64 FLORIDA GEOLOGICAL SURVEY-SEVENTH ANNUAL REPORT. 
This fact is in accordance with the belief that this area was dry 
land during the greater part or all of the Miocene period. 
LACK OF CONTINUITY OF THE PHOSPHATE BEDS. 
From the prospecting records it seems probable that the con¬ 
glomerate representing the phosphate bed is not continuous over the 
whole area. This is doubtless true and is certainly to be expected. 
The old land surface represented by the bed rock being irregular, it 
is apparent that when submerged the accumulation of the phosphate 
conglomerate would take place in the original valleys and depres¬ 
sions while the higher lands were yet submerged. The materials 
of the phosphate stratum are derived not from the marl immediately 
beneath, since that particular spot was quickly covered by the ac¬ 
cumulation of debris, but rather from nearby marls that were as 
yet exposed to the force of the waves or were subjected to the action 
of stream currents. It. is to be expected, therefore, that there are 
spots and doubtless considerable areas over which a pebble con¬ 
glomerate of sufficient thickness to be workable did not accumulate. 
VARIATIONS IN THE VERTICAL SECTION. 
The phosphate conglomerate is itself by no means uniform in 
vertical section. The variations, however, are such as are of com¬ 
mon occurrence in shallow water deposits. If, as is here assumed, 
the phosphate beds were accumulated at the time of the advance of 
the sea across the land surface, it is apparent that the conditions of 
deposition including depth of the water, force of the waves, and 
proximity to land must have been constantly changing, thus account¬ 
ing for variations in the vertical section. 
VARIATION IN THE BED WHEN TRACED LATERALLY. 
If the lack of continuity of the beds, as well as their variation in 
vertical section, has been accounted for, little in addition need be 
said in regard to their variation when followed laterally, since such 
variations follow as a matter of course. 
VARIATION IN PERCENTAGE OF THE PHOSPHATE PEBBLE TO MATRIX. 
Under the theory here proposed it requires no special explana¬ 
tion to appreciate reasons for extreme variation in the percentage 
of phosphate pebble in the matrix. The fact that the materials of the 
