Encyclopædia Britannica, Ninth Edition/Montana

MONTANA, one of the north-western Territories of the United States, is limited on the N. by British Columbia, on the E. by Dakota, on the S. by Wyoming and Idaho, and on the W. by Idaho. Its boundaries, as established

by statute, are as follows:—on the N., the 49th parallel; on the E., the 27th meridian west of Washington, or the 104th west of Greenwich; on the S. and W. the boundary follows the 45th parallel from the 27th meridian west to the 34th meridian west, then turns south along the latter meridian to its point of intersection with the continental watershed, thence along the crest-line of this watershed westward and north-westward until it reaches the Bitter-root Mountains; it then follows the crest of this range north-westward to the point where it is crossed by the 39th meridian west, which it follows north to the line of British Columbia. The total area is about 146,080 square miles—an approximate estimate, as the boundary along the continental watershed and the Bitter-root Mountains has not been exactly surveyed. The average elevation above sea-level has been estimated at 3900 feet.

Topographically, Montana may be separated into two great divisions—that of the plains comprising the eastern two-thirds, and that of the mountains comprising the western portion. The former, a monotonous rolling expanse, broken only by the beds of the few streams which traverse it, and by a few small groups of hills, extends over nine degrees of longitude in a gentle uniform slope, rising from 2000 feet above the sea at the eastern boundary to 4000 at the base of the Rocky Mountains. Except along the streams and upon the scattered groups of hills, this section is entirely devoid of forest-growth of any kind. Vegetation is limited to the bunch grasses, artemisia, and cacti. The grasses are the most abundant and luxuriant near the mountains, where the rainfall is greatest. The mountain section, comprising the western third of the Territory, is composed, in general terms, of a succession of ranges and valleys running very uniformly somewhat in a north-west and south-east direction. The mountains vary in height from 8000 to 10,000, even in isolated cases reaching 11,000 feet, with mountain-passes 6000 to 8000 feet above the sea. Towards the north the ranges become almost continuous, forcing the streams into long and circuitous courses in order to disentangle themselves from the maze of mountains, while, on the other hand, the ranges of the south-western part of the Territory are much broken, affording numerous low passes and water-gaps.

In the mountainous part of the Territory are the head waters of the Missouri (Atlantic basin) and Clark's Fork of the Columbia (Pacific basin). The former rises in the south-west of the territory in three large branches, the Jefferson, Madison, and Gallatin, which meet at the foot of the Gallatin valley at a point known as the &ldquo;Three Forks of the Missouri.&rdquo; Here the Missouri is a good-sized stream, fordable with difficulty even when the current is lowest. From this point to its mouth navigation is possible when the stream is not below its mean height; it is interrupted only at the Great Falls of the Missouri, near Fort Benton, above which, however, it is practically little used for navigation. Its other principal tributaries in its upper course are the Sun, Teton, Marias, Musselshell, and Milk rivers, all of which vary much in size with the season,—the last two being nearly or quite dry near their mouths in the fall of the year. The Yellowstone, one of the most important tributaries of the Missouri, has nearly all its course in Montana, and is navigable for small steamers as far as the Crow Agency, except when the water is low. Clark's Fork of the Columbia is formed by the junction of the Flathead and the Missoula or Hellgate river. The former rises in the mountains of British Columbia and flows nearly south through Flathead Lake to its point of junction with the Missoula. The latter rises opposite the Jefferson river and flows north-westward, receiving on its way several large affluents. Below the point of junction of these streams, Clark's Fork flows north-west along the

base of the Bitter-root Mountains into Idaho. This stream is very rapid, and is not navigable. Its course, as well as those of most of its tributaries, passes through narrow valleys, the surrounding country being well watered and covered with dense forests of Coniferæ.



Sketch Map of Montana Territory.