Scenes and Adventures in the Semi-Alpine Region of the Ozark Mountains of Missouri and Arkansas

by Henry Rowe Schoolcraft

Zinc is abundant, but as the ore is the sulphuret, it is not very valuable. It is not mentioned that calamine, which is the useful ore of zinc, has been found.

As to the geological nature of the country, in which the lead mines are situate, he informs us that "Bellevue abounds in granite;" that the only vein of granite rock in the mine country (as far as he had opportunity to observe) passes across the south-western end of Madison county—runs into Bellevue—is four or five miles wide, and twenty or thirty miles in a direction from south-east to north-west.

The granite is spoken of in another place, (p. 170,) as being a geological phenomenon, as containing imbedded in it or lying upon its surface, gneiss, green stone, porphyry, iron ores, &c.; it is spoken of as a red granite, containing very little mica, and as being used for millstones. It is mentioned as the "only mass of granite known to exist between the primitive ranges of the Alleghany and Rocky mountains," and as being surrounded on all sides, and to an almost immeasurable extent, with secondary limestone.

Again, (p. 193,) the granite is cited as the "old red granite in mountain masses, with some veins of green stone, green stone porphyry, and gneiss;" it is said to terminate in very rough and broken high lands. At page 213, it is mentioned, still again, as giving origin to the river St. Francis, whose "springs gush out among these stupendous piles of red granite." Besides the ores of iron, lead and zinc, "quartz, feldspar, shorl, mica, and graphite are among the minerals furnished by that region," and "green stone, gneiss, and green stone porphyry, are among the larger masses of rock." The green stone, it seems, "is found in large isolated fragments, lying promiscuously among the fragments of granite which have tumbled down from the lofty cliffs above, and is rendered porphyritic by crystals of green and flesh-colored feldspar."

We have no right to doubt that the rock described is granite, as the principal features delineated, correspond with that supposition. As it is described as being solitary, the only granite between the Alleghanies and the Rocky mountains, we are led to ask, is it a portion of the nucleus of our globe, covered on every side, for many hundred miles, with secondary rocks, and here heaving its head through the superincumbent strata, and standing alone? But what are we to conclude of the limestone? We should have liked especially to have had the relations of this limestone with that remarkable granite region pointed out. Does this latter repose on the granite, where it dips obliquely under, as it probably does, in order to find its way beneath the other rocks, and to vindicate its claim to a fundamental position? But, perhaps we are asking more than is reasonable, for, it may be that there are no such sections in the strata as would expose all these facts to view, and enable the observer to decide.

These hints we have dropped, not, we trust, from a captious disposition, but because we have found a real difficulty in conceiving clearly of the geological nature of this limestone, which, it seems, is the basis of the lead-mine country, and therefore it is very important that its characters should be indubitably fixed. We have not been so fortunate as to see Mr. Schoolcraft's specimens; possibly a view of them would have rendered the preceding remarks, in part at least, unnecessary.

Leaving the geological features of the lead-mine district, we proceed to cite some interesting and important facts from Mr. Schoolcraft's work:—"The soil," he remarks, "is a reddish colored clay, stiff and hard, and full of fragments of flinty stone, quartz and gravel; this extends to the depth of from ten to twenty feet, and is bottomed on limestone rock. It is so compact in some places as almost to resist the pick-axe; in others it seems to partake of marl, is less gravelly, and readily penetrated. The country is particularly characterized by quartz, which is strewed in detached pieces over the surface of the ground, and is also found imbedded in the soil at all depths. This is here called blossom of lead. Iron ores and pyrites are also scattered over the surface of the ground, and occasionally lead ore. The mineral productions of the country, in addition to lead, are zinc, iron, ochre, red chalk, saltpetre, sulphur, alum and salt."

The ore (the author remarks) is the lead glance, galena, or sulphuret of lead. It is very rich and beautiful, and specimens in our possession fully confirm Mr. Schoolcraft's account; they have a very broad and perfectly foliated fracture, and a high degree of metallic lustre; they break in cubical fragments, and the minutest portions still retain this form.

We have already observed that large fragments are found loose in the earth: they sometimes weigh four or five pounds; we have such specimens from these mines; they are of a cubical form, and are surrounded, except where they have been broken, by an earthy incrustation.

It is observed that the marly earth thrown out from the pits, enriches the ground, so that in a few years it is covered with a very rank growth of trees, vines, &c., and this is a regular characteristic of old diggings. Innumerable portions of radiated quartz, and sharp fragments of flinty stones are mixed with the clay, and form the first stratum of about fourteen inches. The next is of a red clay, and is four or five feet thick, and less mixed with similar siliceous substances. Then comes a layer of gravel and rounded siliceous pebbles, about one foot thick, containing small portions of lead ore. The thickness of the bed of ore is generally a foot; and the lumps of ore appear to have been rounded by attrition, like common gravel. "This is the character of what is called the gravel ore, and no spars are found accompanying it. The greatest proportion of lead ore is, however, found imbedded in, and accompanied by, the sulphate of barytes, resting in a thick stratum of marly clay, bottomed on limestone rock." They invariably arrive at the rock at the depth of from fifteen to twenty, or sometimes thirty feet; a new process by boring and blasting is now necessary, and most diggers abandon their pits rather than prosecute them at this expense. If, however, as there can be little doubt, the limestone is the real matrix of the lead ore, the time will come when the present diggings will be considered as merely superficial beginnings, and the work will be resumed where hitherto it has been abandoned. It seems that the almost invariable practice of the miners is, to persevere till they strike the rock, and then to go and dig elsewhere; they cannot, if disposed, prosecute the business by levels or galleries, for they are not permitted to carry on their mining except immediately under the surface that is covered by their respective leases, or by twelve feet square, which, if unoccupied, an adventurer may cover by occupancy. Among the substances accompanying the lead, blende and the sulphate of barytes are said to be very abundant; the latter in specimens which we have, is particularly brilliant and white;[24] the quartz is often prettily crystallized, and is so invariable a concomitant of the ore, that the miners, as we have before remarked, give it the meaning appellation of mineral blossom.