134 NORTH-CAROLINA GEOLOGICAL SURVEY. 



Water, 14.640 



Alumina, 52.850 



Protox iron and magnesia, 0.944 



Silica, 39.76 



Lime, 0.398 



Magnesia, O.G50 



It is one of the best fire clays in this country. 



The fusible clays contain lime, iron, potash and soda, all of 

 which vary more or less in the proportions they bear to" the 

 alumine. 



The bed of clay which has been refered to, as forming one 

 of the strata in the series of coast deposites, appears to exist 

 in an uncommon state of purity upon Bogue sound. It is 

 readily moulded and forms a very firm mass on drying ; its 

 grain and texture is very fine and is free from irregular lumps 

 or regular concretions. It is, therefore, homogeneous, and is 

 well adapted for fire-brick, tiles, etc. and may also be em- 

 ployed for door knobs. It is composed of 



Water, 5.70 



Silex, 67.40 



Protoxide of iron, 3.70 



Alumina, 23.08 



Lime, , 0.11 



Magnesia, 0.8 



Potash, 0.4 



Soda, : 0.5 



This clay contains but a small percentage of water after 

 being exposed to the atmosphere for several months. It be- 

 comes nearly as firm as a rock. This bed of clay extends 

 over a wide territory, and at many other points I have ob- 

 served that it is equally fine and compact. It is one of the 

 most persistent beds in the tertiary series. A fine variety of 

 it occurs near Halifax. 



Clay is sometimes employed as a fertilizer; those only, 

 however, which are rich in lime or potash can be regarded 

 as of sufficient importance to warrant the expense of hauling. 

 Clays of a composition similar to the foregoing are not adapted 

 to this purpose. 



The late Prof. Johnston, in summing up the qualities of the 



