32 FLORIDA GEOLOGICAL SURVEY—THIRD ANNUAL REPORT. 
in this section include, aside from the Vicksburg limestones of 
Lower Oligocene age, Upper Oligocene formations of the Apal¬ 
achicola group, Marine Miocene formations, and more or less of 
Pliocene or later materials since all of these formations occur 
in position in the adjacent and uneroded high-lands to the north¬ 
east. In the course of the decay and lowering of the general land 
surface there is naturally more or less shifting of material attended 
probably by the formation of temporary small lakes and streams. 
It is possible that the conditions thus arising may have been suffi¬ 
cient to account for the mixed condition of the materials, the ten¬ 
dency to stratification in places and other evidence of action by 
water without the necessity of assuming a complete resubmergence. 
On this point, however, the writer feels that evidence has not been 
accumulated to form a final opinion. 
FORMATION NAME. 
It is thus apparent that the formation contains a mixture of 
material largely residual from several formations from as early 
as the Lower Oligocene and as late at least as the Pliocene, fur¬ 
ther complicated by subsequent chemical action within the for¬ 
mation itself. The residual material moreover has been reworked 
and in places transported and redeposited. The term Dunnelion 
formation is suggested for these deposits since they were first 
found and are best developed in the vicinity of Dunnelion, Florida. 
EXPLANATION OF PLATE i. 
Fig. i. Phosphate washer for hard rock phosphate in use at pit No. 3, Cummer 
Phosphate Company, Alachua County. 
Fig. 2. Drill for prospection for hard rock phosphate, in use by the Southern 
Phosphate Development Company. The prospect holes are drilled 
through the phosphate formation to the underlying formation, the 
Vicksburg Limestone, which is reached at this locality at a depth 
of 75 to 100 feet. 
Fig. 3. View of incline to pit, in the Croom mine of the Buttgenbach Phosphate 
Company. 
