2i f32] 
level of this portion of the Canal must be kept as high as possible, in 
order to run it above, and to the north of the rugged hanks whicli lie 
between these falls. A dam across the great falls might form a re- 
servoir for the lower portions of the Canal: a wing dam may also be 
required at Seneca falls. It is desirable that the works at Great 
falls should not interfere with the canal which at present turns them 
on the right shore, as it may be useful fur floating rafts and timber, 
when the navigation of the Potomac will be improved. 
The Canal then continues along the left shore, winding round the 
bank which extends from the Great to the Little falls, and from thence, 
along the flats of the same shore, to the head of tide water in the Po- 
tomac. If, however, it be found possible to open a direct comrauiii- 
cation from Seneca falls to Washington, the obstacles which lie be- 
tween the Great and Little falls, may perhaps be avoided. To ascer- 
tain this fact, a level should be run between the Seneca falls and the 
Rock creek which divides Georgetown from Washington. A ravine^ 
running to the north of the Great falls, seems favorable to this line. 
It should he surveyed with care, and a level run on the north ridge of 
the height which runs from the Great falls to Washington, and on the 
eastern point of which is built the town of Georgetown. 
MIDDIE SECTION. 
This section, from the mouth of Savage river, in the north branch 
of the Potomac, extends to the mouth of Bear creek, in the Youghio- 
gheny, on the west side of the Alleganies. It includes the summit level 
of the canal, and from the complicated topography of the ground, the 
height which must be overcome in a short space, and the difficulty of 
securing a sufficient supply of water, in dry seasons, at such an ele- 
vation, presents the greatest difficulties which occur in the whole 
project. 
The little Back Bone Ridge divides the waters, which, in that part 
of the Alleganies, runs east and west; it runs parallel to the great 
Back Bone, through which Savage river forces its way, and the canal 
roust, absolutely, pass through this gap. Between those two ridges 
run Crabtree creek, from S. W. to N. E. and Savage river from 
N. W. to S. E,j the former falling into Savage river four and a lialf 
miles above its mouth in the Potomac. From the west side of the 
little Back Bone fall Deep creek, and the little Youghiogheny, the 
latter runs from E. to W. and, after forcijig its way successively 
through Hoop-Pole ridge, and Roman Nose ridge, joins the great 
Youghiogheny. Deep creek runs at first to the liorth, crossing Hoop- 
pole ridge, and Negro mountain; then, intercepted byMarsh mountain, 
it turns west, and falls into the Youghiogheny. The gap through which 
it forces its way across the Hoop-Pole ridge, is only sixty six yards 
wide, and is calle^l the Narrows. 
The heads of the little and great Youghiogheny, to some miles above 
the point where they join in a single stream, run through marshy 
meadows, known by the name of Glades. The valleys of Deep creek. 
