Campbell] BORAX DEPOSITS OF EASTERN CALIFORNIA. 403 
have a bearing upon the occurrence of borax and its distribution, and 
these are embodied in the following paper. Of necessity the writer 
does not enter into a systematic treatise of the subject, but presents, 
in the form of an itinerary, the data gathered during his trip. 
BORATE. 
The principal deposit of boron salts occurs at Borate, about 12 miles 
north of Daggett, in the vicinity of the old Calico mining district. 
The mineral found here is borate of lime, or colemanite, and it occurs 
as a bedded deposit from 5 to 30 feet in thickness, interstratified in 
lake sediments. These lake beds are composed of semiindurated 
clays, sandstones, and coarse conglomerates, with intercalated sheets 
of volcanic tuff and lava. The rocks are intensely folded, the axes of 
the folds lying in an east- west direction. The lake beds extend in the 
same direction across the mountains for a distance of about 8 miles. 
It has been supposed that these deposits probably continue westward 
under the Pleistocene drift of the desert, but there is no evidence at 
hand to prove such an assertion. In fact, the lake beds at Borate do 
not come down to the foothills of the mountain ; they are cut off and 
infolded with the crystalline rocks of the Calico district. Lake beds 
are present west of Calico Valley, and a bed of colemanite has been 
struck in a shaft in this locality at a depth of 200 feet. Although the 
colemanite is interbedded with sand and clay, it is not coextensive 
with these strata. As a traceable bed it probably extends for a dis- 
tance of a mile and a half; beyond this limit it is very thin, and in 
many places it is wanting in the section. At the Borate mine there 
are two outcrops of colemanite, either on parallel beds or on one bed 
that has been so closely folded as to give two parallel layers about 50 
feet apart. The beds strike approximately east and west, and dip to 
the south from 10° to 45°. A railroad connects the mine with the 
mill which is located on the west side of the mountain, and also with 
the Santa Fe Railway at Daggett. 
DEATH VALLEY. 
The range of mountains on the east side of Death and Mesquite 
valleys is separated into two parts by a low gap formed on lake beds. 
The mass tying north of these sediments is known as Grapevine 
Mountain, and that to the south, including the lake beds, is called 
Funeral Mountain. 
The lake sediments of this region are composed of clay, sand, and 
gravel, with many beds of volcanic tuff and intrusive lava sheets 
toward the base of the series. Coarse gravel abounds near the con- 
tact between these beds and the Paleozoic rocks of Grapevine Moun- 
tain, showing that at the time of deposition this was a shore or bound- 
ary wall of the valley in which the lake was located. The strike of 
