102 REVIEWS 



on clays, building stones, and petroleum are included also. The latter 

 part of the report includes a glossary of more than 400 terms. Each 

 definition of a mineral is followed by a list of the states in which it is 

 found, so that this feature combines the features of glossary and index. 



W. B. W. 



Geology and Oil Prospects of Northwestern Oregon. By C. W. 

 Washburne. U.S. Geol. Survey, Bull. No. 590. Pp. in, pi. 1. 



Great development of California oil fields has led to extended pros- 

 pecting in other regions bordering the Coast Range Mountains. 



The sedimentary rocks exposed in this region range from Upper 

 Eocene to Pleistocene. Shales and coarser elastics of both fresh-water 

 and marine origin greatly predominate, intercolated with tuffs and vol- 

 canic agglomerates. Very little detailed work has been done on the 

 stratigraphy of these systems. Fossils are quite abundant, but there are 

 few if any remains of diatoms, so abundant in the California oil fields. 



The author fails to find indications favorable for oil in this region. 

 The structure in the northern part is a broad, low geanticline, broken 

 by many large igneous masses, and by multitudes of small dikes and 

 faults. That no oil exists is inferred from the fact that in all these 

 breaks in the strata no true oil seeps have developed. Farther south, in 

 Coos County and vicinity, the structure is essentially a broad syncline 

 with low flanking anticlines and few dikes. The structure is favorable 

 for oil reservoirs, but here also oil-seeps, so abundant in Mexico and 

 Southern California, are entirely absent. 



W. B. W. 



Slate in the United States. By T. Nelson Dale and Others. 

 U.S. Geol. Survey, Bull. No. 586. 1914. Pp. 220, figs. 18, 

 pis. 26. 



This report is in the main a corrected and revised edition of Bulletin 

 275 issued in 1906. Since the publication of that bulletin, slates of 

 economic value have been found in several states and additional inves- 

 tigation made in well-known districts. 



Part I of the present bulletin summarizes the present knowledge of 

 the origin, texture, and chemical and mineral composition of slates. The 

 structure of slate is treated with more detail. In Part II more or less 

 detailed descriptions are given of occurrences of slate in fourteen different 



