44 
FLORIDA STATE GEOLOGICAL SURVEY. 
The principal investigations made by the United States Geo¬ 
logical Survey are those by Johnson (1885, 1893),* Penrose 
(1888), Darton (1891), Dali (1892), Eldridge (1893), Matson 
(1909), Clapp (1909),. Vaughan (1909). In addition a number 
of other members of the National Survey have made notes on the 
Florida deposits in connection with the annual statements of the 
production of phosphate contained in the volumes on Mineral 
Industry. 
The Census Bureau investigations are those made by the 
Tenth Census in connection with the study of building stone, by 
which the low grade phosphates were discovered, and the report 
on mineral industries by the Eleventh Census. This latter report 
contains a chapter on the Phosphates of Florida by Edward 
Willis. The Sixth special report of the Commissioner of Labor, 
1893, is devoted to the phosphate industry of the United States. 
A brief review of the Florida phosphate fields was given in 1911 
by William H. Waggaman, of the Bureau of Soils of the United 
States Department of Agriculture. The investigations of the 
phosphate deposits by the Florida State Geological Survey, on 
which this paper is based, have been made at occasional intervals 
as opportunity was afforded since the organization of the Survey 
in 1907. 
The discovery of the hard rock phosphate in 1888 resulted in 
many private investigations of these deposits. Of these private 
investigators a number have made public reports while others 
unfortunately have made no permanent record of their investiga¬ 
tions. Among the earliest of these private investigators was Dr. 
C. U. Shepard, of Charleston, who examined the phosphates of 
the Withlacoochee River section in connection with the organiza¬ 
tion of the Dunnellon Phosphate Company in 1889 and 1890. 
Among others who examined the hard rock deposits during the 
first few years of mining operations and who have published their 
observations are Albert R. Ledoux (1890), Francis Wyatt (1890, 
*The numbers in parenthesis refer to the date of publication as listed 
In the bibliography, not necessarily to the year in which the investigations 
were made. 
