I90 FLORIDA GEOLOGICAL SURVEY-SEVENTH ANNUAL REPORT. 
region, while elevated, was subjected to erosion, resulting in an 
irregular surface. In addition, the limestone, being more or less 
soluble, was dissolved in places, forming subterranean caverns, which 
in falling in gave rise to sinks and large basins, further modifying 
the surface. Then, with a period of submergence, there was a de¬ 
position of sedimentary materials (mostly marine) over this irregu¬ 
lar surface, and their emergence followed in time, attended, no doubt, 
by minor changes in the surface by erosion. The sinks and basins 
remained and as the solution of the limestone has continued these 
have enlarged to form ponds and lakes, and even new sinks are form¬ 
ing at the present time. 
In detail the Ocala area consists largely of rolling and low, hilly 
country, intersected by the Withlacoochee River, with its low, flat 
areas and swamps, and by Tsala Apopka Lake. Coming in at the 
north-central boundary of the area is a body of high hammock land 
belonging to the “middle hammock belt” described in the State geo¬ 
logical reports. It consists of irregular bodies of low hills, ranging 
from 90 to 180 feet above sea level, the tops of which are rounded to 
flat, with some depressed basins and rather smooth, long slopes hav¬ 
ing numerous eroded draws or ravines occupied by small streams 
which empty into sinks on the bottom of the slopes. 
These areas of hammock land are not continuous, occurring as 
scattered islandlike bodies in the rolling sand areas of the country. 
They occur in the area in Marion and Sumter Counties, the largest 
being around Ocala, and are upheld by underlying rock formations. 
The greater part of the area is occupied by what is known as the 
“rolling pine lands.” These lands comprise country of irregularly 
distributed elevations and depressions, largely the result of the great 
number of sink depressions caused by the solution of the underly¬ 
ing limestone. The result is a choppy topography, which here and 
there flattens out to gently undulating. A gently undulating belt 
follows that of the high hammocks, the change in elevation being 
only 10 to 20 feet and averaging about 80 feet above the sea level. 
To the west the rolling sandy lands become much mbre choppy and 
higher, and east and north of the Withlacoochee River attain eleva¬ 
tions of 120 feet on the higher points, with some on the western bor¬ 
der north of Dunnellon reaching 150 feet above sea level. South 
and west of the Withlacoochee the surface is very broken, being 
marked by large and deep depressions, the bottoms of which lie from • 
10 to 40 feet above sea level, while the summits of the surrounding , 
hills attain a height of 150 to 220 feet above sea level. 
