380 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



flowing in valleys that are usually deeply filled with gravel. There is, 

 however, occasionally considerable till beneath the gravel. East Fork has 

 in places but a small amount of drift, for it is largely in a new course opened 

 since the early Wisconsin stage of glaciation. At Richmond the stream has 

 cut about 50 feet into the rock, while the depth of rock excavation is still 

 greater farther south. The other tributaries of Whitewater have for manv 

 miles south from the moraine shallow valleys, their beds being but 1.5 to 

 30 feet below the glacial terraces. 



It is probable that the Whitewater Valley received important contribu- 

 tions of glacial gravel throughout its entire length at the time this morainic 

 system was forming, for the feeders are numerous and the valley has a rapid 

 descent, there being in the g'ravel terraces a fall of nearly 500 feet between 

 their heads and the mouth of the stream, a distance of about 75 miles. It 

 is not certain whether the terraces formed at the early Wisconsin stag-e rise 

 at any point above the level of the gravel filling which accompanied the 

 glacial stage under discussion. 



STKIJE. 



Thirteen observations of striae have been made, or have come to the 

 writer's notice within the limits of this moraine and its inner border plain. 

 With two exceptions these are all in the eastern portion of the district. 

 With three exceptions they bear either directly or obliquely toward the 

 eastern limb, the exceptions being found near Piqua, where the bearing is 

 nearly due south and in western Darke County, where the bearing is slightly 

 west of south. Striae are rare in the western portion of the morainic loop, 

 several rock outcrops having been examined, both within the western limb 

 and on the inner border plain, without success in finding striation. ^ The 

 following is a list of the observations. The bearings obtained b)^ the writer 

 and probably those by other observers have not been corrected for magnetic 

 variation. 



Strife in the vicinity of the main lacmiinic system. 



Angel' ir quarries in Bellefontaine S. 10° E. 



Stattler's quarries, 1^ miles south of Piqua N.-S. 



Zinn's quarry, .3 miles northeast of New Carlisle, near outer border of moraine S. 22° E. 



At roadside, 1 mile west of Zinn's quarry g. 80° E. 



Troy, 6 miles southeast of, on east-west center road in Elizabeth Township S. 2.5° E. 



Troy, 2 miles south of, on west bluff of Great Miami S. 28° E. 



Light's quarry, Dayton, 6 miles north of, east bluff of Great Miami ' S. 19°-33° E. 



' Eeported by Dr. John Locke, Geology of Ohio, 1838, pp. 230-232, fig. 2. 



