6 Geology, &c. of the country west of the Rocky Mountains. 
which flow, as it were through clefts, produced by the baking and 
shrinkage of those plains, at a depth of many hundred feet below 
their surface. 
There are but few places where from the parched plain, on which 
little water is found, vou can descend to the streams below; these 
places are marked by Indian trails. The stream being once gained, 
you look up and behold perpendicular bluffs of one hundred feet in 
height, then by offsets asscending still higher, composed of strata still 
showing in some places the appearance of grey and red sandstone, 
in others, strata partly melted down, and presenting the appearance 
of lava. On one part of this creek gushed out in great’ numbers, 
from the porous bluffs, springs and small creeks of water, apparent- 
ly pure, at the temperature of 100°. 
We here found the Lewis river, a beautiful stream abounding with 
salmon, now the main article of food, for long since, we had passed 
the range of the Buffaloes, which are never seen ata great distance this 
side of the mountains. Here, and in other places further down the 
river, were columns of basalt thirty feet high resting on sand, which 
seemed constantly undermining the rock, and precipitating it far be- 
low. The basaltic bluffs sometimes approach the river, and again 
recede, leaving fine bottoms, over which we travelled ina N. W. 
course, crossing some creeks coming from the $8. W. Thus we 
continued our journey, passing slowly along, so as to permit our 
foot-sore horses to recruit. On the last of Sept., we came to the 
place where the river turns to the north and enters a mountainous 
country, which shuts it in, in a manner completely to obstruct trav- 
elling nigh its banks, but we found an Indian trail leading up a creek, 
which takes first a west and then a north west direction, through a very 
mountainous country, which mountains are composed principally of 
burnt rocks, presenting occasionally however, bowlders of granite and 
other primitive rocks. 
After some days, we came into an oval plain crossed by some 
creeks ; the plain was fifteen miles in diameter, of great fertility and 
apparently surrounded and enclosed by high mountains. On leav- 
ing this plain, our course still continuing north westerly ; we ascend- 
ed a high mountain and travelled along a ridge of the same on an 
Indian trail, when the whole country to the south and west presented 
similar ridges, partially clothed with fine timber. These are called 
the Blue mountains, and are also porous rock. Far in the west could 
be discerned a conical snowy mountain which proved to be Mount 
