Drainage Changes in the Moot^s Run Area 
225 
period j the fact above mentioned disproves the theory that dias- 
trophism caused the diversion of this stream. In further proof 
of the theory that Moot^s Run has taken its present course since 
glacial times, is the fact that in none of the rock gorges in ques- 
tion do we find any glacial drift in situ, either in the bed of the 
stream or on the side of the valley, a condition which would not 
be likely to exist if the glacier had moved over this area since the 
gorges were formed. We find glacial drift on the top of these 
walls, but none within them. 
Since we have seen that neither the diastrophic theory nor 
that of piracy will account for the drainage diversions in Moot^s 
Run, we must turn to the only remaining alternative, the glacial 
theory. 
Glaciation as an adequate cause. The glacial theory seems to 
account for the reversal in a very satisfactory manner. Before 
taking up the relation of the glaciers to the topography of this 
area, we will give a more detailed description of the region. 
If one should start to ascend MooBs Run from its confluence 
with the Raccoon, he would find that for the first mile it is super- 
imposed upon a mantle of glacial drift, which gas wells show to 
be about 200 feet thick. At the end of this mile, where is found 
the iron bridge on the Granville Road three-fourths of a mile 
east of Scott^s Corners, the valley on both sides of the stream 
bed takes on a different appearance. About 75 yards to the 
south of the Granville Road the first outcrop of rock appears on 
the east bank of MooBs Run, The west bank for a long distance 
is a heavy band of drift, a portion of a recessional moraine that 
sweeps away to -the north; the significance of this ice-halt, in the 
present problem, will be made apparent later. The rock on the 
east bank also soon gives place to drift, which forms the east 
bank of the stream for over half a mile southward. The drift 
on the west bank continues to Parry ^s, with the exception of two 
thin outcrops of rock, which are merely an extension of the rock 
slope from the opposite side rather than a distinct rock wall. 
From beneath the drift at Parry’s there emerges a sloping rock 
wall of rather steep gradient. On the east bank the rock appears 
a little farther down stream than it does on the west; from this 
point to the bend, 100 yards south of Parry’s and for another 100 
yards to the west of the bend, the stream is confined by a rock 
channel. Here the south rock wall ends, and, together with the 
