SECOND ANNUAL REPORT-STRATIGRAPHIC GEOLOGY. 
55 
While collecting statistics for the Tenth Census Dr. Smith 1 gath¬ 
ered much valuable information relating to the geology of Florida. 
The results of these geological investigations were published in 1881. 
After summarizing the previous literature Dr. Smith presented evi¬ 
dence to show that limestone of Vicksburgian age underlies nearly the 
entire peninsula of Florida. He gave in part its areal outcrop and 
noted the occurrence of Orbitoides mantelli and Pecten poulsoni, and 
other characteristic fossils in exposures of the limestone here called 
Marianna a few miles southeast of Campbellton, at the Big Spring, 
east of Marianna, and at other localities which he does not name. 
From a limestone collected by him six miles from St. Marks, in 
Wakulla County, Heilprin identified Orbitoides mantelli and pro¬ 
nounced the rock to be ‘'Vicksburg,” but the rock at St. Marks is now 
known to belong to the Apalachicola group instead of the Vicksburg. 
Dr. Smith examined a marl which occurs at various points along the 
Gulf coast and decided that it also was of Vicksburg age. He states 
that this marl forms the basis of the "Gulf Hammock" land in the 
coastal counties from Wakulla County nearly to Tampa Bay in Hills¬ 
boro County. In describing the areal extent of the "Vicksburg,” 
Smith included in it large areas of rock which is now known to belong 
to the upper Oligocene or Apalachicola group; for example, the lime¬ 
stone extending along the Suwanee River for many miles, and the 
limestone at Tampa were, on the observations of others, wrongly in¬ 
cluded in the Vicksburg. He called attention to the fact that the 
Vicksburgian limestone is the prevailing rock in the vicinity of Gaines¬ 
ville and that it is often composed largely of Orbitoides mantelli. 
Other localities included in the Vicksburg were Payne's Prairie and 
Ocala. 
In addition to the localities mentioned above, Smith reports lime¬ 
stone of Vicksburg age at Five Oak and Lake City in the northern 
part of the peninsula. At these localities, as in many other parts of 
the peninsula, the formation is overlain by a few feet of younger rock. 
Dr. Dali 2 gives the following summary of localities where the "Vicks¬ 
burg” limestone has been observed: 
It is impracticable with the data yet printed to determine exactly at how 
many of Smith’s localities the country rock belongs to the Orbitoides horizon. 
Some of them, doubtless, will eventually be shown to be of later age, as will be 
indicated later in this summary. Only those where no doubt seems to exist will 
be specified here. In Alachua County it is widespread, having been observed 
by Smith and Dali at Gainesville and westward to and about Archer, though 
in many places overlain by solutionary residium, remnants or even beds of later 
age but moderate thickness. It had been identified at Silver Spring, 6 miles east 
Am. Jour. Sci. (3) xxi, 292-309, 1881. 
Op. cit. pp. 102-103. 
