NORTH-CAROLINA GEOLOGICAL SURVEY. 97 



Sand, 91.000 



Peroxide of iron and alumina, , 4.700 



Lime, 1.000 



Magnesia, 0.7oO 



Potash, 0.230 



Soda, 0.260 



Water, . . 1.500 



Soluble silica, 0.204 



99.634 







The marl, or this variety of green sand at Kingston, is one 

 of the most sandy varieties known. It was regarded as too 

 sandy to require the analysis to which it was submitted ; but 

 as the marl bed only one mile above had been successfully 

 employed as a fertilizer, and appears to be equally charged 

 with this useless element, I was desirous of knowing how this 

 fact could be explained. It will be seen that the nine per 

 cent, of fertilizing matter is really rich in potash, soda and 

 lime, and, therefore, where a heavy dressing is applied, quite 

 a large amount of this matter is added to the soil, and which 

 contains a small quantity of potash. The sulphuric acid was 

 nob determined, but all of these beds contain it, which is no 

 doubt derived from the sulphuret of iron or pyrites, which is 

 always present. 



An unfinished analysis of a parcel taken from a bed which 

 occupies a similar geological position on the plantation of Col. 

 Green, of Craven county, gave : 



Silex or sand, 83.20 



Peroxide of iron and alumina, 9.00 



Lime, 2.31 



Magnesia, 0.50 



Water, 2.60 



It lies beneath a white eocene marl, has a deep green color 

 in the bed, but becomes brown after being exposed to the 

 atmosphere. It has not been used as a fertilizer, but is un- 

 doubtedly richer than the Kingston marl which produces good 

 eifects upon corn. 



A similar composition obtained in the same beds upon the 

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