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THE SOILS OF FLORIDA. 11 
son County rests upon the Chattahoochee Limestone, the Vicksburg 
being beneath this formation. 
In Gadsden County between the Apalachicola and Ocklocknee 
Rivers the Vicksburg and the succeeding Chattahoochee limestones 
are buried to such a depth beneath later clayey and sandy forma¬ 
tions that they do not appreciably affect the surface topography. It 
should be added, however, that the surface elevation in Gadsden 
County is high, the plateau being approximately 300 feet above sea. 
In the three counties lying next east of Gadsden, Leon, Jefferson, 
and Madison, while the Vicksburg limestone is nowhere exposed, yet 
the Chattahoochee limestone lying above it is occasionally exposed 
and the surface topography shows in the formation of large basins 
through solution and in the occasional formation of sinks, the effects 
of the underlying soluble limestones. The Suwannee River cuts 
through all of the later formations and exposes in its channel and 
valley the upper Oligocene limestones, but does not reach, so far as 
definitely determined, the Vicksburg. The northeastern part of 
Suwannee County and the adjacent part of Columbia County resem¬ 
ble Leon, Jefferson, and Madison Counties in that soluble limestones, 
while only occasionally actually exposed, lie sufficiently near the 
surface to affect the topography, resulting in the formation by solu 
tion of lake basins and sink holes. Over the northern part of Colum¬ 
bia and Baker Counties and thence east to the Atlantic coast the 
Oligocene limestones are buried to such a depth as not to affect the 
topography. At Jacksonville the Vicksburg is buried to the depth 
of 500 to 525 feet beneath later formations. 
In peninsular Florida is found another extensive area, the topog 
raphy and soils of which are influenced either by the Vicksburg 
Limestone itself or by this formation in connection with the overly¬ 
ing upper Oligocene limestones. The Vicksburg is exposed at many 
localities in southern Columbia, Alachua, Levy, Marion, Citrus, 
Sumter and Hernando Counties, and occasional exposures are re- 
t corded in Pasco County and in the northern part of Pinellas 
County.* To the south and east of this area the Vicks¬ 
burg dips beneath later formations. The formation, however, 
affects the surface topography and the soils over a large area bor¬ 
dering its actual surface exposure. All the large section of country 
known as the lake region, owes its characteristic topography, in the 
writer’s interpretation, to the influence of the underlying Vicksburg 
and probably other Oligocene formations. Aside from parts of Su¬ 
wannee and Columbia Counties, and the counties of west Florida 
*Florida Geological Survey, Second Annual Report, page 65, 1909. 
