THE 
AMERICAN GEOLOGIST. 
A MONTHLY JOURNAL OF GEOLOGY 
ALLIED SCIENCES. 
EDITORS AND PROPRIETORS. 
Peof. Samtjei. Calvin, University of Iowa, Iowa City, Iowa. 
Dr. Edward W. Claypole, Bucht'l College, Ak-^on, 0. 
Dr. Persifor Frazer, Franklin Institute, Philadelphia, Perm. 
Dr. Lewis E. Hicks, UniversUy of Nebraska,' Lincoln, Neb. 
Mr. Edward O. Ulrich, Qeol. Survey of Illinois, Neiuport, Ky. 
Dr. Alexander Winchell, University of Michigan, Ann Arbor, Mich. 
Peof. Newton H. Winchell, University of Minnesota, Minneapolis, Minn. 
VOLUME IV. 
July to December. 
MINNEAPOLIS, MINN. 
1889. 
THE SWINBURNK PBINTINa COMPANY 
