CONTENTS. 
PAGE. 
Introduction . 27 
Distribution of the hard rock phosphates.. 27 
Distribution of the pebble phosphates. ...; . 23 
Matrix of the hard rock phosphate deposits...... 28 
Gray sands . 28 
Clay lenses . 28 
Flint boulders . 29 
Limestone inclusions . 29 
Pebble conglomerate . 29 
Vertebrate and invertebrate fossils. 29 
Petrified wood . 29 
The phosphate rock...j.. 29 
Boulders . 29 
Soft phosphate. 29 
Fragmentary rock. 29 
Plate rock . 29 
Pebble rock. 29 
Thickness of the phosphate bearing formation. 30 
Amount of hard rock phosphate.. 31 
Formation name . 31 
Local details . 32 
Suwannee county . 32 
Columbia county . 32 
Alachua county . 33 
Marion county . 34 
Citrus county . 35 
Hernando county. 3(3 
Problems to be accounted for. 37 
Summary of explanation. 37 
Acknowledgments . 38 
Discovery of the Florida phosphate deposits. 40 
Beginning of the Florida phosphate mining indusstry. 42 
Investigations of the Florida phosphate deposits. 4:3 
Review of theories previously proposed. 45 
Albert R. Ledoux. 45 
Francis Wyatt. 45 
E. T. Cox. 46 
N. H. Darton. 47 
W. H. Dali. 47 
Walter B. M. Davidson. 47 
N. A. Pratt. 48 
C. C. H. Millar. 48 
George H. Eldridge. 48 
L. C. Johnson. 50 
Lucius P. Brown. 50 
L. P. Jumeau. 50 
