Whole Number 293 



THE 



JOHNS HOPKINS 

 IJNFVERSITY CIRCULAR 



741 $ 



CONTRIBUTIONS TO 

 GE-LOGY 



AND 



PLANT PHYSIOLOGY 



BALTIMORE, MARYLAND 

 ISHED BY THE UNIVEBSITY 

 ISSUED MONTHLY FROM OCTOBER TO JULY 

 MARCH, 1917 



Entered, October 21, 190C, at Baltimore, Md., as second class matter, under 

 Act of Cengu. of July 16, 1894 



