576 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



view of the results of counting several samples from different horizons in 



the drift, Gilbert remarked as follows : ^ 



These figures give numerical expression to a fact that has been confirmed by 

 the inspection of the surface over large areas, and of the lower portions at manj' 

 points — the fact that the Laurentian rocks predominate over the ordinary sedimentary 

 in the upper portions, while the reverse is true in the lower, and the intermediate 

 parts present a gradation. When a gravel bed occurs near the base of the deposit it 

 is usually, though not invariably, made up of fragments, little worn, of the rocks 

 on which it rests. 



The following represent the more important well records obtained west 

 from the point where the Wabash and Fort Wayne moraines become 

 widely separated. Sections of wells in the portion that is closely associated 

 with the Wabash moraine are presented in the discussion of that moraine. 



On the crest of the Fort Wayne moraine north of Dunkirk, Ohio, two 

 wells at J. P. Dixon's strike rock, one at 44 feet, the other at 46 feet. One 

 mile east, and also on the crest, a well at J. M. Reed's struck rock at 50 

 feet. In all these wells the drift is almost entirely till. Still farther east 

 (in sec. 9, Blanchard township) A. Grillen has a well which struck rock at 

 60 feet, while Mr. C F. Darrett (in sec. 16, Blanchard township) has a well 

 with 100 feet of drift. 



On Hog Creek Marsh, near Dunkirk, several flowing wells have been 

 obtained at 30 to 3.5 feet, from gravel below blue clay. 



At Lima the drift generally has a thickness no greater than the relief 

 of the moraine (about 20 feet), but in one boring within the city limits 1 70 

 feet is reported. It is somewhat thicker than 20 feet south of Spencerville, 

 there being no rock exposed by the Miami Canal, which is excavated to a 

 depth of fully 20 feet at the crest of the moraine. Between the Miami 

 Canal and the State line rock appears at intervals along St. Marys River, 

 but at Rockford a well passed tlu-ough 130 feet of drift, mainly till, while 

 near that village more than 300 feet of drift is reported by Bownocker. 

 At Enterprise (Ohio City) north of Rockford on the inner slope of the 

 moraine the drift is about 60 feet in thickness. In the southwestern part 

 of Van Wert County wells along the crest of the moraine north of 

 Willshire pass through 70 to 100 feet of drift. Several exposures of rock 

 occur between Willshire, Ohio, and Decatur, Ind., along the St. Marys 

 River, at a level 60 to 75 feet below the crest of the moraine. 



1 Geology of Ohio, Vol. I, 1873, p. 547. 



