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NATURAL HISTORY REPORT ON WESTERN DIVISION. 
From the time of leaving Vancouver, on the 18th of July, until we left the Cathlapoot’l river, 
our course was among the western spurs of the Cascade mountains. All this region was densely 
wooded, except a few small prairies. 
The principal trees of this region were the three species of Abies , (spruce and fir,) one oak, 
two maples, one dogwood, one ash. The characters of the shrubs were two wild roses, three 
Spiraeas, an elder, and the “Oregon grape.” Near the streams grew several species of raspberry, 
two poplars, and various willows, which were seen on the river banks throughout the country. 
Two species of huckleberry, a red and a blue fruit kind, were abundant in some parts. Very 
few plants were in flower in the forest, and but few on the plain, the dry season being accom¬ 
panied by an almost complete cessation of vegetation. The small prairies met with were covered 
with a short growth of grass, then dried up, and around the borders of some was a dense growth 
of Pteris, (fern) reaching above a man’s head, and almost impassable in places. Most of these 
prairies are covered by water in wet seasons, which prevents the coniferous trees from growing 
on them, and assimilates their vegetation to that of the river banks. Very few animals were met 
with during this time; the hot weather was probably a reason for their scarcity—driving them to 
the deep shade of the forests and the higher mountains, where a later continuance of rain affords 
better food for the deer, elk, &c. A few small hares, two kinds of grouse, and pigeons, were 
the largest game. 
Leaving the Cathlapoot’l river on the 4th of August, we ascended by a steep and continuous 
acclivity to the higher parts of the mountains, about 5,500 feet above the level of the sea. Here 
the alpine region commenced, which shows itself chiefly in the different class of plants seen and 
in their late growth. The firs of the western slopes were replaced by two spruces, and a few 
pines and larches began to appear. The five snow-peaks seen at a distance showed that trees 
ceased to grow at about 6,000 feet above the sea-level, though vegetation continued much higher up. 
Strawberries, which were gone at Vancouver by the middle of June, were here in abundance. 
A peculiar species of huckleberry, with large purple and finely-flavored fruit, abounded, with 
another producing blue fruit. On the highest hill ascended was found a low spreading juniper, 
very characteristic of alpine vegetation. The grass in most parts was still green, and many 
flowers continued to bloom. Showers of rain and hail descended during our stay. No animals 
were seen peculiar to this region, and nearly all those seen on the west side continued up to the 
highest point reached. Cranes, ducks, and geese were noticed—probably remaining up in these 
high mountains to breed. 
On the 9th of August we commenced descending the eastern slope of the mountains, and at 
once noticed a marked change in the vegetation. Instead of the dense forest of firs covering 
the western side, the prevailing trees were two species of pines and a few oaks; these stood at 
distances of thirty and fifty feet apart, and the ground underneath was open, smooth, and covered 
with a good growth of grass. 
A Ceanothns with fragrant, shining leaves, was the most abundant and characteristic, other 
shrubs appearing. Most of the plants of this region had passed flowering, and the soil was 
already very dry. Excepting a small prairie surrounding a lake, this forest continued on our 
course for about seventy miles. The plants found in flower on this side the mountains were 
nearly all collected. Very few animals were seen in the forest; a few elk, deer, and cayotes 
being the principal. 
Approaching the borders of the plains, some plants peculiar to them were observed, generally 
scattered and stunted in growth. The pines also became smaller and more scattered, ending 
rather abruptly at last. 
August 13.—We entered suddenly upon the plain region, which we continued to traverse for a 
great part of the remainder of the route. From observations made, I am able to mark out the 
western and northern limits of this region in Washington Territory. Commencing at the Columbia 
river, opposite the Dalles, the line of forest growth runs northwesterly, crossing the eastern spurs 
