REVIEWS 829 



within ten miles of the only purely volcanic rock in New York, Vermont, 



or western Massachusetts support this theory. The carbonated waters 



take on calcium and magnesium carbonates from the Little Falls dolomite 



on their upward journey. This conclusion accords with the marked 



tendency of economic geologists in the last decade to lay greater stress on 



the importance of magmatic emissions. 



W. B. W. 



Coal Resources of District No. I (Longwall). By Gilbert H. Cady. 

 Illinois Coal Mining Investigations, Bulletin No. 10, Urbana, 

 1915. Pp. 149, pis. 9, figs. 27, tables 24. 

 The Longwall District, comprising Bureau, Putnam, Marshall, 

 La Salle, and Grundy counties and the adjacent parts of Livingston, 

 Kankakee, and Will counties, an area of about 1,700 square miles, 

 contains nearly six billion tons of available coal and is one of the foremost 

 districts of the state in economic importance. This bulletin is con- 

 cerned with the stratigraphic and structural geology of the region, the 

 economic geology of the coals and accompanying strata, and with the 

 working data developed. The important beds are Nos. 2, 5, 6, and 7, 

 of which No. 2 has been extensively mined. These coals have been 

 studied in a large number of mines. The character of the coal beds and 

 their general structure have been worked out in detail, and many sections 

 through the productive coal measures have been tabulated. In addi- 

 tion to its value in connection with the coal resources, the bulletin is of 

 general interest in that it contains an outline of the geology of the La 

 Salle anticline, including Starved Rock, Deer Park, and the surrounding 

 country. A _ -^ R 



Coal Resources of District No. VII. By Fred H. Kay. Illinois 

 Coal Mining Investigations, Bulletin No. 11, Urbana, 1915. 



Pp. 233 > P ls - 4, ngs. 47- 



District No. VII comprises Macoupin, Madison, St. Clair, Christian, 

 Montgomery, Bond, Clinton, Washington, Perry, Moultrie, Shelby, 

 Fayette, Marion, and parts of Sangamon, Macon, and Randolph counties, 

 an area of about 7,000 square miles, containing coal estimated at more 

 than forty-five billion tons in bed No. 6 alone. The stratigraphy of the 

 coal measures has been carefully studied, and numerous sections have 

 been measured and tabulated. Some interesting structures in the coal 



