OUTLINES. 
125 
The area of rocks of this series near the southern border of the State, 
on the lower Yadkin (Peedee) is a very coarse grained porphyritic gran- 
ite, (in a portion of which, at least, the felspar is triclinic), intersected by 
a succession of heavy dolerytic dikes. 
In the traps and occasionally the granites ot this series, iron pyrites is 
disseminated in small grains and thin films, and in some of the syenytes 
magnetite is a common constituent, and it is also found occasionally in 
veins of several feet thickness, as in the great ledge above mentioned, in 
which these veins are common, both in Cabarrus and Mecklenburg. 
Besides these and epidote, the most common mineral, specular iron 
occurs in at least one locality in considerable quantity, in a quartzytic 
rock in the upper part of Mecklenburg. Agate and rutile are found in 
Mecklenburg, and agate and opal in Cabarrus. Along the southern edge 
of the belt are many productive veins of pyrites carrying copper and 
gold, in Alamance, Guilford, Cabarrus, Rowan and Mecklenburg. 
If there be any significance in structure or in lithological characters, 
this singular body of rocks seems entitled to be placed at the very base of 
the Archaean age, certainly at the bottom of the Laurentian ; and even 
below these, if there be any older rocks exposed anywhere, — the true 
Azoic or Igneous. In the direction of this notion certainly point the ab- 
sence of stratification, the non-occurrence of limestone, and the great pre- 
dominance of syenytes (mostly hyposyenyte), and other iron-bearing and 
basic rocks. I have only placed them as the lower Laurentian, however, 
since there seems to be a general disinclination to suppose that the primal 
igneous core anywhere shows itself to human inspection. This belt may 
well be characterized as the geological axis of the State. 
The group of rocks just described is bounded on the northwest by a 
series of gneisses and feldspathic and occasionally hornblendic slates, which 
extend westward with little interruption to the Blue Ridge, and, except 
a narrow zone of a few miles breadth along the course of that chain, in- 
cludes the whole mountain region to the flanks of the Smoky Mountains, 
through the greater part of its length. These are considered to belong 
to the Laurentian proper. 
The portion of this series which lies east of the Blue Ridge is the 
largest connected area of Laurentian in the State, and covers not less than 
16,000 square miles. Its resemblance to the Raleigh belt is very marked, 
especially in the southeastern part, which consists of a succession of schists 
and gneisses and slates, for the most part thin bedded, and only occasion- 
ally showing granite-like masses and syenytes, which, however, are gen- 
erally in the form of dikes. There is a narrow tract of coarse granite, 
described by Dr. Emmons as a series of veins, along the southeast margin 
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