November 2, 191 1] 



NATURE 



21 



GEOLOGICAL WORK IN THE 

 UNITED STATES. 



'T^HE papers dealt with under this heading are merely 

 ■*■ representative of a large amount of literature 

 devoted to the understanding of the ground on which the 

 United States have become founded. Whether from an 

 educational or from a more economic point of view, this 

 wide territory continues to be actively explored, and the 

 cKistence of State surveys, side by side with that centred 

 in Washington, testifies to the value set upon geological 

 research. The thirtieth and thirt3'-first annual reports of 

 the U.S. Geological Survey, issued by the director, G. Otis 

 Smith, in 1909 and 1910, show how the survey has often 

 preceded its topographers in the field. These reports now 

 indicate the main features of administration and publica- 

 tion during a fiscal year, the scientific papers being wisely 

 -~ued in a separate form. J. M. Nickles supplies biblio- 

 japhies of North American geology for 1908 and 1909 

 (Bulletins 409 and 444), with useful subject-indexes. 



As a sample of the present convenient form in which the 

 Geologic Atlas is obtainable, we may mention folio 169, 

 the Watkins Glen-Catatonk Folio, by H. S. Williams, 

 R. S. Tarr, and E. M. Kindle. In the " field edition," 

 with its low price of 25 cents, the 

 maps are folded into a pocket in 

 the octavio memoir, which sup- 

 plies an illustrated description of 

 the district, occupying 242 pages. 

 Two topographic contoured maps 

 are given, and are followed by 

 two showing " areal geology " and 

 two showing " surficial geology," 

 printed in colours over the topo- 

 graphic groundwork. The district, 

 lying in the Allegheny Plateau, 

 Iietween Lake Ontario and the 

 Pennsylvaijian border, furnishes 

 R. S. Tarr with a good field for 

 glacial investigation. He traces 

 two epochs of ice-advance, the first 

 being especially accompanied by 

 overdeepening of the valleys- 



S. R. Capps describes, in Bulletin 

 386, the " Pleistocene Geology of 

 the Leadville Quadrangle, Color- 

 ado." Here, again, considerable 

 overdeepening and widening of 

 valleys has occurred (p. 12), and 

 the country includes typical topo- 

 graphic features due to glacial 

 erosion and deposition (Fig. i). 

 W. M. Davis has already examined 

 some of these, and his influence 

 may be felt in the explanatory 

 passages with which the present 

 memoir introduces us to the district. 

 The bulletin is eminently one for 



scientific students who may travel in central Colorado. W. R. 

 ("alvert describes (Bulletin 390) the Lower Cretaceous coal- 

 ' riring strata of Lewistown, Montana, in a district where 

 rboniferous and Jurassic beds are also represented. 

 S. Smith (Bulletin 433), in the Seward Peninsula of 

 Alnska, has encountered (p. 97) the phenomena of soil-cap 

 movement that have been somewhat grandiloquently styled 

 " solifluction " by Swedish authors. He describes inde- 

 pendently how the frozen earth receives a burden of 

 detritus, and how this burden flows downhill when the ice 

 below it begins to melt. Materials from various levels of 

 the hills thus become mixed, to the annoyance of the 

 prospector, who seeks his gold in the stream gravels that 

 are liable to be covered by an "earth run." Vegetation 

 flourishes in places on soils laid down, by streams or by 

 earth-sliding, on beds of ice, which originated in ancient 

 snowfalls. The maps in this bulletin show well the 

 auriferous gravels, and the uplifted coastal plain on 

 Norton Sound. In Bulletin 43^, N. H. Darton records " a 

 reconnaissance of parts of north-western New Mexico and 

 northern .Arizona," and illustrates once more the famous 

 canon country. The problem of the sandstone crater of 

 Coon Butte (p. 72), which is 3900 feet in diameter and 600 



NO. 2192, VOL. 88] 



feet deep, is believed to be best met on the volcanic hypo- 

 thesis of a steam-explosion. 



N. H. Darton has also studied the geology and water 

 resources of the Black Hills region in S. Dakota and 

 \yyoming (Professional Paper 65), in continuation of 

 his report of 1901. This district includes, among 

 other bold buttes left by erosion on the plateaus, the 

 remarkable columnar mass known as the Devil's Tower 

 (Fig. 2), which the author believes to be connected with 

 an underlying vent. The nature of the " igneous rock " 

 is not stated. 



Professional Paper 72, by L. C. Glenn, on " Denudation 

 and Erosion in the Southern Appalachian Region," includes 

 a useful essay on erosion for the non-geological reader, with 

 illustrations from areas under vegetation and those from 

 which grass and forests have disappeared. The disastrous 

 effects of sulphuric acid fumes from smelting furnaces are 

 shown in views near Ducktown, Tennessee (Plate xvii.). 

 The paper is thus of interest for geographers, and includes 

 photographs of stream-meanders and river-flood phenomena. 



Palaeontology is represented by several bulletins. E. M. 

 Kindle (No. 391) treats of the Devonian fauna of the 

 Ouray Limestone in Colorado. The upper part of this 

 limestone is marked off by its fossils as Mississippian 



Fig. I. — Spur truncated by glacial erosion, near Crystal Lake, south-west of Leadville, Colorado. 



(h. Carboniferous). Several new species and a new genus 

 of Brachiopods (Syringospira) are described. R. Arnold 

 (No. 396) writes on the " Paleeontology of the Coalinga 

 District, California," where strata from the Franciscan 

 (Jurassic?) series up to freshwater Pliocene beds are repre- 

 sented. The eight unconformities indicate the instability 

 of this western region. G. H. Girty describes (No. 436) 

 the fauna of the Phosphate Beds of the Park City forma- 

 tion in Idaho, Wyoming, and Utah, and points out the 

 existence of a specialised type of Carboniferous fauna 

 widely distributed through the west (p. 10). Brachiopods 

 are scarce, and molluscs are unusually common. G. H. 

 Girty has also (No. 439) reported on the " Fauna of the 

 Moorefield Shale of Arkansas," a Mississippian zone which 

 he allies with the Caney Shale of Oklahoma. 



Elconomic geology is properly dominant in other bulletins. 

 T. N. Dale (No. 404) writes on the granites of Vermont, 

 with illustrations of their utility in the arts. F. L. 

 Ransome, W. H. Emmons, and G. H. Garrey collaborate 

 in a report (No. 407) on the " Geology and Ore Deposits 

 of Bullfrog District, Nevada," an arid region where gold, 

 derived from pyrite, occurs in a series of oxidised or's. 

 Crystalline schists have been developed from Ordovician or 



