6'L 
THE J 
American Geologist 
A MONTHLY JOURNAL OF GEOLOGY 
ALLIED SCIENCES 
EDITORS AND PROPRIETORS: 
Samuel Calvin, Iowa Ciiy, Iowa. 
Edward W. Claypole, Akron, Ohio. 
Francis W. Cragin, Colorado Springs, Colo. 
John Eyerman, Easton, Pa. Frank H. Knowlton, Washington, D.C. 
Ve.ksi¥OrVrp<./.e.k, Philadelphia, Pa. Joseph B. Tyrrell, Ottawa, Ont. 
Robert T. Hill, Austin, Texas. Edward O. Ulrich, Nervport, Ky. 
Warren Upham, Somerville, Mass. 
Israel C. White, Morgantozvn, W. Va. 
Newton H. Winchell, Minneapolis, Afinn. 
VOLUME XL 
January to June, 1893. 
minneapolis, minn. 
The Geological Puhlishi.\(3 Company, 
1893. 
IIUCKENE I'UIil.lSllINC; ( O., TRINTERS. 
