THE lOWAN-WISCONSIN BORDER 



403 



From a study of the sections, it would seem that during the time 

 that the Wisconsin ice sheet margin was in a halting state, a lake 

 was formed immediately to the east of the ice margin in which the 

 above materials were deposited by the glacio-fluvial waters. 



That the lowan drift is overlapped by the Wisconsin drift in cer- 

 tain areas within the township is suggested by the fact that in sec- 

 tions 8 and 9 of Osceola township, and section 12 of Grant town- 

 ship, loess was observed mantling the hills of presumably lowan 

 drift, but when traced westward to the Wisconsin drift margin, it 

 was observed to disappear rather sharply. The lack of sufficiently 

 deep cuts and reliable well logs, together with the great thickness of 

 the Wisconsin drift where the supposed overlapping takes place, 

 make positive statements impossible. 



Pig. 106. — Map showing the lowan-Wisconsin border in Hardin county. 



The lowan-Wisconsin border in northern Hardin county is well 

 defined, though the relief of the Altamont moraine is not so pro- 



