Vol. III. _ No. 12. 



June 19, 1913. 



JOUENAL 



OF THE 



WASHINGTON ACADEMY 



OF SCIENCES 



BOARD OF EDITORS 



Frederick Leslie Ransome Carl S. Scofield Fred. Eugene Wright 



GBOLOaiCAt, SURVET BUREAU OP PLANT INDUSTRY GEOPHT8ICAL LABOBATORT 



PUBLISHED SEMI-MONTHLY 

 EXCEPT IN JULY, AUGUST AND SEPTEMBER, WHEN MONTHLY, 



BY THE 



WASHINGTON ACADEMY OF SCIENCES 



office of publication 



the waverly press 



baltimore, md. 



