ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably 

 prepared and signed by themselves, are forwarded promptly to the editors. 

 Each of the scientific bureaus in Washington has a representative authorized to 

 forward such material to this Journal and abstracts of official publications should 

 be transmitted through the representative of the bureau in which they originate. 

 The abstracts should conform in length and general style to those appearing in 

 this issue. 



GEOLOGY. — The enrichment of ore deposits. W. H. Emmons. U. S. 

 Geol. Survey Bull. 625. Pp. 530. 1917. 



This report is an amplification of an earlier Survey bulletin on the 

 enrichment of sulphide ores (Bulletin 529). Fifteen elements and 

 their compounds not considered in the earlier report are discussed 

 with reference to their reactions in the zone of oxidation. All recent 

 important advances in the subject have been incorporated and the 

 general treatment has been considerably broadened. 



The geologic 'conditions favorable and unfavorable to the forma- 

 tion of enriched mineral deposits are described and the criteria by 

 which such deposits may be recognized are outlined. The natural 

 chemical processes by which enrichment is produced are fully discussed 

 and the behavior of each metal is considered separately and is illus- 

 trated by descriptions of many of its known valuable enriched ore 

 bodies. A. K. 



GEOLOGY. — Notes on the greensand deposits of the eastern United 

 States. George H. Ashley. U. S. Geol. Survey Bull. 660-B. 

 Pp. 27-58. 1917. 



No attempt was made at a detailed survey of the greensands but 

 samples were collected from the most accessible of the deposits and 

 analyzed to determine their percentage of potash. The results of the 

 study show that the richest and largest deposits of greensand occur in 

 New Jersey, extending down into Delaware. Lower grade greensands 

 occur abundantly in Maryland and less abundantly in Virginia, North 

 Carolina, Arkansas, Texas, and doubtless the other Southern States. 



The richest deposits show a potash content around 7 per cent, 



513 



