1.— A RECONNAISSANCE OF THE STREAMS AND LAKES OF WESTERN 
MONTANA AND NORTHWESTERN WYOMING. 
BY BARTON W. EVERMANN, PH. D., 
Assistant, U. S. Fish Commission. 
SUMMARY OF REPORT. 
Iii this paper are presented the results of investigations in Montana and Wyoming 
made during the summer of 1891 under the direction of the U. S. Commissioner of 
Fish and Fisheries. 
In carrying out the instructions furnished by the Commissioner, it was highly 
important that a careful study be made of the physical and natural-history features of 
the streams and lakes of the region. Attention was given to the general characters 
of the streams and lakes, their size, depth, current; the nature of obstructions, if any, 
in the streams; the source of water supply, whether from lakes, springs, or melting 
snow; the temperature of the water at different times and different places; its clear- 
ness, and to what extent contaminated by mining operations or heavy rains; the 
geology of the region through which the stream flows, and the composition and nature 
of the bottom and banks of each river or lake. 
In studying the natural-history features of the streams special attention was given 
to the kinds of fishes they contain, their abundance, size, condition, and distribution ; 
also to the invertebrate life, such as crustaceans, insects, and mollusks, serving as food 
for the fishes. 
The important question of the geographical distribution of fishes was kept con- 
stantly in mind, and attempts were made to trace the limits in the range of certain 
species, and to determine, if possible, the definite solution of certain difficult problems 
presented in the distribution of the trout and blob in Yellowstone National Park. 
In making my investigations looking toward the selection of a suitable site for a 
fish-cultural station, visits were made to as many places as our time would permit, or 
as was necessary for the purposes of the investigation. The station for this region 
would be devoted almost exclusively to the hatching and rearing of various species 
of trout and other Salmonidce. The requirements for the successful operation of such 
a station may be stated briefly as follows : 
1. Pure water: (a) A constant supply of not less than 1,000 gallons per minute. 
(b) The temperature should not at any time exceed 50° or 55°, and would better be 
under 50°. (c) There should be no danger of contamination from any source. 
2. Suitable g round : (a) The amount should be 20 to 30 acres. (b) It should lie 
conveniently near to the source of water supply, (c) There should be sufficient fall 
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