6oo abstracts: geology 



analysis is detailed: (i) The determination of the minute quantities 

 of iron in optical glass; (2) the separation and determination of zinc; 

 (3) the separation and determination of lead and barium occurring 

 together; (4) the separation of calcium or barium from relatively large 

 quantities of aluminum occurring with almost no iron; (5) the determi- 

 nation of those elements in boric acid glasses with which the boric acid 

 interferes. Attention is called to the universal presence of hygroscopic 

 moisture in powdered glass samples. Some data by E. S. vShepherd on 

 gases in glass are given. E- T. A. 



GEOLOGY. — Salt resources of the United States. W. C. PhalEn. 

 U. S. Geol. Survey Bull. 669. Pp. 284, pis. 17, figs. 16. 1919. 



This bulletin describes the geology of the salt deposits of the United 

 States, discussing separately by States the position and extent of 

 deposits, and the stratigraphy and structure of the region, and gives 

 a bibliography for each State. It also gives theories of origin and 

 formation of salt deposits ; the chemical composition of saline materials ; 

 and statistics of the production of salt in the United States from 1880 

 to 191 7. R. W. Stone. 



GEOLOGY. — Clays and shales of Minnesota. Frank F. Grout. U. 

 S. Geol. Survey Bull. 678. Pp. 251, pis. 16, figs. 38. 1919. 



This bulletin comprises a discussion of the distribution, origin, prop- 

 erties, classification, and adaptability of the clays and shales of Minne- 

 sota. An attempt has been made to test all the more important de- 

 posits with sufficient exactness to determine for what purposes they 

 may be used. The general character of each geologic formation and 

 the character of the clay products made from it by the several methods 

 of manufacture are set forth. Deposits suitable for common brick 

 are abundant and widely distributed in many accessible localities in 

 the eastern part of the State. The red laminated clay of the eastern 

 counties makes good red brick and may be used as a slip glaze for semi- 

 refractory ware. R. W. Stone. 



GEOLOGY. — The Anvik-Andreafski region, Alaska. George L. Har- 

 rington. U. S. Geol. Survey Bull. 683. Pp. 69, pis. 7. 1918. 

 The Anvik-Andreafski region as described in this report embraces 

 the territory west and north of the lower Yukon River between Anvik 

 and Andreafski rivers and an extensive area of low-lying country im- 

 mediately contiguous to the Yukon on its east and south sides. 



