296 FLORIDA GEOLOGICAL SURVEY-SEVENTH ANNUAL REPORT. 
eludes a chain of narrow keys and islands lying nearly parallel with 
the western shore, which gives it approximately 128 miles of water 
front. 
The base map of the county, showing the location of roads, 
towns, schoolhouses, churches, dwellings, railroads, streams, etc., 
was made by plane-table traverse as the soil mapping progressed. 
The county was originally plotted into sections, and although these 
are not of uniform size, few containing exactly 1 square mile, the 
base map has been made to conform to these long-established lines. 
The level and undulating type of topography characteristic of 
the Coastal Plain predominates, although in some sections rolling to 
hilly country exists. The highest elevations are found north of 
Wall Springs and about the northern end of Lake Butler. Natural 
drainage is best established in the western part of the county, and 
this section shows the greatest development. At St. Petersburg and 
in the vicinity of Green Springs other well-drained areas are found. 
The low and poorly drained areas known as “flatwoods” are 
most extensively developed southeast of Largo, extending nearly to 
St. Petersburg. These lie only a few feet above sea level and con¬ 
tain numerous water and grass ponds. (See fig. 73.) The few 
streams are small and sluggish, and during times of heavy rainfall 
this low-lying land is inundated and remains in a wet condition 
for a considerable period. South and east of Lake Butler and ex¬ 
tending to the Hillsboro County line is another extensive area of 
poorly drained soils. This differs from the “flatwoods” in the 
southern part of the county in that it contains no water and grass 
ponds, but abounds in swamps and depressed areas which support 
a dense growth of cypress. No cypress trees are found in the 
southern part of the county. 
The shore is indented by many tidewater estuaries and salt 
marshes. The only stream in the county of any importance is the 
Anclote River, which has its source in Pasco County. This is a 
tide-water stream and is navigated by small craft for a considerable 
distance. Lake Butler, the largest body of water within the 
boundaries of the county, is 6 miles long and about a mile wide, and 
has an underground outlet. 
Pinellas County, formerly the western portion of Hillsboro 
County, was organized in November, 1911, and 1 Clearwater, situ¬ 
ated about midway on the western coast on Clearwater Harbor, was 
made the county seat. According to the census of 1910, this town 
