Vol. VI No. 11 



June 4, 1916 



JOURNAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 William R. Maxon Edson S. Bastin N. Ernest Dorset 



NATIONAL MUSEUM GEOLOGICAL SURVBT BUMAU OF STANDARDS 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST. AND SEPTEMBER, WHEN MONTHLY 



BY THB 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



WILLIAMS & WILKINS COMPANY 



BALTIMORE, MD. 



Entered a* <teoond-ciasg matter July 14, 1011, at the post office at Baltimore, Maryland, under the Aot of 



July 16, 1894 



