382 REVIEWS 



Geological Report on Arenac County. By W. M. Gregory. Michi- 

 gan Geol. and Biol. Surv. Publ. 11, Geol. Series 8. 191 1. 

 Pp. 148, pis. 6, figs. 18, map i. 

 The county is underlain by Mississippian and Pennsylvanian forma- 

 tions which dip slightly to the south. The economic resources are very 

 slight. Limestone, gypsum, and clay are of local usefulness. 



T. T. Q. 



Annotated Bibliography of Iowa Geology and Mining. By Charles 



Keyes. Iowa Geol. Surv., Vol. XXII. 1913. Pp. 908. 



Most of the first 150 pages of the bibliography are given to historical 



material. The bibliography is arranged alphabetically under the names 



of authors and subjects. 



T. T. Q. 



Prince George's County. By William Bullock Clark. Maryland 



Geol. Surv. 191 1. Pp. 251, pis. 13, figs. 3. Accompanied 



by Prince George's County Atlas, 2 maps. 



The sixth of a series of reports dealing with the physical features of 



the several counties of Maryland. A full discussion of the stratigraphic 



geology of the county accompanies a description of the physiography, 



mineral resources, soils, forests, climate, and hydrography. 



The geologic formations represented in the county range from 

 Archean to very recent. After the Archean, no formations are repre- 

 sented below the Potomac group of the Comanchean. Later formations 

 represent the Cretaceous, the Eocene (Pamunkey), the Miocene (Chesa- 

 peake), and later periods. 



T. T. Q. 



The Manhattan Schist of Southeastern New York State and Its 



Associated Igneous Rocks. By Charles Reinhard Fettke. 



A dissertation (Columbia). Annals N.Y. Acad. Sci., XXIII, 



April 30, 1914, pp. 193-260, Plates VIII-XV. 



The erosion of northeast-southwest trending anticlines and syn- 



clines has exposed the Manhattan schist in a series of roughly parallel 



belts south of the Highlands of the Hudson and east of the Hudson 



River. The Manhattan is a quartz-mica-feldspar schist and the young- 



