74 BULLETIN OF THE BUREAU OF FISHERIES. 
trunks of gigantic willows are exposed, conclusively showing that for a considerable 
time during its past history the lake was much smaller than at present. The prin- 
cipal source of water supply is Ana River, a stream unique in many particulars. It 
rises from a group of several springs which pour out clear, cool water, forming a 
stream about 15 feet wide and 4 feet deep with a current so swift that it is difficult 
to stand against it. It is not more than 5 miles long and flows in a deep channel 
cut in the floor of the lake basin. Sagebrush and other desert plants grow to its 
very edge and, judging from the landscape alone, no one 200 yards from either the 
springs or river would suspect their presence. Some of the springs form large 
pools apparently of great depth, which are held in conical basins, the surface of the 
water lying 50 or more feet below their rims. The temperature of the water is 
60° F., reported to be constant throughout the year. 
The Rim Rock Mountains tower perhaps 2,000 feet abet the western side of 
the lake. Their slopes are very steep, in some places dropping off in precipitous 
cliffs of great height. Their crests are covered with trees, small pines and junipers 
extending in some places far down their sides. At the base of the mountains along 
nearly the entire western side of the lake is a narrow belt of meadows and marshes, 
kept green by springs and small rivulets. The east side of the lake is barren and 
desolate in the extreme. The water is bordered by extensive mud flats, beyond 
which are great wastes covered with alkaline dust or shifting sand, the sand piling 
up against the low hills which skirt the valley. In the distance the hills and bluffs 
eradually rise to a height approaching a thousand feet. 
Summer Lake is separated from the Chewauean Marsh by only a slight 
elevation. Between Summer and Silver lakes is a divide apparently not less than 
500 feet high. 
Silver Lake Valley is bordered on the west by a high basaltic wall, which, though 
more or less broken by hills and canyons, continues well around the southern end. 
On the eastern side of the valley this same wall rather abruptly slopes down to a 
point where the ancient outlet is said to be located, again to rise and extend to the 
northward with an irregular outline of hills and mesas. 
The inlet of the lake comes from the Pauline Marsh, lying to the northward, 
which in turn receives Bear, Bridge, and Silver creeks, streams of considerable size, 
draining the northern ranges of the Winter Mountains. The water of the lake, 
which is turbid and slightly alkaline, was at its maximum height when seen by the 
writer. It covered nearly the whole floor of the southern part of the valley and no 
beaches appeared above its level. This condition was said to be only temporary, 
however, the size of the lake being subject to considerable variation. Not long ago 
it contracted until nearly dry, remaining so for a year or more. At the time many 
dead stumps of sage ‘brush were found standing where they once grew, far within 
the present shore line. 
Alkali Lake is an extensive pond lying in a desolate and forbidding region 
about 20 miles north of Abert Lake. It is the desiccated remains of a former great 
lake which was probably over 200 feet deep. On the low land not far from the 
shore is a spring pool about 50 feet across. Its water is fresh, slightly turbid, 
and is said to remain at a temperature of about 64° F. It swarms with fish 
(Rutilus), great numbers coming to the surface on the appearance of food. Many 
