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APPENDIX. 
than if both walls are pure crystaline Gneiss, and it is almost invariably 
the case that when a vein is walled with the kind of shale just mentioned, 
the Mica is so much impregnated with Magnetite as to be unfit for the 
ordinary commercial uses. There is another feature of these granite 
dikes worthy of note. The Feldspar in some of them has been decom- 
posed and constitutes Kaolin. Where the Feldspar is in this condition, 
other things being favorable, the Mica is usually well crystalized and of 
good quality, though other veins, where the vein matter is solid, yield 
largely of Mica of good size and quality. 
The Mitchell county mines when I visited them in the summer of 1873, 
promised good results. Operations were carried on upon some four or 
five mines in the neighborhood of Bakersville, perhaps the most impor- 
tant one being the Sinkhole mine, the property of Messrs. Heap & Clap. 
The vein at this locality is a soft one — the Feldspar being in a decom- 
posed state. Most of the work done upon this vein has been with the 
pick and without blasting. The yield of mica has been large, and the 
quality excellent. The vein is perhaps half a mile in length, and at the 
time of my visit gave no signs of diminishing in depth. If the water can 
be controled it is valuable property. An interesting feature of this mine 
is the ancient work done upon it. Large excavations have been made by 
some ancient race of people of whose history we know nothing. They 
evidently did the work for mica, because the vein does not bear any me- 
talic ore. Moreover, nothing but fragments of mica have been found in 
immense dump-heaps, while the vein yields an abundance of large sized 
mica. The race must have been one possessing a considerable degree of 
civilization, and certainly attached an economical value to the mica. 
There is, however, no trace of evidence as to what use they applied it. 
They were of the race of mound builders, and their occupancy of the 
country could not have been later than the days of the Toltecs. 
I have been informed . that other evidence of old workings exists in 
that section. 
I cannot speak in detail of all, the mines in Mitchell. That section is 
evidently rich in mica. Two mines are mentioned in Yancey as profita- 
ble for working. The mine of Jos. W. Gibbs on south Toe river, about 
eight miles south-east of Burnsville, was not fully open at the time of my 
visit. The vein seemed to be large, some eight or ten feet in thickness, 
and in proportion to the cubic feet worked out yielded one pound of 
trimmed mica to every three and three-elevenths cubic feet of the vein 
worked out. I have recently been informed that Mr. Gibbs is still ope- 
rating with profit upon the mine. 
The Ray mine, situated about four miles south-east from Burnsville, 
