484 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



to be till from top to bottom (nearly 100 feet), but exposures are not suffi- 

 ciently extensive to enable one to fully decide this matter. 



Bowlders are exceedingly numerous in the river valley just below 

 Sidney, there being one field in which there are 1,000 or more per acre. 

 At no othei' point along the upper course of this stream were they observed 

 in such numbers. 



No records of wells were obtained nor extensive natural exposures 

 observed along the moraine between the Great Miami and the State line. 

 The thickness of the drift in this portion of the moraine is seldom more than 

 50 feet, and several exposures of rock occur on its outer border along Grreen- 

 ville Creek. There are knolls along the south side of Greenville Creek, 

 east of Greenville, which contain much assorted material, but also contain 

 till. These, however, seem more likely to belong with the drift of the 

 main morainic system than with the Union moraine. Bowlders are very 

 numerous along Greenville Creek from the east border of these knolls 

 (about 3 miles east of Greenville) eastward to the meridian of Bradford 

 Junction, a distance of 6 or 7 miles. It seems not improbable that tlie 

 bowlders are a dependency of the Union moraine. They are mainly 

 small and well rounded, and thus difiPer from the bowlders which are 

 scattered over the plains to the south, the latter being large and angular. 

 The difference in size and angularity may, however, be accidental and 

 indicate nothing as to separate ice advances. 



At Greenville much variation in the thickness of the drift is reported, 

 there being borings which pass tlu'ough nearly 100 feet of drift, while near 

 by, both on the east and west, oiitcrops of rock occur. In the vicinity oi' 

 Union gas- well borings show a variation in thickness of about 160 feet. 

 the greatest thickness of drift reported being 220 feet, while the least is 60 

 feet. In several borings for gas made within 5 or 6 miles of this city the 

 drift was found to be nearly all till. In some borings a small amount of 

 gravel was found just above the rock. In the well having 220 feet of drift, 

 however, which is situated on the crest of the moraine, about 2 miles west 

 of Union, there was but a small amount of till, as shown in the following 

 section: 



Drift ^penetrated near Union, Lid. 



Feet. 



Till 40 



Gravel 30 



Sand .„„., 147 



