Drainage of Eaccoon Creek 



67 



my own judgment. The marginal stream theory seems reasonable to 

 me, while the last mentioned theory occurs only as a possibility.*' 



Fig. 1. 4 — the course of Raccoon Creek in pre-glacial times ; B — the course of 

 Raccoon Creek during the waning of the Wisconsin Glacier, with the boundary of 

 Wisconsin Glaciation ; C — the course of Raccoon Creek immediately after the waning of 

 the Wisconsin Glacier ; D — the present course of Raccoon Creek, with sand deposits 

 indicated. 



As already indicated, I believe that the immediate cause of the 

 change of drainage in Post- Wisconsin times lies in the sand dune 

 topography of the region. The two valleys are filled with sand and 



* Since presenting this paper I have received the suggestion from Mr. W. M. 

 Tucker of Indiana University that this region might be similar to Scioto River district 

 in southern Ohio, which has been described in a folio of the U. S. Geol. Survey. In 

 that case we must presume that during the glacial period the Wabash built up a terrace 

 of sufficient size, in itself, to bar the entrance of the minor stream. 



