DEPARTMENT OF THE INTERIOR 
UNITED STATES GEOLOGICAL SURVEY 
GEORGE OTIS SMITH, Director 
Bulletin 372 
BIBLIOGRAPHY 
OF 
NORTH AMERICAN GEOLOGY 
FOR 
1906 and 1907 
WITH SUBJECT INDEX 
BY 
F. R WEEKS and J. M. NICKLES 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1909 
