214 Frank Carney 



line of the ice at its extreme position. It has been found that 

 the glacier margin varied in shape with the topography. Wher- 

 ever valleys existed, minor tongues extended beyond the main 

 body of the ice; the relief in eastern Licking County is irregular, 

 consequently there were several ice dependencies. Consulting a 

 map ^ of the ice front in this county, one niay note that in the vicin- 

 ity of Wilkins' Run a minor dependency extended eastward over 

 a mile ; that along the parallel of Newark, a dependency reached 

 into Muskingum County, a distance of some six or seven miles 

 beyond the main glacier. Eastward from Buckeye Lake, an- 

 other dependency extended through Jonathan Creek ; this latter 

 ice tongue appears itself to have been irregular, sending out sec- 

 ondary branches into confluent valleys. 



Many interesting problems are connected wdth the more accur- 

 ate mapping of the ice front. It is hoped that students in several 

 parts of the state may take up this work, and that eventually the 

 glacial boundary line in Ohio may more accurately represent real 

 conditions. 



ICE FRONT LAKES 



The divide between the Ohio River and Lake Erie basin drain- 

 age is to-day very irregular. The rivers which flow into Lake 

 Erie send their waters to the Atlantic by way of the St. Lawrence. 

 If a barrier should be raised across the St. Lawrence at the eastern 

 end of Lake Ontario, this lake would enlarge; if the barrier were 

 sufficiently high, and a similar obstruction were placed across the 

 Mohawk valley near Rome, N. Y., Lake Ontario would blend 

 eventually with Lake Erie. If such a barrier stood only across- 

 Niagara River, the waters of Lake Erie would continue to deepen 

 till some other outlet were discovered. 



During its recessional stage, as soon as the ice sheet had wdth- 

 draw^n northward from the divides between the tributaries of the 

 Ohio River and Lake Erie, water began to pond along its margin. 

 This happened at many disconnected places. Each local lake 

 thus formed increased in size till its waters flowed southward 

 towards the Ohio, and, with further recession of the ice sheet, 

 these small local lakes grew larger, and blended. At first they were 

 distinct, because local divides existed between them, divides that 



' F. Carney, Journal of Geology, vol. xv, (1907), pp. 488-495, fig. 2. 



