REVIEWS 721 



of dark silicates next the intrusive, and do not apply the term to the 

 zone of light-colored silicates or to the marble. 



No evidence of enrichment through the action of meteoric waters 

 was noted in any of the deposits. Leaching is shallow. 



The average tenor of the deposits worked near Bishop, California, 

 is about 0.5 per cent of WO3; ore mined in the Mill City, Nevada, 

 district averaged about 2 per cent of WO3. 



E. S. Bastin 



Geology of the Non-metallic Mineral Deposits Other Than Silicates. 

 Vol. I. Principles of Salt Deposition. By A. W. Grabau. 

 First edition. New York: McGraw-Hill Book Co., 1920. 

 Pp. xvH-435, figs- 125. 



This volume is a treatise on applied stratigraphy. The author 

 designates it as "a hand-book of salt-geology," using the term salt to 

 include phosphates, nitrates, borates, and similar deposits, as well as 

 common salt. 



The author discusses first the sea as a source of saline deposits, basing 

 a number of his conclusions on the careful work by Van't Hoff on the 

 famous Stassfurt deposits. This is followed by a well-illustrated chap- 

 ter concerning the conditions by which sea salts are deposited in nature, 

 emphasis being placed on their organic deposition. 



In the discussion of lagoonal deposits, it is concluded that many of 

 the older salt deposits, generally believed to have been formed after 

 the manner postulated by the bar theory, cannot be accounted for in 

 this way, inasmuch as they are non-fossiliferous. Lagoonal deposits, 

 such as those forming in the Karatugas Basin, contain fossils. 



A chapter is devoted to the classification of terrestrial salts, and the 

 larger portion of the book is devoted to a discussion of their origin, method 

 of concentration, and distribution. Throughout the book numerous salt 

 lakes and salt basins of various t5^es are described, and their deposits 

 discussed. 



Attention is given to the mooted questions of the origin of nitrates, 

 phosphates, and dolomites, and the several theories which have been 

 advanced to explain them are stated. 



In the chapter on "Deformation of the Salt Bodies," the author 

 favors the view of Rogers that the salt domes of Louisiana and Texas are 

 of exogenetic origin, but doubts whether all the characteristics of salt 

 domes can be accounted for without the action of endogenetic forces. 



