500 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



along this portion of the moraine, but, hke the terminal loop, it includes 

 very few lakes, basins, and marshes. 



In conclusion it may be remarked that the belt has throughout its 

 entire length, from the Michigan line around to the Scioto Basin, and also 

 in its continuation across that basin, very little variety in topography, and 

 in this respect is unlike the interlobate moraine on its northwest border 

 and the main morainic system of the Maumee-Miami lobe, both of which 

 present a variable topography, ranging at frequent intervals from gentle 

 swells to sharp knobs and basins. 



STRUCTURE AND THICKNESS OF THE DRIFT. 



The general thickness of the drift belonging to this moraine probably 

 falls below 100 feet along the criest, and if the whole width of the moraine 

 be considered, it falls below 50 feet; but this constitutes only a small pro- 

 portion of the drift of this region. As shown by well records given below, 

 the thickness in places is about 500 feet. In such cases the greater part is 

 likely to be the deposit from earlier ice advances. 



In discussing the structure, also, it is necessary to distinguish between 

 the drift belonging to this moraine and that deposited during the earlier ice 

 advances. Throughout nearly the entire length of this moraine assorted 

 material constitutes but a very small percentage of the upper portion of the 

 drift, or that portion produced by the ice sheet at its latest advance into 

 this district. At earlier advances there appears to have been more assorted 

 material deposited; at least the deep borings usually pass through a large 

 amount. So far as this moraine is concerned, therefore, the drift is mainly 

 till. It is oxidized to a depth of 8 or 10 feet, but the oxidation is light, the 

 color being a grajdsh rather than brownish yellow. Below this depth the 

 color is a grayish blue. 



Bowlders are numerous, especially in Jay, Delaware, and Blackford 

 counties, Ind. They are Canadian crj^stallines, but an occasional Paleozoic 

 limestone occurs. In Jay County the bowlders appear to be more numerous 

 near the inner border than on any other portion of the moraine, and in 

 places abound on the plains just north of the moraine. The most con- 

 spicuous bowlder belt on this plain was observed between Salamonie, Ind., 

 and Fort Recovery, Ohio. In Delaware County, Ind., there is a conspicuous 

 bowlder belt on the outer border of the moraine along the Mississinawa River 



