226 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



Huron and Michigan. In the district south of Lake Huron it extended 

 much farther south than in the more elevated and broken district on its 

 borders. 



The notch in the drift border near Cincinnati appears to be about in 

 the lee of the elevated tract in Logan County, Ohio, standing between the 

 Scioto and Miami basins, and this relation suggests the caiise for the notch 

 or slight indentation displayed. 



The reentrant in southern Indiana was no doubt made more prominent 

 by reason of the elevated and broken country which the ice sheet there 

 encountered, while the southward protrusion on its east border was aided 

 b)^ the low, smooth countrj^ in the path of that part of the ice sheet. It 

 seems probable that these local conditions may have been responsible for a 

 difference of several miles in the irregularity of the drift border, but they 

 can hardly be held responsible for the lobation or protrusion of 70 miles 

 which the border displays. The great basins encountered by the ice sheet 

 before reaching its extreme limits appear to have been the chief factors in 

 causing the lobation. 



How far within the limits of the Wisconsin drift the border of the 

 lUinoian drift lies in northeastern Ohio, and districts farther east, has not 

 been determined. It will perhaps be made known b}' well sections. 



SECTION III. THE BORDER OF THE WISCONSI^T DRIFT. 



The Wisconsin di'ift extends nearly or quite to the glacial boundary 

 in the reentrant angle in southwestern New York. It also reaches or closely 

 approaches the limits of glaciation in eastern Ohio and the western edge 

 of Pennsylvania. But elsewhere in the region under discussion the border 

 of the Wisconsin drift lies some distance back from the glacial boundary. 

 In southeastern Indiana it falls short 50 to 60 miles, and in southwestern 

 Ohio 10 to 40 miles, as may be seen by reference to PI. II. 



The late Wisconsin drift seems to reach about to the border of the 

 early Wisconsin, and possibly in places beyond it, in central and eastern 

 Ohio and in northwestern Pennsylvania. But in southwestern Ohio and 

 southeastern Indiana, as indicated in PI. II, the early Wisconsin drift has 

 a marked extension beyond the late Wisconsin. The time relations of the 

 Wisconsin drift in the district east from the reentrant angle in soutliwestern 

 New York have not been fully settled. It remains to be determined whether 



