QUATERNARY FORMATIONS THE DRIFT. 



217 



elevation, over which it passes obliquely and descends into a pre- 

 glacial valley. The material of this chain is chiefly composed of 

 rounded, well-w T orn limestone gravel, mingled with a large propor- 

 FIG. 10. tion of sand, and more or less clay, 



with occcasional small bowlders, as 

 in the preceding case. !Nb flexure 

 of the crust can be supposed to 

 have taken place, capable of bring- 

 ing the bases of these hills and 

 ridges to the same level, which 

 would be necessary in accounting 

 for them by the action of water or 

 floating ice. Besides, the general 

 configuration of the adjacent coun- 

 try and the nature of its superficial 

 deposits preclude the idea of sub- 

 mergence of either side of the range. 

 Another case occurs in the valley 

 of Grand river, between the vil- 

 lage of Markesan and Manchester, 

 in Green Lake county. The chain 

 of drift hills stretches across the 

 main valley, which is occupied by 

 the Grand river, and was doubtless originally the cause of the detour 

 which that stream makes through the site of the village of Markesan. 

 In all of the three cases above mentioned, the general direction of the 

 ridges is transverse to that of glacial movement, which harmonizes 

 with the view here entertained, that they are terminal moraines. 



II. BOWLDER CLAY, OR TILL., 



Reference has already been made to the fact, that, previous to the 

 formation of the great moraine, the Kettle Range, the glacier pushed 

 southward in the Rock river valley, abrading the surface, modifying 

 its contour, and finally, on its retiring, left the material strewn upon 

 the surface. This constitutes the earliest drift formation within the 

 limits of the dis'": '"t under consideration. It consists of a commingled 

 mass of clay, sand, gravel, and bowlders variously arranged with ref- 

 erence to each other, and spread out irregularly over the surface of 

 the rock below. As would naturally occur under the circumstances, 

 a portion of this is sorted and stratified, forming beds of brick clay 

 or of sand or of gravel, and leaving in certain localities accumulations 



Moraine in the town of Beloit. 



