EXPLOKATIONS IN COLORADO AND UTAH. 
9 
B.— ARKANSAS BASIN. 
The Arkansas Eiver rises in the mountains to the north of Leadville. It flows 
southward through a broad park-like valley, grassy in its upper part and becoming 
arid lower down. This valley is bounded on either side by lofty mountains, with 
snow-banks which are the source of many ice-cold streams. At Salida the river turns 
abruptly to the east, breaking through the mountains in a deep and rocky caiiou, by 
which it reaches the level of the sage plains. Throughout the region above the caiiou 
the Arkansas is clear and cold, in every way well suited for trout. Placer-mining at 
Leadville and Granite has much reduced the number of Ashes in the river by filling 
the water with clay, but they still abound in all the tributary streams. Below the 
canon the river becomes warmer and more muddy, and no trout are found there, the 
fauna from Caiiou City down being much the same as that of the rivers of Kausas. 
The Ashes of the Arkansas were examined at the following points: 
1. Arlmnsas River and its Lake Fork near Leadville. (Seined at a bridge across 
Lake Fork between Evergreen Lakes and the village of Malta, about 3 miles west of 
Leadville.) — The river and the Lake Fork are about equal in size and entirely similar 
in character, flowing with a moderate current through green meadows, shaded by wil- 
lows, and with occasional deep holes in the bends. The streams are each about 15 feet 
wide and the bottom is gravelly. The temperature is about 02°. These streams are 
ideal trout-brooks. Trout are very abundant and with them Bhiiiichthys duleis. Spe- 
cies taken at Leadville are marked L in the followiug'list. 
2. The Evergreen Lalces are a series of trout-ponds, wholly or partly artificial, fed 
by cold streams from the flanks of Mount Massive. One of these streams, having its 
rise in the largest permanent snow- field in Colorado, has been chosen by the U. S. 
Fish Commission as the site of its hatchery. No better location could be desired. 
3. Twin Lalces. — These two lakes, formed by a moraine-dam at the foot of Mount 
Elbert and Mount Grizzly, are the largest lakes on the east side of the divide in Colo- 
rado. The two lakes are separated also by a moraine, across which they are con- 
nected by a short stream, perhaps an eighth of a mile long. The lower lake is the 
larger of the two, and is about 3 miles long by 2 wide. The upper is about l.J miles by 
2. The lower lake is said to average 40 feet in depth, its lower part being extensively 
shallow, the middle and the south side very deep. The bottom is largely gravelly 
and covered with water plants. In some places are piles of boulders. The shallow 
north side of the lake is full of Najas and other water weeds, growing 3 to 5 feet high 
in water 10 feet deep. Among these plants the trout chiefly feed. In them they often 
escape after taking the fly by breaking the leader. “Shrimps” {Oammarus} are very 
abundant in the weeds. The upper lake is a little colder and not quite so well stocked 
with fish. Its area is about one- half that of the lower lake. Our collections were 
made in the lower lake, most of the trout being taken with the fly by Mr. George E. 
Fisher. Besides the two forms of trout, the lake contains suckers (0. teres) and Rhin- 
ichthys duleis. Species from Twin Lakes are marked T in the list. The inlet of 
the upper lake is a very elear, eold stream of considerable size. A water-fall in this 
stream formerly checked the ascent of the trout, but it has now been destroyed by 
blasting. 
4. Lake Cree/l^near Granite. — Lake Creek, the outlet of Twin Lakes, is a very clear 
stream with green borders running across a desolate mesa, a glacial moraine, down to 
