Cave Regions of the Ozarks and Black Hills

by Luella Agnes Owen

The explanations thus given of the excavation and subsequent refilling and decoration of the limestone caves of Kentucky and Indiana apply equally well to those of other states; but it is to be remembered that at the time of Dr. Owen's report, onyx, the most beautiful and valuable of dripstones, had not yet been discovered in the United States; while now especially fine deposits are known in California, Utah, Missouri, South Dakota and Arkansas; the Missouri supply being exceptionally valuable on account of the marvelous delicacy and beauty of its coloring; nor can it soon be exhausted, as deposits have been found in eight counties and further exploration will no doubt discover more.

Concerning the Subcarboniferous, or Mississippian Series in Part I., Vol. IV., Missouri Geological Survey, Dr. C. R. Keyes says: "In the great interior basin of the Mississippi the basal series is exposed more or less continuously over broad areas, extending from northern Iowa to Alabama, and from Ohio to Mexico."

While this broadly extended series of limestone is honey-combed in many places and all directions by wonderful caverns, those of the Ozark regions in Missouri, although comparatively little known, are well worth knowing, and are possibly the most ancient limestone caves in the world. Of the region in which they occur, Dr. Keyes, in the volume last quoted, says: "The chief typographical feature of the state has long been known in the Ozark uplift, a broad plateau with gentle quaquaversal slopes rising to a height of more than one thousand five hundred feet above mean tide, and extending almost entirely across the southern part of the district. On all sides the borders of this highland area are deeply grooved by numberless streams flowing in narrow gorges. Against its nucleus of very ancient granites and porphyries the Ozark series of magnesian limestone was laid down. Then the area occupied by these rocks was elevated, and around its margins were deposited successively the other members of the Paleozoic. The Ozark region was thus the first land to appear within the borders of the present state of Missouri." He further says: "Although it has long been known that the Magnesian Limestones are older than the Trenton, and that they lie immediately upon and against the Archæan crystallines unconformably, their exact geological age has always remained unsettled. There seems to be but little doubt, however, that part of the series is equivalent to the Calciferous of other regions. It is also pretty well determined that certain of the lower beds, all below the 'Saccharoidal' Sandstone perhaps, are representatives of the Upper Cambrian or Potsdam. These conclusions appear well grounded both upon stratigraphical and faunal evidence. The rocks of the Ozark region have not as yet received the necessary detailed study to enable the several lines of demarkation to be drawn with certainty. This investigation is now being carried on as rapidly as possible, and promises very satisfactory and interesting results in the near future."

"The early geological reports represent the Magnesian Limestone series as made up of seven members. Following Swallow, these may be briefly described in the present connection. Beginning at the top, they are:

First Magnesian Limestone.
First, or Saccharoidal Sandstone.
Second Magnesian Limestone.
Second Sandstone.
Third Magnesian Limestone.
Third Sandstone.
Fourth Limestone."

"The Fourth" Magnesian Limestone, or lowest number of the Ozark series recognized, has its typical exposures along the Niangua and Osage rivers in Morgan and Camden counties.

Professor Swallow, in his Missouri Geological Survey Reports I. and II., 1853 and 1854, says: "Caves, natural bridges and subterranean streams occur in the valley of the Osage and its tributaries." The same authority of forty years ago also mentions that "Some of the grandest scenery in the State is produced by the high castellated and mural bluffs of this (Third Magnesian Limestone) Formation, on the Niangua and the Osage." Another reference to the scenery on these rivers describes it as "Wild and grand, beautiful and unique;" with "gaudy-colored bluffs." In the section on building materials he remarks: "One of the most desirable of the Missouri marbles is in the Third Magnesian Limestone on the Niangua. It is fine-grained, crystalline, silico-magnesian limestone of a light drab, slightly tinged with peach-blossom, and beautifully clouded with the same hue or flesh color. It is twenty feet thick and crops out in the bluffs. This marble is rarely surpassed in the qualities which fit it for ornamental architecture."

The Ozarks in the extreme southern portion of the state are even less known to the world, but the scenery is grand, the climate delightful, and the caves worthy of a visit for themselves alone. The State of Missouri being one third larger than England, and of equal size to Switzerland, Holland, Belgium and Denmark combined, it is not surprising that interesting discoveries are still to be expected.

The climate is so varied on account of the range in latitude and altitude, and the natural resources are so great, the claim has been made that if the State were surrounded by an impassable wall, its citizens need not be deprived of any article necessary to a refined and luxurious mode of living: and according to Mr. Henry Gannett in "The Building of a Nation," the population in 1890 was 73.42 per cent. native whites of native parents, the colored a little less than 6 per cent., and nearly two-thirds of the balance, native born of parents, one or both of whom were foreign.

Although the Ozark region has not yet received sufficient attention to dull its charm for the explorer, the fact has been established that its earliest sedimentary rocks are of the Cambrian Age and still occupy mainly the position in which they were originally deposited. Therefore we need not be surprised to discover that some, at least, of the excavations are proportionately ancient; and that the Natural Bridges are the last remaining positive evidence of their former existence and final collapse. That the Natural Bridges of Missouri mark the destruction of more ancient caves than the one preserved to geological history by Virginia's grand attraction, seems quite evident. The greater age of the rocks indicates the possibility of earlier excavation while their undisturbed position suggests that destruction resulted, not from violent earth movement, but from the slow action of agencies requiring long periods of time.