Besides these various groups of mountains, there are a few detached peaks worthy of note, which can not be conveniently classified with any of the principal ranges. PLATEAUS. A considerable portion of the Park area is composed of what may be termed plateaus, elevated tracts of land, not so high as the mountain ranges, but much higher than the valleys. Ordinarily, these are to be found along the divides between the larger streams. The more important are the Pitchstone Plateau, between the Snake River and the head waters of the Bechler and Fall Rivers, with a mean altitude of 8,500 feet; Highland Plateau, between the Yellowstone and the Madison Rivers, altitude 8,300 feet; Mirror Plateau, between the Yellowstone and the Lamar Rivers, altitude 9,000 feet; Mt. Everts Plateau, between the Yellowstone and the Gardiner, altitude 7,000 feet; and the Madison Plateau, west of the Lower Geyser Basin, altitude 8,300 feet. VALLEYS. These form an exceedingly important part of the Park topography. The largest is Junction Valley, including its branches along the Yellowstone and the Lamar Rivers. It is an extensive, grassy tract, stretching well back upon the mountain sides, and forming a fine pasturage for game. For scientific research, its fossil forests and other features make it an extremely interesting section. Hayden Valley is the next in size and importance, and occupies an important tract along the Yellowstone River, between the Lake and Falls, mostly on the west side, in the vicinity of Alum Creek. The Madison Valley, and its extensions up the Firehole and Gibbon Rivers, are chiefly noteworthy as being the locality of the three great geyser regions of the Park. The Swan Lake Flats, Willow Park, the Shoshone and Falls River Basins, are other important examples of typical mountain valleys. ALTITUDES. The lowest point in the Park is at the junction of the Yellowstone and the Gardiner Rivers, 5,360 feet above sea level; the highest is the summit of Electric Peak, six miles distant, 11,155 feet. To give a general idea of the altitudes of different points in the Park, particularly of those which the tourist visits, the following list is presented:[AT]