207 
an irregular, winding course follows along the top of the volcanic lava. 
flow in a general northwesterly direction, leaving the park nearly west 
of the Upper Geyser Basin. 
Five main channels carry off the waters from the park to the valleys 
below. On the eastern side of the great water-shed the Yellowstone, 
Madison, and Gallatin contribute their waters to the Missouri, while 
the Suake and alls Rivers on the opposite side add their share to the 
Columbia. The Yellowstone River, already a magnificent stream be- 
fore it leaves the mountains, drains more than one-half the area of the 
park, including the entire eastern border, together with the eastern 
side of the Gallatin Range, which, through the Gardiner River, pours its 
waters into the Yellowstone. The streams upon the western slope of 
the Gallatin Range empty into the Missouri by the Gallatin River. 
Both the Gibbon and the Firehole find their sources among springs on 
the plateau, and after draining the principal geyser basins unite to form 
the Madison. Falls River, a picturesque stream, collects the large 
drainage from the Pitchstone Plateau and the southern end of the Madi- 
son Plateau, and leaves the park at the extreme southwest corner. 
Snake River, however, drains the greater part of the country on the 
west side of the water-shed, collecting immense bodies of water com- 
ing from the northern ends of the Teton and Wind River Ranges and 
the southern slopes of the voleanic plateau. Taken together, these 
accumulated waters make the Snake a broad river before it leaves the 
mountains, 
On the plateau, upon both sides of the water-shed, oceur several 
large bodies of water, Yellowstone, Shoshone, Lewis, and Heart Lakes 
being especially noteworthy for their size and beanty. Scattered over 
the country, both on the plateau and in the surrounding mountains, 
are numerous smaller lakes and ponds, occupying for the most part 
shallow basins of glacial origin. ‘The view from the summits of either 
Mount Sheridan or Mount Hancock presents a grand and picturesque 
scenery of diversified forms, and a country so dotted over with lakes 
as to receive the appellation of the lake region of the Park. ‘Thou. 
sands of hot springs add their waters to the cold water of the surface. 
Meadows, marshes, and swampy areas characterize the entire area in 
strong contrast with most Rocky Mountain scenery. These lakes are 
the reservoirs of the larger streams. The Yellowstone is the largest 
lake in North America at so high an elevation (7,741 feet). It has a 
surface area of 121 square miles, and an indented shore-line of nearly 
100 miles. Only preliminary soundings have as yet been made, but over 
a very considerable area the depth is known to be more than 250 feet. 
Less than 6 miles from the Yellowstone, in a deep depression on the 
plateau, lies Shoshone Lake, with an area of nearly 12 square miles. 
A short distance to the southward, at the west base of Mount Sheridan, 
oecurs Lewis Lake, measuring 44 square miles, and on the opposite side 


