THE HOME OF THE KLAMATH PEOPLE. xvii 



eruption, the series of the principal peaks, as the Three Sisters, Mount 

 Jefferson, and Mount Hood, marking tlie general direction of the ridge. 



The formation consists of a dark and hard basaltic and andesitic lava, 

 which also forms numerous extinct volcanic cones and basins lying on the 

 east side of the range (Mount Scott, Crater Lake, craters in Sprague River 

 valley, etc.). Tiiis formation underlies the whole of the Klamath River 

 headwaters, but sti'atified deposits cover it at many places, consisting of 

 .sandstone, infusorial marls, volcanic ashes, pumice-stone, etc. Prof. J. S. 

 Newberry* describes this volcanic rock as "a dark vesicular trap". 



East of the basin of the Klamath Lakes and south of the Columbia 

 River water-shed lies an extensive territory extending to the east towards 

 Owyhee River, and having its largest area in Nevada and Utah. It has 

 been called the Great Basin of the Interior, and has an average altitude of 

 5,000 feet. The numerous fault-fissures intersecting it from north to south 

 form its principal geologic feature. In the Quaternary period long and 

 narrow lakes marked those faults on the obverse side of their dip; and 

 even now, when evaporation has left these depressions almost dry, small 

 bodies of water mark the site of the fissures even where erosion has oblit- 

 erated most traces of a fracture of the earth's crust. The most conspicuous 

 of these fissures in the basaltic formations are in Oregon, northern Cali- 

 fornia and Nevada: the valley of Quinn River, Alvord Valley with Pueblo 

 Valley, (ruano Valley, Warner Lake with Long and Surprise Valley, Abert, 

 Summer, and Silver Lake Valley. A geologic reconnaissance of the country 

 west of this northwestern portion of the Great Basin, the central parts of 

 which were once filled by the Quaternary Lake Lahontan, with its enormous 

 drainage basin, would probably prove a similar origin for the two Klamath 

 Lakes with Klamath Marsh, and for Goose Lake Valley. 



These two secondary basins lie nearest the base of the great mountain 

 wall of the Cascade Range, and therefore receive a larger share of the 

 rain precipitated upon it than the more distant ones. The supply of water 

 I'eceived during the year being thus larger than the annual evaporation, 

 the excess flows off" in the streams which drain the basin. There is much 

 analogy between the basin of the Klamath Lakes and that of Pit River; 



• Pacific Railroad Eeports, 1854-'55j vol. 6, part 2, pp. 34-ii9. 

 ii 



