GEOGRAPHY OF OREGON. 27 



western wall of the valley of the Lewis, the great southern branch of the 

 Columbia. North of the 47th degree are other ridges, which appear 

 to be continuations of the Blue Mountains ; but they are less defined, 

 and are distinguished by other names. The region between the Blue and 

 the Far-West Mountains embraces several tracts of country comparatively 

 level, and some valleys wider than those of the Pacific region ; the soil is, 

 however, less productive, and the climate less favorable for agriculture, 

 than in the places similarly situated nearer the ocean. The most exten- 

 sive valleys are those traversed by the streams flowing into the Columbia 

 from the south, between the Far- West range and the Blue Mountains, 

 particularly the Walla-Walla, and the Falls or Chutes Rivers : the plains, 

 as they are called, though they are rather tracts of undulating country, 

 are on both sides of the northern branch of the Columbia, between the 

 46th and the 49th parallels of latitude. The surface of the plains consists 

 generally of a yellow, sandy clay, covered with grass, small shrubs, and 

 prickly pears ; in the valleys farther south, the soil is somewhat better, 

 containing less of sand and more of vegetable mould, and they give sup- 

 port to a few trees, chiefly sumach, cotton-wood, and other soft and use- 

 less woods. The climate of this whole region is more dry than that of 

 the country nearer the Pacific ; the days are warm, and the nights cool ; 

 but the want of moisture in the air prevents the contrast of temperature 

 from being injurious to health, and the country is represented, by all who 

 have had the opportunity of judging by experience, as being of extraordi- 

 nary salubrity. The wet season extends from November to April; but 

 the rains are neither frequent nor abundant, and they never occur at any 

 other period of the year. In the southern valleys there is little snow; 

 farther north it is more common, but it seldom lies long, except on the 

 heights. Under such circumstances, it will be seen that little encourage- 

 ment is offered for the cultivation of this part of Oregon. On the other 

 hand, the plains and valleys appear to be admirably adapted for, the 

 support of cattle, as grass, either green or dry, may be found at all times, 

 within a short distance, on the bottom lands or on the hill sides. The 

 want of wood must also prove a great obstacle to settlement, as this indis- 

 pensable article can only be procured from a great distance up the north 

 branch of the Columbia, or from the Pacific region, with which the 

 passages of communication through the mountains are few and difficult. 

 The country farther east, between the Blue Mountains and the Rocky 

 Mountains, appears to be, except in a very few small detached spots, ab- 

 solutely uninhabitable by those who depend on agriculture for subsistence. 

 It is, in fact, a collection of bare, rocky mountain chains, separated by 

 deep gorges, through which flow the streams produced by the melting of 

 the snows on the summits ; for in the lower grounds rain seldom falls at 

 any time. On the borders of the Lewis, and of some of the streams 

 falling into it, are valleys and prairies, producing grass for cattle ; but all 

 the attempts to cultivate the esculent vegetables have failed, chiefly, as it 

 is believed, from the great difference in the temperature between the day 

 and the succeeding night, especially in the summer, which is commonly 

 not less than thirty, and often exceeds fifty, degrees of Fahrenheit's ther- 

 mometer.* North of the 48th parallel, the climate is less dry, and the 



* The thermometer was seen by Wyeth, at Fort Hall, on the Lewis, near the 43d 

 parallel of latitude, at the freezing point in the morning, and at ninety-two degrees of 

 Fahrenheit in the middle of a day in August. Frosts occur at this place in nearly 

 every month in the year. 



