2j6 SCIENCE SKETCHES. 



and went away contented with that. A much 

 better angler, Mr. Charles J. Fisher of Leadville, 

 was not satisfied with our conclusions, and insisted 

 that we should go back with him. We did so, and 

 were rewarded by many specimens of the beautiful 

 " Yellow-fin Trout," 1 first introduced to science 

 in 1889. This is a large trout with bright yellow 

 fins, a yellow stripe along the sides, pale flesh, 

 and the black spots very small and all gathered on 

 the tail. It has not yet been found in any other 

 waters. It is very different in structure and aspect 

 from the Greenback Trout which swarms with it 

 in the Twin Lakes. It must be descended from 

 the Colorado Trout, which inhabits the other side 

 of the Divide. How it crossed the Saguache 

 Mountains from the Gunnison or from the Roaring 

 Fork, no one can now say, but that this crossing 

 was a fact I have no reason to doubt. 



At this point the " lay of the land " renders a 

 diversion necessary. When you come overland to 

 San Francisco by way of the Central Pacific, 

 after you have passed Ogden an hour or so, you 

 will notice a break in the mountains to the north- 

 ward. Through this break to the Snake River the 

 waters of the Great Salt Lake once flowed. It 

 was not a salt lake then, and it was much larger 

 than now. The old lake has been called Lake 

 Bonneville. You may trace its former boundaries 

 as terraces upon the slopes of the hills. You can 

 see them from the car windows, looking out in 

 almost any direction. Through this break once 



1 The Yellow-fin Trout of Twin Lakes is Salmo my kiss mac- 

 donaldi Jordan & Evermann- 



