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 on the lake bottom.  It must not be supposed that the ore is deposited as a fine mud or sediment.  On the contrary, in this lake ore, as it is called, we have an excellent illustration of what is called concretionary action—­that is, the tendency of matter when in a fine state of division to aggregate its particles into masses about some central nucleus, which may be a fragment of sunken wood, a grain of sand, or indeed a pre-formed small mass of itself.”

It is claimed for this water ore, which is gathered like oysters, that mixed with bog ore and magnetic iron, and smelted with charcoal, the result as obtained is strong, durable and high priced.