EXPLORATIONS IN COLORADO AND UTAH. 
25 
the Main Divide. All these streams are well stocked with trout, their fauna being pre- 
cisely like that of the Gunnison. 
The lower San Juan enters the desert country and receives large numbers of 
“ sand arroyos,” dry beds flooded with mud after a rain. The water becomes warm, 
thick, and yellow, although all the upper sources of the river are clear and cold. 
It is thought that the lower San Juan and the Colorado would be well suited for 
the growth of the larger cat-fishes as Leptops oUvaris, Ameiums nigricans, and per- 
haps Ictalurus punctatus. It would be well to make a plant of these at Green Eiver 
Station, and one on the San Juan at Arboles. 
15. Bio de las Animas Perdidas. — The Animas Eiver is the largest tributary of 
the San Juan. It rises in the mountains above Silverton. Above its canon of “ Lost 
Souls,” it is clear, shallow, and swift, flowing through an open canon with a bottom 
of rocks. In its upper course it is said to be without fish, one of its principal tribu- 
taries, Mineral Creek, rising in Eed Mountain and Uncompahgre Pass, being highly 
charged with salts of iron. 
In the deep and narrow “ Canon de las Animas Perdidas ” are many very deep 
pools, said to be full of trout. Below the canon is “ Ilermosa Park,” in which, for 
some 15 miles, the river flows over sandy bottom, with many deep holes and slight 
cnrrent. In these holes are many trout, and with them Pantosteus delphinus, Agosia 
yarrowi, and Cottus hairdi punctulatus. 
At xXnimas City, above Durango, the stream enters a stony mesa, a glacial moraine, 
which, by its dam, has formerly made a lake of Hermosa Park. From this point, for 
miles below, the bottom is so covered with boulders that seining is impossible. At 
Durango the river is 2 to 3 rods wide and 2 to 4 feet deep j in the deeper holes, 6 to 8. 
The temperature is about 68°. The stream was seined at various places from Animas 
City to a point about 5 miles above Durango. 
At Durango it is said that the larger suckers (X. cypho, C. latipinnis) and the “ White 
salmon” [Ptychoclieilus) ascend the river in the spring, going back to deep water after 
spawning in the summer. 
16. Leitner^s Greelc, at Durango. — This is a little stream entering the Animas opposite 
Durango. In summer it is 2 to 3 feet wide, shallow, clear, and warm (72°) with sandy 
bottom. It contains Cottus hairdi panctulatus and Agosia yarrowi. Higher up its 
deeper pools are said to contain small trout. 
17. Bio Florida. — This is a clear, cold stream, flowing into the Animas below Du- 
rango. It was seined at several points above the bridge about 8 miles east of Durango 
and north of Florida Station. It flows through a wooded valley over round boulders 
and with few deep places. Trout are abundant ; also Pantosteus delphinus, Agosia yar- 
rowi, and Cottus hairdi punctulatus. The last-named species lurks under every stone in 
the river. 
18. La Plata Biver. — West of the Animas Eiver is the Eio la Plata. It rises in 
the mountains above Fort Lewis, but the water mostly sinks in the sand and gravel 
below the fort. There are some trout here, but it is said that the stream contains too 
much iron to be well adapteel for fish. It was not visited by us. 
19. Bio de los Pinos (seen at Ignacio), the next river east of Eio Florida, is a clear, 
swift stream, with gravelly bottom, 2 rods wide and 1 to 3 feet deep. It runs through 
a broad valley which may become valuable for agriculture. I atn told that Patrick 
