THE lOWAN-WISCONSIN BORDER 



401 



north of Lime creek, Lime creek valley, section 35, Fertile town- 

 ship, and section 36, Danville township, is lake deposit, is highly 

 fossiliferous, and is of Wisconsin age. 



The lowan-Wisconsin border in Cerro Gordo county is every- 

 where quite well defined. The Altamont moraine within this county 

 presents an area of heterogeneously grouped knobs and undrained 

 basin-like depressions. The margin of the moraine meets the gently 



IOWA - WISCOMSIW BOROelt J I" . ».i™ 



Pig. 104. Map of the lowan-Wisconsin border in Worth county. 



undulating lowan drift plain with a rather sharp line of demarca- 

 tion. In the northwest part of the county, where the Altamont 

 moraine enters the county, its surface irregularities are very pro- 

 nounced, while in the central and southern parts the surface 

 irregularities are less marked. Little or no outwash material is 

 to be seen. Drainage from the ice margin was along stream courses 

 that were determined previous to the Wisconsin ice invasion. Gravel 

 trains are prominent along many of these streams leading eastward 

 from the Wisconsin margin. 



In Franklin county the boundary line between the lowan and 

 Wisconsin drift sheets is quite conspicuous, except locally. There 

 are local areas where the marginal front of the Altamont moraine 

 shows pronounced outwash. Such an area is to be found in sections 

 5, 8, 9, 15 and 16 of Reeve township. Here the Wisconsin border 

 should be extended eastward as shown in figure 118. 



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