a Glacial epoch might be produced without any alteration in the geographical conditions. And if, on the other hand, either through the earth plunging into a more gaseated region of space, or through some catastrophe, the atmospheric pressure were to be much increased, the resulting increase of temperature might be very great, and a genial age might be the result—a rise of 50°F. might Leadily DescOber nema If two bodies flying about in space come into collision they may generate a mass of gas, and if this mass of gas hap- pens to get in the earth’s path it may be caught up. — Indeed, if we as- sume that the earth’s atmosphere maintained a strict equilibrium with the interstellar molecules at, say, a distance of 1,000 miles from the earth’s surface, then a doubling of the almost infinitesimal pressure there would necessitate a doubling of the pressure at the earth’s surface. Of course this supposition is only used for the purpose of illustrating the fact that a small alteration of interstellar pressure, if spread over a suf- ficiently vast space, might eventually give rise to a considerable change in the atmosphere...... the problem of atmospheric interchanges is so complicated that I may at all events hope to enjoy my hypothesis for a considerable time before anyone succeeds in giving it a really decisive overthrow. Its great advantage as a theory of the Glacial epoch is, that it does not require geographical changes such as are usually postu- lated in connection with all other theories, even the Astronomical one.* *Geol. Magazine, TV, vol. mm, pp. 64, 65, Feb., 1895. Editorial Comment. Di Instead of regarding this hypothesis as possibly acceptable, the present writer sees an apparently crucial and insuperable objection to it in the great and sudden changes of climate which we know to have taken place in Arctie regions within the Pleistocene period. It has been generally held, and no doubt rightly, that the oncoming of the Glacial period was quite gradual and slow, and that its termination, with the melting away of the ice-sheets during the Champlain epoch, was geologically very sudden. This would perhaps accord with Culverwell’s suggestion of slow loss of the earth’s atmos- phere while the ice-sheets were being amassed, and with sud- den increase of the atmosphere bringing the Ice age to its end. Better, however, as I think, these wonderful climatic results can be shown to have depended on great epeirogenic uplifts of the land areas which became glaciated, and on the depres- sion of these areas in the Champlain epoch, giving again a genial climate and melting away the ice. The observations Which appear fatal to Culverwell’s explanation, but not incon- sistent with my epeirogenic theory, are those of Dall in Alaska and of Baron Toll in the New Siberia islands. After a stage of glaciation in each of these regions, there supervened a temperate climate, mostly melting away the ice-sheets; veg- etation flourished on the drift which had been englacial and finally became superglacial; and herds of mammoths and other large animals pastured on the shrubs and herbage. Then suddenly came a much colder climate, after the culmina- tion of the Ice age, under which the mammoths were over- whelmed and became extinct; but their frozen bodies, un- thawed to the. present day, are occasionally washed out of alluvial river banks. It is the sudden change from mild con- ditions to those of severe cold which the atmospheric theory cannot account for, and it may be confessed that we should not expect such a change to result even from any combina- tion of epeirogenic movements, variations in volume and di- rection of sea currents, changes in prevailing courses of winds, exceptional storms, ete.; but the latter class of causes is un- doubtedly the more probable, and the very deep fjords and continuations of river valleys beneath the sea tell unmistaka- bly of great elevation of the glaciated lands immediately preceding the Ice age. 258 The American Geologist. April, 1895 Without attempting to solve the puzzle, we may only add the reason for the assertion that the ice observed beneath the drift and mammoth remains by Dall, and by others before him, on the shore of Esehseholtz bay in Alaska,* and by Baron Toll on Lyakhoff island of the New Siberia group,t is due to the accumulation of néve snows and their consolidation into ice, rather than to the freezing of shallow lakes or infil- trating surface waters, as Russell, Dall, and Howorth have supposed. Russell’s explanations may probably be true for many parts of the tundras of Alaska and Siberia; but in the two localities noted, where abundant animal remains occur in the drift above the ice, the structure of the ice itself proves it to be remnants of ancient ice-sheets. The researches of Grad, Klocke, Forel, and others, have shown that all glacier ice preserves the granular structure which has its beginning in the change of the névé from snow to ice. Lake ice, on the other hand, has a prismatic or co- lumnar structure. The glacier granules, varying in size and occasionally so large as from one to two or three inches in di- ameter, are irregular or without parallelism in the directions of their crystalline axes; but the prisms of lake ice are perpendicular to the freezing surface. Glacier ice in the pro- cess of melting reveals its granular condition, and this is dis- tinctly noted by both Dall and Toll. Writing of the ice-clitfs of Eschscholtz bay in northwestern Alaska, Dall remarks: The ice in general had a semi-stratified appearance, as if it still re- tained the horizontal plane in which it originally congealed. The sur- face was always soiled by dirty water from the earth above. This dirt was, however, merely superficial. The outer inch or two of the ice seemed granular. like compacted hail, and was sometimes whitish. On the New Siberia islands, about 1,400 miles west-north- west from the Alaskan ice-cliffs, the same structure is noted (Nature, Jan. 31, 1895): The chief geological result is the settling of the real positions of the layers which contain relics of the mammoth. They are undoubtedly Post-Glacial, as they overlie the masses of underground ice which form *Am. Jour. Sci., III, vol. xx1, pp. 104-111, Feb., 1881; U. S. Geol. Sur- vey, Bulletin 84, 1892, pp. 260-268. (Compare comments by N. H. Win- chell, Am. Jour. Sei., If, vol. xx1, pp. 858-860, May, 1881.) +Geol. Magazine, III, vol. x, pp. 107-111, March, 1898; Nature, vol. 11, p. 327, Jan. 31, 1895. Review of Recent Geological Literature. 259 the chief rock of the great Lyakhoff Island, and which, as Baron Toll’s observations now prove, are remains of the great ice-sheet which for- merly covered both the islands and the mainland, and whose moraines have now been discovered on the mainland. Moreover, these ice masses have the typical granulated structure of the glacier ice, which proves that they have originated from the snow-cover, and could not have originated from any sort of running water. As to the Post-Glacial lay- ers which overlie the above, they contain, besides shells of Cyelus and Valvata and well-preserved insects, full trees of Alnus fruticosa, willows, and birch, fifteen feet high, and bearing perfectly well-preserved leaves and cones. The northern limit of tree vegetation thus spread during the Mammoth period full three degrees of latitude higher than it spreads now, @. ¢., up to the 74th degree, and the mammoths and rhinoceroses of the time lived upon the patches of meadow clothed with the above bushes. It is worthy of note, that the masses of underground ice are not found in the lower parts of the Arctic coast which are known to have been covered by the Post-Pliocene sea, and that they only occur where the land rises a few hundred feet above the present level of the sea—that is, above the level of the Post-Pliocene ocean. WwW. U. Revie OF RECENT GEOLOGICAL PIPE RA TURE: Manual of Geology, treating of the principles of the science with special ref- erence to American geological history. By James D. Dana. 1087 pages; 1575 figures in the text; and two double-page maps._ Fourth Edition. (American Book Co., 1895.) The first edition of this Manual was brought out in 1862, the second in 1874, and the third in 1880. After having been before the public a third of a century, and after its author has been engaged in geology and zoology during sixty years, the Manual in the present edition includes frequent illustrations and examples (as on pages 266, 280, etc.) of