UNITED STATES DEPARTMENT OF THE INTERIOR 

 ROGERS C. B. MORTON, Secretary 



GEOLOGICAL SURVEY 

 V. E. McKelvey, Director 



Library of Congress catalog-card No. 73-600060 



For sale by the Superintendent of Documents, U.S. Government Printing Office 



Washington, D.C. 20402 — Price (clothbound) $9.15 domestic 



postpaid or $8.50 G.P.O. Bookstore 



Stock Number 2401-00307 



