TOPOGRAPHY. 77 



UPLAND PLAIN OF WESTERN OHIO AND EASTERN INDIANA. 



The preglacial topography of the remainder of the region west of the 

 hilly country of Ohio is so greatly disguised by drift that it must be largely 

 conjectured from well data. The drift usually overtops the old divides, 

 making it difficult to trace their position. From the available data it appears 

 that much of western Ohio and eastern Indiana had a somewhat uniform 

 upland level between 800 and 1,000 feet above tide, or nearly 300 feet 

 above the lower portions of the Maumee and Scioto basins. The rim on 

 the western border of the Scioto Basin has a rock surface standing in places 

 1,200 to 1,300 feet above tide, but averaging scarcely moi-e than 1,100 feet. 

 There was also an altitude of about 1,100 feet in the high part of Indiana 

 near the headwaters of White and Whitewater rivers, in Randolph and 

 Wayne counties. It was at these high parts of the upland that reentrants 

 were formed between the ice lobes, as shown by the morainic loops. 



KNOBSTONE ESCARPMENT AND SHALE BASIN OF SOUTHERN INDIANA. 



At the western border of the region under discussion in southern 

 Indiana there is a prominent escarpment of the Waverly or Knobstone, 

 facing a low basin formed in the Devonian shales. Its highest points, 

 however, are but little more than 1,000 feet above tide, and its general 

 elevation is about 900 feet. Its prominence is due, therefore, not to great 

 altitude, but to the contrast with the low-lying basin on its border. This 

 basin stands scarcely more than 500 feet above tide and is so narrow as to 

 resemble a broad river valley. It was apparently formed, however, by 

 subaerial degradation rather than by active stream corrasion. That it was 

 not formed by glacial action is shown by its having in the unglaciated dis- 

 tricts about the same depth and breadth as in the glaciated 



HILLY COUNTRY. 



The topography of the hilly portion of the region under discussion 

 appears to be as largely due to the action of streams and ordinary subaerial 

 degradation as that of the plain portion. The folds, faults, or other disturb- 

 ances of the strata have been in neither case sufficient to produce an 

 appreciable effect. The writer has been unable to discern remnants of a 

 peneplain in any part of this hilly country. The highest hills probably 

 stand somewhat below the old Cretaceous peneplain so well displayed on 



