92 FLORIDA GEOLOGICAL SURVEY SIXTH ANNUAL REPORT. 



VIRGINIA. 



The recently discovered phosphate deposits of southwestern Vir- 

 ginia, if not of sufficient grade and quantity to be of economic value, 

 are nevertheless of much scientific interest. The beds, which con- 

 tain the phosphate nodules and grains, lie near the base of the De- 

 vonian, and are a little less than a foot thick. The highest grade 

 rock at this locality was found to contain 54.97 per cent tricalcium 

 pliosphate, although the average of the rock is of somewhat lower 

 grade. While the phosphate was found. at only two localities, the 

 strata with whicli it is associated were traced for a distance of 

 . twenty miles, and it is probable that additional phosphate localities 



will be discovered.* 



NORTH CAROLINA. 



The phosphate deposits of North Carolina lie in a belt extend- 

 ing from the South Carolina line northwestward to the Neuse 

 River. The area is from 15 to 20 miles wide and lies from 20 

 to 25 miles from the coast. The layer of phosphate rock is said 

 Lo be from 6 to 20 inches thick. The rock occurs in lumps, shading 

 from a light gray to dark green, and varying in size from rocks 

 weighing half -a pound to half a ton or more. Analysis of a con- 

 siderable number of samples indicated that deposits could be se- 

 lected that would run from 28 to 57 per cent tricalcium phosphate. 



Another type of deposits found in North Carolina is that known 

 as conglomerate rock, which was worked to a limited extent from 

 about 1885 to 1899, the rock being ground and applied as raw 

 phosphate to the soil.f This deposit, consisting of coprolites and 

 fish bones has a thickness of from 3 to 5 feet, and in places under- 

 lies a limestone or marl. A sample of the conglomerate as a whole 

 was found to contain only 11. 16 per cent tricalcium phosphate, the 

 balance being chiefly calcium carbonate, silica, iron and aluminum, 

 A number of the coprolites from, the conglomerate ground up and 

 mixed, analyzed about 30 per cent tricalcium phosphate. 



ALABAMA. 



A small amount of phosphate was mined in Alabama in 1887, 

 although operations • were afterwards discontinued. The phos- 



*Phosphate Deposits in Southwestern Virginia, by George W. Stose, U. S. 

 Geol. Siir. Bull. 540-L, 1913. 



tU. S. Geol. Survey, Mineral Resources, 1883 and 1884, pp. 788-793. 



