44 BULLETIN 61, U. S. DEPARTMENT OF AGEICULTUEE. 



Sufficient data are not available properly to characterize this area. It is not unlike 

 the Silver Peak Marsh. The potassium content of No. 2 brine, the highest, is less 

 than for the average of the Sih^er Peak brines. The high content in the single sam- 

 ple of the crust material is not considered significant, smce samples of this material 

 occasionally run high in potassium. 



Death Valley. 



Death Valley receives the drainage of the Amargosa River. The drainage area is 

 given as 23,160 square miles by Free's table of basin areas. The area of the playa is 

 approximately 160 square miles, not including Mesquite Valley in the northern end. 

 The ratio of basin to playa is 144 to 1. 



The valley lies between the Panamint Range on the west and the Amargosa Range 

 on the east. It has a length of 120 miles and a width varying from 3 to 10 miles. Much 

 of the valley area lies below the sea level. The lowest point on the topographic sheet 

 is —280 feet. Ball states that some 15 miles farther south from this point the 

 depression is 125 feet deeper. The Panamint Range reaches its maximum elevation 

 at Telescope Peak, 11,045 feet, an air-line distance of about 12 miles from the —200- 

 foot contour of Death Valley. The Amargosa Range reaches an elevation of 6,397 feet 

 at Funeral Peak, a distance of 6 miles from the —200-foot contour; 6,725 feet at Pyra- 

 mid Peak, a distance of about 12 miles from the —200-foot contour; and 5,420 feet at 

 Chloride Cliff Peak, a distance of 10 miles from the —200-foot contour in Death Valley. 

 The Panamint Range averages from 7,000 to 9,000 feet altitude and the Amargosa 

 from 6,000 to 7,000 feet. The maximum grade on the west from Telescope Peak to 

 the valley is 920 feet per mile (9.8°), and on the east, measured from Funeral Peak, 

 1,066 feet per mile (11.4°). The canyons leading to the valley do not approximate 

 these grades, except in their upper ends, but the aA^erage grade is very steep. In 

 consequence of these steep grades and the torrential character of the occasional rain 

 storms, alluvial fans and moxintain aprons have been developed on a vast scale. The 

 narrowness of the valley has resulted in the development of a structure similar to 

 that shown in figure 4. Undoubtedly many of the fans overlap beneath the central 

 basin. 



The floor of the valley is level, but on the flanks are low hills, some of Tertiary 

 sediments (PL I, fig. 2), and some of alluvial material representing the residual 

 portions of alluvial fans attacked by recent erosion. Mesquite Flat, in the northern 

 end of the valley, is covered with sand dunes. There are no positive evidences of a 

 lake during Quaternary times. Some evidences of a shallow, recent lake in the area 

 east of Bennetts Wells are discernible in faint shore lines, which indicate a depth of 

 6 to 12 feet. 



An enormous deposit of salt occupies the lowest depression. The salt area begins 

 south of Salt Creek, 6 miles northwest of United States land monument No. 34, and 

 extends to a point south of Mesquite Spring. The length of the salt area is from 30 

 to 32 miles, and its width ranges from 2 to 4 miles. Over a large part of this area the 

 salt appears as a crust composed of pinnacles and fantastic, twisted masses. (PI. 

 II, fig. 1.) It is said that some of the rough salt pinnacles reach a height of 6 feet. 

 The average height of those I saw would be from 1^ to 2 feet. The thickness of the 

 rough salt varies. Campbell^ states that it can not be less than 1 foot thick. Free 

 states that the thickness of the upper crusts is 18 inches. Below this is 3 feet of mud, 

 then 18 inches of salt, and then mud to 10 feet at the place where he tested. 



In the so-called sink east of Bennetts Wells and about 18 miles south of Furnace 

 Creek Ranch is an area of smooth salt. (PI. II, fig. 2.) On the eastern edge of the 

 valley this is separated by a narrow rim of mud and rough salt from the alluv^ial wash 

 of the Amargosa Range. On the north the area is bounded by rough salt which extends 

 across the floor of the valley. The first foot of the smooth salt area is composed of 

 layers of crystalline salt 2 or 3 inches thick, separated by thin seams of mud and sand. 

 Brine comes to within a fraction of an inch of the surface. A slight scraping of the 

 surface is followed by the flowing in of the brine. The surface of the salt is divided 

 into small polygonal areas by thin cracks through which the underlying brine has been 

 drawn and in crystallizing has left low welts of crystallized salt cementing the cracks 

 together. As far as I have been able to ascertain, no measurements of the thickness 

 of this salt have been made. B. K. Brockington estimates that the total area of 

 incrustation is approximately 150 square miles. Of this about one-third, or 50 square 

 miles, is smooth salt, the greater part of this being in the sink east of Bennetts Wells. 



In the rough salt area, holes show a brine to be within 1 or 2 feet of the surface. 

 Within this area also occur potholes, circular openings from 2 to 4 feet in diameter 



1 Bill. No. 200, U. S. Gcol. S irvsy, p. 18. 



