TOFOGRAPHY OF ROUTE FROM THE MISSISSIPPI TO THE COLUMBIA. 175 
river, crossing the Big Hole mountains; thence about five days’ march, traversing the extreme 
headwaters of Wisdom river and Jefferson fork, again crossing the main range to Fort Hall, 
(about one hundred miles through the well known sand and sage desert of the Snake River valley.) 
Returning, he crosses the basin again by a more easterly route, crossing the two streams mentioned 
about a day’s march above their junction, his route leading almost wholly through prairie valleys 
of great beauty and reported fertility. Leaving the basin by a small branch of Wisdom river, 
he crosses the Rocky mountains for the fourth time, and enters the greater mountain feature 
already described by the South fork of Hell Gate river, on which he reports a more extensive 
district of open country than any before observed, and a considerable hot spring. He calls this 
broad valley the Deer Lodge prairie, which, from its great extent and reported advantages, will 
probably, when better known, dispute the palm of superiority even with the famous valley of St. 
Mary’s. 
The Blackfoot fork, St. Mary’s river, Lou Lou fork, and the western slope of the Bitter Root 
mountains, with the Jefferson fork, Wisdom river, &c., were explored and described by Lewis and 
Clark; but those celebrated travellers having had no object beyond that of exploration simply, 
and having left no topographical data beyond general description, the recent more systematic 
explorations may be considered as essentially new, as they were absolutely necessary for any 
practical purpose. 
The Great Plain of the Columbia, or Plateau of Spokane, as it has been called, is bounded on 
the north by those rivers, on the west by the former, and on the south and east by the Blue and 
Rocky mountains; it is about two hundred by one hundred and fifty miles in its greatest length 
and breadth, and presents such a curious variety of surface, that it has been alternately called 
a barren sage plain, rocky plateau, sterile waste, and sandy desert. A great deal might be said 
to show that it is either or all of these, but there can be no doubt that it possesses many points 
of interest which time only will develop. It contains numerous lakes and rivers, the latter 
flowing almost invariably in canons of proportionate dimensions, from the great fissure which 
holds the Columbia to the litle cracks in the surface peculiar to every streamlet. Large tracts 
contain little else than huge masses of columnar basalt, projecting to different heights, from ten 
to one hundred feet; extensive swales occur, covered with bunch-grass ; and sometimes we pass 
through many miles of short rounded ridges and hillocks, arranged, as it were, in rows, and laid 
towards the same cardinal point; while near Wallah-Wallah are large fields of artemisia in deep 
sandy soil, the most unfavorable part of the whole route. As might be supposed, the best sections 
of the Great Plain are found in the immediate vicinity of the mountains, where a deeper soil 
accumulates from the wash of the hills; but the extreme western portion, near the Columbia, 
presents little else than a miserable desert of drifting sand, alternating with sage plains and 
naked volcanic rocks. The examination of the Grand Coulée by Lieutenant Arnold shows 
another instance of the little reliance to be placed in unauthorized reports; instead of connecting 
across the northwestern bend of the Columbia some seventy miles, and being, as might be 
supposed, the old bed of that river, it extends but twenty-five miles, with the form of an 
immense cafion, and then is soon lost in the general level of the plateau. 
Not unfrequently on the rivers and streams the cafion walls disappear in rounded slopes, which 
open out into valleys and flats where moderate grazing is found, and sufficient of brush-wood and 
dwarf cedar, poplar, &c., for fire-wood, while in very extensive sections the bunch-grass affords 
pasturage that might be called abundant. The soil, which is mostly decomposed trap-rock, of 
various depths, but generally thin, cannot be denied to possess properties of productiveness ; 
and on the swales it is vegetable mould, which only requires cultivation to prove its capability, 
while the rivers and lakes abound in fish, but the hungry wolf is the only tenant of the plain. 
The region, altogether, however, is not very attractive in any respect, and can only be looked 
upon as a new field of enterprise when the more favored wilderness shall have been subdued to 
the ever-increasing requirements of civilization. 
