NORTH- CAROLINA GEOLOGICAL SURVEY. 



Silex, 34.60 



Water, 12.30 



Organic matter, 41 90 



Peroxide of iron, 3.70 



Alumina, 5.10 



Soluble silica, 0.40 



Lime, 0.4S 



Magnesia, 0.27 



Potash 0.13 



Soda, 0.1 



Phosphoric acid, 0.12 



This soil, though exposed in paper in a dry room for two 

 months to the air, contained more water than the preceding. 

 Its composition should be calculated without the water. So 

 it is probable that the phosphoric acid, if obtained and calcu 

 lated from the full proportion of earthy matter, would show a 

 more striking result. But it is evident that there can be no 

 deficiency of this important element, inasmuch as the crop is 

 one which is necessarily rich in phosphates. The depth of 

 this rich vegetable soil varies from 5 to 10 feet, rarely less 

 than five feet. This may be taken too as the usual depth of 

 the soils of this description, not only in Hyde, but in all the 

 eastern counties where swamp and pocosin lands prevail. 



16. There are but few instances on record, where a soil 

 has been under cultivation a century, and still retains its ap 

 parent original fertility. It must of course have lost a large 

 amount of phosphoric acid, potash and lime ; still the crops 

 are equal in measure to what they were when first cultivated. 

 In order to test the value of a soil which had borne a crop for 

 one hundred years, and during the whole period had not re 

 ceived a bushel of manure, I selected a parcel of it at a dis 

 tance from buildings, or from a spot which could not Jiavr 

 received any artificial aid. 



This parcel gave the following result, on submitting it to 

 analysis : 



Silex, 50.00 



Organic matter, 22.20 



Peroxide of iron and alumina, 8.00 



Lime, 0.10 



Magnesia, 0.09 



Potash, . 0.02 



