THE SOILS OF FLORIDA. 
33 
drainage operations now being carried on by the State make use of 
the channels already cut out to the ’Glades by the largest of these 
streams, continuing and deepening them into the ’Glades. 
Another large area of land imperfectly drained by surface 
streams is found in the northwestern part of St. Lucie and the 
southern part of Brevard Counties. Extensive drainage operations 
by private enterprise are being carried on in this section. Five 
townships lying near the head waters of the St. Johns Riyer in this 
section are being drained by the Felsmere Farms Company. In 
these operations the Sebastian River, which flows into the Atlantic, 
is utilized, the channel being deepened and continued to the un¬ 
drained land. 
The Okefinokee swamp of Southern Georgia and the smaller 
swamps which constitute its southward extension into Florida, in¬ 
cludes a large area lying between the head waters of the Suwannee 
and the St. Marys Rivers to which surface drainage by streams has 
not yet penetrated. Many smaller areas occur throughout the State 
that have not yet been drained by surface streams, the topography 
being immature. 
It is a striking fact that erosion is more rapid in the limestone 
than in the non-limestone sections, and that the limestone country is 
encroaching on the non-limestone country. Evidence of this fact is 
found both in west Florida and in peninsular Florida. In Washing¬ 
ton County the Vicksburg Limestone lies at or near the surface in 
the northern part of the county, but dips in passing to the south. 
In crossing this county from north to south it is observed that an 
escarpment of approximately 100 feet in height marks the line be¬ 
tween the limestone and non-limestone country. The rise to the 
plateau is known locally as Sexton Hill. Orange Hill, Oak Hill and 
other hills are outliers from the plateau. Holmes valley repre¬ 
sents the transition grounds from the limestone country to the 
plateau. The history of the development of the topography of this 
county is easily understood. The limestone country of the northern 
part of the county is slowly encroaching on the non-limestone coun¬ 
try to the south. Similar conditions are found in Jackson County. 
The narrow belt of lake region topography which includes Round 
Lake and other lakes on the St. Andrews Bay and Atlanta Railway 
represents the transition line between the limestone and the non¬ 
limestone sections of this county. 
In the northern part of peninsular Florida the limestones are near 
the surface over a considerable area bordering the Gulf, including 
parts of Suwannee, Columbia, Alachua, Marion, Sumter, Pasco, 
3—Gr 