geological processes and principles from the author's observations during all these years, in which he has seen the science vastly expanded and the geologic exploration of North America and all other parts of the world carried forward until now few large dis- tricts remain entirely unknown as to the history recorded in their rock formations. Professor Dana’s studies of coral islands and of voleanoes during his voyage in the Wilkes Exploring Expedition, in 1838 to 1842, and in his visit to the Hawaiian islands again. in 1887, have given a special value to his discussion of these subjects; and his doctrine of the gradual growth of North America as a typical continent, first announced in 1846, has well stood the test of a half century of rapidly progressing in- vestigation and theories. Throughout the volume, as in Lyell’s works, a prominent and stimulating feature is the brief reference to discover- 260 The American Geologist. April, 1895 ies and authors, with dates, marking stages of noteworthy extension of the science and establishment of its chief principles. For each of the great eras and periods, the authorship and date of first use of their present names, with their synonymy, are noted, affording useful clues for the student in entering any special studies of stratigraphy or pale- ontology. The grand divisions of the volume. and the order of their considera- tion, ave physiographic, structural, dynamical, and historical geology. In the preface Prof. Dana says: ‘‘As the rewritten book shows, new principles, new theories, and widely diverse opinions on various sub- jects are among the later contributions, along with a profusion of new facts relating to all departments of the science. The Cambrian forma- tion has been traced through a large part of the continent, and the number of its fossils has been increased, chiefly by C. D. Walcott, from a few to hundreds. The Appalachian Mountain structure has been shown by Clarence King, Dr. G. M. Dawson, and R. G. McConnell, to have been repeated in the great post-Cretaceous mountain-making of the Rocky Mountain region. The Reptiles. Birds, and Mammals of the Mesozoic and Tertiary have continued coming from the rocks until the species recognized much outnumber those of any other continent. The canons and other results of erosion in the west have thrown new light, through their investigators, on the work of the waters. Besides, the science of petrology has elucidated much of the obscure in the constitu- tion, relations, and origin of rocks.”’ It was not to be expected that this summary of North American geol- ogy, by one who has held so prominent a part in its development, would accord with the views of other prominent geologists in all details, or even in some important correlations and opinions concerning the origin of debated formations. Taking two or three of the author’s interpreta- tions, where they differ from those held by others who have done much field work on the formations under consideration, we may note the ret- erence of the Keweenawan series to the Middle or Lower Cambrian, in- stead of the Algonkian system, which latter is not accepted for its proposed place between the Cambrian and Archean: the assignment of the Lafayette formation to the Pleistocene period, and to freshwater deposition by flooded rivers, instead of the Pliocene age and marine origin which have been much claimed for it; and the opinion that lake Agassiz, in the basin of the Red river of the North and of the great Manitoba lakes, was due to a land barrier on the north, as was thought by Gen. G. K. Warren, instead of to the retreating ice-sheet, as was suggested in 1872 by Prof. N. H. Winchell. © This lake was the largest one of many due in common either to land or ice barriers. Professor Dana thinks that the fullness of the Champlain subsidence, at the end of the Glacial period, was attained after, not before, the time of lake Agassiz, and after the expanded Late Glacial representatives of the great lakes tributary to the St. Lawrence. Though the reviewer can- not agree with this opinion, it is most heartily welcomed as an impor- Review of Recent Geological Literature. 261 tant contribution to the present active investigations by many workers in this field of our Quaternary lacustrine geology. The whole volume is a rich thesaurus of the principles and methods of observation and reasoning, and includes also a vast multitude of the details, of this science in its varied branches treating of the formation and metamorphism of rocks, physiography, orogeny and epeirogeny, biologic evolution, and paleontology. It is not ouly a text-book for the college student, but a handbook for the professional geologist. It comes as the worthy consummation of a long life of exceptional earnestness ~ and success in the work of teacher, investigator, editor, and author. About a fifth part more pages, and a fourth more illustrations, are contained in this work than in its last previous edition. It is very well - printed, and has a copious topical index, to which also one giving retf- erences to citation of authors might be usefully added. W. U. Distribution of the Land and Fresh-water Mollusks of the West Indian re- gion, and their evidence with regard to past changes of land and sea, By CHARLES TORREY Stmpson. (Proc., U. 5. National Museum, vol. xv, pp. 423 450, with Plate xvr; 1894.) This essay treats of the Tertiary history of the West Indies, to which Profs. J. W. Spencer and R. T. Hill have recently given attention from the geologic side. The biologic conclusions of Mr. Simpson are as follow: ‘7A considerable portion of the land snail fauna of the Greater Antilles seems to be ancient and to have developed on the islands where it is now found. There appears to be good evidence of a general elevation of the Greater Antillean region, probably some time during the Eocene, after most of the more impor- tant groups of snails hid come into existence, at which time the larger islands were united, and there was land connection with Central Amer- ica by way of Jamaica and probably across the Yucatan Channel, and there was then a considerable exchange of species between the two re- gions. At some time during this elevation there was probably a land- way from Cuba across the Bahama plateau to the Floridian area, over which certain groups of Antillean land mollusks crossed. At this time it is likely that the more northern isles of the Lesser Antilles, which seem to be volcanoes of later Tertiary and Post-Pliocene date, were not yet elevated above the sea, or if so they have probably been submerged since. After the period of elevation there followed one of general sub- sidence....-:. The connection between the Antilles and the mainland was broken, and the Bahama region, if it had been previously elevated above the sea, was submerged; the subsidence continuing until only the summits of the mountains of the four Greater Antillean islands re- mained above the water. ‘Phen followed another period of elevation, which has lasted no doubt until the present time, and the large areas of limestone uneovered (of Miocene, Pliocene, and Post-Pliocene age) in the Greater Antilles have furnished an admirable field for the develop- ment of the groups of land snails that survived on the summits of the islands.”’ W. U. 262 The American Geoloyist. April, 1895 The Devonian System of eastern Pennsylvania and New York. By CHARLES S. Prosser, (Bull. U. S. Geol. Sury., No. 120, pp. 1-81, 1894, distributed 1895.) The author has given a very careful detailed study of the data de- rived from a large number of sections and bearing upon the correlation of the Devonian formations of Pennsylvania with those of New York. The accounts of the various sections abound in interesting details, and in the conclusions derived therefrom the author finds himself at vari- ance in several particulars with the determinations of the Pennsylvania geologists. The latter regarded a dark sandy shale lying at the top of the Hamilton as the Genesee shale; Prosser shows that it has little re- semblance lithologically and none in its fossils to the typical Genesee, which he holds to be absent in these sections. The geologists of the Pennsylvania survey referred to the Tully limestone a light gray stratum, rich in Hamilton fossils, especially its corals, but with none of the species characteristic of the Tully. As the upper beds of the Ham- ilton shales in central and western New York abound in limestones, and as these limestones in Monroe and Pike counties, Pa., are capped by a Hamilton shale, the inference is that they are not of the same age as strata referred to the Tully limestone in central Pennsylvania, whence typical Tully species have been reported. To the Lower Portage, Prof. Prosser refers 1,150 ft. of sandstone and shales regarded by I. C. White as Chemung. Overlying these is the Starucca sandstone, regarded by White as belonging to the upper Chemung and considered by Lesley as Catskill. Prosset considers it probable that ‘‘beginning with the green- ish shales and sandstones of the Starucca and the New Milford red shales [considered by White as representing the base of the Catskill], there is a series of deposits equivalent to the Oneonta sandstone of New York, which, as is weH known, gradually passes into the- beds of’ typical Middle and Upper Portage in central New York.” The Delaware flags with Orthonota ? parvula Hall, and the Montrose shales with Spirifer mesastrialis in the upper part, are placed with the Chemung. Tee Gs Notes Paléontologiques, II, Crustacés; Description de quelques Trilobites de Vordovicien @ Kealgrain. By J. BERGERON. Under the name Calymene lenniert, the author describes an immense species of this genus equaling in size the great forms cited by Hall and Oehlert from the lower Devonian. A new species of Trinucleus (T. gre- niert) is also described. J, Men. Ueber die stratigraphischen Beziehungen der bihmischen Stufen F, G, H, Barrande’s zum rheinischen Devon. By FE. Kayser and E. HOLZAPren. (Jahrb. der k. k. geolog. Reichsanst., 1894, vol. 44, pp. 479-514.) Since the full and final demolition by Kayser, of the alleged Silurian age of the F, G and H stages in the so-called “Silurian basin’? of Bohe- mia, an accomplished fact which has received substantial corroboration from correlative faunas and careful students of the Devonian in various parts of the globe, there remained as ‘‘unfinished business” the deter- mination of the precise equivalence and position of these faunas in the Review of Recent Geological Literature. 263 Devonian column. Some variation of opinion has been expressed in regard to this by different paleontologists, none more conservative than that of Kayser, who has before regarded the three divisions, F (with the exception of F-1), G, H, as representing the lower Devonian, none more extreme than that of Frech, who suggested that they might be construed as an-exemplification of the entire Devonian series. The present work is a detailed and exact analysis of the stratigraphical re- lations of these faunas with those of the Rhine section of the Devonian, and its essential results are as follows: The etage IF°-1 (including the *‘koniepruser-kalk’’) represents the entire lower Devonian and is equivy- alent to the Erbray limestone of France, some of the Ural limestones, and the Lower Helderberg of New York. The etage F-2 is not homoge- neous, but consists of two sharply defined divisions; the higher, or Mnenian limestone, is the equivalent of the greifensteiner-kalk, and hence lower Middle-Devonian. Etage G-1 probably belongs to the same horizon. Etages G-2 and G-3, H-1 and H-2, are younger than earliest Middle-Devonian and are all later stages of the Middle-Devonian. JaMGs Noch ein Wort ithber We Nothwendigheit den Terminus “norisch” fiir die Tlalistitter Kalhke aufrecht zu erhalten. By A. Brrrner. (Verhandl. der k. k. geolog. Reichsanst. 1894, No. 15, pp. 391-398.) There has been of late considerable discussion among the Austrian geologists as to the applicability of the term ‘‘norisch’’ or norian, by which Mojsisovics designated a certain zone of the Trias: and it has been contended, among other things, that the name was preémpted by TT. Sterry Hunt fora division of the Archean. Whether the term be written ‘norisch,.’’ norian, or noric, it is the same word, and Bittner shows that while Hunt introduced the term in 1870, Mojsisovies made use of the expression ‘‘norische Stufe’’ first in March, 1869, The term has, therefore, unquestionable priority in its applicationsto the Trias: Jor MeaGs Thirteenth Annual Report of the New York State Geologist, 1894. 1,015 pp., 86 lithographic plates, 67 half-tone plates, 470 maps and cuts. This volume contains the report of D. D. Luther on the geological section at the Livonia salt shaft, with an introductory chapter by Prof. Hall and supplementary chapters by J. M. Clarke: also, special reports on the Helderberg limestones, the geology of Albany county, of Ulster county, and of the Mohawk valley, by N. H. Darton;on the economic geology of Albany and Ulster counties, by F. L. Nason: on the geology of Essex county, by J. F. Kemp: Clinton county, by H. P. Cushing; a part of St. Lawrence and Jefferson counties, by C. H. Smyth, Jr.: Cattaraugus and Chautauqua counties, by F. A. Randall: Chenango county, by J. M. Clarke: further, an account of the discovery of platyenemic man in New York, by W. H. Sherzer, the genera of the Fenestellidiw, by G. B. Simp- son, and the concluding part of the Handbook of the Brachiopoda, the first part of which was given in the report for 1891 (published 1894). 264 The American Geologist. April, 1895 aL new Insectivore from the White River Beds. By W. B. Scorr. (Proce. Acad. Nat. Sci., Phila., 1894, pp. 446-48.) In-this paper Dr. Scott de- scribesa new insectivore resembling somewhat the genus Sorer, although differing sufficiently to remove it from this genus. It is called Proto- soree and represents a very primitive type of Soricida. Deseription, as quoted from the author, as follows: Maxillary dentition much as in Sorex, but with less reduced third molar, and smaller internal Cusps on last premolar. © Mandible with four minute teeth between the molars. and the large precumbent incisors.’ The species 2. erassus (sp. noy.) is described from anadult individual and is ‘“‘characterized by the short broad face, vaulted palate, straight alveolar border, aud by the relatively large size.” From the White River Miocene of South Dakota, and dis- covered by Mr. M.S. Farr. ees Notes on « collection of Silurian fossils from Cape George, Antigonish, Nova Scotia, with descriptions of four new species. By Henry M. Amt, D. Sce:, F. G.S., etc.: (Ex. Proc. Trans. Nova Scotia Inst. Se., Halifax, Ne S., 2d Series, No.1, Part 4, pp. 411-415.) The paper is based on the col- lections of Silurian fossils made by Messrs. Hugh Fletcher and J. Me- Donald, during the summer of 1886, at the extremity of Cape George, Antigonish county, Nova Scotia. In age the fossils indicate the presence of Lower Helderberg or Ludlow rocks. They correspond to. those of Division “*D™ of the Arisaig section in Pictou, although the facies is quite distinet so far as the collections go. The new species are not figured, but have been described with care. The forms recognized from the collections comprise the following: Annelida. 12. Modiolopsis exilis Béd/ings. 1. Serpulites longissimus JZurchison, 13. Nuculites (Clidophorus) erectus n. var. Flall, 2. Tentaculites niagarensis ? Ha//. 14. ss sp. indt. & ss canadensis, n. sp. Gasteropoda. Brachiopoda. 15. Bucania, sp. 4. Discina nova scotica, n. sp. 16. Holopea reversa Had/. 5. Discina fletcheri, n. sp. Cephalopoda. 6. fs orientalis, n. sp. 17. Orthoceras, cf. O. annulatum Sow- 7. Lingula rectilatera /fal/. erby. 8. yt sp: ? 18. ve sp. indt. g. Orthis (Rhipidomella) assimilis Ostracoda. Flali, 19. Leperditia, sp. 10. Rhynchonella formosa Had/. Vertebrata. Lamellibranchiata. 20. Onchus (?) sp. 11. Orthonota equilatera A/ad/. Geological map of Essex county, Massachusetts; Report on the Geology of Essex county, Mass., to accompany map. By Joun H. SEARS, Curator of Mineralogy and Geology, Peabody Academy of Science, Salem. (Bull. Essex Institute, vol. xv1, 1894, pp. 22.) In this map and report the au- thor presents the results of several years’ work upon the complex rocks of northeastern Massachusetts. Several reports of progress have pre- viously appeared in the same proceedings, beginning with those of 1889. The present report is mainly devoted to the systematic classification and description of the rocks represented on the map. Under plutonic rocks of hypidiomorphic granular structure are described (1) hornblendic- Review of Recent Geological Literature. 