30 GOLD AND TIN DEPOSITS OF SOUTHERN APPALACHIANS. 
these rocks contain the first record of life on the earth. It was later shown that the speci- 
mens which he supposed to be fossils were not of organic origin. Lieber, working in the 
late fifties, regarded the Kings Mountain series as Silurian. « Kerr b in 1875 placed the 
Kings Mountain series in the Huronian system and considered the other rocks of the area 
as Laurentian. Becker c and Nitzed concluded that the metamorphic rocks of the cen- 
tral Carolinas were of Algonkian age. 
From the description of these rocks and their structure Dr. C. W. Hayes favors the view 
that they are Cambrian, and hence that the Blacksburg fold is a syncline — one of a series 
to which belong several others known in the region farther west. 
Acquaintance with the rocks occurring to the northwest of this area leads Mr; Arthur 
Keith to believe that the schistose rocks here described belong somewhere between the 
beginning of the Cambrian and the end of the Carboniferous; that the metamorphism 
which affected them took place in or at the close of the Carboniferous, and consequently 
that the unfoliated igneous rocks are post-Carboniferous. 
Satisfactory proof of the presence of fossils in these rocks has never been made, although 
the discovery of organic remains has been several times reported, e 
It seems unlikely that the age of these rocks will ever be determined by biologic evidence, 
because it is doubtful if such evidence, even if it has ever been present, is preserved. It is 
conceivable, however, that some place in the limestone may be found where there has been 
so little alteration that fossils may remain and be identified. 
It is far more probable that the age of the rocks will be determined only by stratigraphic 
methods. Extremely careful study, consisting in tracing formations and gradations in 
character from rocks of known age continuously up to these very rocks, will be required to 
reach final conclusion b}^ lithologic or structural correlation. Any opinion based on no 
more definite stratigraphic relation to known rocks than has yet been found can at best be 
only tentative. 
These metamorphic rocks are in some places on the east overlain by beds of the "Newark" 
system, now regarded as Triassic, showing that these rocks must have been formed and 
rendered schistose before Triassic time. The last intense metamorphism which affected 
the rocks of the eastern United States took place in the Carboniferous period. These rocks 
must therefore be Carboniferous or older. 
Several facts point to pre-Cambrian as the probable age of these rocks. The seemingly 
entire absence of fossils is such an indication. So far as known to the writer, proved Pale- 
ozoic rocks in the Southern Appalachians are by no means so much metamorphosed as the 
schists here described. As stated by Mr. Lindgren, also (p. 120), granite is nowhere known 
in the South intrusive into rocks proved to be Cambrian or younger. Yet the metamorphic 
rocks here described are cut by granite which in many places is little or not at all foliated. 
In the Cranberry quadrangle, about 80 miles to the northwest, folded sediments, somewhat 
metamorphosed in places, and, assigned by Keith to the Cambrian, unconformably overlie 
gneisses, schist, and intrusive granite which appear to correspond in a general way to the 
rocks of the area here concerned. Keith shows that the underlying rocks were much meta- 
morphosed previous to the deposition of the Cambrian./ It seems probable that the rocks 
of this central Carolina region belong to the same pre-Cambrian complex as those in the 
Cranberry district. In support of this view, the porphyritic rocks here described certainly 
cut some of the schists, and corresponding tuffs are interbedded with the schists. As has 
been stated on page 23, Keith considers the porphyries of this region similar to the volcanic 
a Lieber, O. M., Survey of South Carolina, vol. 3, p. 149. 
b Kerr, W. C, Geology of North Carolina, 1875, p. 133. 
c Becker, G. F., Gold fields of the Southern Appalachians: Sixteenth Ann. Rept. U. S. Geol. Survey, 
pt. 3, 1895, p. 260. 
dNitze, H. B. C, Bull. North Carolina Geol. Survey No. 3, 1896, p. 44. 
ed. Lieber, op. cit., vol. 2, pp. 87-88; vol. 3, p. 149; Emmons, E., Geol. Rept. Midland Counties of 
North Carolina, 1856, pp. 60-64; Marsh, O. C, Am. Jour. Sci., 2d ser., vol. 45, 1868, p. 217. 
Geologic Atlas U. S., folio 90, U. S. Geol. Survey, 1903. 
