the streams of this system became separated and differentiated as a dis- 

 tinct drainage system earlier than did those of the Platte, Arkansas, Rio 

 Grande, Colorado, or Columbia, or else that they are streams of more re- 

 cent origin and have never been connected at any time with any of the 

 streams containing trout. Such a history as this for the Cheyenne, to- 

 gether with the shallow, muddy, alkaline character of its lower portion, 

 seems to be a reasonable explanation of the absence of trout from the 

 Black Hills * 



The effect of the peculiar alkali water of the Cheyenne and the lower 

 course of the streams flowing from the Black Hills has been to reduce the 

 fishes to a nearly uniform pale, faded or bleached appearance. Except 

 those found above the alkali water, they are almost wholly without pig- 

 ment cells of any kind. Perhaps the most extreme case of bleaching is 

 that of the flat-headed minnow, Platygobio gracilis, which, of all American 

 fishes, seems to be the one most perfectly adapted to these alkali streams. 



The following is a list of the species of fishes obtained in the Black 

 Hills and vicinity : 



SILCRID/K, OR CATFISHES. 



1 . Noturus jiaviis Rafinesque. Yellow Cat. South Fork of Cheyenne 

 River at Cheyenne Falls, and Belle Fourche River at Belle Fourche. 



2. Ictalurus punctalus (Raf.) Channel Cat. Middle Creek at Belle 

 Fourche. 



CATOSTOMIDJE, OH SUCKERS. 



o. Carpiodes car j no (Raf.) Carp Sucker. Found by us only in the Belle 

 Fourche. 



4. Pantosttux jordani Evermann. This species recently described by 

 me as new (Bull. IT. S. Fish Com., XII., Art. 2, 51-56, January 27, 1893,) 

 was found by us in most of the streams of the Black Hills, viz : White- 

 wood, Spearfish, Crow, Rapid and Hat creeks, and in the Belle Fourche. 

 For full description, see the Bulletin mentioned above. 



5. Catostomus teres sucklii Girard. Common Western Sucker. Found in 

 Middle, Crow, Chicken, Rapid, Cottonwood and Hat creeks, and in the 

 Belle Fourche. 



6. Moxostoma macrolepidotum duquesnii (Le Sueur.) The Belle Fourche 

 and South Fork of the Cheyenne, and in Redwater Creek. 



*In his paper on " The North American Species of Salmon and Trout," printed in the 

 U. S. Fish Commission Report for 1872-1873, Dr. Suckley, in giving the habitat of Salnm 

 leivisi(S. mi/kiss), credits it to the " Black Hills, Nebraska, Dr. Hayden." I have been un- 

 able to verify this reference, and I believe it to be an error. 



