490 The American Naturalist. [June, 
begins. The gorge runs on past L m to the center of the next 
curve at OO, completing the curve at the point n. 
The river, however, does not follow this course, as will be 
seen by following the shaded portion which represents the 
present river course, but turns at a right angle and runs 
through a rock cut 150 feet wide, with overhanging walls at 
both g and e. 
Just south of c’ the railroad has made a rock cut 45 feet 
deep on a very sharp curve in order to get through the gorge. 
The rock g, known as Black Hand Rock, stands out with a 
bold front 45 feet high and 250 feet long next to the river, 
where the tow-path of the canal had to be blasted out. The 
rock slopes on its top toward the north, and presents an over- 
hanging wall about 20 feet high on that side. 
Within the large open area of the unoccupied curve north 
of g there is a low mass of rocks presenting the form indicated 
at m, with a vertical rock exposure 10 feet high on the south 
side of the mass and gradually falling off into the lower chan- 
nel OO, which is only 4 to 5 feet above water level. Atn, and 
between g and m, are ponds of water on a level with the water 
of the river. The channel, between g and m, is about 70 feet 
wide, while that between m and L is 200 feet also between 8 
and the vertical cliff H, on the east side of the channel, is 290 
feet. . 
Continuing the large curve L, OO, n southward to R, there 
is, on the east side, a long, straight bluff, SS, 45 feet high at 
the present river front, and gradually decreasing to about 
feet at its southern end. On the high ground between X and 
this channel there is a light drift covering as indicated by the 
dotted portion. This drift covers the west wall of the channel 
except at Y, where the rock is exposed. At YY there is no & 
carpment, but the high hill presents a very distinct curve as 1S 
shown by the contour lines. Between Y, YY; Z and the 
double cross, there is a low drift plain with a form shown by 
the contours. The river does not follow this low gap which 1s 
nowhere over 15 feet above its present level, but has bee 
channel through the rocky spur H and S, 300 feet wide eat 
45 feet deep to present water level. The river here has abou 
30 feet of water. 
