THE 
American Geologist 
A MONTHLY JOURNAL OF GEOLOGY 
AND 
ALLIED SCIENCES 
Editor: N. H. WINCHELL, Minneapolis, Minn. 
ASSOCIATE EDITORS. 
Florence Bascom, Bryn Mawr, Pa. 
Charles E. Beecher, New Haven, Conn. 
Samuel Calvin, lo^va City, Iowa. 
John M. Clarke, Albany, N. Y. Persifor Frazee, Philadelphia, Pa. 
Edward W. Claypole, Pasadena. Cal. Ulysses S. Grant, Evanston, III. 
Herman L. Fairchild, ifoc/iesfer, iV. F. George P. Merrill, Washinqton. D. C. 
Warren Upham, St. Paul, Minn. 
Israel C. White, Morgantoion, W. Va. 
VOLUME XXV 
January to June, 1900 
Minneapolis, Minn. 
The Geological Publishing Company 
1900 
The Fbanklin Printing Co., Printers 
