THE 
AMERICAN GEOLOGIST 
A MONTHLY JOURNAL OF GEOLOGY 
ALLIED SCIENCES 
EDITORS AND PROPRIETORS: 
Samuel Calvin, lozva City, lozua. 
Edward W. Claypole, Akron, Ohio. 
Francis W. Cragin, Topeka, Kansas. 
John Eyerman, Easton, Pa. Arthur Lakes, Golden, Col. 
Persifor Frazer, Philadelphia, Pa. Andrew C. Lawson, Berkeley, Cal. 
Robt. T. Hill, Austin, Texas. Edward O. Ulrich, Newport, Ky. 
Israel C. White, Morgantown, W. Va. 
Alexander Winchell, Ann Arbor, Mich. 
Newton H. Winchell, Minneapolis, Minn. 
VOLUME VII. 
January to June, 1S91. 
MINNEAPOLIS, MINN. 
The Geological Publishing Company. 
1S91. 
BUCKEYE PUBLISHING COMPANY, PRINTERS. 
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