CONTENTS. 
Page 
Introduction --- 29 
Location of Deposits--- 29 
Problems to be Accounted For----- 31 
Summary of Explanation Offered - 31 
Geology of Southern Florida-—- 32 
Stratigraphic Succession -- 33 
Eocene- 33 
Ocala Formation - 33 
Oligocene - 33 
Tampa Formation- 33 
Alum Bluff Formation- 34 
Pliocene - 41 
Bone Valley Formation--— 41 
Pleistocene -- 44 
Geological Structure---- 45 
Succession and Thickness of Formations as shown by Well Records 45 
Geologic History-— ? - 54 
Period of Deposition of Eocene Sediments —-- 54 
Post-Eocene Period of Emergence and Erosion- 54 
Period of Deposition of Upper Oligocene Sediments-— 54 
Post-Oligocene Period of Emergence and Erosion- 55 
Period of Deposition of Pliocene Sediments- 55 
Changes in Level during Pleistocene Time - 55 
Summary of the Geologic History-- 56 
The Land Pebble Phosphate Deposits- 57 
The Phosphate Bed a Pebble Conglomerate Accumulated under Marine 
or Estuarine Conditions - 58 
Structural Features and Local Details in the Phosphate Bed, the Over¬ 
burden, and the Bed Rock- 61 
Unconformity within the Phosphate Bed- 61 
Irregularities in the Top Surface of the Bed Rock- 63 
Absence of Formations of the Miocene Period- 63 
Lack of Continuity of the Phosphate Bed- 64 
Variations in the Vertical Section--—•--- 64 
Variations in the Phosphate Bed when Traced Laterally- 64 
Variation in Percentage of Phosphate Pebble to Matrix- 64 
Variation and Thickness of the Pebble Conglomerate- 65 
Color of the Rock- 65 
Variation in the Grade- 65 
Sink Holes- 66 
Stream Beds- 66 
Clay Beds Beneath the Pebble Phosphate Conglomerate- 66 
Sand and Fine Pebble Beneath the Pebble Phosphate Conglomerate-- 67 
Iron Rock in the Overburden - 67 
Incoherent Surface Sand and Soil - 68 
Hardpan in the Sub-Soil - 68 
26 
