824 REVIEWS 



Geology of North Creek Quadrangle. By William J. Miller. 

 New York State Museum, Bull. No. 170, 1914. Pp. 90, pis. 

 14, rigs. 9, map 1. 



This quadrangle lies wholly in Warren County, New York, in the 

 southeastern Adirondacks. It is of geologic interest chiefly because of 

 certain rock types and structures. At the present time no rocks of 

 later age than Pre-Cambrian are present, but Paleozoic outliers just 

 off the map seem to prove that late Cambrian and probably early Ordovi- 

 cian sediments have been removed. The Grenville series makes up the 

 meta-sedimentary rocks, and the author believes the evidence favors 

 their Archeozoic rather than Proterozoic age. This series has a lime- 

 stone member of remarkable thickness, 10,000-12,000 feet, and below 

 this is 3,000 feet of quite pure quartzite. 



About 60 gabbro outcrops are shown on the map, usually with 

 elliptical ground-plans. Their form is that of small stocks or bosses, 

 rather than dikes. The author believes these gabbro occurrences 

 furnish strong evidence in favor of Daly's magmatic stopping and 

 assimilation hypothesis. The igneous masses were not intruded by 

 pushing aside the country rock, but rather by a process of replacement. 

 Marked primary variations in the gabbros and the presence of inclusions 

 as xenoliths are cited in support of this theory and seem to make a 

 strong case. 



Garnets are present in the area in quantities of some economic 

 importance. Some of the occurrences are attributed to the assimilation 

 of Grenville sediments, and subsequent crystallization from "original 

 magmas." This use of the term "original magma" for a magma that 

 has assimilated considerable quantities of sediments is questionable. 



W. B. W. 



The Waierlian Formations of East Central Kentucky. By W. C. 

 Morse and A. F. Foerste. Kentucky Geol. Survey, Bull. 

 No. 16. Pp. 76, figs. 5. 



Stratigraphic relations of the Mississippian beds in Kentucky are 

 of interest for economic reasons. In Ohio and West Virginia forma- 

 tions in the Waverly series are oil- and gas-producers and their extension 

 into Kentucky is a fact of considerable importance. 



This report covers twelve counties in the east-central part of the 

 state. The beds were traced southward from known sections in Ohio, 



