Geology and Mineralogy. 329 



chapters of the connected volcanic eruptions, and also of the 

 accompanying changes in continental level, for which the wide- 

 reaching hypothesis is suggested that the disappearance of the 

 lake and the elevation of the center of the basin stand related as 

 cause and effect. A discussion of this subject was given by the 

 author in this Journal in 1886 (vol. xxxi, 284). Like other 

 recent publications by the Geological Survey, Mr. Gilbert's 

 monograph is profusely illustrated with excellent plates, which 

 add much to the clearness of presentation. 



2. First Annual Report of the Geological Survey of Texas, 

 1889; E. T. Dumble, State Geologist. 410 pp., 8vo, with maps, 

 plates and other illustrations. — This volume opens with "a 

 review of Texas Geology as developed by the work of the Survey," 

 prepared by the Director of the Survey. The rest of the volume 

 consists of the reports of the working geologists. The " pre- 

 liminary report of the Gulf Tertiary of Texas, by R. A. F. Pen- 

 eose, Jr., gives an excellent account of the formations, together 

 with economic notes on the iron ores, building stones, clays and 

 lignites and other mineral resources of this part of the state. 

 A brief description of the Cretaceous rocks of Texas, and their 

 economic uses, by Robert T. Hill, follows. The brief statement 

 in this volume is, for the most part, a resume of the author's 

 extensive observations. W. F. Cttmmings has two reports, 

 one on the southern border of the Central Coal-field, and the 

 second on the Permian of Texas and its overlying beds. The 

 author dwells at length on the economic geology of the regions, 

 besides giving some account of the formations. The next is a 

 preliminary report on the Coal fields of the Colorado river, by 

 Ralph S. Tarr. The author in the course of his survey arrived 

 at important conclusions with regard to the presence of Lower as 

 well as Upper Carboniferous beds. The views of this careful 

 geologist are published also in the " American Geologist " for 

 September, 1890; besides a brief note in vol. xl, of this Journal. 

 W. von Streerawitz has a preliminary statement on the geology 

 of Trans-Pecos, Texas, relating especially to the character of the 

 country and its mineral resources. The last of the reports is by 

 Prof. Theodore B. Comstock, on the " Central mineral region of 

 Texas," and covers over 150 pages. The Central mineral region of 

 Texas is occupied in part by Archaean rocks, and twenty-five 

 pages of the report are devoted to them. Subdivisions of the 

 Archaean into systems and groups are proposed, but the account 

 shows that a careful and comprehensive study of the region is 

 required to give them authority and we refer for them to the 

 volume. The Paleozoic and overlying rocks of the region are 

 also described and their orographic movements discussed. Notes 

 follow on the metallic and other minerals, and the various eco- 

 nomic products of the region. 



3. Geological Survey of Missouri ; A. Winslow, State Geolo- 

 gist. — The House, in th-e Legislature of Missouri, has recently 

 voted to double the original appropriation for the survey of the 

 State. The sum recommended is $40,000 for the year. 



