MAIN MORAINIC SYSTEM OF THE MIAMI LOBE. 373 



observed beiug southeast of Dayton, in the vicinity of Beavertown, and 

 south and southwest of Germantown, but in neither of these places do they 

 compare in number with those in the main belt. 



On the inner member the distribution of bowlders is somewhat irregu- 

 lar. The eastern limb is liberally strewn Avith them throughout its encire 

 length, though they are not so numerous as in the bowlder belt of the 

 middle member. The terminal portion of the loop and the western limb 

 are sparingly supplied with bowlders, but have small areas in which the 

 number is as great as in the main belt. 



There are parts of the inner border plain on which bowldei's are as 

 numerous as anywhere in the main bowlder belt. The most conspicuous 

 of these tracts lies along the Stillwater River, the bowlders occurring 

 abundantly along this stream for several miles below Ludlow Falls and 

 also on the plains east of the stream along a line running from West 

 Milton to Troy. Over an area of several square miles they are so thickl}' 

 strewn that stone wall fences are made from them and they form a serious 

 hindrance to the cultivation of the soil. The entire district embraced 

 between the morainic system under discussion and the next moraine to the 

 north is plentifully supplied with bowlders, scarcely a farm being free from 

 them, but they seldom so greatly interfere with agriculture as they do 

 about Ludlow Falls. These bowlders probably represent englacial mate- 

 rial dropped during the recession of the ice sheet. So far as the writer 

 could discover, they do not form belts that can be correlated into well- 

 defined systems or lines and are not so suitable as moraines for showing 

 the outline of the ice margin. 



CHARACTER OF THE OUTAA^ASH. 



In this discussion the deposits of the valley of ilad River will first be 

 considered, after \vhich the valleys to the west will be taken in tuiTi. 



Mad River finds its source in the reentrant angle between the Scioto 

 and Miami lobes, at an altitude about 1,250 feet above tide. There is not 

 such deep gravel filling here as at points lower down in the valley. The 

 village of Zanesville is located in the valley about 2 miles below the head 

 of the river, and it is reported that the gravel has here a depth of but 12 to 

 20 feet, the remainder of the drift to a depth of 120 feet being mainly clay. 

 The surface of the valley bottom at Zanesville is nearly plane and has the 



