934 THE JOURNAL OF GEOLOGY. 
claimed by various authors that the formation of drumlins was 
due to the erosion of a thick sheet of till by differential currents 
in the ice bottom. If this hypothesis is a true one, the source of 
the currents is readily found in the passage of ice over escarp- 
ments and other irregularities. It seems that the presence of the 
arched currents with regions of relatively inactive ice below over 
drumlin regions must give the weight of evidence largely to the 
theory of deposition, though the points of descent of the cur- 
rents were points of erosion, in all probability, and these must 
have had some influence in determining the exact location and 
form of the drumlins. 13, (C, (CASS, 
GEOLOGICAL LABORATORY, CORNELL UNIVERSITY, 
May, 1895. ° 
