72 The Phosphates of America. 



G. No phosphate in workable quantities. 



H. The highest point in the tract very densely grown, big bowlders 

 of phosphate and sandy conglomerate on surface. Fifteen 

 small pockets of phosphate, ending in limestone at a depth 

 of thirteen feet. 



The total acreage covered by these widely scattered PHOSPHATE 

 DEPOSITS was set down at EIGHTY-THREE ACRES, and the character, 

 quantity and composition of the phosphate itself, as shown by 

 the pits dug and by the material extracted from them, were es- 

 timated after experiment to be as follows : 



CHARACTER AND QUANTITY OF PHOSPHATE BED. 



Bowlder material, large and small, after 



screening 13 per cent, of the mass. 



Debris and whitish phosphate, soft and 



plastic 29 " " " 



Sand, clay, flints and waste 58 " " " 



100 



AVERAGE ANALYTICAL VALUE OF THE PHOSPHATES (AFTER SUN-DRYING), 



Bowlders. Debris, etc. 



Phosphoric anhydride (P 2 O 5 ) 37.00 30.00 



Oxides of iron and alumina (clay) 4 . 25 7 . 50 



After this analysis of the bowlder material had been made, the 

 remaining lumps were all broken up with a hammer into pieces 

 averaging l inches in size and very carefully washed, with con- 

 stant shaking on a fourteen-mesh screen held under a stream of 

 water. After being thoroughly dried in the sun, the washed ma- 

 terial was put through a hand-crusher, then ground to the fineness 

 of seventy-mesh, and submitted to analysis. The results, which 

 have a most important bearing on the vexed question as to the form 

 of combination in which the iron and alumina of these phosphates 

 chiefly occur, were in this case as follows : 



Phosphoric anhydride (P 3 O 5 ) 38.10 



Oxides of iron and alumina 1 . 73 



The thickness of the phosphate bed varied in different places 

 from 3| to 27 feet, but was found to have an average of about 8 

 feet. Assuming that this thickness would yield, say, 5000 tons to 

 the acre (a conservative computation), we reach a probable total of 

 415,000 tons for the entire tract, of which, according to the experi- 

 ments summarized above, about fifty-five thousand tons might be 

 high-grade "bowlder," containing, say, eighty per cent, of bone 



