246 GEOGRAPHICAL MEMOIR. 
To the north the Flathead lake, twenty-five miles long and six miles wide, is spread open 
before you, with extensive prairies beyond ; and on the west, sloping back from the banks of 
the Flathead river, a mingled prairie and forest country is seen. Неге in a compact body, is 
one of the most promising countries in this whole region, having at least two thousand square 
miles of arable land. Flathead river above the lake is formed by the waters of three streams, 
the northeast flowing from the pass pursued by Mr. Tinkham in October, 1853, and which, in 
the reports, has been named the Marias Pass. Its northwest branch, Maple river, has its rise 
in longitude 114? 50’ and in latitude 48? 40’, and connects by a low divide and through a 
timbered country with the Koutenay river, furnishing a route which was pursued by Lieutenant 
Mullan in his trip to the latter stream in April, 1854. The eastern branch, Swan river, joins it 
only three miles above the lake, and probably furnishes a route to the two Marias Passes, par- 
tially explored by Mr. Doty in 1854. Below the lake the Flathead river flows, following its 
windings some fifty miles to it junction with the Bitter Root, where the united streams assume 
the name of Clark’s Fork. In this distance it is 100 to 200 yards wide, and so deep as to be 
fordable with difficulty at low water, its depth being three feet at the shallowest places. Its 
current is rapid, and there is a fall of fifteen feet five miles below the lake. About eighteen 
miles below the lake it receives a considerable stream from tlie northwest, called Hot Spring 
creek, which was followed down by Lieutenant Mullan, on his return from the Koutenay, in May 
1854, for thirty miles. In its valley, and around it, is also a large extent of fine land. Nearly 
opposite a small stream runs in from the east, and another from the same side ten miles below, 
by which there are routes to the upper part of Big Blackfoot valley. "Three miles below the 
last it receives Jocko Fork from the south, and then turns abruptly in its course from south to 
northwest, receiving in the remaining nineteen miles to the Bitter Boot only small streams, of 
which Kamas Prairie creek, from the north, is the principal. None of the branches of Clark's 
Fork above the junction can be considered navigable, but the river itself, (Flathead,) with the 
exception of the rapids and falls below the lake, which may be passed by a short canal, gives a 
navigation of at least seventy-five miles to the head of Flathead lake. 
Clark’ s Fork empties into the Columbia about four.tenths of a mile north of the 49th parallel, 
as determined by a single observation made in 1853, but it cannot, however, be considered as 
accurately fixed. At its mouth is a fall of fifteen feet in height and a hundred and fifty yards in 
width. Ata distance of a quarter of a mile from the main stream it passes througha deep gorge 
in the range, where it has a further fall of three feet. From this point to the Mission of St. 
Ignatius (seventy miles by the river) it has never been explored. Aboutone hundred and thirty 
miles above its mouth is the Pend 4 Oreille or Kalispelum lake, which is a beautiful sheet of 
water about forty-five miles in length, formed bv a dilation of the river. The river is sluggish 
and wide for some twenty-six miles below the lake, where rapids occur during low water. 
Steamboats could ascend from this point to a point nine miles above the lake, or eighty miles in 
all. At high water they could ascend much further. Between the Cabinet (twenty-five miles 
above the lake) and a point seventy-five miles below the lake (a total distance of one hundred 
and forty miles) the only obstacle which occurs is where the river is divided by rocky islands, 
with a fall of six and a half feet оп each side. The Hudson Bay Company’s large freight boats 
are in the habit of ascending from the lower end of Pend d’ Oreille lake to the Horse Plains, а 
distance of about one hundred and thirty-five miles, making only two portages. Above the 
Cabinet the river would be excellent for rafting purposes. Its greatest rise and fall is fifteen 
feet. The valley of Clark’s Fork is generally wide, arable, and inviting settlement, though 
