Vol. VI No. 12 



June 19, 1916 



JOURNAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

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



NATIONAL MUSEUM GEOLOGICAL SURVEY BUREAU OF 8TANDABD8 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY. AUGUST, AND SEPTEMBER, WHEN MONTHLY 



BT THB 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OF PUBLICATION 



WILLIAMS & WILKINS COMPANY 



BALTIMORE, MD. 



Entered aa seoond-olass matter July 14, 1911, at the post office at Baltimore. Maryland, under the Act of 



July 16, 1894 



