402 CONTRIBUTIONS TO ECONOMIC GEOLOGY, 1902. [bull. 213. 
orating the waters of Clear Lake, about 80 miles north of San Fran- 
cisco, where it was first produced on a commercial scale in 1864. 
Subsequently the lake water was enriched by the addition of crystal- 
line biborate of soda, which was collected from the alkaline marsh 
surrounding the lake. The industry flourished at this and other 
lakes in California until, in the early seventies, borax in large quan- 
tity and in a very pure condition was discovered on many of the alka- 
line marshes of western Nevada and eastern California. Refining 
plants were established in the vicinity of Columbus, Nev., and at 
several points in California, the most important of the latter being in 
San Bernardino County, at Searles's marsh, west of the Slate Range; 
in Inyo County, near Resting Spring; and at the mouth of Furnace 
Creek in Death Valley. These plants flourished for a time, even 
though the finished product in many cases had to be transported by 
teams to the railroad, 100 miles distant; but the increased production 
of borax in this country, together with the importation of large 
amounts from Italy, so reduced the price that in a few years most 
of the plants were abandoned. 
About 1800 it was found that the borax crust on most of the marshes 
is a secondary deposit, being derived from the leaching of beds of 
borate of lime in the Tertiary lake sediments that abound in the 
region. This discovery revolutionized the borax industry, for the 
bedded deposits are much more extensive, are more easily accessible, 
and are in a purer condition than the marsh crusts. The marshes 
were abandoned and a mine was established on a bedded deposit at 
Borate, 12 miles northeast of Daggett, San Bernardino County, Cal. 
At the present time this plant, owned by the Pacific Coast Borax 
Company, is the chief producer of borax and boracic acid in this 
country. The value of this deposit led to extensive prospecting in 
various parts of the region and to the discovery, in Death Valley, of 
enormous deposits that far excel those now being worked near Daggett. 
The borax of Death Valley, as well as that near Daggett, occurs in 
a regular stratum, interbedded with the semiindu rated sands and 
clays that make up the bulk of the strata. These beds are generally 
regarded as of Tertiary age, and they are supposed to have been 
deposited in inclosed bodies of water. 
Since the bedded deposits of borax always occur in association with 
strata of this character, it is probable that careful study and search 
will reveal deposits of this nature in localities other than Death Val- 
ley and Daggett. 
For the purpose of locating outcrops of lake beds, and studying 
their relations and contents, the writer made a rapid reconnaissance 
across southern California in the spring of 1900. The trip was too 
hastily made to permit of detailed examinations, or of observations 
much beyond the line of travel, but many facts were found which 