265 granitite, (2) granophyric-granitite, contact-zone, (3) augite-nepheline- syenite, (4) hornblende-diorite. (5) quartz-augite-diorite, (6) muscovite- biotite-granite, (7) granitic-hypersthene-diabase (norite). Among effu- sive voleanic rocks of porphyritic structures, including tuffs, volcanic breccia and agglomerate, are (8) rhyolites or quartz-porphyry, under which head are united all the so-called felsites, ete. Of olivine rocks with no feldspathic constituent, Mr. Sears reports outcrops of (9) serpentine- peridotite in Newbury, (10) biotite-mica-peridotite in Andover. Archean rocks occur in the form of (11) hornblende-granitic-gneiss in Middleton, Boxford, and Georgetown, (12) porphyritic-granitic-gneiss in Georgetown, West Newbury. and Amesbury. As arkose or ‘‘con- glomerate-granite”’ is noted (13) a muscovite-granitic-gneiss held by the author “to belong to a series of more or less crushed granite conglom- erates Which have been washed and reconsolidated from the decay of the muscovite-biotite-granite of the region or from some similar rock farther to the north.”” Of the schistose rocks is (14) ampibolite-gneiss of different origin in several parts of the field. Members of the Lower Cambrian sediments occur as (15) mica-schist, (16) corderite-gneiss, (17) zoisite-gneiss, (18) limestone, slate, quartzite, and sandstone. (19) Another deposit is composed of large pebbles of granite, limestone, and mica-schist. (20) Bostonite or keratophyre covers a breccia and other members of the rhyolite and quartz-porphy ries slop- ing into Marblehead harbor. Bostonite isa name given by Rosenbusch toa rock like keratophyre. which occurs as a dike instead of as a sur- face flow. (21) A tinguaite dike in Manchester. the sole recorded oc¢- currence in Massachusetts, cuts the hornblende granitite and augite- nepheline-svenite at Pickard’s point. (22) Essexite, a basic augite- nepheline rock of porphyritic habitus outcrops on Salem Neck, Winter island, and in Beverly and Marblehead. (23) Dikes of quartz-porphyry are shown on the map in the places where they cut more ancient rocks of the same series or the old rhyolites. (24) As arkose or conglomerate- vranite is described asmall deposit at Magnolia and in Saugus Centre. The map also shows (25) diallage-gabbro, rocks first noticed by Dr. M. E. Wadsworth; (26) a liparite dike about seven feet wide cutting diorite and granite, in Throckmorton’s cove on the Marblehead side of Forest river: (27) red slate, the ‘‘jaspilite’’ of Saugus Centre, Lynn, and Nahant, a memberof the Olenellus Cambrian; (28) andalusite-schist on Nahant, at Lynn, ete.: (29) vein rocks, carrying lead, silver, and copper ores. A list of publications referring te the geology of Essex county closes this report. In the field) work on which this map is based, Mr. Sears collected several thousand specimens, and over one thousand thin sections have been examined under the microscope. Material has also been collected for the preparation of a map of the glacial geology of the same area. To Mr. Sears is due great credit for the indefatigable in- dustry with which he has worked out this intricate maze of highly al- tered sediments and entangled series of intrusive and effusive igneous rocks. 00g 00% ool a) “Ras a4) aaoge al ste Qi jaay ui sapn}iy VF apeudtsap Sain GLy ‘WYHd/) NIDUV AA Ag Ee "YOUN NUFHLNOS ONY SFLVLG O3LIN] NUFLY aYDUT UOISSAIIY S]I Jo SaGe]y pur INIMOHS dVW ‘AX “IOA ‘LSINOTOUD NVOIUANY AHL, ON ] ‘smosze Ay papou ase BLIGS [erIe] dD 4 “payop ae svaly payrronouy Jaays-a2] Al) Jo valy UINMIXEPY ey) 5 U 6S De Wl 2 AMERICAN GEOLOGIST. Vou. XV. MAY, 1895. No.5. CLIMATIC CONDITIONS SHOWN BY NORTH AMER- ICAN INTERGLACIAL DEPOSITS.* By WARREN UPHAM, Cleveland, Ohio. (Plate X.) CONTENTS. Fluctuations of the borders of the Ice-sheet during both its growth and decline.... 273 Early interglacial lignite on the Missinaibi and Kenogami rivers...... 275 Records of the Drift rae limited to the culmination and departure ia ne ice: sheet . apnon 276 Boreal and Arctic Betis probably har nate “of Ceca deposits) dame the epoch of general ice accumulation........ Bisa seteeare 270: Temperate species of ae eae deposits during the enoen ais ice enacts ean 277 Minnesota and Iowa.. ECBOu BOSCO OPO SING Gana CO DoOe OR OO REC OSES EN en y/o) Northwestern inert wg ae ohel ste marinieioletoersinys eieieeracis stele ce coreomacietee: ZO Southern Illinois, efor Baal Ghion. SCOP ICDIZG CSO SCE ee orn iontate me toy Toronto and Scarboro, Ontario.. yoaunnte fee itnais, sfu.siatontoresapeiseraisislrsh aisien me oriee ZO5 New England and New Branewict:. Sats ar bis eletehelene tite wane eG IE Division of the Glacial period in the Glacial one Gbanipiia Bidcis. aes ot eet es Remodsanuue pochs OM@waternanye time ann.cecewee’ foes cw cic oes nice se detecme 204. Bipochstandistagesiol the Glacialupenlodt-cusis. Again, on page 919, the name Palo Duro beds is *Second Annual Report Texas Geological Survey, p. 431, t Fourth Annual Report Texas Geological Survey. tFourth Annual Report Texas Geological Survey. 396 The American Geologist. June, 1895 used. It is said, also, on page 919, ‘‘ The preceding list of genera has been prepared for this place for the most part by W. B. Scott.” It will be readily seen from the above quotations that by the right of priority, the name Palo Duro cannot be used for these beds, for I had already described them under the name Goodnight division; I found the beds, collected the fossils, and gave the name to beds occupying a defi- nite horizon with sufficient particularity for identification. All this was done months before the name Palo Duro was suggested by Prof. Scott, who has never been at the type locality, las never seen any of the fos- sils from there unless he saw those I collected, nor has he ever given a description of the strata composing the divisions, nor has he given a defi- nite description of the locality of the beds. There are several other errors in Prof. Scott’s paper. The fossils were not found by Cope, they are not Loup Fork. They were not found near Palo Duro canon. The fossils were found by myself. The beds are above the Loup Fork. They do not occur on Palo Duro canon, but on Mulberry canon, which is not even a branch of the Palo Duro, and the beds described, so far as known, do not occur within ten miles of any part of Palo Duro canon, and it would be a misnomer to call them by that name. The name Palo Duro for these beds must give place to Goodnight, the one first used by myself in describing them, notwith- standing the fact that the attempt has been made to substitute one for the other in the ‘*Manual of Geology’’ by Dana. If priority is not to control then utmost confusion will be the result. W. I. Cummins. Geological Survey of Texas. STAGES OF RECESSION OF THE NortH AMERICAN ICE-SHEET SHOWN BY GLACIAL LAKES. During the past year this magazine and the Ameri- can Journal of Science have presented numerous papers by Mr. F. B. Taylor and Prof. J. W. Spencer, describing the evidences of Pleistocene bodies of water in the basins of the great Laurentian lakes, marked by ancient ‘shore lines from near the present lake levels up to maximum hights of 500 to 600 feet or more. The extensive submergence, follow- ing the period of deposition of the boulder-clay or till, is ascribed by these authors to depression of the St. Lawrence drainage area so low as to admit the sea to the limits defined by the highest beaches. The al- ternative view, which attributes the Pleistocene shore lines to lakes dammed onthe north and northeast by the receding ice-sheet, is held by Gilbert, Chamberlin, Leverett, and others, including the present writer; but it has had scanty advocacy in the AMERICAN GEOLOGIST while these articles by Taylor and Spencer have been appearing. Another recent writer, Prof. A. C. Lawson, from his examination of the shore lines about the north side of lake Superior, concludes that they were formed by a lake; but he supposes its existence to have been due to land barriers, not to the waning ice-sheet. In the American Journal of Science, however, for last January, I have endeavored to give a sum- mary of the evidence for the origin of all the ancient high shores about the Laurentian lakes by the obstruction of the continental glacier dur- Correspondence. 