FISHES OF THE MISSOURI RIVER BASIN. 337 



with soil so charged with alkali as to bo, in many places, almost with- 

 out vegetation; indeed, a considerable portion of the Mauvaises Terres 

 or Bad Lands lies in the drainage basin of the Cheyenne. This soil 

 erodes with great ease, and, as a consequence, the water of the river 

 is never clear. The only trees seen along the Cheyenne were a few 

 cottonwoods. At Edgemont a small stream known as Cottonwood 

 Creek Hows into the Cheyenne. This is a muddy creek with only a few 

 species of fishes, chief among which are Platygobio gracilis, HybognatJms 

 nuchale evansi, and Catostoviu.s griseus. The temperature of the water 

 was 40° at noon, October 19, when the air was 59°. 



Fall River. — This is a considerable stream, formed just above the 

 town of Hot Springs by the union of Warm Creek and Cold Creek, the 

 first of these deriving its water from numerous warm or hot springs. 

 The larger warm springs at the town pour their waters into the 

 creek there and the water is quite warm for some distance below. On 

 October 18, when the air was 50° at noon, the water was 65° at a point 

 2 miles below the town. At the town the temperature of the water in 

 the creek was <S0°. This water is strongly impregnated with lime, and 

 as a result the Ghara which fills the stream grows very rank and forms 

 thick deposits along the banks and in the bed of the stream. In places 

 it has become quite hard, but upon attempting to walk over it one will 

 frequently break through the crust and sink into the soft mud beneath. 

 Besides the Ohara, there are several species of algse growing luxuri- 

 antly, and in this mass of vegetation the smaller crustaceans and other 

 minute forms of animal life abound. The only species of fish which 

 we found living in this warm water was the western dace (Ixhinichthys 

 cataractce duleis). 



Hat Creel;. — This stream was examined October 21 at Ardmore, 

 S. Dak., about Ih, miles from the Nebraska line. It is a small alkali 

 stream about 10 feet wide, inches in average depth, and flowing about 

 a foot in i' seconds. At the time examined it was flowing more water 

 and was muddier than usual, owing to recent rains. The bed is in 

 most places of very soft mud; the banks are rather high and of blue or 

 white adobe clay, which is sticky in the extreme when wet. There are 

 occasional deeper holes in the stream, where the characteristic fishes 

 of the region are found in considerable numbers. This stream is sub- 

 ject to sudden floods and dries up to mere isolated pools in the summer 

 and early fall. The headwaters of the stream are said not to dry up 

 so much as docs the lower course. The country is prairie, easily eroded, 

 and the water is always muddy or milky in appearance. At 5 p. m., 

 when the temperature of the air was 52°, that of the water was 46°. 

 The principal lishes found here were the rlatheaded minnow and the 

 silvery minnow (Hybognathus nuchale evansi), both of which were 

 abundant. There were also a tew western dace and suckers. 



Beaver Creek rises in the western part of the Black Hills, flows south 

 and empties into the South Fork of the Cheyenne Biver. We examined 

 it near the L. A. K. rauch, 5 miles from Newcastle, Wyo., October 20, 

 F. r. 91 22 



