522 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



This exposure reveals, in places, a clayey gravel containing bowlderets, the 

 whole intercalated between beds of assorted material. 



Two miles north of Huntington, on the plain east of the moraine, a 

 well struck rock at 112 feet, and another, 2 miles farther north, at 140 feet. 

 In both wells the drift was almost entirely till. A well about 6 miles 

 northeast of Huntington struck rock at 131 feet. Here also the di'ift is 

 almost entirely till. A well 3 miles north of Roanoke, in southern Whitley 

 County, 160 feet in depth, does not reach the rock. The bluffs along the 

 old lake outlet from Huntington to Roanoke are composed mainly of till, 

 sand and gravel being no more abundant there than on the uplands. 



A well situated on the moraine, about 3 miles southeast of South 

 Whitley (in sec. 1, Cleveland Township), failed to obtain water at a depth 

 of 70 feet. It was entirely through till. Other wells in the vicinity are 

 but 20 to 40 feet deep, and obtain abimdance of water from beds of sand 

 and gravel included in the till. 



At Columbia City, as stated on a preceding page, the drift has a thickness 

 of 224 feet while the general thickness from there northward into northern 

 Michigan is apparently not far from 300 feet. For records of these wells 

 reference may be made to the preceding discussion, pages 503-505. 



INNER BORDER PHENOMENA. ■ 



Between the Salamonie moraine and the Wabash River, which in east- 

 ern Indiana flows parallel with and a few miles north of the moraine, there 

 is a till plain, which as a rule is quite smooth and in places so very flat 

 that the excavation of large open ditches has been found necessary to carry 

 off the surplus rainfall. There is a general decrease in altitude from the 

 moraine northeastward to the river, so that the crest of the moraine stands 

 75 to 100 feet or more higher than the bluff of the river. 



This plain is covered with a deep black soil, and is timbered with beech, 

 maple, elm, ash, etc., while the moraine carries much oak associated with 

 the kinds of timber just mentioned. Oak is, however, less predominant 

 than ill the Mississinawa, Wabash, and St. Marys moraines. Exposures of 

 the subsoil in this flat region are so slight that it is difficult to determine its 

 character. In some places a silt or subaqueous clay was noted, but whether 

 this deposit is of much extent was not determined. Such silts are often 

 local and signify nothing as to general conditions of drainage. 