397 ing its departure in the closing or Champlain epoch of the Ice age, with citations of the voluminous literature of this subject. The map which accompanied that paper is reprinted in the May AMERICAN GEOLOGIST as Plate X, delineating provisionally seven stages of the ice-sheet, from its maximum extent to the time, late in the process of the ice departure, when the sea appears first to have found an avenue of inflow to the St. Lawrence and Ottawa valleys and the basin of lake Champlain by the melting away of the glacial barrier across the present course of the St. Lawrence in the vicinity of Quebee or farther northeast. The high Pleistocene shores from lake Superior to lake Ontario, and the highest shores above the marine beds eastward, seem to me to be clearly referable to glacial lakes; and for comparison with the opinions of Spencer, Taylor, and Lawson, the sequence of events represented in Plate X by the seven stages of culminating and waning glaciation is here brought very concisely into review. 1. Greatest extension of the ice-sheet; Mt. Washington and the Green and Adirondack mountains enveloped to their summits by the continental glacier: its surface thence rising northward across the St. Lawrence valley to the Laurentian highlands. The Kansan stage of Chamberlin’s classification (third edition of the Great Ice Age, 1894, and Journal of Geology. vol. m1, pp. 270-277, April-May, 1895). 2. Boundary of the waning ice-sheet at the Altamont moraine, the earliest and outermost of the series traced across the northern United States, marking pauses or slight readvances which interrupted the gen- eral glacial retreat. This time, coming after Chamberlin’s intervening Aftonian and Iowan stages, was at the beginning of his Wisconsin or moraine-forming stage. 3. Maximum area of the Western Superior glacial lake, 500 to 600 feet above the west part of lake Superior, with outlet through northwestern Wisconsin by the Bois Brulé and St. Croix rivers. The glacial lake Warren, outflowing past Chicago, reached north along the greater part of the basin of lake Michigan; and the Western Erie glacial lake out- flowed past Ft. Wayne to the Wabash river. 4. Maximum area of lake Warren, 400 to 600 feet above lake Superior and the north part of lake Huron and Georgian bay: extending east somewhat beyond lake Nipissing, and to Crittenden in southwestern New York, with shores now raised by differential uplift nearly 300 feet above the east end of lake Erie. 5. Boundary of the ice-sheet passing east of lake Nipissing, thence south to the vicinity of Toronto, and east along the north side of the Mohawk river. The glacial lake Algonquin, held by an ice barrier only at the lowest passes east of Georgian bay, with outflow south by the St. Clair and Detroit rivers, was at first tributary to the very short-lived glacial lake Lundy, above the east part of the present lake Erie, but later to the glacial lake Iroquois by the Niagara river, which then be- gan its existence and the erosion of the gorge below its receding water- fall. 6. Recession of the ice-sheet past the north side of the Adirondacks; 398 The American Geologist. June, 1895 lakes Iroquois and Hudson-Champlain thus merged in the glacial lake St. Lawrence, which had a level about 250 feet below lake Iroquois and about 50 feet above the sea. 7. Rapid melting of the border of the ice-sheet by the laving action of the lake St. Lawrence on the west and of the sea in the gulf of St. Law- rence on the east, finally cut through the ice-barrier, permitting the sea to come into the moderately depressed St. Lawrence, Ottawa and Cham- plain valleys, its southwestern limit being at the Thousand Islands, be- low the mouth of lake Ontario. Prof. C. H. Hitchcock, in the May number of the AMERICAN GEOLO- GIST (pages 330-335), cites abundant proofs of the transportation of drift from northwest to southeast across the highest mountains of New En- gland, which could have resulted only from the accumulation of the ice-sheet so thick as to fill the St. Lawrence valley and to have greater altitude there and on the Laurentide highlands than on the mountain region south of the St. Lawrence. Eastward the ice had a lobate bor- der, with one lobe covering New Brunswick and Nova Scotia, while an- other extended from Labrador southeasterly over Newfoundland to the Grand Bank. An intervening tract, reaching northwesterly into the ice-sheet at least to the Magdalen islands, was exempted from glacia- tion.* Rain storms, sweeping northeasterly as now over the same region, melted away the southwestern border of the ice-sheet and caused it to recede chiefly from southwest to northeast; but farther eastward, when the storms within a half day, more or less, had advanced to distances of 100 to 200 miles upon the ice-sheet, their precipitation was doubtless changed to snow, causing the ice there to increase in thickness, and transferring the summit of the ice covering the St. Lawrence valley gradually farther and farther to the northeast. It seems thus very probable that the ice may have remained latest as a barrier across this valley even as far northeastward as Metis, nearly 200 miles below Que- bec, which I think to be indicated by the glacial strice as these are de- scribed by Mr. Robert Chalmers.+ The same predominarmtly south west- ward striation extends thence along the St. Lawrence valley, lakes On- tario and Erie, and onward to southern Illinois. Throughout this distance of more than 1,200 miles the glacial recession, as shown by the strizw, was from southwest to northeast, and the barrier of ice holding the Laurentian glacial lakes was melted back from Chicago to Quebec, or perhaps even to the lower part of the present St. Lawrence estuary, previous to any opportunity for the sea to come into the valley. More than twenty years ago, Profs. N. H. Winchelland J. S. Newber- ry referred the Late Glacial submergence in the basins of the Red river of the North and the river St. Lawrence to lakes held by the de- parting ice-sheet. Their opinion is well sustained, as the present writer believes, by the observations which have since been gathered in more *Geological Survey of Canada, Report of Progress for 1879-80, Part G. AMERICAN GEOLOGIST, vol. XV, pp. I98, 203, March, 1895. +Am. Journal of Science, III, vol. xL1x, pp. 273-275, April, 1895. Personal and Scientific News. 399 extended mapping of the old shores and in determinations of their alti- tudes and changes of level. Traces of other ice-dammed lakes have been also carefully studied in New Hampshire, New Jersey, New York, the Ohio valley, and the Souris valley in North Dakota and Manitoba. Such lakes are also recorded by the Parallel Roads of Glen Roy, and by high beach lines in the valleys on the east side of the Seandinavian mountains. No marine fossils occur in the beaches or other contempo- raneous deposits; but fresh-water molluscan shells are found in these deposits within the area of lake Agassiz, which occupied the basin of the Red river and of the Manitoba lakes, and in the beaches and deltas of lakes Warren, Algonquin and Iroquois. These bodies of water are thus proved to have been lacustrine; and the differential inclinations of their shores demonstrate that no land barriers, but only the receding ice, could have confined them on their north and northeast sides. WARREN UPHAM. 119 Oakdale Ave., Cleveland, Ohio, May 15th, 1895. Rano AIAN D SCIENTIFIC NEWS. THE GEOLOGICAL Society oF WASHINGTON has recently is- sued a pamphlet of 46 pages which contains the presidential address of C. D. Walcott, entitled ‘The United States Geolog- ical Survey,” and abstracts of minutes and lists of officers and members, 1898-1894. It is edited by the secretaries, Whitman Cross and J. 8. Diller. The total membership is 156, of which 120 are active and 36 corresponding members. THe Museum oF Comparative ZooLoay, Cambridge, Mass., has undertaken to publish, as one volume of its 4to memoirs, a monograph of “The North American Crinoidea Camerata,” by Charles Wachsmuth and Frank Springer. As is well known, the authors have devoted years of careful work to the preparation of this monograph, which is expected from the press during the early part of 1896. The volume will contain 600 to 700 pages of text, and will be accompanied by an atlas of 83 plates. As the edition of so elaborate a publication must naturally be limited, subscriptions are asked for at an early date. The subscription price is thirty dollars. A Lire oF Louis AcaAssiz, by Jules Marcou, will soon be is- sued from the press of Macmillan & Co. The work will be in two volumes, 8vo, with illustrations. The author had oppor- tunity to know Agassiz intimately, both in Europe and in America. THe WALKER PRIZE, given by the Boston Society of Natu- ral-History, has been this year awarded to Dr. E. W. Clay- pole of Buchtel College, Akron, Ohio, for an essay on the Devonian formations of the Ohio basin. 