26 
CONTENTS. 
PAGE. 
Discussion of theories. 50 
The fossils of the hard rock phosphate deposits. 56 
Source of the phosphoric acid. 58 
Agency by which the phosphate has accumulated. 59 
Relation of the phosphate to the underground water level. 59 
The formation of boulders. 60 
Silica boulders . 60 
Phosphate boulders. 61 
Formed by the replacement process. 61 
Formed by precipitation. 61 
Secondary deposition of phosphate. 62 
Origin of the plate rock. 62 
Localization of the hard rock deposits. 63 
Limitation of the hard rock phosphates. 63 
Physiographic types in central Florida. 63 
The gulf hammock belt. 64 
The hard rock phosphate belt... 64 
The middle Florida hammock belt. 64 
The lake region. 65 
E'conomic relation . 66 
Bibliography . 66 
PLATES. 
Plate No. 
1. Phosphate boulder showing secondary deposition. 
2. Laminated phosphate boulder. 
3. Phosphate rock. x 
4. Teeth of mastodon from the phosphate deposits. 
5. Teeth and foot bone of horse, and teeth of mastodon. 
6. Sharks’ teeth from the phosphate deposits. 
7. Sharks’ teeth from the phosphate deposits. 
8. Phosphate washer and prospect drill. 
9. Phosphate pit after the removal of the phosphate. 
MAPS. 
Map showing the limestone region of Central Florida. 
Map showing the location of the hard rock and land pebble phosphates. 
