FISH FAUNA OF LAKES OF SOUTHEASTERN OREGON, 75 
may also be seen swimming about among clumps of alge in the stream flowing from 
the spring. They are smaller than those found in the spring at Abert Lake. 
Malheur and Harney lakes are extensive bodies of alkaline water. They are 
in a huge basin with # nearly flat floor, bordered in many places by great walls of 
basaltic rim rock. Malheur Lake receives the Donner and Blitzen River, flowing 
from the Stein Mountains on the south, and the Silvies River, which drains a part 
of the mountainous region to the northward. Harney Lake, the deeper and more 
salty of the two, often acts as an overflow basin for Malheur Lake. It is also fed 
by Silver Creek and a group of large, warm springs on the western side which have a 
constant temperature of 70° F. A stream of considerable size and several pools fed 
by these springs harbor great numbers of minnows. 
Altogether the lakes receive the drainage of a vast territory, the tributary 
streams increasing the amount of water greatly during the winter and spring. As 
the dry season progresses the inflow diminishes and the evaporation increases, 
while the lakes rapidly contract and their salinity grows more pronounced. The 
constantly widening mud flats, with their glistening surfaces, and the drying up of 
the marshes add greatly to the general desolation of the valley. 
Harney and Malheur lakes are separated from Warner, Abert, Summer, and 
Silver lakes by a broad, desolate expanse of sage plains and sandy desert, scored 
by the dry channels of ancient rivers and sparsely dotted with small playa lakes 
which contain water for only a short time during the year. 
The Malheur basin was once drained by the Malheur River, a part of the Colum- 
bia system. There is evidence “ to show that it was cut off from that svstem by 
voleanic action in comparatively recent geological times. The basins of the other 
lakes are completely and widely isolated from any system having connection with 
the ocean. Although little appears to be known of their geological history, they 
may for the present be regarded as unconnected parts of what may be termed the 
Oregon lake system. It is to be noted that the lakes of this group receive their 
water supply from a mountainous region on the southwest. <A large portion of 
this same territory is drained by streams which flow into Klamath and Rhett 
lakes to the westward, and also by others connected with Goose Lake, lying far- 
ther south. It is well known that Klamath and Rhett lakes are integral parts of 
the Klamath River system.’ Goose Lake belongs with the Sacramento system, 
although the water seldom rises high enough to flow out through the broad channel 
leading from the lake to Pitt River. In appearance it is very different from the 
lakes of the Oregon system. The basaltic rim rock so characteristic of the region 
to the northward is almost entirely wanting, while in its stead the lake is surrounded 
by a gently sloping, fertile valley, the northern portion of which is very broad and 
i «Russell, Israel C., Notes on geology of southwestern Idaho and southeastern Oregon, Bulletin U. S. Goleman 
Survey No. 217, p. 22. 
> Rhett or Tule Lake formerly had an indirect connection with Klamath River through Lost River Slough. The lake 
served at times as an overflow basin for Klamath River. In a letter on the subject Mr. Elmer I. Applegate, of Klamath 
Falls, writes: ‘‘ Until a few years ago Lost and Klamath rivers were connected by what was known as Lost River Slough, 
which carried a stream of considerable size during high water, offering no obstruction during a large portion of the sum- 
mer to the passage of all fishes inhabiting the waters of either river. No water passes through this channel now, it 
having been diked in order to confine the water to Klamath River, and thus lower the level of Tule Lake."’ 
B. B. F, 1907—6 
