Vol. VII No. 8 



April 19, 1917 



JOUKNAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 



N. Ernest Dorset Adolph Knopf A. S. Hitchcock 



[ BTJBEAC OP STANDARDS GEOLOGICAL SURVEY BUREAU OF FLANT INDTJ8TBY 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST, AND SEPTEMBER, WHEN MONTHLY 



BY THE 



WASHINGTON ACADEMY OF SCIENCES 



office of publication 



williams & wilkins company 



baltimore, md. 



Entered as second-class matter July 14, 1911, at the post office at Baltimore, Maryland, under the Act of 



July 16, 1894 



