26 GOLD AND TIN DEPOSITS OF SOUTHERN APPALACHIANS. 
leaving a small amount of red residual soil at the surface. (See PL II.) The granites 
and gneisses are much less affected than the more schistose rocks, but are somewkat decom- 
posed near the surface, the principal change being the conversion of feldspar into kaolin. 
Those pegmatites which are poor in feldspar are fairly resistant to decomposition, and 
some of them outcrop distinctly; but the feldspar-rich varieties are readily affected by 
weathering. In most cases where observed, the porphyritic and tuffaceous rocks have 
been sufficiently silicified to enable them to resist extreme decomposition. The diabase 
dikes very commonly outcrop in the characteristic "nigger-head" fashion, showing that 
the rock has not been greatly decomposed. 
STRATIGRAPHY AND STRUCTURE. 
The broadest features of the structure of this area and its relation to the rest of the 
Appalachian province have been outlined on pages 10-1 1. All the foliated or schistose rocks 
strike in a northeasterly direction, varying from N. 20° E. to N. 65° E., and dip at high 
angles, usually between 45° and 90°, either to the northwest or to the southeast, but 
probably most commonly to the northwest. 
Undoubtedly the best place for studying the structure within the area described is along 
the Kings Mountain Range, particularly in the vicinity of Blacksburg, S. C. The strati- 
graphic relations are much more evident there than elsewhere and furnish the necessary 
kc\ for deciphering the structure. Moreover, the intimate dependence of the distribution 
of the tin deposits on the structure of the Kings Mountain belt warranted the expenditure 
of more time on the examination of the geology of this particular locality than was possible 
in other places. Yet even here the study was so hasty that the writer does not feel justified 
in attempting to enumerate, in exact order, the formations which occur, nor to represent 
their respective attitudes in a sketch. The Kings Mountain belt will be first described 
and remaining portions of the area will be considered later. 
KINGS MOUNTAIN BELT. 
RELATIONS OF THE ROCKS. 
The Kings Mountain Range is made up of nearly all the schistose rocks described in the 
preceding pages. A broad view in the field confirms the idea that many of these rocks 
are of sedimentary origin by revealing a stratigraphie succession characteristic of sedi- 
mentary formations. Impure quartzites, biotite and sericite schists, and partially mar- 
morized limestones, representing original sandstones, conglomerates, shales, and lime- 
stones, are bedded with true sedimentary regularity. At the limestone quarry south of 
Gaffney, S. C, the limestone is seen passing upward into impure quartzite, which is exposed 
in typical development along a road not far to the northeast. On the west bank of Kings 
('reek, near the point where it enters Broad River, a quartz-rich conglomerate with a chloritic 
matrix is exposed. It probably represents a transition into the quartzitic beds which occur 
just above, capping the bluff on the eastern side of the creek. On the summit of Drayton- 
ville Mountain is a similar occurrence of much-metamorphosed conglomerate passing into 
quartzite .a 
Intercalated with these several rocks are layers of iron and manganese ores and bands of 
graphite or graphitic schist. As might be expected, these beds are less persistent and^ 
regular than the strata which inclose them. It is believed that the iron, manganese, and I 
graphite beds represent localized deposits in bogs or swamps, while the sandstones, shales, 
and limestones were deposited in much more extensive basins, possibly in the ocean itself. 
It should be stated here, however, that not all the iron deposits of the Kings Mountain 
belt are attributable to such an origin. 
a Cf. Tuomey, M., Re.pt. Geol. and Agr. Survey South Carolina, 1844, p. 18; Geology of South Carolina, 
1848, p. 77; arid Lieber, O. M., Survey of South Carolina, vol. 2, 1858, pp. 40-42. 
