ELISHA MITCHELL SCIENTIFIC SOCIETY. 6^ 



The Phosphate Rock of Sampson and Duplin. — The question sug- 

 gested by the above : Whence came the original phosphate rock ? 

 was quickly answered by the discovery in the up-country (in Samp- 

 son, Duplin and Onslow counties,) of continuous beds of phosphate 

 of a similar character, separate and distinct from the lime forma- 

 tion. A gentleman from Duplin county sent me, August 7th, 

 some pieces of dark, gritty phosphate, which he said existed there 

 in a bed in large cakes and lamps. A visit to the location showed 

 that they were the very things we were looking for. This phosphate 

 varies in composition as did the first described, thougli it is mostly 

 richer, on account of the impregnation of the former with carbonate 

 of lime. It contains from 15 to 40 per cent, of coarse sand, 2 to 4 

 per cent, of carbonate oi lime, and from 30 to 60, and even 70 per 

 cent, of phosphate of lime, with smaller amounts of oxide of iron, 

 alumina, magnesia, &c. The lumps occur in continuous horizontal 

 layers, varying in depth Irom the surface to 15, and possibly 20 feet 

 deep, the layer being usually 8 to 16 inches thick. The cakes and 

 lumps have been partially dissolved and rounded at the corners. 

 They are occasionally perforated, though not so frequently, or to 

 anything like the same degree, as the South Carolina phosphates. 

 The unbroken lumps weigh frequently 200 to 500 pounds; there are 

 very few small ones, that is smaller than a hickory nut. The sur- 



t 



face sr.il is a very sandy loam, the subsoil is a stiff or yellowish clay. 

 The phosphate rock is found immediately underneath a stratu n of 

 2 to 4 feet of this clay imbedded in a coarse sand. Underneath this 

 is another stiff, fine-grained, blueish clay. At other places the rock 

 occurs underneath the marl. 



What the extent of these beds is it is impossible to say at present. 

 The rock occurs mostly in the coves along the little creeks, and is 

 exposed in the ditches, creek banks or marl pits, although in some 

 localities it is upon the uplands. The rock of a given locality is of 

 very uniform composition, though it varies considerably mile by 

 mile. We find in this up-country rock corresponding to all of the 

 different grades and qualities of the jjhosphate of the conglomerate 

 beds of Pender and New Hanover. The two rocks can be shown to 

 be similar, when sufficient allowance is made for the changes to 

 which the rebedding has subjected the one and the action of the 

 soil-waters in the porous sand has modified the other. There can 

 be little doubt, then, that the phosphate first describvid came origi- 

 nally from beds similar to those existing to-day in Sampson and 

 Duplin. 



This is not the place to discuss the industrial features of this dis- 



