556 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



plains cany a larger amount of beech, maple, elm, and other kinds of 

 trees that flourish in a deep black soil, but do not find so good a habitat in 

 the thin clayey soil of the moraine. Along a part of its course within the 

 Scioto Basin, as indicated above, there is a prairie. The surface clay 

 contains many pebbles, but bowlders are rare. A large proportion of the 

 surface pebbles are crystalline rocks of Canadian derivation, and nearly 

 all of the bowlders are of this class of rocks. The till is of a yellowish- 

 brown color at surface, changing to a brighter yellow at a depth of 4 to 5 

 feet, and this in turn to a gray color at 10 to 15 feet. 



The most conspicuous bowlder belts on this moraine are to be found 

 along the Aboit River and the borders of the old lake outlet; elsewhere 

 they are not a striking feature. The bowlders are mainly granites and 

 are well rounded. But few show striated surfaces. These and other bowl- 

 der belts north of the old lake outlet have been interpreted by Taylor 

 to indicate interglacial stream concentrations followed by readvances of 

 the ice sheet.^ 



In the Ohio portion of the moraine scores of gas wells have been 

 put down, for it passes through the Lima gas and oil district. Where 

 best tested (in southeastern. Allen County, Ohio), the thickness along the 

 crest of the moraine is 60 to 100 feet, with an occasional greater thickness 

 where a buried valley is struck. Thus, in the vicinity of Cridersville, a 

 much greater amount has been penetrated in several of the wells; one, 

 known as the George De Long well, is reported by Orton to have pene- 

 trated 428 feet, while the Lydia De Long well penetrated 335, and Cobb, 

 Page & Co.'s well penetrated 300 feet. The buried valley in which these 

 wells are sunk must be narrow, for within less than a mile in all directions 

 rock is struck at 20 to 50 feet. Attention was called, on a preceding 

 page, to wells south of St. Marys which passed through about 400 feet of 

 drift, but the connection between these points has not been made out, 

 though a connecting valley probably exists. Along the direct line through 

 Wapakoneta and Moulton rock is usually struck at 80 to 150 feet, so that 

 if it occurs along that line it must be very narrow. In the vicinity of the 

 town of St. Marys the thickness of the drift ranges from 24 feet to over 

 400 feet. From St. Marys westward to the State line the general thickness 

 along the moraine is about 60 feet, though there are places where it is 



^Moraines of recession, etc., by F. B. Taylor: Jour. Geol., Vol. V, pp. 438-441. 



