IOWA ACADEMY OP SCIENCES. 
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southeastward into Grand river, a stream that is post Kansan 
in Madison county. Middle river, west of Lincoln township, 
formerly uniting in section 21 of Lincoln township with the 
stream from Grand River township, flowed in a large curve 
northward and then eastward, leaving in the bow thus formed 
that delightful and somewhat romantic “Devil’s Backbone.” 
East of Barney the main part of Clanton creek seems to have 
flowed northward across section 35 of Walnut township. 
The following streams are in preglacial valleys of their own: 
North river. Middle river, South river, Clanton creek, and the 
principal parts of Cedar creek, Jones creek and Steels branch; 
but the valleys are all much modifled by the drift, and there is 
evidence of long- continued erosion during the time that was 
post- Kansan and preloessal. The smaller ravines forming the 
heads of the larger ra^vines are post-glacial. 
