212 Frank Carney 



THE GLACIAL DEPOSITS OF OHIO 



Local topography is always a factor both in the distribution 

 and in the nature of glacial deposits. The gross relief features of a 

 region determine the outline of the ice during its precessional and 

 recessional movements. Minor relief features and the quantity 

 of waste material present have a bearing on the amount of drift 

 which the moving ice may locally acquire. Since moraines and 

 other glacial deposits represent the debris within the ice, it follows 

 that conditions tending to give the ice a load are factors to be con- 

 sidered in studying the drift of an area. 



Glacial lobes in Ohio. Before the glacier had moved into Ohio, 

 the lowland, which is now the basin of the present Lake Erie, 

 induced in its front a pronounced lobation. This basin gave the 

 ice sheet its general outline through Ohio and part of Indiana. 

 Topographic features in Ohio determined the grosser marginal 

 details on the south side of that lobe. 



Commencing in the northeast part of the state, we will consider 

 the relief features that determined the shape of the glacier margin. 

 Preglacially, the Grand River valley was mature. For this reason, 

 its course was filled by an extension of ice reaching ahead of the 

 main sheet. Along the margin of the Grand River lobe, moraines 

 accumulated. It is by a study of the moraines that we are able 

 to-day to outline the form of these lobes. During the extreme 

 reach of the glacier, the Grand River depression ceased to impress 

 its topography on the shape of the ice front, as the sheet had 

 extended south beyond the headwaters of the valley. Again, 

 during the recessional stages, the lobe pattern of this valley became 

 evident. 



When the ice sheet was near its southern limits, south of or in the 

 vicinity of Canton, its front described an arc, the western limit 

 of which stood near Mansfield. This minor lobate form appears to 

 be due rather to higher bounding altitudes than to a marked 

 valley. If a valley lowdand existed here, its axis should be along 

 a line from Millersburg to Wooster. The drift here is heavy, 

 and some work has already been done, showing that former drain- 

 age lines have been buried. 



The Scioto River valley induced a beautiful lobation in the 

 ice front, till it had retreated north of Marion. Between Marion 

 and Chillicothe are manv rudelv concentric lol^ate moraines, 