400 The American Geologist. June, 1895 Tue University or Kansas has recently distributed the fol- lowing statement concerning a geological survey of the state: In conformity with the law under which the University of Kansas is now working, the Board of Regents, at a recent meeting, formally or- ganized the University Geological Survey of Kansas, with Chancellor F. H. Snow, ex-oflicio director; professor S. W. Williston, paleontolo- gist; professor Erasmus Haworth, geologist and mineralogist, and pro- fessor E. H. 8S. Bailey, chemist. In addition to these, other members of the university faculty will be engaged upon the work of the survey, as well as the advanced students of the departments of geology and paleontology. An effort will also be made to centralize and unify the energies of different geologists in the state who have been doing valuable work along different lines of geo- logical investigations. Already a considerable start has been made and the co-operation of different geologists of the state has been secured. The policy of the survey will be conservative, with the expectation that it will be continued and eventually include all other branches of the natural history of the state. The gencral stratigraphy of the state will first be elaborated in order that it may be used in the furtherstudy of various questions of economic and scientific importance, all of which will be taken up as rapidly as existing conditions from time to time will permit. Work in the Coal Measures of the state has been in progress for two summers, and volume I of the report is now almost ready for publica- tion. Other volumes will appear at irregular intervals. Those already under preparation are; one on coal, oil and gas: one on the vertebrate paleontology of the state; and one on the salt and gypsum deposits of Kansas. AN IMPROVED ROCK CUTTER AND TRIMMER is described by Mr. Edgar Kidwell in the American Journal of Science for May. This machine is quite simple in construction and has been used by the Michigan Geological Survey during the last year with good results. It can be obtained from Merrill Brothers, 465 Kent Ave., Brooklyn, N. Y. Mr. T. C. Horxins, formerly of the Arkansas Geological Survey, has been appointed assistant geologist in Indiana. He, together with Mr. Blatchy, state geologist, expects to spend the coming field season working up the building stones of the Carboniferous. AN ATLAS OF THE STATE OF New York will be published in a few weeks by Julius Bien & Co. Among other features it will contain temperature, rainfall, and hypsometric maps of the state. Dr. J. G. Norwoop, Emeritus Professor of Physics in the University of Missouri, died May 6th, in his eighty-eighth year. He is well known to western geologists through his reports which accompany the “ Report of a Geological Survey of Wisconsin, Iowa and Minnesota,” by Dr. D. D. Owen. In a future number we expect to present a sketch of Dr. Nor- wood’s life, written by Prof. G. C. Broadhead. INDEX TO VOL. XV. A Acid eruptives of northeastern Maryland, C. R. Keyes, 39. Adams, F. D., A further contribution to our knowledge of the Laurentian, 67. Agassiz, Louis, Life of, 399 Age of the earth, 382. Age of the Galena limestone, N. H. Winchell, 33. eae Geological map of,E. A. Smith, Arne Geological Survey, Report on the geology of the Coastal plain, E. A. Smith, 266. American Association for the Advance- ment of Science, 195. American Tertiary Aphide, 8. H. Scud- der, 123. Ami, H. M., Note on a collection of Si- lurian fossils from cape George, An- tigonish, Nova Scotia, 264. An amusing error, 120. Annals of British geology, 1893, J. F. Blake, 387 Arctic climate, secular changes of, 254. Auriferous gravels of the Sierra Nevada, H. W. Turner, 371. Average elevation of the United States, Henry Gannett, 62. B Bailey, E. H.8., 400, Bain, H. F., 335; Central Iowa section of the Mississippian series, 317. Baltzer, A.,. Remarks on the Berner Ober- land sections of Prof, H. Golliez inthe geological handbook of Switzerland, 1894, 62. Banded structure of some Tertiary gab- bros in the Isle of Skye, A. Geikie and Dodou. Teall: 123: Barlow, A. F., On some dikes containing huronite, 68. Bascom, Dr. Florence, 336. Bayley, W.8., 67,68; The peripheral pha- ses of the great gabbro mass of north- eastern Minnesota, 67; A summary of progress in mineralogy and petrogra- phy in 1894, 186. Beecher, ©. E., Further observations on the ventral structure of Triarthrus, 91. Beitrage zur Kenntniss der Gattung Oxy- rhina, C. R. Eastman, 267, Bell, Robert, On the honeycombed lime- stones in the bottom of lake Huron, 63. Bergeron, J., TIrilobites de l’ordovicien d’Ecalgrain, 262. Broadhead, G. C. » 400. Brown, E. F., 272. Bryson, John, The ups and downs of Long Island, 1&8. Buchtel College, Paleontological notes from, BE. W. Claypole, 1, 363. Burlington limestones, Erosion during the deposition of the, F. M. Fultz, 128. Cc Camptonite dikes near Danbyborough, Vt., V. F. Marsters, 368. Canadian localities of the Taconic erup- tives, N. H. Winchell, 356. Case, E. C., On the mud and sand dikes of the White River Miocene, 248. Central Lowa section of the Mississippian series, H, F. Bain, 317. EEppeloron beginnings, J. M. Clarke Ghanhenige T.C., 66, 67; Glacial phenom- ena of North America, 53; Recent gla- cial studies in Greenland, 497 ; Notes on the glaciation of Newfoundland, 203. Cladodont sharks, Recent contributions to our knowledge of the, E. W. Clay- pole, 363. Cladodus clarki, Ona new specimen of, . W. Claypole, 1. Clark, W. B., 67, 329, Clarke, J. M,, Sketch of G. H. Williams, 69; Cephalopod beginnings, 125. Claypole, E. W., 187, 399; On a new speci- men of Cladodus clarki, 1; Recent con- tributions to our knowledge of the Cla- dodont sharks, 363. Clendenin, W. W., 130. Climatic conditions shown by North American interglacial deposits, Warren Upham, 273. Clypeastridz, A new Cretaceous genus of, F. W. Cragin, 90. Coast ranges, A contribution tw the geol- ogy of, A.C. Lawson, 342. Johen, E,, Meteoritenkunde, 328. Columbus formation in northwestern II- linois, O. W. Hershey, 7 Conanicut island, RK. 1., The geology of, G. L. Collie, 386. Contribution to the geology of the Coast ranges, A. C. Lawson, 342 Correction, F. B. Taylor, 394. Cragin, F. W., A new Cretaceous genus of Cly peastride, 90. Cretaceous fossil plants from Minn., Leo Lesquereux, 384. Crucial points in the geology of the Lake Superior region, N. H. Winchell, 153, 229, 295, 356. Crystalline limestones, ophiolites, and associated schists of the eastern Adi- rondacks, J. F. Kemp, 67. Crystallized slags from copper smelting, A. C. Lane, 68. Cummings, W. F., 395. Cushing, H. P., The faults oH + Chuay: township, Clinton C Jo., N. Y., 66 D Denes, Remarks on, J. T. James, 337. Dana, J. D., 836; Manual of geology, 259. Danbyborough, Vt., Camptonite dikes near, V. F. Marsters, 368. Darton, N. H., 67, 68. Dawson, G. M., 195. Deep shaft at Livonia, N. Y., 379. Denton, F. W.., 272. Description de quelques trilobites de Pordovicien d’Ecalgrain, J. Bergeron, 262. Development of the corallum in Favo- sites forbesi, var. occidentalis, G. H. Girty, 131. A question of priority, 402 Devil's cork-screw and allied fossils, J. T. James, 3837. Devonian system of eastern Pa. and N.Y., C.8. Prosser, 262. Discrimination of glacial accumulation and invasion, Warren Upham, 200. Distribution of the landand fresh-water mollusks of the West Indian region, C. T. Simpson, 261. Divisions of the Ice-age in the United nin tee and Canada, C. H. Hitchcock, 330. Drumlin accumulations, Warren Upham, 194. Dumble, E. T., 67. Early Protozoa, G. F. Matthew, 146. Earth’s age, 382. Eastman, ©. R., Beitrage zur Kenntniss der Gattung Oxyrhina, 267. EDITORIAL COMMENT. State academies of science, 46; An amusing error, 120; The fossil fishes of Canyon City, Colo., 121; Glacial geology of Great Britain and Ireland, 180;Secular changes of Arctic climate, 254; The Shaw mastodons, 325; The deep shaft at Livonia, N. Y., 379; The earth’s age, 382. Emerson, B. K., 63. Erosion during the deposition of the Eorlingten limestones, F. M. Fultz, 128. Eruptive epochs of the Taconic or Lower Cambrian, N. H. Winchell, 295. Eruptives, acid, of northeastern Mary- land, C. R. Keyes, 39. F Fairchild. H. L.,67; The geological his- tory of Rochester, N. Y., 50; The length of geologic time, 51; Glacial lakes in western N. Y., 202; Lake Newberry the successor of lake Warren, 202. Faults of Chazy