Cave Regions of the Ozarks and Black Hills.

by Luella Agnes Owen.

CHAPTER I.

A GENERAL VIEW.

"O'er mountains bright with snow and light, We crystal hunters speed along, While grots, and caves, and icy waves, Each instant echo to our song; And when we meet with stores of gems We grudge not kings their diadems."

--_Thomas Moore._

The southern half of the State of Missouri, and the Black Hills of South Dakota, offer exceptionally delightful regions for the study of caves, or Speleology as it has been named, and the sister sciences of geology and geography at the same time. In fact it is impossible to study either without giving attention to the other two, and therefore, instead of being separate sciences, they are the three branches of a great scientific trinity.

The regions here referred to enjoy the advantage, and at the same time suffer the disadvantage, of being comparatively little known to the ever restless tide of tourists who naturally hail with pleasure the announcement that some easily accessible, and thoroughly charming spot, has escaped their attention altogether, with a marvelous store of attractions which are both extremely old and wholly new.

Each of these regions has a peculiar geological history not repeated in any other portions of the earth's surface: each is blessed with its own peculiar style of beautiful scenery: and each vies with the other and all the world besides for the supremacy of its truly wonderful caves.

Yet it should be well understood that the claims are not based on an unworthy spirit of rivalry, nor any desire to deny the greatness and beauty of already famous members of the Cave family. It is simply an announcement that the family is much larger than has been generally supposed, and the more recently presented members worthy of the full measure of distinguished honors.

The geological authorities of both states have for many years mentioned the beauty and importance of these regions, and urged their claims to public attention, but have been prevented, by the pressure of other duties, from giving to the caves such careful study and full reports as they deserve, as it would have been a pleasure to give, and as has been possible in states of less extent where the general work of the department is more advanced, and the volume of tourist travel created an early demand for scientific explanation.

Without any great difficulty we can understand the process of cave excavation by the action of percolating acidulated water on the limestone, and its subsequent removal as the volume of surface drainage diverted to the new channel gradually increased. But it is not so easy to offer a reason for the varied forms with which the caves are afterwards decorated. Why is it the charmed waters do not leave the evidence of their slow pa.s.sage only in plain surfaces of varying widths, and the stalact.i.tes and stalagmites whose formation we can readily account for? And why do not the deposits take the same forms in all caves with only such variations as would naturally result from differences in topography? The law is written, but in unfamiliar characters that render our reading slow and uncertain. Yet it is conspicuously noticeable that those caves showing the most delicately fragile and wonderfully varied forms of decoration are those traversed by the most sweeping and changeable, or even reversible, currents of air; which might lead to the conclusion that the moisture is sprayed or converted into a light, misty vapor, and then deposited in exactly the same manner as the beautiful frost-work at Niagara: the direction and force of the current determining the location of the frail deposits.

Since the largest and most important caves occur in limestone, a little special attention to the cause of their occurrence there may serve to show that although speleology has only recently received its name and been elevated to the rank of a separate and independent science, it is one of the earth's ancient inst.i.tutions.

Our geologists, who have unearthed many secrets not dreamed of even in Humboldt's "good phylosopy," have settled the question of how the different kinds of caves were formed, according to the character of rocks they are in, or their location and depth, and the natural agencies to whose action they show signs of having been subjected.

Dr. H.C. Hovey, in his "Celebrated American Caverns," says: "In visiting caves of large extent, one is at first inclined to regard the long halls, huge rifts, deep pits and lofty domes, as evidences of great convulsions of nature, whereby the earth has been violently rent asunder. But, while mechanical forces have had their share in the work, as has been shown, the main agent in every case has been the comparatively gentle, invisible gas known as carbonic acid. This is generated by the decay of animal and vegetable substances, and is to a considerable degree soluble in water. Under ordinary circ.u.mstances one measure of water will absorb one measure of carbonic acid; and the eye will detect no difference in its appearance. Under pressure the power of absorption is rapidly increased, until the water thus surcharged has an acid taste, and effervesces on flowing from the earth, as in Saratoga water.

