THE PLEISTOCENE OR GLACIAL PERIOD 867 



hundred feet or more in height. Not rarely they are about as steep 

 as the loose material of which they are composed will lie. The 

 " kettles" are the counterparts of the elevations. They may be a 



Fig, 577. Drumlins in contour, near Clyde, N. Y. (U. S. Geol. Surv.) 



few feet, or many rods, or even furlongs in diameter. They may 

 be so shallow that the sagging at the center is scarcely observable, 

 or they may be scores of feet in depth. Where steep-sided depres- 

 sions are closely associated with abrupt hillocks, the topography 



