UNION MORAINE. 483 



well penetrated about 350 feet of drift, striking rock at an altitude only 600 

 to 625 feet above tide. 



At Sidney a gas boring near the Big Four Railway station, about 

 30 feet above the level of the river, penetrated 115 feet of drift, mainly 

 sand and gravel, but only a mile south of the city rock appears in the river 

 valley, forming bluffs 16 to 20 feet high. Outcrops of rock are frequent 

 between this point and Piqua. 



In a cutting made by the Big Four Railway, just west of the crossing 

 of the Cincinnati, Hamilton, and Dayton Railway in Sidney, the following 

 succession of till sheets is exposed : 



Raihvay (nitting n^ar Sidney, Ohio. 



Feet. 



1 . Yellow till 12-15 



2. Blue till 4-6 



3. Yellowtill 3-5 



4. Blue till (exposed) 10-12 



Near the standpipe in the northern part of Sidney, and nearly one-fourth 

 mile distant from this railway cut, Nos. 1 to 3 are exposed, the thickness of 

 the upper yellow till being 15 feet, and of the blue till 6 to 10 feet. The 

 base of the lower yellow till is not exposed. It is probable that only the 

 upper yellow and blue tills belong to the moraine under discussion, and 

 that the lower tills are earlier. There is no striking difference between the 

 rock constituents of the upper and lower sheets. In each sheet numerous 

 pebbles of Lockport (Niagara) limestone occur, a large percentage of which 

 are glaciated. 



In the east bluff of the Great Miami, a mile south of Sidney, there are 

 extensive exposures of cobble and gravel, above which there is a capping of 

 till 10 to 12 feet in thickness. The cobble beds are in places so firmly 

 cemented as to break through the pebbles more readily than around them. 

 The pebbles are mainly Lockport (Niagara) limestone, but crystalline peb- 

 bles of Canadian derivation are not rare. A few bowlders a foot or more 

 in diameter are embedded in the cobble deposit, so that it consists of a,n 

 unusually coarse assorted material. In this exposure it is probable that 

 only the capping of till belongs to the moraine under discussion, and the 

 assorted material may either belong to an earlier advance or have been 

 deposited just before the ice sheet covered the valley and deposited the till. 

 In the west bluff, opposite the exposure of assorted material, there appears 



