12 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Flathead Lalce . — This lake, tlie largest in the State, lies 35 miles northward from 
Ravalli. It is about 30 miles in length from north to south and averages perhaps 12 
miles in width. It is a very beautiful sheet of water, whose shores at the south end 
are without timber, but toward the north dense forests of pine and other evergreen 
trees come down to the water’s edge. In the northern portion are several small islands 
tolerably well timbered. This lake lies in what appears to be an immense glacial 
valley, the lake itself being due to the enormous moraine lying at its lower end and 
through which the outlet has been cut. It is said to be very dee]) in many places, 
but we have no exact data upon that point. The waters are clear and cool. 
Flathead Lake is perhaps as well supplied with fish as any body of water in the 
State. Mountain trout are abundant, grow to a good size, and are readily caught; 
salmon trout or bull trout are also common and are caught at certain seasons in 
considerable numbers by trolling. The Columbia River sucker also occurs in the 
lake, while the two large minnows, the Columbia chub and the u squawhsh,” are very 
abundant. At the different landings where our steamer stopped we amused ourselves 
by fishing for these species with hook baited with pieces of beef. Each species bites 
very readily and each shows some game qualities. It seems to make but little differ- 
ence with what the hook is baited. In one instance, a very large “ squawfish” was 
taken with the fly by Mr. Clapham in Swan River, who felt sure he had a very fine 
trout until it was landed. So abundant are these two species, and so readily do they 
take the hook, that they often prove quite an annoyance to him who is fishing for 
nobler game. Whitefish are also found in the lake and, judging from the number 
of young that we saw, would seem to be common. However, those persons best 
acquainted with the lake, with whom we talked, did not know of its occurrence there; 
and, still more curiously, the Oregon chub is known as u whitefish ” by those familiar 
with the lake. 
Flathead Fiver . — At its north end, Flathead Lake receives its principal affluent, 
Flathead River. This is a large stream coming into the United States from British 
America west of Chief Mountain Lake, flowing through the lake, and then continuing 
southwest to join the Missoula as already described. We ascended the Flathead 
River 28 miles to the new town of Demersville, where it is still a very large and very 
deep stream with a rather swift current. Some 30 miles above Demersville the current 
becomes more rapid, the head of navigation being at Columbia Falls, near where the 
three forks of the river unite. The fishes of this part of Flathead River are, so far as 
we know, the same as found in the lake. At Demersville we found mountain trout, 
squawfisk, and Columbia River chubs quite common. Salmon trout are also caught 
there, but we saw none. 
Sivan Fiver . — Nearly east from the mouth of the upper Flathead River is the 
Swan River. Big Fork, Swan River, Sweating-house River, and Sweating River are 
different names by which this stream is known on different maps, but it is more 
generally known to citizens of that part of Montana as Swan River. It rises on the 
Divide southeast of Flathead Lake, near the head of the Clearwater, a tributary of 
Big Blackibot River. It flows about SO miles northwest and then widens out to 
form Swan Lake. Narrowing again, it continues northward and then westward for 
about 20 miles further and then flows into Flathead Lake, only about 3 miles east 
of Flathead River. Swan River, at the outlet of Swan Lake, is about 75 yards wide 
and averages about 5 feet in depth. Surface temperature at 3 p. m., August 3, 65°. 
