Geology and Mineralogy. 223 



5. Earth Evolution and its Facial Expression; by William 

 Herbert Hobbs. 8vo, pp. 178, 84 illustrations. New York, 

 1921. (The McMillan Company). — Professor Hobbs states that 

 the purpose of this volume is to assemble and make available for 

 the non-technical reader the author's ideas on certain questions of 

 theoretical geology. He favors the planetesimal hypothesis of 

 Chamberlin, but suggests an order of accretion which will 

 account for the peculiar distribution of densities in the earth. 

 He believes that the present figure of the earth resembles a 

 tetrahedron, but that this figure has developed slowly as a result 

 of secular cooling, the form at the end of the Paleozoic era sug- 

 gesting a huge twinned crystal. Igneous magma is formed by 

 the fusion of shale at a moderate depth on relief of pressure 

 during folding or faulting. Thus laccolites develop essentially 

 in place, and are the result rather than the cause of the doming 

 in overlying strata. All arcuate mountains have been made by 

 underthrustiiig of sediments against continental masses, the 

 active force resulting from subsidence of ocean floors. Some 

 regions in and bordering the Pacific ocean are at present suffer- 

 ing rapid change, as indicated by earthquakes, volcanic activity, 

 terraces, and fore-deeps. The book closes with the suggestion 

 that investigations in the Pacific will cause a great reduction in 

 present estimates of geologic time. c. r. l. 



6. West Virginia Geological Survey; I. C. White, State 

 Geologist. Morgantown, W. Va. — Recent publications include 

 the following : 



Detailed Report on Nicholas County; by David B. Reger. 

 1921. Pp. xx, 847 ; with 34 half tone plates^and 22 text figures. 

 Accompanied by a separate case of topographic and geologic 

 maps. In the preparation of this exhaustive report Mr. Reger, 

 assistant geologist, has had the assistance in the field of W. Arm- 

 strong Price, paleontologist, and in the office work, of R. C. 

 Tucker and J. D. Sisler. Mr. Tucker has had charge of the 

 preparation of the maps and the calculation of the areas and 

 tonnage of the various coal beds. 



The coal development of Nicholas County has only just begun 

 because of partial lack of rail facilities. It contains three 

 important coal formations extending across the county, from 

 northeast to southwest. These are the New River Coal Group, 

 the Kanawha Group, and the lower members of the Allegheny 

 Series. The report contains a chapter on the paleontology of 

 Nicholas County and a short description of the chert deposits of 

 West Virginia. The price, including case of maps (delivery 

 charges paid), is $3.00. Extra copies of topographic map, 75 

 cents; of the geologic map, $1.00. 



New Edition of Coal, Oil, Gas, Limestone, and Iron Ore Map. — 

 This map has been thoroughly revised, showing oil and gas pools, 



Am. Jour. Sci.— Fifth Series, Vol. Ill, No. 15.— March, 1922. 

 16 



