PHOSPHATES. 65 



There are two varieties to be distinguished, a friable, dark 

 colored, porous, calcareous sandstone, and a light gray, friable, 

 siliceous limestone. The former, derived from a siliceous dark 

 blue limestone, weathering into flags from the fraction of an 

 inch up to eighteen inches in thickness, occupies the lower 6 or 

 8 feet of the strata. The gray or upper phosphates are from 10 

 to 25 feet aggregate thickness, though it is not probable that all 

 this thickness of strata is highly phosphatic at any one place. 

 These are derived from a light bluish gray limestone that is 

 often crystalline and that weathers into scales and flags from 

 a fraction of an inch to two or three inches in thickness. 



None of these phosphates, so far as they have yet been in- 

 vestigated, comes up to the grade of the Mount Pleasant rock ; 

 75 per cent, of bone phosphate, though it is quite possible that 

 future careful prospecting will discover them in Alabama. 

 Small quantities of the rock have been mined about a mile west 

 of Veto, on the L. & N. railroad. 



Some 19 well weathered samples from this part of Alabama 

 have been subjected to analysis with the result that 5 contained 

 from 60 to 70 per cent, of bone phosphate; the others varied 

 from 20 to 50 per cent, with one exception, and this contained 

 less than 13 per cent. 



The formations of the Coastal Plain at several horizons, hold 

 beds of phosphatic materials which might well be utilized upon 

 our soils. 



Cretaceous Formation. At the base of the Selma Chalk or 

 Rotten Limestone division of this formation, there is a bed of 

 phosphatic green sand in which occur irregular concretions and 

 nodules of phosphate of lime. 



In the disintegration of this bed the nodules of phosphate are 

 left in considerable quantity scattered over the surface and rep- 

 resent in the aggregate, a very great quantity of the material, 

 since the bed extends nearly across the state near or through Eu- 

 taw, Greensboro, Marion, Hamburg, Prattville, and Wetump- 

 ka. In no place, however, have they been found in sufficient 

 quantity for profitable working. 



On the other hand, the phosphatic green sands of this belt 

 and of that next to be mentioned, are of nearly identical quality 

 with the marls of New Jersey, which have been used with such 



