Part 27

Certain conditions are to be taken into account in deciding whether a cave afforded a desirable permanent shelter to primitive man. It should be accessible; the floor should be dry, at least fairly level, and sufficiently free from large rocks to allow the inmates to move about freely; the entrance should be large enough to permit free passage and to light the interior to a distance that would insure protection from the elements. Temporary shelters or camping places might be deficient in some of these particulars and still be resorted to frequently; but if there were opportunity for choice, a man with intelligence to select a cave in which to live continually would, it is fair to assume, look for one possessing such features.

If such conditions, once established, were free from the mutations of time, the explorer would have but little difficulty in deciding upon a suitable site for his labors. But limestone, more than any other solid rock, is subject to constant erosion, crumbling, and falling; while the soil and loose fragments resulting from such action move downward year by year over the slopes and into any cavities where they can find their way. In the course of centuries the entire aspect of a cave may be so altered as to bear no resemblance whatever to its original appearance. Consequently a careful study must be made of the immediate surroundings, in order to determine what topographical changes may have occurred since the earliest time within which it is probable that man may have existed in that locality. Should the floor, at present, be of solid rock; or covered with only a slight layer of earth; or have a stream flowing over it; or show by marks upon the walls that it is subject to inundation either from adjacent streams or by surface water which finds its way in through sink holes; or be in such situation as to make it apparent that the original bottom was thus flooded in comparatively modern times, even though such may not now be the case--in any such event excavation would be labor wasted. On the other hand, all the necessary requirements for a convenient residence may now be present, and yet result from causes which have begun to operate within the historic period. In other words, there are very few cases in which the present appearance of a cave is to be deemed a certain or even an approximate indication of its actual state a few thousand years ago. There is only one way to determine whether extended excavations may possibly result in satisfactory returns, and that is to sink shafts or run trenches in the superficial deposits.

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INDIANA

The cave region of this State extends from Owen and Morgan Counties to the Ohio River. The caverns and sink holes gradually increase in number and size toward the south, until they culminate in Wyandotte Cave, second only to Mammoth Cave of Kentucky in extent, and in the so-called "valleys" of Harrison County which are in reality nothing but sink holes several square miles in extent. Some of the caverns are described in detail by W.S. Blatchley, the State geologist, in the Twenty-first Annual Report of the Survey (1896). Very few of those mentioned by him are at all suitable for permanent occupancy, though several would afford excellent shelter except in the rainy season, at which time most of them have the floors muddy or perhaps covered with water for weeks in succession. Such as were visited in these explorations will now be taken up in their order.

LAWRENCE COUNTY

ROCK LEDGE QUARRY.--Early in 1903 periodicals mentioned an interesting discovery made at this place. According to the report, workmen in excavating a cut for a railway found an old cave entirely filled with stalagmite matter. In this, 10 feet below the former top of the cave--the cut did not extend to the bottom of the stalagmite--were discovered some bones which were pronounced by "several physicians" to be those of a human being. Among them was a "jaw tooth" (molar) and part of a skull. Correspondence failing to elicit any satisfactory information, a visit was made to the site. The cave could not be traced in either direction from the railway cut; but it had plainly served as an outlet for several large sink holes on the hill above it. Nothing could be learned here regarding the matter except that the objects had been found and were then in the museum of the State University at Bloomington. This place was next visited and the specimens inspected. There were many fragments still imbedded in the matrix, which was travertine rather than stalagmite. No exact determination of them had been made, but only casual inspection was needed to see that none of them could be human. The "jaw tooth" was from a peccary, the "human skull" was the carapace of a tortoise.

SHILOAH CAVE.--It was reported that, although the entrance to this cavern, 7 miles northwest of Bedford, was in a sink hole, the floor was level and accessible. The opening is almost at the bottom of the sink, whose slope is quite steep. After every rain the water runs in; and while the floor is level, as stated, it has a constant stream of water flowing over it and is in absolute darkness.

DONNEHUE'S CAVE.--Although water flows continuously from the entrance, the amount of discharge was said to be small and the cave floor level and covered with earth, while the cave itself was large and well lighted. The approach, however, is quite difficult; the earth is nowhere more than 2 or 3 feet thick, and after a heavy rain the stream extends from wall to wall.

Between Bedford and Donnehue's cave is one, unnamed, at the head of a ravine which was once an extension of the cavern. The opening is of fair size but the floor is of rock and the outflow of water is steady.

Just outside the corporate limits of Bedford, to the south, is an opening in the cliff at the head of a deep ravine, more in the nature of a rock house than of a cave. It would make an excellent shelter for a few persons, being accessible, protected from winds, and close to water. While it may have been so used formerly, the deposit of earth and stone on the floor is very scanty and anything beneath could well be quite modern.

Two caves were reported 2 miles south of Bedford. One is a small opening from which a stream issues, flows across a meadow, and enters the other cave, which is much larger. They are parts of one passage, the roof between these openings having broken down, and the stream is the same which finds its outlet at Donnehue's cave.

Several other caves in the vicinity of Bedford were visited. They are all small and of no importance from an archeological standpoint.

