Gl 



often an inch or more in diameter, with borders more or less 

 rounded by magmatic absorption, and the interior replaced 

 to a greater or less extent by secondary minerals. These 

 diabases form are easily recognized type of dyke rock, and 

 it was proposed to use the name "Huronite diabase" as a 

 petrographical term in tracing the distribution of boulders. 

 The greater number of dykes described by Mr. Barlow as 

 containing "Huronite" are northward from Lake Huron, 

 but there are others in Minnesota and in the Labrador 

 peninsula. 



HOW DO GLACIERS MOVE? 



JOHN J. JANNEY. 



[ABSTRACT.] 

 The author argues against the regelation theories of 

 Tyndall and CroU and concludes that the motion is pro- 

 duced simply by gravity aided by the expansion and con- 

 traction due to changes of temperature. 



NOTES ON PERONOSPORA (PHYTOPHTHORA) 



INFESTANS. # 



E. W. CLAYPOLE, AKRON, O. 



[ABSTRACT.] 



June 4, 1S96. 



A few years ago I was growing potatoes in a lot near 

 my house and the season being wet the well known potato 

 disease broke out and became very destructive. Not hav- 

 ing for many years had an opportunity of studying this 

 fungus, I took advantage of the occasion. 