township, Clinton Co., N. Y., H. P. Cushing, 66. Fauna des unterdevonischen Riffkalkes, | Fritz Frech, 122. Favosites, Development of the corallum ITV Gretklle GrinbyaeLo le Foerste, A. F., 187. Formation of lake basins by wind, G. K. Gilbert, 66. Fossil fishes of Canyon City, Colo., 121. FOssILs. Cladodus, 1, 363. Cretaceous flora of Minn., 384. Cretaceous Foraminifera of Minn., 384. Daimonelix, 337. Equus, 272. = Favosites, 131. Oxyrhina, 267. Pithecanthropus, 16. Porocystis, 122. Protosorex, 264. Protozoa, 146. Radiolaria, 57. Scutellaster, 90, Triarthrus, 91. Fowke, G., 187. Frech, Fritz. Die Fauna des unterdevon- ischen Riffkalkes, 122. From the Greeks to Darwin, H. F. Os- born, 184. Fultz, F. M., Erosion during the deposi- | tion of the Burlington limestones, 128. Further contribution to our knowledge of the Laurentian, F. D. Adams, 67. Further observations on the ventral structure of Triartirus, C. E. Beecher, Index, G Galena limestone, The age of the, N. H. Winchell, 33. Gannett, Henry, The average elevation of the U.8., 62. Geikie, Arch., On the banded structure of some Tertiary gabbros in the Isle of Skye, 123. Geikie, James, The great ice age and its relation tothe antiquity of man, 52. Geologic history of Missouri, Arthur Winslow, 8&1. Geologic time, The length of, H. L. Fair- child, 51. Geological history of harbors, N. 8. Sha- ler, 59. Geological history of Rochester, N. Y., H. L. Fairchild, 50. Geological map and report of Eseex Co., Mass., J. H. Sears, 264. ee reacel map of Alabama, E. A. Smith, oo. Geological Society of America, Baltimore meeting, 65; Pleistocene papers, 197. Geological Society of Washington, 399. Geology of Angel island, F. L. Ransome, Dil: Geology of Conanicut island, G. L. Col- lie, 386. Geomorphogeny of the coast of northern California, A. C. Lawson, 387. Georgia, A preliminary report on the marbles ofS. W. McCallie, 329. Geotektonische Probleme, A. Kothpletz, 328. Gilbert, G. K., 203; The formation of lake basins by wind, 66; The tepee buttes,66; Stratigraphic measurement of Creta- ceous time, 67; Notes on the gravity de- terminations reported by Mr. G Putnam, 388. Girty, G. H., Development of the coral- lum in Favosites forbesi, var. occiden- talis, 131. Glacial geology of Great Britain and Ire- land, 180. Glacial lakes in western N. Y., H. L. Fair- child, 202. GJacial phenomena of Newfoundland, Labrador and southern Greenland, G. F. Wright, 198. Glacial phenomena of North America, T. C, Chamberlin, 53. ; Glaciation of Newfoundland, T. C.Cham- berlin, 2038. Golliez, H., Geological handbook of Switzerland, 62. Goodnight beds, 395. Granite of Pike’s Peak, Colorado, E. B. Mathews, 68. Granites and Greenstones, Frank Rutley, 123. Granites of Cecil Co., in northeastern Maryland, G. P. Grimsley, 46. Grant, U.8., 272, 3836; The name of the copper-bearing rocks of Jake Superior, 192. Gravity determinations, transcontinental series, G.R. Putnam, 388. Great Ice age, James Geikie, 52. Grimsley, G. P., Granites of Cecil Co., in northeastern Maryland, 40. Griswold, L. 8..68. Gulliver, F. P., The tepee buttes, 66. H Hall, C. W., The pre-Cambrian floor in the northwestern states, 67. Hall, James, 130. Haworth, Erasmus, 400. Index. Herrick, C. L., 187. Hershey, O. H., The Columbia formation in northwestern Illinois, 7. Highland level gravels in northern New England, C. H. Hitchcock, 199. Hinde, J. G., Radiolarian chert from Cal- ifornia, 57 Historical sketch of investigations of the Lower Silurian in the upper Missis- sippi valley, N. H. Winchell and C. Schuchert, 384. Hitchcock, C. H., 67, 203; Highland level gravels in northern New England, 199; Divisions of the ice age in the United States and Canada, 330. Hobbs, W. H., Summary of progress in muneralogy and petrography in 1894, 6. Holzapfel, E., Ueber die stratigraphis- chen Bezeihungen der béhmischen Stu- fen F, G, H, Barrande’s zum rheinis- chen Devon, 262. Honeycombed limestone in the bottom of lake Hereus Robert Bell, 68. Hopkins, T. G.. 400. Hubbard, L. Ti 272. Huronite, On some dikes containing, A. F, Barlow, 68. Hypsometric map of Missouri, C. R. eyes, 314. I}linois, Columbia formation of north- western, O. H. Hershey, 7. Improved rock cutter, 400. Inequalities in the old Paleozoic sea bot- tom, J. E. Todd, 64. Interglacial deposits,Climatic conditions shown by North American, Warren Upham, 273. Hee Geographical Congress, 195. Iowa Geological Survey, 335. Irving, R. D., The Penokee iron-bearing series of Michigan and Wisconsin, 326. J James, J. T., Remarks on Daimonelix, or “devil’s corkscrew,’’ and allied fossils, 337 James, U. P., 336. Johns Hopkins University, geological de- partment, 64. K Kayser, E., Ueber die stratigraphischen Bezeihungen der bohmi-chen Stufen F, G, H, Barrande’s zum rheinischen De- von, 262. Keith, Arthur, 66. Kemp, J. F., 68; The ore deposits of the U. S.. 57; The crystalline limestones, ophiolites and associated schists of the eastern Adirondacks, 67 Kansas Geological Survey, 400. Kendall, F. P., Glacial geology of Great Britain and Ireland, 180. Keyes, ©. R., 66, 385; Acid ernptives of northeastern Maryland, 39; Paleontol- ogy of Missouri, 267; A hypsometric map of Missouri, 314. Kidwell, Edgar, 400. Kiimmel, H, B., Lake Passaic, 329. L Lake Algonquin, The second, F. B. Tay- lor, 100, 162, 394, Lake Newberry the successor of lake Warren, H. L. Fairchild, 202. Lake Passaic, R. D. Salisbury and H. B. Kimmel, 329. 403 Lake Superior Mining Institute, 196, 272. Lake Superior region, Crucial points in the geology of the, N. H. Winchell, 153, 229, 295, 356. Lane, A. iC The relation of grain to dis- tance from margin in certain rocks, 68; peverelbzed slags from copper- smelt- ing, 68 Lawson, A. C., A contribution to the ge- ology of the ‘Coast ranges, 342; The ge- omorphogeny of the coast of ‘northern California, 387. Lead and zine deposits of Missouri, J. D. Robertson, 235. Length of geologic time, H. L. Fairchild, 51 Lesquereux, Leo,Cretaceous fossil plants from Minn., 384. Lewis, H. C., Glacial geology of Great Britain and Ireland, 180. Lherzolite- serpentine and associated rocks of the Potrero, San Francisco, Chas. Palache, 52. Lindgren, Waldemar, 68. Lindstrém, G., 328. Livonia, N. Y., deep shaft, 379. Loeschman, E., 122. Louisiana, The stratigraphy of north- western, T. W. Vaughn, 205, Lower Cambrian rocks in eastern Cali- fornia, C. D. Walcott, 67. Lower Cambrian, The eruptive epochs of the Taconic or, N. H. Winchell, 295. Lower Cambrian, The paleontologie base of the Taconic or, N. H. Winchell, 229 Lower Cambrian, The stratigraphic base of the Taconic or, N. H. Winchell, 153. Lower Silurian Brachiopoda of Minn., ¥ H. Winchell and Chas. Schuchert, Lower Silurian Bryozoa of Minn, E. O. Ulrich, 386. Lower Silurian sponges, graptolites and corals of Minn., N. H. Winchell and Chas. Schuchert, 385. M Maine Geological Survey, 272. Manual! of Geology, J. D. Dana, 259. Marcou, Jules, 399. Marine Algee from the Trenton limestone, R. P. Whitfield, 183. Marsh, O. ©., 196. Marsters, Wiebe. eae dikes near Danbyborough, Vie; Maryland,Acid em ese ae northeastern, C. R. Keyes, 39; Granites of Cecil Co., GP. Grimsley, 40. Massachusetts, Geology of Essex Co., J. H. Sears, 264, 266. Mastodon bones in Ohio, 272. Mastodons, The Shaw, 325. Mathews, E. B., Granites of Pike’s peak, Colo., 68. Matthew, G. F., Early Protozoa, 146. McCallie, 8. W., A preliminary report on the marbles of Georgia, 329. McGee, W J , 66. Mechanics of Appalachian structure, Bailey Willis, 60. Merrill, G. P., 68. Meteoritenkunde, E. Cohen, 328. Microscopical fauna of the Cretaceous in Minnesota, A. Woodward and B. W. Thomas, 384. Michigan Topographical Survey, 272. Minnesota Geological Survey, Paleontol- ogy, 384. Minnesota, Preliminary report of field 404 work in northeastern, Warren Upham, MINERALS. Crossite, 52. Huronite, 68. New soda amphibole, 52. Mississippian series of central Lowa, H. F. Bain, 317 Missouri Geological Survey, 196, 335, 336; Sheets 2 and 8, 58. Missouri, Geological history of, Arthur Winslow, 81; Lead and zine deposits of, J. D. Robertson, 235; Paleontology of, C. R. Keyes, 267. Mud and sand dikes of the White River Miocene, KE. C. Case, 248. Munuscong islands, F. B. Taylor, 24. Museum of Comparative Zoology, 399. N Name of the copper-bearing rocks of lake Superior, U.S. Grant, 192. Nason, H. B., 336. New Cretaceous genus of Clypeastride, F. W. Cragin, 90. New forms of marine Alga, R. P. Whit- field, 183. New insectivore from the White River beds, W. B. Scott, 264. New