PLEISTOCENE HISTORY OF LOWER WISCONSIN RIVER 683 



sandy and so poor as farm land that it is called locally "Prairie" 

 or "Barrens." 



There are three possibilities to be considered in discussing the 

 origin of the low terrace: It is either the valley train of the late 

 Wisconsin ice advance or was cut from the early Wisconsin valley 

 train by waters from a glacial lake, or is a combination of the two. 



Fig. 5 — Diagram showing the relation of the terraces in the four valleys east of 

 Mazomanie. Black Earth and Halfway Prairie creeks contain the high terrace while 

 the two shorter valleys do not. 



a) Alden is of the opinion that the low terrace is the result of 

 deposition by glacial waters from the late Wisconsin invasion, while 

 the upper terrace resulted from the early Wisconsin advance.^ The 

 evidence is as follows : Of the four small valleys east of Mazomanie, 

 the two longer ones contain the upper terrace while the shorter 

 ones do not.^ This, Alden interprets as meaning that the ice of 

 the early Wisconsin invasion did not reach the heads of the shorter 

 valleys, discharging its waters only through the longer ones and 

 building in them the high terrace (Fig. 5). 



' W. C. Alden, op. cit., pp. 191-93 and 244-45. 



^ The northern one does contain several small patches (see Fig. 5). 



