13G REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



"^riic toll(»wiii.i; l)ii('r account of the ])iincii)al cliaiacteristics of tlie 

 park from an ichtliyolo^ical staiMli)()iiit is from tlie report of Dr. Jor- 

 dan :* 



Tlie Yellows! ono Park is a high plateau, havini; a general elevation of 7,000 to 

 8,000 feet above the sea. Its (intire surface, with the cxeeption of the Gallatin 

 Range of mountains in the northwest and some granitic summits in the northeast, 

 is covered with lava, with its varieties of ohsidian, rhyolito, 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 ]»robably Pliocene. Its existence Avas of 

 conrse fatal to all fish life in this region. Since its surface has become cold, the 

 streams flowing over it, most of them now wholly imaffected by the heat within, 

 liavebecorao 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 falls situated in deep canons. Excejit in the Yellowstone audits 

 tributaries, iu Gibbon River and in Lava Creek, no fishes have been found above 

 these falls, and the iiresence of fishes in the F^pper Yellowstone and Lava Crcick is 

 doubtless due to the imjierfect character of the watersheds separating these streams 

 from others. Outside of the park, the falls in Clark Fork of the Yellowstone exclude 

 fish from that river, and perhaps the Great Shoshone and American Falls iu Snake 

 Eiver exclude from the upper part of the stream the fauna of the Lower Columbia. 

 Another supposed obstacle to the spread of fish life in the Yellowstone Park is the 

 presence of the innumerable hot springs, solfataraa, and geysers, for which the 

 region is famous. 



Br. Jordan's trip was made somewhat late in the season, and on that 

 account was considerably hurried, but he was, nevertheless, enabled to 

 study the leading points in the problem which had been suggested to 

 him. Yellowstone Kiver and Lake, inciluding all their western tribu- 

 taries, were examined at many places, and also all the principal streams 

 and lakes of the Madison and Snake River basins. The total number 

 of fishes discovered was 10, of which 2 belong to the Salmonidw (the 

 Rocky Mountain trout and tlie whiteflsli), 1 is the miller's thumb or 

 blob, 1 the grayling, 4 are minnows and chubs, and 2 suckers. No- 

 Avhere above the falls, except in the Yellowstone and its tributaries, in 

 (Tibbon River, and in Lava Creek, were any tishes found. The miller's 

 thumb or blob was very abundant above the falls iu Gibbon River, and 

 its presence there is unexi>lained; but the oc<'urrence of trout in Lava 

 Creek, where they arc common, is supposed to be due to the imperfect 

 character in some places of the watershed which surrounds it. The 

 grayling is restricted to the extreme northwestern part of the park. 

 ])r. Jordan describes with much care the peculiarities and distribution 

 of the different species, and the characteristics of all the principal lakes, 

 rivers, and creeks in the ]>ark, making his report invaluable as a guide 

 in the stocking of those waters. 11 is conclusions regarding the suita- 

 bility of certain areas for tiiat ]mrpose are also A^ery important. 



*A reconnaissance of the streams .lud lakes of the Yellowstone National Park, 

 Wyoming, in the interest of Iho F. S. Fish Commission. By David Starr Jordan, 

 IJuU. U. S. Fisii Com., ix, for 1889, pp. 11-03, pis, vii-xxii, and one map. 



