394 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



drift tract, and then the course of the morainic belts bordering them on the 

 north, west, and south, there seems reason for concluding' that the ice cur- 

 rents parted a few miles northwest of this elevated district, one portion of 

 the ice passing southeastward along the northern side of the highlands, 

 while the other passed nearly south along the western side, and then swung 

 eastward, doubling about the southern side. A cause for this parting of 

 currents and winding of the ice sheet is found in the obstruction presented 

 by this highland tract, whose highest points stood 200 feet or more above 

 the general elevation of the districts north and south of it, the highlands 

 being 1,400 to 1,500 feet above tide, while the boi'dering tracts are 1,200 

 to 1,300 feet. The ice sheet seems to have overridden the highest hills, but 

 not to have had sufficient force to continue beyond them, while the stronger 

 currents on the lower lands, both to the north and the south, continued east- 

 ward, and b)^ their convergence nearly coalesced east of these highlands. 

 Though partially oven'idden by the ice sheet, the highlands seem not to 

 have been subjected to so long nor so vigorous glaciation as the lower 

 tracts that surround them. 



Northwest and west from Mansfield the moraine consists of closely 

 aggregated knolls 16 to 20 feet, more or less, in height. Near Lexington 

 the knolls occasionally reach a height of 30 feet or more. Basins are 

 numerous in the vicinity of that village on the lowland tracts bordering 

 Clear Fork. Several were observed which have an area of about an acre 

 and a depth of 15 or 20 feet. They occupy a gravel plain which stands 40 

 or 60 feet above the stream. This gravel plain constitutes the head of a 

 terrace, and is of importance, since it apparently indicates that the ice margin, 

 at the time the main moraine was forming, was as far west as Lexington. 

 Instead of crossing Clear Fork 20 miles southeast of Mansfield, as interpreted 

 by the earlier students, it seems more probable that it crossed the stream 6 

 miles southwest of that city. 



The knolls near Fredericktown, just referred to, are in chains which 

 have a northwest-southeast trend, following nearly the course of the West 

 Fork of Owl Creek. They constitute the border of the moraine that sweeps 

 around the western end of the belt of thin drift whose outline was given 

 above, and they lie several miles east of the main morainic belt. Their 

 contours are sharp, and the larger ones rise abruptly to a height of 25 or 30 

 feet. This member of the morainic series appears to continue directly east 



