ECONOMICAL GEOLOGY. 
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readily inferred that there mint be an abundance of clay of all sorts in 
the state. The vast Tertiary and Quaternary tracts of the eastern section 
abound in beds of potter’s clay, lire clay, &c. And among the older for- 
mations also, are numerous seams and beds of kaolin resulting from the 
decomposition of the felspathie rocks. One of the largest of these beds 
is found near Greensboro, a few miles south. It is white and fine — 
grained and is reported to cover several acres; and other smaller beds of 
the same region are represented in the Museum. One of these on a par- 
tial analysis, gives S2 per cent of silica, the residue being mostly alumina. 
Another sample of the same sort, a white, almost impalpable dust, from 
Johnston county, near Clayton, gave silica 67 per cent. Both of these 
and many other specimens, from a number of counties, Chatham, Wake, 
Guilford, &c., have the appearance of what is called sometimes " moun- 
tain meal.” Other specimens of very fine hydrows silicates are often 
brought to the Museum for meerschaum. One of these, from Burke 
county, gave water 15.9 per cent , alumina 44, magnesia 3.8. 
The following analysts of clays were made for the Survey by Dr. 
Genth and Mr, Chatard, his assistant : 
Silicic Acid and Quartz, 56.63 60.93 72.25 S6.47 
Alumina, ., 26.22 26.58 11.28 ) 
Sesquioxide of Iron, 5.93 1.71 3.62 \ 1-1 
Magnesia, 0.00 0.35 1.75 0.47 
Lime, 0.30 0.99 0.00 0.17 
Water, 10.92 9.44 11.10 6.16 
The first is from Harnett county, and represents a large bed of fine, 
purplish clay, at Spout Spring on the Western Railroad. The second is 
from a bed said to be large, near Shoe Heel Depot, Robeson county ; fine 
and white. The other two are from a bed of fine whitish, ash colored 
clay, called Dirt-eater’s Clay, on Major Blount’s farm, in Lenoir county. 
Under this head may be placed the beds of argillite, or pyrophyllite 
slate, — agalmatolite , in the southwest corner of Chatham. This la a 
large deposit belonging to the Huronian series, which has a quite extensive 
range; occurring in Montgomery and other parts of Chatham. If is 
popularly called soapstone, and has the soapy feel of that mineral, but 
contains only 3.02 per cent, of magnesia. This substance has been an 
article of trade to Hew York, on a large scale and for many years. It 
is used in the manufacture of paper,— wall-paper especially, soaps, cos- 
metics, pencils, &c., and for various adulterations. 
