8 BULLETIN 102, PART 2, UNITED STATES NATIONAL MUSEUM. 
In the United States, therefore, phosphate rock is and must re- 
main the dominant source of fertilizer phosphorus. The chief pro- 
ducer at present is Florida, which contributes normally 75 per cent 
of our annual output of 3,000,000 tons. There this material forms 
three types of deposits, known as rock phosphate, pebble phosphate, 
and soft phosphate; but all are essentially flat-lying, superficial 
beds of solid rock or loose, bowldery material, representing chiefly 
a concentration of phosphatic substance through the superior solu- 
bility and removal of the associated rock. The nature of these de- 
posits enables them to be economically worked by means of large 
open pits, and their position near seaboard affords cheap transporta- 
tion to manufacturing centers such as Savannah, Charleston, Nor- 
folk, and others, as well as ready exportation to Europe. 
Other deposits of interest and value as being within reach of the 
eastern fertilizer centers lie in South Carolina, Tennessee, Ken- 
tucky, and Arkansas, but these are smaller in output as well as in re- 
serves, and, with the exception of those in South Carolina, less 
favorably located than the Florida deposits. All the eastern deposits 
combined, however, would sustain the increasing domestic consump- 
tion but a few decades; and hence unusual interest attaches to the 
discovery in 1906 that a belt of country, later found to extend from 
near Salt Lake City in Utah to Helena, Mont., includes a number of 
beds of phosphate rock. A careful survey of this region by the 
United States Geological Survey has disclosed a measurable ton- 
nage of phosphate rock far greater than known elsewhere in the 
world — and the field is not yet thoroughly explored in its entirety — 
but the material is not high-grade throughout, and the supply, while 
large, is by no means inexhaustible. The western deposits have not 
as yet been worked to any significant extent, owing to the fact that 
there is practically no local demand for fertilizers, while a long and 
costly freight haul walls off eastern markets. Their development 
awaits a local need or exhaustion of eastern deposits, but may be 
accelerated by the successful application of a process now known 
for extracting the phosphoric acid in concentrated form so as to 
reduce the freight on unit values. Possibilities of a local phosphate 
industry are opening up in connection with the manufacture of 
sulphuric acid from waste smelter gases at such near-by mining 
centers as Butte, Mont. 
The War has seriously affected the phosphate-rock industry, prac- 
tically cutting off the exports, which in 1913 amounted to 42 per 
cent of the total production. This burden fell chiefly on Florida, 
from which the great bulk of the exports was shipped; while Ten- 
nessee, in normal times the second largest producer, being little con- 
cerned with exports, has actually had a slight industrial advance. 
The phosphate-rock industry, in general, has suffered an additional 
