Although the copper mines of the mound-builders were their most important ones, they had others by which they procured things that were of no less value to them. Of the coal, which constitutes the mainspring of modern civilization, and of iron, its most important adjunct, though existing in unequaled abundance in the country they inhabited, and trodden under foot in their daily vocations, they seem to have been utterly and strangely ignorant. Yet they worked with much labor the mines of mica in North Carolina, from which they procured what was by them highly prized as an ornament; the soap-stone quarries of the Alleghany range, where they obtained material for their domestic utensils and the all-important ceremonial pipe; and those of flint in Ohio and elsewhere, from which came the material out of which the greater number of their tools and weapons were fashioned.
In addition to these, I can assert from my own observation that they worked at least one lead mine in Kentucky, and sank wells from which they obtained petroleum in all our principal oil regions.
As these facts have not been reported by others, and yet are unquestionable, I venture to emphasize them with a few words of description.
Near Lexington, Ky., is a vein of lead ore which is traceable for half a mile or more through cultivated and forest land. The ore is galena in heavy spar, which has resisted the solvent carbonic-acid water that has removed the limestone wall rocks and shows conspicuously at the surface. Thus it attracted the attention of the mound-builders, who seem to have prized the galena only for its brilliancy, as we find it in many of the mounds, but so far we lack evidence that it was smelted. To obtain it in the mine to which I have referred, they made a deep trench along the course of the vein, taking out the ore to the depth of perhaps ten or twenty feet. One hundred yards or more of this trench is now visible, running through forest which has never been disturbed by the whites. Here it is five or six feet deep, and is bordered on either side by ridges of the material thrown out. On these, trees are growing which have reached their maximum dimensions, showing that at least five hundred years have elapsed since the mine was abandoned.
The working of the oil wells by the mound-builders is as plainly proved. When drawn to Titusville by the first successful oil wells, I was struck by the peculiar pitted surface of the soil of the forest which covered the bottom lands of Oil Creek. The pits were ten feet or more in diameter, and two to three feet deep, contiguous, and innumerable. Subsequently I discovered that each of these funnel-shaped depressions marked the site of an ancient well, sunk through the alluvial deposits, but not into the rock.
