EXPLORATIONS IN YELLOWSTONE NATIONAL PARK. 
43 
the services, as guide, of Mr. Elwood Hofer, to whom we are indebted for much valua- 
ble help. Mr. E. E. Lucas, of the distributing division of the U. S. Fish Commission, 
also aided us materially by collecting specimens from tributaries of Madison River 
and Henry River. Mr. Arnold Hague, of the U. S. Geological Survey, also gave us 
considerable valuable information. 
The following is a classified list of the waters examined, those lakes and streams 
containing trout being printed in italics : 
Yellowstone Basin : 
Yellowstone River. 
Yellowstone Lake (altitude, 7,741 feet). 
Riddle Lake (altitude, 7, 900 feet). 
Solution Creek. 
Bridge Bay Creek. 
Arnica Creek. 
Trout Creek. 
Alum Creek. 
Cascade Creek. 
Sulphur Creek. 
Antelope Creek. 
Tower Creek. 
Lo.st Creek. 
Elk Creek. 
Oxhow Creek. 
Geode Creek. 
Black tail Deer Creek. 
Lava. Creek. 
Lupine Creek. 
Gardiner River. 
Twin Lakes. 
Obsidian Creek. 
Beaver Lake. 
Yellowstone Basin — Continued: 
Winter Creek. 
Indian Creek. 
Glen Creek. 
Madison Basin : 
Madison Rirer. 
Firehole River. 
Iron Spring Creek. 
Little Firehole Creelr. 
Goose Lake. 
Nez Perc6 River. 
Gihhon River. 
Canon Creek. 
Rorsethief Spriny. 
Snake River Basin : 
Shoshone Lake (.altitude, 7,740 feet) 
Heron Creek. 
Lewis Fork. 
Lewis Lake (altitude, 7,720 feet). 
Heart Lake (altitude, 7,469 feet). 
Witch Creek. 
Howard’s Creek. 
Henry’s Lake. 
The Yellowstone Park is a high plateau, having a general elevation of 7,000 to 
8,000 feet above the sea. Its entire surface, with the exception of the Gallatin range 
of mountains in the northwest, and some granitic summits in the northeast, is covered 
with lava, with its varieties of obsidian, rhyolite, etc. This mass of lava covers to a 
great depth what was previously a basin in the mountains. According to Mr. Hague, 
the date of the lava flow is probably Pliocene. Its existence was of course fatal to all 
fish life in this region. Since its surface has become cold, the streams flowing over it, 
most of them now wholly unaffected by the heat within, have become well stocked with 
vegetable, insect, and crustacean life, but are for the most part destitute of fishes. 
The cause of this absence of fishes is to be found in the fact that nearly all the streams 
of the Park on leaving the lava beds do so by means of vertical water-falls situated in 
deep canons. Except in the Yellowstone and its tributaries, in Gibbon River and in 
Lava Creek, no fishes have been found above these falls, and the presence of fishes in 
the Upper Yellowstone and Lava Greek is doubtless due to the imperfect character of 
the water-sheds separating these streams from others. 
The following is a list of the water-falls in the Park, supposed to be unsurmount 
