ON THE NORTHWEST COAST OF LAKE SUPERIOR. 379 
The gorge disappears at the Great Fall, which is forty-five feet in width, and 
eighteen feet high. In very high water this fall is probably sixty feet wide, and 
over twenty-five feet in perpendicular height. Above this place the banks are low, 
and the river from fifty to sixty feet wide, and so continues for half a mile, when 
No. 154 again comes up, dipping to the southeast, at an angle of 11°, and forming 
the walls of a gorge fifteen feet deep, and from twelve to fifteen feet in width. This 
continues for the distance of four hundred yards, when the lower beds become very 
hard and compact, and assume a decidedly trappous character. The rocks here 
form several beautiful cascades, and are traversed by veins of No. 156, one of which 
is six inches wide. Two hundred and fifty yards further on, the rock becomes still 
more compact, and presents a somewhat crystalline aspect (No. 157); and imme- 
diately beyond this, a ridge of greenstone (No. 158) crosses the river. The lower 
part of this ridge resembles syenite (No. 159) in general appearance, while the 
central portion is more compact, and finer-grained, and more like the ordinary 
greenstones (No..160). Beyond this, the river runs parallel with the ridge for half 
a mile, when it winds through low bottoms as far as we ascended it. 
One mile beyond the last ridge mentioned, on the east side of the river, is a hill 
composed of red clay and marl, and overlaid by boulder-drift. 
GORGE AND POTHOLES OF KAWIMBASH RIVER. 
There are many remarkably large potholes in the rocks of this river. Indeed, 
the river appears to have cut out the gorges by the sinking of lines of potholes. 
which were gradually enlarged until they broke into each other. The sides of the 
