126 NOKTH-CAKOLINA GEOLOGICAL SURVEY. 



parts of this State. The use of marl has renovated the coun- 

 try, a profitable trade has sprung up which will not only ben- 

 efit the owners of rnarl pits, but that part of the agricultural 

 community who avail themselves of this substance, when it 

 can be brought from a distance to their doors. 



94. The mode of calculating the money value of a marl, 

 is founded upon the fact, that the percentages represent the 

 absolute weights in the compound, thus one per cent, of 

 phosphate of lime is equivalent to one pound in a hundred. 

 This number, one, or one pound multiplied by 20, and then 

 estimated by the value per pound of the substance, gives its 

 value in 100 Ibs. of marl ; or, if there is 2,16 phosphoric acid, 

 the product is 4,32, which multiplied by 5 cents, the value per 

 pound of phosphoric acid gives $2.16,0, or two dollars and 

 sixteen cents, the value of this substance in a hundred pounds 

 of marl. The object to be secured in washing the marl, is to 

 raise the percentage of phosphoric acid sufficiently to make 

 it a merchantable substance, and thereby benefit the agricul- 

 tural community far and wide. 



CHAPTER Y. 



Animal manures Fish Crabs Cancerine composition of fish before and 

 after drying Compost of Crabs- Preservation of the offal of fish at the 

 large fishing establishments. 



95. The best interests of agriculture require a ready 

 and cheap supply of manure. Its prosperity depends upon 

 it. Without fertilizers, it would be impracticable to sustain 

 this branch of business, except in some highly favored districts 

 where the supply has been prodigally provided. A source 

 from whence an immense supply in some localities may be 

 obtained is the ocean. The myriads of fish, for example, 



