124 
GEOLOGY OF NORTH CAROLINA. 
the general character of a considerable proportion of the rocks of this 
series. 
Silica, 
Alumina, 
Sesquioxide of iron, 
Magnesia, 
Lime, 
Soda, 
Potassa, 
Loss by heating, . . . 
100.01 
75.92 
14.47 
0.88 
0.09 
0.02 
4.98 
4.01 
0.64 
This analysis is taken from the American Journal of Science and Arts 
for March, 1862. 
The absence of anything like stratification or foliation is conspicuous 
throughout the region. In the northern part of the outcrop in Gran- 
ville county, and in the southern, near the Catawba River, the doleryte 
dikes are of so coarse a texture as to present striated faces of labradorite 
crystals 4 and f- of an inch broad. 
One of the largest terranes or outcrops of a single kind of rock is the 
syenytic ledge which crosses the southeastern side of Mecklenburg, and 
occupies a breadth of several miles along the west side of Cabarrus, be- 
ing traceable for many miles by the huge dark bowlder-like masses which 
stand thick through the forests and fields, many of them 10 to 15 and 20 
feet- in diameter. Another quite extensive outcrop is that of a very 
coarse light-colored, easily decomposed felspathic granite, which crosses 
the railroad a few miles west of Salisbury, in Rowan county, and extends 
southwest many miles into the southern end of Iredell. The crystals of 
felspar which weather out of the rock in great quantities, are often two 
to three inches in length, and frequently twinned. A similar ledge is seen 
also on Long Creek, in Gaston county. Ledges of very coarse pyroxen- 
yte and hornblendyte are common, and one of these in the west side of 
of Guilford county seems to pass into Lherzolyte. And in the tract be- 
yond the Blue Ridge, in Mitchell county, on the Nolech ueky River, 
occurs an enormous ledge of doleryte, extending several miles along the 
river, much of it very coarsely porphyritic, and on the west side of the 
river is a heavy outcrop of coarsely crystalline hornblendic rocks, among 
which is a dark gray mass which seems to be hypersthenyte, and within 
a few miles in three different directions are three chrysolvte hills. 
