THE 
Pan-American 
Geologist 
A Monthly Journal pjevoted to Speculative 
Geology, Constructive Geological Criticism, 
AND Geological Record 
Edited by 
Charles Keyes, Des Moines, Iowa 
Associate Editors: 
Prof. Edward W. Berry, Baltimore, Md. 
Dr. Henry S. Washington, Washington, D. C. 
Prof. Gilbert D. Harris, Ithaca, N. Y. 
Volume XXXVII 
PUBLISHED BY 
GEOLOGICAL PUBLISHING COMPANY 
DES MOINES, IOWA 
1922 ^ 
