246 GLACIAL FORMATIONS OF ERIE AND OHIO BASINS. 



The breadth is in places fully a half mile. It is covered to considerable 

 depth with sand and gravel. 



Below Acmaton the gravel terrace appears on the east side and is well 

 displayed from Panther to Verona, a distance of 3 miles. In places the 

 width is nearly a mile. The altitude as determined by Jillson is about 965 

 feet above tide, but the writer found places where it rises to nearly 1,000 

 feet. Wells 30 feet in depth do not reach the bottom of the gravel. In 

 places there is considerable sand. An old channel of the river, standing 

 about 250 feet above the present stream, connects on the south with the 

 Allegheny at Verona and on the north with the valley about 1^ miles above 

 Verona. It passes back of hills that stand perhaps 400 feet above the river. 

 It seems to have been occupied by the river after the deposition of the old 

 or high-level gravel, for this gravel rises in that vicinity' to a higher level 

 than the channel. 



Below Verona the gravel appears on the west side and is well displayed 

 back of Claremount at an altitude of about 250 feet above the river (Jill- 

 son). It has in places a width of about one-half mile. It contains consid- 

 erable coarse gravel and cobble. From Claremount down to the mouth 

 of the Allegheny there are only occasional narrow terrace remnants on the 

 west side of the valley. 



On the east side the gravel filling makes a singular detour southward 

 from Morningside to East Liberty, and thence eastward past Allegheny 

 cemetery to the river, encircling high uplands. At East Liberty it occupies 

 the northern end of an abandoned oxbow of the Monongahela, known as the 

 East Liberty Valley. The gravel is well displayed on the west side of 

 Negley Run, and thence westward to the Allegheny cemetery, up to an 

 altitude 260 to 270 feet above the river, and about 60 feet above the old 

 oxbow channel of the Monongahela. It is mainly a very fine gravel with 

 a large admixture of sand. West from the cemetery an old gravel is found 

 down to a level only about 100 feet above the river. The exposures show 

 coarse blocks for a few feet above the rock floor, such as appear along a 

 river bed, and above this is gravel of medium coarseness. The old grada- 

 tion plain stands nearly 200 feet above the river, or about 100 feet above 

 the lower limit of the old gravel. Possibly 100 feet of trenching preceded 

 the deposition of the gravel, but here, as at Arnold, the relation of the 

 gravel deposition to valley trenching remains uncertain. 



