112 FLORIDA GEOLOGICAL SURVEY—‘NINTH ANNUAL REPORT. 
grees C., 35-6% ; at 1020 C, 34-0% ; at 1050 C., 33.2%; at 1080 C., 33.4%; at 1110 
C, 33-8%; at 1140 C., 33-6%; at 1170 C., 33-6%; at 1200 C, 33.7% ; at 1230 C., 
32.8% ; at 1260 C., 34.4% ; at 1290 C, 33.7% ; at 1320 C., 33.5%. A sandy buff 
burning clay which retains an open porous structure at temperatures up to 1320 
degrees C. (2408 degrees F.). May have some use in the manufacture of soft 
porous common building brick. 
FULLER’S EARTH. 
The fuller’s earth deposits which are mined in Gadsden County 
extend into the southwestern part of Leon County and the western 
part of Wakulla County. The known exposures of fuller’s earth 
are found chiefly near the Ocklocknee River in the southwestern 
part of Leon County. That they have not been worked is due 
probably chiefly to the lack of suitable transportation. 
1 
• PHOSPHATE. 
No workable phosphate beds are known in this area. The Alum 
Bluff formation, however, carries some phosphate rock, although 
probably not in commercial quantities. Gray calcareous phosphatic 
sandstone, chiefly as nodules or interrupted layers, are of frequent 
occurrence throughout this area. Occasional samples of this rock, 
derived probably from near the base of the Alum Bluff formation, 
have been found to contain as much as from 50 to 70 per cent of 
calcium phosphate. As a rule, however, the sand rock is much 
lower in phosphate. Hard rock phosphate has been reported also 
from near Wacissa in Jefferson County. 
ROAD MATERIALS. 
The principal road building materials of this area are sandy 
clays and limestones. The clays are very generally distributed over 
the northern part of Leon and Jefferson counties. The limestone, 
as has already been stated, is found chiefly south of the clay belt in 
the southern part of Jefferson and in the eastern part of Wakulla 
counties. At the present time both of these materials are. being 
extensively used, the sand clays for the roads in the northern part 
and the limestone rock for the roads in the. southern part of the area. 
WATER SUPPLY. 
The water supply in this area is obtained from springs and wells. 
The wells from which the city water supply at Tallahassee is taken 
