68 WILLIAMS— DEEP KANSAN PONDINGS IN 



13,500 feet radius. The wall of the stoss (southern) side rises 520 

 feet in one third of a mile, and reaches 2,100 feet in a long hill of 4 

 miles between the 1,500-foot contours. Its southern side drops to 

 the trench from Bone Run to Cass Run. The summit of the latter 

 rises to 1,566 feet, with a length of i^ miles between the 1,500- 

 foot contours. The two trenches are about i mile apart : the latter 

 curving in an opposite direction from the former, with a direction 

 mainly westward. Its width at 1,800 feet is the same as that of the 

 northern one, and for over i mile its width at 2,000 feet is less than 

 three fourths of a mile. Its steepest wall is where the southern 

 side is crossed by the boundary line between Qiautauqua and Cat- 

 taraugus counties. Its rise is 580 feet in 1,300. 



Thence southward into Pennsylvania, through Warren to Mc- 

 Kean County, the crest of Quaker Ridge falls below 2,000 feet only 

 in two places, where narrow passes lead from the South Branch of 

 Sawmill Run — the northern, to Frew's Run, with floor about 1,970; 

 the southern, to Storehouse Run, floor about 1,925, leading to a con- 

 siderable trench which opens on the Conewango floodplain just 

 north of Ackley. 



After the covering of these the ponded water escaped at many 

 places over the somewhat irregular, but level, crest of the Ridge — 

 all above 2,020 feet — and the streams were gathered into four main 

 flows, which passed through the troughs of Jackson, Ackley, Hatch, 

 and Glade runs. With such distribution of power the trenching is 

 long and shallow, and of note only at the lower parts. The eleva- 

 tion of the ponding is now above 2,020 feet, and slightly over 500 

 feet above that from Barnes. 



Big Bend Ponding. 



The overprint on the topographic quadrangle of Olean, N. Y., 

 in the envelope attached to the back cover of Leverett's Monograph,- 

 seems to confirm Carll's^ elevation of 2,154 feet. Small areas rising 

 above it are marked " Driftless." Larger ones away from the scour 

 of the marginal canyon against the north side of Mount Hermon, 

 which also rise above it, are enclosed and marked " South Edge of 

 Ice," " Glacial Boundary," and " Border of Glaciation." 



