THE SOILS OF FLORIDA. 
27 
lime sink regions are further evidence of underground solution. The 
extensive shallow lake basins of Leon, Jefferson, Columbia, Alachua, 
Hernando Counties, and elsewhere; are the evidence of advanced 
stages in the degradation of the land surface by underground solution 
which has occurred apparently since the deposition of these deposits 
and has involved their removal largely from the areas in question. 
In the non-limestone sections of the State the erosion is chiefly 
by surface wash and is measured by the development of 
streams and stream valleys. The valley of the Apalachicola River 
has apparently been widened and deepened and shifted to the east 
since the deposition of this material. This is indicated by the bluffs 
along the east border of the river capped by this formation and now 
standing 160 to 200 feet above the river valley. In the non-limestone 
sections, lateral streams have developed giving more or less perfect 
dendritic drainage. This extensive development and branching of 
small streams cutting through these deposits is seen in the northern 
part of Escambia, Santa Rosa, Gadsden and Liberty Counties. In 
most of the other counties the free development of surface streams 
has been more or less interfered with by underground solution. 
The amount of erosion and disintegration to which the formation 
has been subjected is such as to give weight to the view that the 
material accumulated during either Pliocene or early Pleistocene. 
In considering the material, however, we must not lose sight of the 
fact that it has not been proven that this material covering an exten¬ 
sive area, necessarily all belongs to a single formation of the same 
age, since similar processes may have given rise to similar materials 
at various times and places. 
TOPOGRAPHY. 
Notwithstanding that Florida, the second largest State east of 
the Mississippi River, is extensive in area, no point within the State 
is distant from the coast more than 75 miles, and no elevations are 
found exceeding 300 or 310 feet above sea level. Originally, doubt¬ 
less, the topography was comparatively simple, the rise in elevation 
being, with minor exceptions, gradual from the coast inland. How¬ 
ever, as the result of differential erosion and other factors, well 
marked topographic types have developed, and at the present time 
the topography is varied. 
The topographic development has been determined largely by 
the geologic structure, and the key to the topography of the State is 
obtained by observing the distribution of the limestone and the non- 
