OUTWASH OF ILLINOIAN AGE. 289 



Logan remnants are very extensive, occupying one-third to one-half the 

 width of the old valley. From that point to Chauucey nearly all the 

 gravel has been removed down to a level as low as the Wisconsin gravel; 

 but between Chauncey and Athens a section of the old valley is abandoned, 

 and more than a square mile of the gravel filling is preserved. Below 

 Athens no remnants of the old gravel were noted. Possibly the deposit 

 was not carried in large amount farther down the valley than the abandoned 

 section above Athens. 



SALT CREEK VALLEY. 



As indicated in the discussion of the drift border, the North, or main, 

 Fork of Salt Creek appears to have held a small glacial lake during the 

 deposition of the Illinoian drift, into which but little material except fine 

 silt was carried. The lake discharged across an old divide near the point 

 where the present stream passes from Hocking into Vinton County, into a 

 valley that opened southward to the Scioto, but it seems not to have carried 

 much material into that valley. 



The South Fork of Salt Creek, though lying apparently entirely outside 

 the limits of glaciation, is so situated that the glacial accumulations on the 

 Scioto at the mouth of the creek held a lake in the creek valley into which 

 the glacial waters passed, and at the head of which they opened a passage 

 southward to the Ohio. This lake received a large amount of fine calcareous 

 sediment, the depth at the present divide between Salt Creek and Symmes 

 Creek near Camba being not less than 90 feet. 



SCIOTO VALLEY. 



Attention was called in the discussion of the Illinoian drift border to a 

 prominent gravel terrace on the Scioto, which heads at the glacial boundary 

 east of Chillicothe. ' This terrace, which at its head stands about 100 feet 

 above the Scioto, has been built up at that point from below river level. 

 Passing southward, down the valley, one finds the glacial gravel covering 

 a series of rock shelves, which show a slight increase in altitude in that 

 direction. It declines in altitude about 50 feet in passing from the glacial 

 boundary to the mouth of the Scioto, where it barely comes to the level of 

 the rock shelves. From more than 100 feet opposite Chillicothe the depth 

 of the gravel becomes reduced to but 15 feet at Coopersville, near the line of 



MON XLI 19 



