Geography of Ohio 213 



indicating the successive positions of the glacier in its recessional 

 movement through the Scioto valle}'. 



The Miami River valley also occasioned a lobate outline in the 

 ice sheet, most pronounced at its maximum extension. This 

 relief feature appears to have imposed itself upon the ice only- 

 while its margin was south of Troy. The western part of the Miami 

 lobe included territory in Indiana. The highland in Logan 

 county accounts for the irregular course of the Erie lobe moraines 

 in that vicinity, as if they were festooned at a point north of 

 Belief ontaine. 



After the ice sheet, during its recessional stages, had withdrawn 

 northward from the above valleys, its outline was determined 

 by the basin of Lake Erie. Therefore, in the northern part 

 of the state the moraines are concentric, bordering this basin; 

 whereas, south of this area they are arranged in a series of loops, 

 occupying the valleys just described. Between these minor 

 basins, the ice formed a reentrant angle. The position of this 

 reentrant angle is marked by the coalescence of the drift of the 

 lobate moraines; consequently, we have concentrated drift along 

 a more nearly north-south line wherever the lobes blended. 

 Between the Miami and Scioto lobes, this blending of frontal 

 moraines accounts for the thickened drift northward from Spring- 

 field to the vicinity of Kenton. On the eastern side of the Scioto 

 valley, the drift is heavy from Lancaster to Mansfield; this 

 thickened drift marks the margin of the Scioto ice lobe, east of 

 which there was no corresponding lobe until we reach the meridian 

 of Millersburg. The depression, whose axis appears to be deter- 

 mined by the line connecting Millersburg and Wooster, blends into 

 that of the Grand River lobe along the meridian of Canton, 

 between which place and Akron the drift is very thick. 



Ice lobe margins. Leverett's map of the drift in Ohio gives the 

 distal positions of the glacier, as indicated by the more conspicu- 

 ous retreatal moraines.*^ To determine accurately the minor 

 details of the ice front will require more study. Neither our 

 Federal nor State Surveys have been able to take up this work. 

 It will necessarily require a great deal of time and expense. In 

 some parts of our state, particularly in Licking County, on the 

 east side of the Scioto lobe, closer study has been given the out- 



« Monograph XLI, U. S. Geol. Surv. (1902), plate ii. 



