34 
OUR MINERAL RESERVES. 
The phosphate reserves in the East are not large, and domestic use 
can be found for all this material. 
The States of Florida, Tennessee, and South Carolina have for 
many years been the main source of phosphate rock in the United 
States. The output of Florida, the leading State in phosphate-rock 
production, has about reached its maximum, particularly so far as 
the hard-rock industry is concerned. The land-pebble industry 
continues to show a vigorous growth. 
In Tennessee the brown-rock deposits, which several years ago 
were given but a brief future existence, promise to yield as much or 
more phosphate than has already been extracted from them, as they 
are now worked on a large scale with modern machinery and under 
modern mining methods. Pioneer methods are, however, still em 
ployed in some parts of the brown-rock phosphate regions and are 
attended by a great waste of good material. With the passing of 
the brown and blue phosphate fields into the control of the larger 
fertilizer corporations, which practice modern mining methods and 
have installed expensive plants to treat the mined rock, a gradual 
change has taken place, and the life of the fields is being thereby 
prolonged. 
. The South Carolina field was the first to be exploited on a com 
mercial basis. Though mining has fallen off in this field it is quite 
likely that much rock remains for future use. As the most readily 
accessible material has been removed, the remaining rock will be 
correspondingly expensive to mine. The product, moreover, being 
of medium grade, can not compete with higher-grade rock in the 
manufacture of superphosphate. Hardly any rock is being exported 
from this field at the present time. 
The new western phosphate field was discovered in 1906, and 
although for economic reasons it has not yet produced on a large 
scale, the main production of phosphates in the future will probably 
come from the West, where the principal deposits are located on 
the public domain. Some of the economic reasons that retard the 
development of the western phosphate fields are comparative new 
ness, lack of transportation facilities, high freight rates, and re 
moteness from centers of consumption. 
Since the discovery of the western fields systematic investigation 
has been prosecuted by the Survey, and this work has resulted in 
the discovery of new and important deposits and has greatly added 
to the known extent of the deposits. Lands remaining in Govern 
ment ownership that are known to contain valuable phosphate de 
posits and those that are believed to contain such deposits have been 
temporarily withdrawn from entry. These reserves are located in 
Florida, Idaho, Utah, Wyoming, and Montana. The work of sur 
veying the western phosphate lands is still going on, and it only