76 BULLETIN OF THE BUREAU OF FISHERIES. 
low, a considerable part of it being inundated most of the time and covered with 
a rank growth of tules. Toward the south the tule belt rapidly narrows and the 
valley slopes a litthe more abruptly up to the mountains. On the eastern side 
the mountains rise about 3,000 feet and are well timbered, large pines in many 
places extending down almost to the water’s edge, while west of the lake they are 
much lower and support very few trees. The lake is said to be shallow, its greatest 
depth not exceeding 25 feet. On approaching the water an old beach of coarse 
gravel and small boulders may be observed, indicating that the surface has been 
6 or 8 feet higher in the recent past. In wading out somewhat over 200 yards, 
where one’s depth is reached, two other well-marked beaches are crossed. During 
very dry seasons the first of these is laid bare. An elevation of the surface of the 
water to the height of the outermost beach would cause the lake to overflow, pour- 
ing out through the channel leading to the southward. The lake receives numerous 
streams flowing in from all sides, Drew and Cottonwood creeks, which rise in the 
Winter Mountains, being the largest. Along the eastern side are many small 
streams of clear, pure water, the more important of which—Fandango, Lassen, 
and Davis creeks—are fed late in the summer by banks of snow lying high in the 
mountains. 
LOCAL DISTRIBUTION AND RELATIONSHIPS OF THE FISH FAUNA. 
In a discussion of the fish fauna of the lakes of southeastern Oregon it is neces- 
sary to keep in mind the relative position of their respective basins, and to simplify 
this matter an outline map of the region is presented (facing p. 102). 
It has been observed that the Malheur basin is closely related, both geograph- 
ically and geologically, with the Columbia. The first haul of the seie-net in Silvies 
River, which brought out such forms as Acrocheilus alutaceus and Ptychocheilus ore- 
gonensis, indicated plainly that it also bears a close faunological relation with that 
system. A careful examination of available material fails to show that the fishes 
which are isolated in the Malheur basin have visibly differentiated from their con- 
geners in the Columbia. A still closer affinity exists between the fishes of the 
Kamath and Goose Lake basins and the river systems with which they are each 
connected by open or temporary waterways. 
In an examination of the relationships of the fauna of what has been termed 
the Oregon lake system, one immediately turns to the species inhabiting the neigh- 
boring basins. ‘The close proximity of the Sacramento, Klamath, and Columbia 
systems has been referred to, and it appears that with certain species found in 
these rivers the Oregon lake fishes are most intimately related. On a survey of the 
ageregate fish fauna of these river systems it seems that the various species may be 
divided for certain reasons into three fairly well defined series or groups. In the 
first series there may be brought together an assemblage of forms that are anadro- 
mous, or at least able to withstand salt water. They are the lampreys, sturgeons, 
sticklebacks, cottoids, trout, and salmon. Species of this group are generally dis- 
tributed throughout the three systems or else are represented in each by closely 
related forms.“ ‘To a second series may be assigned a number of distinetly fresh- 
aCertain cottoids, as C, princeps, C. rhotheus, and others, whose relationships have not been carefully studied, might 
be included in this group as having probably descended from marine forms. 
