34 BULLETIN OF THE BUREAU OF FISHERIES. 



RIVERS AND LAKES OF THE LAHONTAN SYSTEM. 



The LahoQtan system drains a huge basin embracing about 40,700 square miles 

 of arid and semiarid tableland which is roughly broken by barren and rugged mountain 

 ranges. It includes on the west the abrupt and often precipitous forest-covered wall 

 of the Sierras, with its towering masses of snow-covered peaks, and it stretches away 

 to the east, north, and south in an apparently endless extent of forbidding desert. The 

 system includes six isolated basins, viz, the Truckee River, Honey Lake, Eagle Lake, 

 Quinn River, Walker River, and the Carson- Humboldt. Here are found rivers of con- 

 siderable size, many perennial creeks, and smaller streams of more or less intermittent 

 flow, besides several large, deep, and very beautiful lakes. (See map, p. 86.) 



Truckee River is the largest and most important stream of the system. It originates 

 as the outlet of Lake Tahoe, descends 2,460 feet in about 100 miles to Pyramid and 

 Winnemucca Lakes, where its water is carried off by evaporation. Rising in a forested 

 region (pi. iii, a), it passes down a wooded canyon and emerges on the desert, where its 

 banks are alternately bordered by irrigated fields, sage-covered sands, and barren rocks 

 (pi. m, b). Its lower course is inclosed for a considerable distance between walls of eroded 

 Quaternary sediments, beyond which the gorge broadens into a green-carpeted forest 

 of large cottonwoods. Just before entering Pyramid Lake the river bifurcates, a lateral 

 channel, known as Winnemucca Slough, abruptly turning to the right and conveying 

 a considerable part of the water into Winnemucca Lake. The surface of the latter is 

 lower than Pyramid Lake, and at times after unusually high water a back flow sets in 

 from Pyramid Lake through the slough. The water of both lakes is remarkably limpid 

 except near the inlets. It is brackish to a degree which prevents the growth of arbor- 

 escent vegetation along the shores, yet the submerged rocks are covered with algae 

 and the water swarms with fishes. The monotony of the arid shores occasionally is 

 broken by towering, castellated tufa crags, which suggest ancient ruins, and the valleys 

 are bordered by high rugged mountains, against whose sides are plainly traced the levels 

 of a greater lake (pi. iv, a), often in overhanging tufa masses of fantastic form. Pyramid 

 Lake contains several small islands, on two of which are large breeding colonies of 

 water birds. 



Honey Lake is a very shallow body of water, which receives Long Valley and Susan 

 Creeks. The latter is a trout stream of considerable size. 



Eagle Lake is large, deep, and irregular in outline. Apparently it was once a 

 tributary to Lake Lahontan, but is now separated from Honey Lake Basin by a wall 

 of permeable rock, from the base of which many springs unite to form a branch of Susan 

 Creek. The water of Eagle Lake is clear and cold. The western and southern shores 

 are largely forested. The surface level is subject to periodical fluctuations, recently 

 rising so high as to submerge a considerable area and kill many large conifers. Pine 

 Creek is the only tributary. 



Carson and Humboldt Rivers flow from opposite directions into Carson, South 

 Carson, and Humboldt Lakes. These are shallow evaporation basins, irregular and 

 inconstant in outline, their waters laden with silt and charged with mineral salts. 



Quinn River debouches on the almost level floor of Black Rock Desert. For a 

 large part of its course it is sluggish and muddy, winding here and there through exten- 

 sive marshes. 



