ECONOMICAL GEOLOGY. 
303 
It will be noted that felspar is the predominant element, and that this 
belongs mainly to the soda section,— probably oligoclase. The rock is 
■evidently capable of resisting the action of the climate indefinitely, as 
there is no visible effect of erosion, in the case of the capitol, in 40 years. 
Other quarries have been opened in the neighborhood of Raleigh, in 
which the gneiss shows the same general characteristics, with differences 
of color, grain, &c. The Henderson Quarry, in Granville county, furn- 
ishes a harder and more quartzose rock, of a darker gray color. There 
are several quarries as far east as Edgecombe and Wilson, near the Wil- 
mington and Weldon Railroad. The former of these was used for the 
foundation courses of the U. S. Post Office in Raleigh, and likewise in 
various structures along the railroad. It is of a slightly greenish-gray 
■color, quite hard, and doubtless durable. 
A fine light colored feldspathic granite, specked with a small per- 
centage of black mica, is quarried in Warren county. Extensive quarries 
have been wrought also near Salisbury, at Dunn’s Mountain. And re- 
cently a very light colored, almost white granite is obtained from the 
same locality, and has been adopted for the superstructure of the post 
office building already mentioned. It is a beautiful stone, of fine and 
uniform grain, dresses well and resembles marble at a little distance. It 
is marred by the occurrence in certain parts of the mass, of minute octo- 
hedral crystals of magnetite, which under the action of the lime of the 
cement, gives it a slight ferruginous stain in patches ; but it is not probable 
that they will affect the durability of the stone. This is a true granite, 
and the ledge is of great extent. The predominant ingredient here also 
is feldspar, partly, at least, of the soda section. A very coarse porphy- 
ritic granite with large crystals of orthoclose, has been mentioned else- 
where as common along the western side of the central granite belt, pass- 
ing a few miles west of Salisbury, across the southern end of Iredell 
county, and reappearing in large force on Long Creek, in the middle of 
Gaston. In places this is a good building stone, while in others, as the 
first named locality, it weathers too readily. A granite of the same gen- 
eral description, that is, coarse and porphyritic, occurs on the lower 
Yadkin (Pedee), in Richmond and Anson. This is of a slightly greenish 
color, contains oligoclase or albite instead of orthoclase, at least in part, 
and forms a very fine and durable building stone. Quarries have been 
opened in many places in the gneiss and granite ledges of the piedmont 
and mountain sections, more especially along the railroads where such 
material is in demand for various engineering structures. The mountain- 
ous ledges of porphyroidal gneiss (augen-gneiss), heretofore described, so 
abundant and conspicuous in Hendersou county, about Flat Rock, Hen- 