"Rain-water, falling amid leaves and gra.s.s, and sinking into the soil, absorbs large quant.i.ties of carbonic acid. On reaching the underlying limestone, the latter is instantly attacked by the acidulated water in which it is dissolved and carried away.

"It is agreed among geologists, amazing as the statement may seem, that the immense caverns of Virginia, Kentucky and Indiana, including Mammoth Cave itself (the largest of all), were eaten out of the solid ma.s.s of limestone by the slow, patient, but irresistible action of acidulated water."

Professor N.S. Shaler says: "The existence of deep caverns is a sign that the region has long been above the sea."

Through the kindness of Professor C.J. Norwood, Chief Inspector and Curator of the Geological Department of Kentucky, it is possible to quote the first official report made on the caves of that state and published in 1856, in Volume I., Kentucky Geological Survey Reports.

Dr. Norwood says: "Referring to the 'Subcarboniferous Limestone' (now known as the St. Louis group of the Mississippian series), Dr. Owen says: 'The southern belt of this formation is wonderfully cavernous, especially in its upper beds, which being more argillaceous, and impregnated with earths and alkalies, are disposed to produce salts, which oozing through the pores of the stone effloresce on its surface, and thus tend to disintegrate and scale off, independent of the solvent effects of the carbonated water. Beneath overhanging ledges of limestone, quant.i.ties of fine earthy rubbish can be seen, weathered off from such causes. In these I have detected sulphate of lime, sulphate of magnesia, nitrate of lime, and occasionally sulphate of soda. The tendency which some calcareous rocks have to produce nitrate of lime is, probably, one of the greatest causes of disintegration.'"

"Most extensive subterranean areas thus have been excavated or undermined in Edmonson, Hart, Grayson, Butler, Logan, Todd, Christian and Trig. In the vicinity of Green River, in the first of these counties, the known avenues of the Mammoth Cave amount to two hundred and twenty-three, the united length of the whole being estimated, by those best acquainted with the Cave, at one hundred and fifty miles; say that the average width and height of these pa.s.sages amount to seven yards each way, which is perhaps near the truth; this would give upwards of twelve million cubic yards of cavernous s.p.a.ce which has been excavated through the agency of calcareous waters and atmospheric vicissitudes."

Page 169: "On the south side of Green River the platform of limestone forming the descent into Mammoth Cave is two hundred and thirty-two feet above Green River."

"The entrance to the cave, being thirty-eight feet lower than this bed of limestone, is one hundred and ninety-four feet above Green River. In the above two hundred and thirty-two feet there are several heavy ma.s.ses of sandstone, viz.: at one hundred and twenty-five, one hundred and forty-five, one hundred and fifty, one hundred and sixty and two hundred and fifteen feet, but it is probable that most of these have tumbled from higher positions in the hill, as no alterations of sandstone have been observed at these levels in the cave. From an elevation of from two hundred and forty to two hundred and fifty feet, the prevalent rock is sandstone without pebbles, which can be seen extending up to three hundred and twelve feet to the foundation of the Cave Hotel. The united thickness of the limestone beds on this part of Green River, is about two hundred and thirty feet, capped with eighty feet of sandstone.

About midway of the section on this part of Green River, are limestones of an obscure oolitic structure, but no true oolite was observed. Many of these limestones are of such composition as to be acted on freely by the elements of the atmosphere, which, in the form of nitric acid, combine with the earthy and alkaline bases of calcareous rock, and give rise to the formation of nitrates with the liberation of carbonic acid; hence the disintegrated rubbish of the caves yields nitrate of potash after being treated with the ley of ashes and subsequent evaporation of the saline lixivium. The wonderfully cavernous character of the subcarboniferous limestones of the Green River valley, and, indeed, of these particular members of the subcarboniferous group throughout a great part of its range in Kentucky and Indiana, is due in a great measure to this cause, together with the solvent and eroding effects of water charged with carbonic acid. The 'rock-houses' frequently encountered both in this formation and in the limestones of Silurian date, are produced by similar causes; the more easily disintegrated beds gradually crumbling away, while the more durable remain in overhanging ledges. By the oxidation of other elements, sulphates of oxide of iron and alkalies result, which, by double decomposition, with carbonate of lime, give rise to the formation of gypsums which appears in the form of rosettes, festoons and various other imitative forms on the walls and ceilings of the caves. Crystallizations of sulphate of soda and sulphate of magnesia are not uncommon, both in some of the caves and in sheltered situations under shelving rocks."

