3 'S FLORIDA GEOLOGICAL SURVEY-SEVENTH ANNUAL REPORT. 
found to contain 40.45% tri-calcium phosphate. A sample of the 
calcareous and phosphatic marl taken from the property of C. A. 
Griscom near Lake Iamonia in Leon County at a depth of 10 feet 
below the surface gave the following analysis. 
Analysis made by the State Chemist, L. Heimburger, analyst. 
Moisture- 
Insoluble matter _ 
Phosphoric acid (P 2 0 5 ) 11.56, equivalent to tricalcium phosphate 
Calcium oxide (CaO) 5.06, equivalent to calcium carbonate_ 
In Hamilton County calcareous and phosphatic sands probably 
of this formation are found exposed in the sinks and along the 
stream beds west and north of Jasper. A limited amount of pebble 
phosphate derived from the same formation, is found in the stream 
beds at Jennings, near the State line. In Columbia County typical 
gray phosphatic and calcareous sands of the Alum Bluff formation 
are seen well exposed at Langston sink about four miles northwest 
of Lake City. A similar rock containing an abundance of light and 
dark colored phosphate pebble is found in Columbia and Bradford 
Counties on Olustee Creek near Lulu. Here also in the small 
streams tributary to Olustee Creek are found quite considerable sec¬ 
ondary deposits of phosphate pebble derived from this rock. Another 
locality in Bradford County in which the phosphatic marls probably 
representing the Alum Bluff formation may be seen is the large sink 
near Brooker. The following section of this sink is from the 
writer’s report on phosphates in the Second Annual Report of this 
Survey, pp. 239-240. 
Section at the sink three miles southeast of Brooker. 
13. Covered and sloping_*- 14 feet. 
12. Cream or light colored marl full,of small shells_ 23C feet. 
11. Yellowish sand matrix holding black pebble phosphate- 5 feet. 
10. Sandy limestone ledge with fossils - % foot. 
9. Yellow sand matrix with pebble phosphate- 4 feet. 
8. Concretionary limestone ledge--- 2 1 / i feet. 
7. Steel gray colored sand-clay oxidizing yellow- 5 feet. 
6. Concretionary ledge containing pebble phosphate-- 1 foot. 
5. Sandy matrix with pebble phosphate- •- - 4 feet. 
4. Concretionary ledge - 5 feet. 
3. Clayey matrix holding black pebble phosphate- 5 feet. 
2. Concretionary ledge--- i /4 feet. 
1. Clayey matrix holding black pebble phosphate- 4 feet. 
Total depth to the water’s edge- 75 feet.. 
— 22.73% 
— 4397 % 
— 25.27%, 
___ 9.03% 
