270 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



exposed in a pit on the south slope of the hill. Masses of it are used for 

 building stone walls in that vicinity. 



The drift knolls east of Bern Station have in several places been opened 

 for gravel, but they are composed in part of a 'stony till. 



A fine exposure of till is made by a railroad cutting one-half mile east 

 of Junction City and very near the glacial boundary. The till there has 

 blocked the valley of East Rush Creek to a height of 100 feet above the 

 stream and caused the stream to be deflected around a rock hill.^ 



For several miles northeast from Junction City the drift border lies 

 along the west side of a prominent ridge, and the view from the ridge shows 

 a great contrast between the glaciated and unglaciated territory. In the 

 unglaciated territory there are deep, sharp valleys, while in the glaciated 

 the valleys seem to have been filled 50 to 100 feet or more. Numerous 

 exposures of till 10 to 15 feet thick may be seen at roadsides and along 

 ravines in the vicinity of the drift border all through the region between 

 the Hocking and Licking rivers. In the Licking Valley, as noted above, 

 there is a great filling of silt with a capping of gravel and sand. 



North from the Licking Valley for a few miles the drift has a very 

 attenuated border, but near Fallsburg a sheet 10 to 20 feet or more in 

 depth sets in at the drift border, and from there northward to the Walhond- 

 ing the immediate border shows numerous exposures of till several feet in 

 depth. North from the Walhonding the drift margin again becomes very 

 attenuated, and continues so to the point where it passes beneath the Wis- 

 consin drift. In places only an occasional bowlder is found to indicate the 

 presence of the ice sheet. But within 5 miles back from the border in the 

 valley of Mohican Creek, thick deposits of drift occur, which, as above 

 noted, are in places aggregated in large knolls. 



SECTION II. GENERAL ASPECTS OF THE ILLINOIAN DRIFT SHEET. 



The preceding remarks apply mainly to the border of the lUinoian 

 drift. It remains to discuss features back from the border. 



The Illinoian drift sheet is well exposed only in the district lying out- 

 side the limits of the Wisconsin drift, for the thickness of the Wisconsin drift 

 is usually so great as to completely conceal it. This outlying district has, 

 in the region under discussion, an area of 6,400 square miles, more or less, 



'See W. G. Tight: Bull. Denison Univ., Vol. IX, 1897, p. 36 