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 Archaean 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 surpa.s.sed 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 lat.i.tude and alt.i.tude, and the natural resources are so great, the claim has been made that if the State were surrounded by an impa.s.sable 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.

Before proceeding to a discussion of the caves visited personally for the gratification of private interest, it is desirable to know what attention has been given to the subject, incidentally, in the course of regular official duty on the Missouri Geological Survey.

CAVES DESCRIBED IN THE STATE REPORTS.

Although many unknown caves must yet be discovered in the imperfectly explored portions of the vast Ozark forests, these finds are already so numerous as to seldom attract attention according to their just desserts.

One of the comparatively recent of these discoveries is Crystal Cave, at Joplin, described on page 566, Vol. VII., Missouri Geological Survey Report 1894.[1] It was opened in the lower workings of a shaft of the Empire Zinc Company, and "The entire surface of the cave, top, sides and bottom, is lined with calcite crystals, so closely packed together as to form a continuous sheet and most of them of great size, and well formed faces. Scalenohedra as much as two feet long are sometimes seen, and others a foot or more in length are common. Planes or crystal ghosts, sometimes with pyrite crystals, marking stages of growth in the calcite crystals, are often distinguishable. The entire absence of anything like stalact.i.tes is noticeable, and together with the presence of the crystals, show that the cave was completely filled with water during their growth." In the same volume, all those counties in the extreme southwest corner of the state, whose geological age has not heretofore been considered positively determined, are mapped as Lower Carboniferous, and Lower Silurian, with the Coal Measures covering portions of Barton and Jasper and appearing in a few small, scattered spots in Dade, Polk, Green and Christian counties, and some scanty lines of Devonian fringing the edges of the Silurian in Barton and McDonald.

Other State reports make mention of many caves and fine springs, and also several natural bridges worthy of special notice. In Mr. G.C.

Broadhead's report for 1873-1874, he gives a short but interesting chapter on caves and water supplies, in which he says that "Caves occur in the Third Magnesian Limestone, Saccharoidal Sandstone, Trenton, Lithographic, Encrinital and St. Louis Limestone."

"In Eastern and Northeast Missouri there have not been found many large caves in the Encrinital Limestone, but the lower beds of this formation in Southwest Missouri often enclose very large caverns; among the latter may be included the caves of Green County with some in Christian and McDonald. Those in McDonald I have not seen, but they are reported to be very extensive and probably are situated in the Encrinital Limestone."

Under the head of "Special Descriptions" he says: "On Sac River, in the north part of Green County, we find a cave with two entrances, one at the foot of a hill, opening toward Sac River, forty-five feet high and eighty feet wide. The other entrance is from the hill-top, one hundred and fifty feet back from the face of the bluff. These two pa.s.sages unite. The exact dimensions of the cave are not known, but there are several beautiful and large rooms lined with stalact.i.tes and stalagmites which often a.s.sume both beautiful and grotesque life-like forms. The cave has been explored for several hundred yards, showing the formations to be thick silicious beds of the Lower Carboniferous formations."

"Knox cave, in Green County, is said to be of large dimensions. I have not seen it, but some of its stalact.i.tes are quite handsome."

"Wilson's Creek sinks beneath the Limestone and appears again below."

"There are several caves near Ozark, Christian County, which issue from the same formation as those in Green County. On a branch of Finly Creek a stream disappears in a sink, appearing again three-quarters of a mile southeast through an opening sixty feet high by ninety-eight feet wide.

Up stream the cave continues this size for a hundred yards and then decreases in size, and for the next quarter of a mile further it is generally ten by fourteen feet wide. A very clear, cool stream pa.s.ses out, in which by careful search crawfish without eyes can be found."

"There is another cave a few miles south of Ozark, and another ten miles southeast occurs in the Magnesian Limestone."

"In Boone County there are several caves in the Encrinital Limestone.