PEBBLE PHOSPHATE DEPOSITS. 
6l 
sible that to some such slight oscillations in level accompanied by 
the reworking of the shore deposits may be due the accumulation of 
the conglomerate to a workable depth over the limited area in which 
the bed is minable. 
That such minor oscillations occurred, is not only in the nature 
of the case probable, but is possibly indicated by an unconformity 
found in the phosphate bed, an account of which is given in the para¬ 
graph which follows. 
STRUCTURAL FEATURES AND LOCAL DETAILS IN THE PHOS¬ 
PHATE BED, THE OVERBURDEN AND THE BED ROCK. 
If the view as to the origin of the phosphate deposits here pre¬ 
sented is correct it should be possible to apply the principles involved 
in the explanation of some of the many irregularities in the phos¬ 
phate beds, and in doing so to further test the validity of the theory 
itself. 
UNCONFORMITY .WITHIN THE PHOSPHATE BED. 
The northernmost plant in the land pebble section at the present 
time is that of the Coronet Phosphate Company located in Hillsboro 
County three.miles southeast of Plant City. The following sections 
were observed in pits Nos. i and 2 of this plant. 
Section in pit No. 1, Coronet Phosphate Company. 
1. Pale yellow incoherent sand ___ 4 feet. 
2. Gray indurated sand--- 4 feet. 
3 Conglomerate of phosphate pebble, bone fragments, water 
worn flints and pebbles- 1 to 1V2 feet. 
4. Buff yellow and olive green clay with phosphate pebble-2 to 5 feet. 
5. Yellow clay and marl, “bed rock” at bottom of pit. 
Section in pit No. 2, Coronet Phosphate Company. 
1. Incoherent sand - 6 feet. 
2. Indurated sands_ 2 feet. 
3. Conglomerate of phosphate pebble, bone fragments, water worn 
flints and coral---- PA feet. 
4. Buff yellow and olive green clay matrix in which phosphate pebble 
is imbedded_._ 5 feet. 
The superficial pale yellow sand is of medium fine texture and is 
non-fossiliferous. The indurated gray sand is also non-fossiliferous 
in the upper part. Towards the base, however, this sand grades into 
the conglomerate previously mentioned, the lower one to one and 
one-half feet being a very rich phosphate conglomerate. (No. 3 of 
the sections). 
