314 The American Geologist. May, 1892 
the main part of these elevations very generally dip from the 
center outward. Where the elevations are elongate, the axis 
from which the layers dip is the same as the axis of the ridges. 
The surface of these hills and ridges is often marked by an abun- 
dance of large bowlders. The mantling till, where it exists, is 
continuous with the till which constitutes the surface of the 
‘‘oround moraine landscape” belt, in the immediate neighborhood, 
The association of these ridges and hills with the terminal moraine 
(Eudmordne), has led Schroeder to the belief that they are closely 
associated with the latter in origin (p. 110), as well as in position. 
Their form is ascribed neither to erosion, nor to accumulation. 
They are regarded as swells or folds pressed up by the ice at its 
border, during a period when the edge of the ice was nearly con- 
stant in position. Because of the peculiar sort of disturbance 
which the stratification of these elevations has sometimes suffered, 
Dr. Wahnschatfe’s inference seems justified, that lateral thrust by 
the ice must also have played some part in their origin. Wahn- 
schaffe appears to agree with Schroeder that these hills and ridges 
were essentially contemporaneous in origin with the terminal mo- 
raine (Hidmordue). From the description before us, it is not 
clear that they do not constitute an element of the ‘ground mo 
raine landscape.” It will be seen that Wahnschatfe and Schroed- 
ers view concerning the time and method of origin of these sand 
and gravel hills, corresponds somewhat closely with Dr. Keil- 
hack’s view concerning the time and the method of origin of the 
elevations and depressions of the region designated ‘ground 
moraine landscape.” We have already seen that Dr. Wahn- 
schatfe’s view of the origin of the ‘‘ground moraine landscape, ” 
is different. But we believe that Dr. Keilhack’s explanation of the 
“eround moraine landscape” is more nearly correct, and that it is 
in perfect harmony with Wahnschatfe and Schroeder's view con- 
cerning the origin of the sand and gravel hills and ridges asso- 
ciated with the terminal moraine (Hndmordne), and with the 
“oround moraine landseape.”’ Dr. Wahnschatfe indicates the 
close association of the one class of drift hills with the other, but 
unfortunately he does not state whether the sand and gravel hills 
are more commonly associated with the outer or with the inner 
border of the ‘ground moraine landseape.’’. He would seem to 
imply that the association of the German terminal moraine (4nd- 
morcdne) with the hills here noted, is very close; but since he does 