Jersey Geological Survey, 329. New Jersey, surface geology of southern, R. D. Salisbury, 203. New York, 18th Annual Report State Ge- ologist, 263. Newell, F. H., 49. Newfoundland, Notes on the glaciation of, T. C. Chamberlin, 203. Nipissing beach on the north Superior shore, F. B. Taylor, 304. North American interglacial deposits, Warren Upham, 273. Norwood, J. G., 400. Notes on a collection of Silurian fossils from cape George, Nova Scotia, H. M. Ami, 264. Oo Observations on the glacial phenomena of Newfoundland, Labrador and southern Greenland, G. F. Wright, 198. Ohio Geological Survey, 187. On anew specimen of Cladodus clarki, E. W. Claypole, 1. Ore deposits of the U.5., J. F. Kemp, 57. Orton, Edward, eeeeal Survey of Ohio, 187. Osborn, H. F., From the Greeks to Dar- win, 184, Pp Palache, Charles, The lherzolite-serpen- tine and associated rocks of the Po- trero, San Francisco, 52; On a rock from the vicinity of Be rkeley contain- ing a new soda amphibole, 52. Paleontologic base of the Taeonie or Lower Cambrian, N. H. Winchell, 229. Paleontological notes from Buchtel Col- lege, E. W. Claypole, 1, 363. Paleontology of Minnesota, N. W. Winch- ell and others, 384. Paleontology of Missouri, ©. R. Keyes, 267. Penokee iron-bearing series of Michigan and Wisconsin, R. D. Irving and C. R. Van Hise, 326. Peripheral SRIEae of the great gabbro mass of northeastern Minn., W.S. Bay- ley, 67. Personal and scientific news, 64, 130, 195, 272, 335, 899. Index. Pirsson, L, V., 66. Pithecanthropus erectus, 196. Pleistocene papers at the Baltimore meet- ing of the Geological Society of Amer- ica, 197. Porocystis pruniformis Cragin, Fritz Frech, 122. Posepny, Franz, 336. Powell, J. W., 13th Annual Report U. 8. Geological Survey, 48. Pre-Cambrian floor in the northwestern states, C. W. Hall, 67. Preliminary report of field work in north- eastern Minn., Warren Upham, 51. Preliminary repert on the geology of South Dakota, J. E. Todd, 136. Preliminary report on the marbles of Georgia, S. W. McCallie, 329. Prosser, C. S., 196; Devonian system of eastern Pa. and N. Y., 262. Putnam, G. R., Results of a transconti- nental series of gravity measurements, 388. Q Quartz keratophyre and its associated rocks of the Baraboo bluffs, Wis., Sam- uel Weidman, 68. Gaaien of priority, W. F. Cummins, oe. R Radiolarian chert from California, J. G. Hinde, 57. Ransome, F. L., The geology of Angel is- land, 57 Rautff, Herman, Ueber Porocystis pruni- formis Cragin, 122. Recent contributions to our knowledge of the cladodont sharks, E. W. Clay- pole, 3638. Recent glacial studies in Greenland,T, C. Chamberlin. 197. Recent publications, 124, 267, 389. Reid, H. F., 67; Variation of glaciers, 200. Relation of grain to distance from mar- gin in certain rocks, A. ©. Lane, 68, Remarks on Daimonelix, or “‘devil’s corkscrew” and allied fossils, J. T. James, 337. Remarks on the Berner Oberland sections of Prof. H. Golliez in the Geological Handbook of Switzerland, 1594, A. Baltzer, 62. Report on the geology of Essex Co.,Mass., J.H. Sears, 264. Report on the geology of the Coastal plain of Alabama, E. A. Smith, 266. Review of recent geological literature, 48, 122, 183, 259, 326, 384. Robertson, a D., The lead and zinc de- posits of Missouri, 235. Rochester, N. Y., Geological history of, H. L. Fairchild, 50. Rothpletz, A., Geotektonische Probleme, 328. Rutley, Frank, Granites and greenstones, 123. S Salisbury, R. D., 67, 201, 229; The surface formations of southern New Jersey,203. Sansi, Francesco, Sulla serpentina, etc., 49, San Francisco, Lherzolite-serpentine, Chas. Palache, 52 Schuchert, Charles, Sponges, graptolites and corals from the Lower Silurian of Minn., 385; Lower Silurian Brachiopoda of Minun., 8&6. Index. Scott, W. B., New insectivore from the White River beds, 264. Scudder, 8. H., The American Tertiary Aphide, 123. Sears, J. H., Geology of Essex Co., Mass., 264; Recent subsidence and elevation in Essex Co., Mass., 266. Second lake Algonquin, F. B. Taylor, 100, Secular changes in Arctic climate, 254. Shaler, N. 8., 66; Geological history of harbors, 59. Sharpless, F. F., 272. Shaw mastodons, 325. Simpson, C. T., Land mollusks of the West Indian region, 261. Smith E. A., Geological map of Alabama 56; Geology of the Coastal plain of Ala- bam, 266. Smock, J. C., Geological Survey of New Jersey, 329. Smyth, C. H., Jr., 67. Snow, F. Hg, 400. Some dikes containing huronite, A. F. Barlow, 68. South Dakota Geological Survey, 186. Spencer, J. W., 66. 2.00, 2038. Sponges, graptolites and corals of the Lower Silurian in Minn., N. H. Winch- ell and Chas. Schuchert, 385. Springer, Frank, 399. Stages of recession of tle North Ameri- can ice-sheet shown by glacial lakes, Warren Upham, 396. State academies of science, 46. Stratigraphic base of the Taconic or Low- er Cambrian, N. H. Winchell, 153. Stratigraphic measurement of Creta- ceous time, G. K. Gilbert, 67, Stratigraphy of northwestern Louisiana, T. W. Vaughn, 206. Subsidence and elevation in Essex Co., Mass., J. H. Sears, 266. apie serpentina, etc,, Francesco Sansi. Summary of progress in mineralogy and petrography in 1894, W. §. Bayley and W. H. Hobbs, 186. Surface formations of southern’ New Jer- sey, R. D. Salisbury, 203. aly Taconic, Eruptive epochs of the, N. H. Wincell, 295. Taconic eruptives, Canadian localities, N. H. Winchell, 356. Taconic, Paleontologic base of the, N. H. Winchell, 229. Taconic, Stratigraphic base of the, N. H. Winchell, 153. Taylor, F.B., The Munuscong islands, 24; The second lake Algonquin, 100, 162, 394; The Nipissing beach on the north Superior shore, 304; A correction, 394. Teall, J. J. H., On the banded structure of some Tertiary gabbros in the Isle of Skye, 123. Tepee buttes, G. K. Gilbert and F. P. Gulliver, 66. Thomas, B. W., Cretaceous Foraminifera from Minn., 384. Thompson, A, H., 49. Todd, J. E., Inequalities in the old Pale- ozoic sea bottom, 64; Voleanic ash bed near Omaha, 130; Report on the geolo- gy of South Dakota, 186. Triarthrus, Further observations on the ventral structure of, C. E. Beecher, 91. Turner, H. W., Auriferous ‘gravels of the Sierra Nevada, 371. 405 U Ulrich, £, O., 187, 385; Historical sketch of investigations of the Lower Silurian in the upper Mississippi valley, 384; Lower Silurian Bryozoa of Minn., 386. Ue College, geological department, 196. United States Geological Survey, Thir- teenth Annual Report, 48. : Upham, Warren, 67, 203, 204, 336; Prelim- inary report of field work in northeast- ern Minn., 51; Drumlin accumulation, 194; Discrimination of glacial accumu- lation and invasion, 200; Climatic con- ditions shown hy North American interglacial deposits, 273; Stages of re- cession of the North American ice- sheet shown by glacial lakes, 396. Ups and downs of Long Island, John Bryson, 188. Van Hise, C. R., The Penokee iron bear- ing series in Michigan and Wisconsin, 326. Variations of glaciers, H. F. Reid, 260. Vaughn. JT. W., Stratigraphy of north- western Louisiana, 205. Vermeule, ©. C., 329. Voleanic ash bed near Omaha, J. E. Todd, 130. WwW Wachsmuth, Charles, 399. 2 Walcott, C. D., 66, 399; Lower Cambrian rocks in eastern California, 67. Walker prize, 399. Weed, W. H.., 66. Weidman, Samuel, Quartz keratophyre and its associated rocks of the Baraboo bluffs, Wis., 68. White, David, 67. Whitfield, R. P., 67, 187; Marine Algse from the Trenton limestone, 183. Williams, G. H., Sketch of by J. M. Clarke, 69. Williams, H. 5., 67. Willis, Bailey, 68; Lhe mechanics of Ap- lachian structure, 60, Williston. S. W.. 400. Wilson, H. M., 49. Winchell, N. H., 336, 884; The age of the Galena limestone, 33; The stratigraphic base of the Taconic or Lower Cam- brian, 153; The paleontologic base of the Taconic or Lower Cambrian, 229; The eruptive epochs of the Taconic or Lower Cambrian, 295; Canadian loecali- ties of the Taconic eruptives, 856; Pale- ontology of Minn., 884: Historical sketch of investigations of the Lower Silurian in the upper Mississippi val- ley, 384; Sponges. graptolites and corals from the Lower Silurian of Minn., 385; Lower Silurian Brachiopoda of Minn., 386. Winslow, Arthur. Missouri_ Geological Survey, Sheets 2 and 3, 58; The geologic history of Missouri, 81. a Wolff. J. B., 329. Woodward, Anthony, Cretaceous Foram- inifera from Minn.. 384. Woolman, lewis. 829. Wright, A. A . 187. Wright. G. F., Observations on the gla- cial phenomena of Newfoundland, Lab- rador and southern Greenland, 198. Zz Zine and lead deposits of Missouri, J.D. Robertson, 235. TY OF ILLINOIS-URBANA nN 08526 ,