THE Jj^ 
American Geologist 
A MONTHLY JOURNAL OF GEOLOGY 
AND 
ALLIED SCIENCES 
Editor: N. H. WIXCIIELL, Minneapolis, Minn. 
ASSOCIATE EDITORvS: 
Florence Bascoxi, Bryn Mawr, Pa. 
Charles E. Beechkr, A'evv Haven, Conn. 
Samuel Calvin, Io\v.% City, Iowa. 
John M. Clarke, Albany, N. Y. Persifor Frazer, Philadelphia, Pa. 
Edward \V. Clavpole, Pasac/ena, Cat. Ulvsses S. Grant, Evanstoa, III. 
Herman 'L.F\irch\i.u, Rochester, \.Y. George P. Mkrrii^x^, Washington, D.C. 
Warren Upham, St. Paul, Minn. 
Isabel C. White, Aiorgantown, W. Va. 
VOLUME XXYII 
January to June, 1901 
Minneapolis, Minn. 
H. W. Wilson 
1901 
The University Press of Minnesota 
