552 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



Ashland leads across the valley near the head of the terrace, there being an 

 open valley south of the road with a terrace standing about 25 feet above 

 the stream, while toward the north the valley and its slopes are dotted with 

 drift knolls and ridges 10 to 20 feet in height. 



On the uplands between this tributary of Lake Fork and Jerome Fork 

 the moraine has rather feeble expression, its knolls and ridges being but 10 

 to 15 feet high. It stands, however, nearly 20 feet above the tract south 

 of it. 



In the valley of Jerome Fork, north of Ashland, it is well developed, 

 with numerous basins, and with knolls often 15 to 25 feet in height. 



West of Jerome Fork the moraine enters a less hilly district than that 

 to the east. The preglacial valleys and ridges are either entirely obscured 

 or are represented only by broad sags and low divides whose slopes are 

 scarcely appreciable to the eye. The moraine is, therefore, a more conspic- 

 uous feature than in the hilly districts, though it has little, if any, stronger 

 expression. Its knolls and ridges commonly fall between 10 and 25 feet 

 in height, and basins are not numerous, but there is a nearly continuous 

 main ridge with well-defined crest, which stands 15 to 30 feet or more 

 above the outer border district. 



The knolls are somewhat sharper and higher on the eastern and 

 western borders of the Scioto-Sandusky Basin than in the central portion, 

 their height in the central portion being usually but 5 to 10 feet. The 

 central ^jortion was a prairie region when the country was settled, while 

 the borders were heavily timbered. Whether the softening of contour in 

 the prairie district is due to a more rapid subaerial erosion there than 

 in the timbered districts, or to original differences in features occasioned 

 by the ice sheet, has not been determined. Neither is it apparent why this 

 district was untimbered, for, as in the great prairies of Illinois and other 

 western States, timber flourishes wherever introduced by the residents. 



This jDrairie tract differs from the level and marshy prairies which 

 appear on portions of the continental divide in Ohio in being dry land and 

 in having an inclined surface whose altitude has a range of fully 150 feet 

 It is not probable, therefore, that it is an old lake -bottom, as has been 

 supposed by many of the residents. 



In Indiana this moraine presents considerable variation in contour, 

 portions of it being a smooth ridge as in western Ohio, while other portions 



