Vol. III. No. 13. 



July 19, 1913. 



JOURNAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 

 Frederick Leslie Ransome Carl S. Scofibld Fred. Eugene Wright 



QBOLOaiCAL SURVEY BUREAU OP PLANT INDUSTRT GEOPHYSICAL LABORATORT 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST AND SEPTEMBER, WHEN MONTHLY, 



BY THE 



WASHINGTON ACADEMY OF SCIENCES 



OFFICE OP PUBLICATION 



THE WAVERLY PRESS 



BALTIMORE, MD. 



