BORDERING ON VERMILION RIVER. 315 
in a northwest direction, from our last camp. Here the slates resemble No. 509, 
and are succeeded by No. 512, at the detroit connecting the middle with the north- 
western portion of the lake. The next rocks, going north, are Nos. 513 and 514, 
which, with Nos. 515 and 516, lie between Nos. 513 and 517, No. 516 being next 
the granite. (See Section 2, Pl. 2, N, from Upper Pinnette River to Rainy Lake.) 
No. 517 was the first granite seen in place near the lake. It forms a low ridge, 
and, judging from the point where it struck the opposite shore, bears northeast and 
southwest. : 
September 2d. In little more than an hour after starting this morning, we dis- 
covered the outlet of the lake, and again began to descend Vermilion River. There 
is a rapid about four hundred yards long at the commencement of the river, the 
water falling in that distance about twenty-five feet. The fall is over mica slate 
(No. 518), which is traversed by granite veins, some of them very large. The 
granite is felspathic, the felspar being white, and in large crystals. About a 
mile below this, rapids again occur, the river falling about ten feet in five hundred 
and twenty yards. This fall, like the last, is over mica slate, with granite veins 
traversing it in every direction. The rocks here (No. 519) show a transition from 
a very fine-grained to a very coarse-grained mica slate, and from the first to a 
eneissoid rock. The granite veins are either all quartzose or felspathic. One 
mile and a half below this is another exposure of mica slate, bearing east by north, 
and dipping to the north-northwest at an angle of 46°. (No. 520.) The rapid at 
this place falls about six feet; and a short distance below is another rapid, with a 
fall of five feet, over mica slate. The rock at this place is crossed in every 
direction by granitic veins from half an inch to ten feet wide; while layers of 
granite are intercalated with the slate, and conform to the dip and bearing. In 
some places the slates are fine, in others, coarse; and again, at other points, 
graduate into gneiss, and the gneiss into granite. 
Soon after passing the last-named rapids, the river spreads out into a lake, about 
a mile and a quarter long, and from three hundred to three hundred and fifty yards 
wide, with no perceptible current. At the lower end of this lake, a narrow channel, 
sixty or seventy feet wide, conducts around a granite ridge (No. 521) into another 
lake. In about four and a half miles, this lake narrows to one hundred and 
seventy-five yards in width, but soon widens again to three hundred yards, which 
width it maintains for three and a half miles, to its termination. Between the 
last-named ridge and the end of the lake three other granite ridges were seen, all 
having the same northeasterly bearing. These lakes are bordered by extensive 
tamerack swamps, which also extend between the granite ridges as far as the eye 
can reach. 
At this point is a portage, seventeen hundred yards long, over three ridges of 
granitic rocks. The portage is a very rough one, the narrow path at many places 
running along the verge of a deep, rocky precipice on one hand, with steeply- 
inclined rocks rising to a great height on the other. The rapid, which begins at 
the foot of the lake, is a very bad one, and falls at one point twelve feet in as 
many yards. It is about a mile and a quarter long; and the total fall in that 
distance is, according to the measurement of Col, Whittlesey, seventy-eight feet. 
