50 ROUTE NEAR THE FORTY-SEVENTH AND FORTY-NINTH PARALLELS. 
tude 98°; from that point to Fort Union, about one-fourth could be settled. Above Fort 
Union, Lieut. Grover says: ‘‘On the lower portion of the river (between Fort Benton and 
Fort Union,) there are many quite extensive bottoms well adapted to agricultural purposes. 
There is a good deal of arable land, also, in the vicinity of Fort Benton, and in the Sun River 
valley.’”’ The proportion of cultivable bottom lands on this section of the river is much less 
than one-fourth. The Mouse River valley is represented to be fertile, as its growth of ash, 
elm, and oak indicates. Describing that portion of the route from Fort Union to Fort Ben- 
ton, Governor Stevens writes, ‘‘ The bottem lands, both of the Missouri and Milk rivers, are 
composed of clay and sand, &ec.”’ 
The space between the Rocky and Cascade mountain chains is principally occupied, between 
the parallels of 45° and 49° latitude, with mountain masses and the great elevated plain of 
the Columbia. 
From the main Cascade chain the generally sterile soil extends eastward ever the dry 
region until the rain that falls upon the Coeur d’ Alene, Bitter Root, and other mountains, 
begins to be felt; we then have grazing. The soil improves in quality as the mountains 
are approached, the valleys of which are represented as fertile, perhaps influenced in some 
degree by the nature of the mountain debris that have been washed upon them. The Colum- 
bia river and its affluents, in their lower courses within the limits above mentioned, are 
stated to carry gravel and sand, but no fertilizing matter. 
It is their upper or mountain valleys (between the Cascade and Rocky mountains) only that 
are productive ; their lower are uncultivable. 
The fertile or cultivable areas are most probably the exceptions to the general character of 
the soil between these two mountain chains, and are of limited extent. 
The soil, too, of a large portion described as fertile, is most probably better adapted to grazing 
than to farming. The valley of St. Mary’s, and other mountain valleys in that region, and 
west of the Bitter Root mountains, are represented to have dark gravelly soils. The prairies 
on the Columbia river are also more or less gravelly. The middle and western parts of the 
plain of the Columbia are sandy, rocky, and sterile; here and there are swales, having rich 
mould; bunch-grass, varying in degree of sparseness of growth, is found over a large portion 
of its surface. 
Lieutenant Mullan says of the St. Mary’s valley, which has been considered as a kind of 
standard, ‘‘the soil of the valley of the Bitter Root (St. Mary’s) is fertile and productive, well 
timbered with pine and cotton-wood, but whose chief characteristic and capability is that of 
grazing large herds of cattle, and affording excellent mill-sites along the numerous mountain 
streams.”’ 
Probably about one-fourth of the area of the valley is cultivable, the remainder being suit- 
able for grass-lands only. 
Dr. Suckley, referring to the Hell Gate, Bitter Root, Clark and Columbia rivers, and to 
the Dalles, says, ‘‘there are a few pieces of excellent land along these rivers.’? The valley 
of Clark’s fork is heavily timbered with pine; there is no grass. 
Within the limits of Washington Territory, between the Cascade and Rocky mountains, 
there are 7,356 Indians. Within the same Territory, west of the Cascades, the areas being 
as 3 to 1 about, there are 6,903 Indians. This may give some indication as to the capabilities 
of the soi] for supporting animal life. 
West of the Cascade mountains there are generally prairies, soon exhausted by cultivation, 
but offering good grazing; clay formations that are arable, and rich river bottoms. The fall 
of rain in the year is about 47 inches; the temperature is moderate. 
Governor Stevens estimates that there are 4,000 square miles of tillable land on the eastern 
slopes of the Rocky mountains, and that the mountain valleys on the western slopes contain 
6,000 square miles of arable land, _ 
The preliminary report of the geologist of the party, made from Washington Territory, 
