g the
beauty of Fairy Cave, Mr. Irwin suggested that only a quarter of a mile
further on was another, recently discovered and worthy of a visit,
although small.

In that region of steep hills and sharp-edged rocks, a great amount of
travel can be added to the experience of a tender-foot in a short
distance. The quarter of a mile seemed to stretch out in some mysterious
way as we worked on it, but the variety and abundance of attractions are
more than ample compensation.

The view was fine, including as it did the deep ravine and grassy,
wooded slopes rising three hundred feet above, with here and there a
handsome ledge of marble exposed like the nearly buried ruin of a
forgotten temple of some past age. Scattered about in great profusion
among the broken rock on the surface of these hill-sides we observed a
water deposit of iron ore. It is a brown hematite and in some cases
shows the structure of the bits of wood it has replaced. Since this
region has from the earliest time produced a generous growth of
vegetation, the decay of which has yielded a never-failing supply of
acids to assist in carving the caves and then in their decoration, the
presence of the ore is not difficult to account for. The whole Ozark
uplift being rich in iron, the acidulated drainage waters coming into
contact dissolved and took it in solution, to re-deposit where and when
conditions should be favorable. These conditions were found in the basin
among the hills and along its outlet.

In the Popular Science Monthly of January 1897, a short article by J.T.
Donald, entitled "A Curious Canadian Iron Mine," describes the same
thing going on at the present time in Lac a la Tortue, a small body of
water in the center of a tract of swamp land, which produces the
vegetation necessary to supply the acid required for a base of
operation.

Of the manner of deposition he says: "The solution of iron in vegetable
acid (in which the iron is in what the chemist calls the form of a
protosalt) is oxidized by the action of the air on the surface of the
lake into a persalt, which is insoluble, and appears on the surface in
patches that display the peculiar iridescence characteristic of
petroleum floating on water. Indeed, not infrequently these films of
peroxide of iron are incorrectly attributed to petroleum. These films
become heavy by addition of new particles; they sink through the water,
and in this manner, in time, a large amount of iron ore is deposited o