THE 
American Geologist 
A MONTHLY JOURNAL OF GEOLOGY 
ALLIED SCIENCES 
EDITORS AND PROPRIETORS: 
Sajiuet. Calvin, loira City, Iowa. 
Edward V\'. Claypole, Akroi, Ohio. 
Francis W. Cragin, Colorado Springs, Colo. 
John Eyerman, Eanton, Pa. l\. D. Salisrury, Madison,Wis. 
VeuhjfokFrazeji, Philadelphia, Pa. Andrew C. La wson, Berkeley, Cal. 
KoRERT T. HiEL, Austin., Texas. Joseph B. Tyrrelt., Ottawa, Ont. 
Edward O. Ulrich, Neirport, Ky. 
IsRAEii C. White, Morgantoirn, West Va. 
Newton H. Winchelt,, Minneapolis, Minn. 
VOLU^rE X. 
.Jl'LV I'O DKrEMRER. 1892. 
.MINNEAPOLIS, MINN. 
The (iKor.oGirAL PirBLisnixG Oo^ipanv 
1892. 
T,. KIMli.M.L riMNIIMi (<>., I'KINTEKS. 
