TALC. 
Various folios issued by the United States Geological Survey have 
contained data relative to North Carolina talc deposits. This material 
has been combined, and forms,, with additional data collected during 
the last field season, the paper presented below. 
TALC DEPOSITS OF NORTH CAROLINA. 
Bv Arthur Keith. 
One of the chief sources of talc in the United States is the series of 
deposits in North Carolina. These are found almost exclusively in 
the mountain region at the western end of the State, but one class of 
rocks in which talc is found appears to a limited extent in the 
Piedmont Plateau as well. 
Talc is a hydrous silicate of magnesia, and is notable for its infusi- 
bility, its softness, and its smooth, greasy feel. On account of these 
characteristics its various uses have been developed. Its infusibility 
fits it for gas tips and vessels which have to stand extreme heat. The 
massive varieties are manufactured into pencils and articles for mark- 
ing. Little of the North Carolina talc is suitable for cutting into 
pencils, practically all of that character coming from the narrow belt 
in Cherokee and Macon counties. When scratched or rubbed against 
any ordinary surface the talc gives a white streak. Its softness also 
renders it easily cut, sawed, or ground into powder. Its unctuous 
nature enables its powder to diminish friction. 
There are two general sources of the North Carolina talc. It occurs 
as a series of lenticular masses and sheets in the blue and white 
Cambrian marbles along the Nantahala, Valley, and Nottely rivers. 
These rocks, termed the Cherokee marble, have a length of about 40 
miles in North Carolina, and are continued in Georgia for a much 
greater distance. The development of talc is much less in Georgia, 
however, than in North Carolina. The second class of talc deposits 
is connected with the bodies of soapstone which are found at many 
more or less separated places in the Archean rocks of North Carolina* 
Bull. 213—03 28 433 
