18 BORAX OF DEATH VALLEY AND MOHAVE DESERT. [bull. 200. 
were seen. The bed is composed of a mass of crystalline colemanite 
which mines readily and with little waste. 
In the western foothills of Funeral Mountain a bed of this mineral 
is exposed in the ravines for a distance of a quarter of a mile, and 
along this outcrop it varies in thickness from a few inches to 20 feet. 
At no point is it a solid regular bed, but it consists of irregular masses 
and stringers of colemanite embedded in clay. The crystals are small, 
seldom exceeding a quarter of an inch in diameter, and the large 
masses are nearly pure. According to Superintendent Roach, of the 
Pacific Coast Borax Company, the largest mineral deposit occurs about 
9 miles up Furnace Creek on a nearly direct line between the outcrops 
just described. At this point he reports a bed of boracite 60 feet in 
thickness. This was not seen by the writer, but there are strong indi- 
cations of the presence of minerals of this character, and it is probable 
that large deposits occur in this locality. 
Borax was once manufactured 2 or 3 miles north of the point where 
Furnace Creek emerges from the hills into Death Valley. The plant 
was situated on the margin of the alkaline marsh, and the crude mate- 
rial was derived from a certain part of the marsh where colemanite 
accumulated. It is now known that the mineral is derived by solution 
from the bedded deposit described above, and that its accumulation on 
a certain part of the marsh is due to the solution being carried to that 
place by a small stream. 
Death Valley contains an immense salt field, which may in time 
become valuable. It extends south from above the old borax works 
at least 30 miles. At the place where it is crossed by the road from 
Furnace Creek to Bennett Wells it is nearly 3 miles wide, and it prob- 
ably varies from 2 to 4 miles in different parts of the basin. The salt 
is not white, like the marsh at Salton, in Colorado Desert, but it is 
brown with dust and sand that is constantly being blown upon it. 
The salt stands in pinnacles 2 to 3 feet in height, making a surface 
so rough that it is impassable for a horse until the projections are 
pounded down with a sledge. With the implements at hand the 
thickness of the crust could not be determined, but it can not be less 
than 1 foot of solid salt. A sample collected in the middle of the field 
on this l'oad shows that the salt is composed of chloride of sodium, 
94.54 per cent; chloride of potassium, 0.31 per cent; sulphate of 
sodium, 3.53 per cent; sulphate of calcium (hydrous), 0.79 per cent; 
moisture, 0.14 per cent; undissolved residue (gypsum and clay), 0.50' 
per cent; total, 99.81 per cent. The presence of the large amount of 
mechanical impurities, as well as the large percentage of sulphate of 
soda, would render refining necessary before the salt could be placed 
upon the market, a process that would be very expensive under 
present conditions of great scarcity of fuel and water and lack of rail- 
road transportation. 