DONNELSON'S CAVE.--"The mouth of the cave is found at the head of a deep gorge worn through the limestone by a good-sized stream which flows from the cave and down the gorge to the broader valley beyond. Many centuries ago the cave extended the full length of the gorge, and the waters of the stream flowed directly from its mouth into the valley. The roof of the underground channel finally became so thin that it collapsed, the gorge was then started, and as the centuries went by grew in length, the cave becoming ever shorter by the continued falling of the roof.

"Three passages open directly into the mouth of the cave. The right hand passage has the level of its floor about 5 feet above that of the entrance, while the opening on the left is 12 feet above the level of the stream and very difficult to enter without a ladder. The middle passage extends straight back from the common vestibule or main entry. The latter is 25 feet long, 21 feet high, and 18 feet wide, but at its farther end is reduced to the narrow middle passage between great masses of limestone. The water in this passage is waist deep and explorations must be made by wading or in a light canoe. One hundred feet within is a magnificent cascade, where the stream rushes and leaps down a narrow passage with such violence that the noise is plainly heard at the entrance.

"The right-hand passage for the first 100 feet is about 10 feet high by 15 wide, with a clay bottom and a roof on a level with that of the vestibule. It then expands into a large room, 230 feet long and 40 feet wide, which lies east and west at right angles to the entering passage. This narrows at the west end to 20 feet, and at one point the outer air flows in through a small opening in the roof. From near the small end of the room a narrow passage starts off to the southward and can be traveled for 200 feet, when it becomes too small for further advance. Along this passage a small stream flows, disappearing through a hole in the floor near the entrance to the larger room. Other than this, both right and left passages leaving the main entry are dry.

"The passage at the left of the main entrance to the cave is about 150 feet long by 20 broad, and contains no points of especial interest." [W.S. Blatchley.]

It may be added to the above description that a heavy rain causes a rapid rise of several feet in the stream through the middle passage.

The cavern is situated 31/2 miles east of Mitchell. It has been fitted up by the State University as an experiment station for the study of underground fauna and flora.

The branch to the right is never entirely dry. Throughout the year water trickles or seeps over the stones and keeps the mud soft and sloppy, while after extremely heavy rains the water may be 2 or 3 inches deep for a short time--enough to keep all the earth washed from the floor for 50 or 60 feet from the entrance.

The northern or left branch presented a smooth, solid floor of rock at the beginning. The roof is about 13 feet above the floor, being a flat stratum broken by a joint-seam along which there is a slight fault. A ledge of friable sandstone 31/2 feet thick lies next below the roof. The disintegration of this gave a dry covering to the clayey earth which covered the floor almost to the extreme edge of the rock overhanging the stream and gradually rose toward the rear, where it entirely filled the space from floor to roof. The distance between the side walls is 8 feet at the mouth. They diverge slightly, and at 65 feet are about 12 feet apart. Here they separate more sharply, forming a chamber 30 feet in diameter, measuring on every side to the contact of the earth and the roof. At the extreme rear a slight wash or depression in the earth revealed the top of a vertical solid wall, thus marking the limit of the cave in that direction. It seems, however, to extend farther to the east and the west than it can now be followed; in fact, the indications are that at one time a considerable cross-cavern extended along this line.

The work of clearing out this branch began at the entrance. The superincumbent earth was removed by a trench whose boundary was the solid rock on each side until the cave widened to more than 8 feet between the walls; then a width of 7 to 9 feet was excavated midway between the sides, the entire trench having a length of 92 feet, or reaching nearly to the vertical wall at the rear. For about 60 feet the earth was removed to the rock floor. At this distance the floor dipped. The bottom of the trench continued to follow the same level it had held to this point, in the belief that the dip in the floor was due to a crevice or slight erosion channel and would soon disappear, bringing the rock to its normal position. This was not the case; several holes were dug, the deepest one 3 feet, into the mingled clay and rock, without finding any evidence of a solid bottom. The conclusion seemed certain that the passage leading from the entrance of the cave to the large room at its farther end was only a tributary or branch of a cross-cave extending in an east and west direction, as intimated above. Prof. Eigenmann, of the State university, reached the same conclusion through surveys not connected with this work. Under the circumstances further digging seemed useless; for if this should be a cross-cave the bottom would probably, almost certainly, be on a level with the stream now flowing through the central passage, while if it should prove to be only a cellar-like deepening, it would not be utilized for a habitation.

At 30 feet from the entrance the accumulated earth had a thickness of 6 feet; from there it rose gradually to the roof at the end.

At 37 feet, in a pocket of coarse sand on the rock floor, such as settles in a gentle current, were four fragments of bone. There is not enough of them to identify with certainty, but they seem to belong to a deer, a turkey, and some bird about the size of a quail.

At 66 feet in, a foot lower than the surface of the bedrock (being 5 or 6 feet beyond the above-mentioned dip), were small fragments or particles of charcoal, or what had every appearance of such. They were in earth that showed the lamination or stratification due to successive water deposits, and had been introduced in the same manner. The entire earth deposit below the sand capping showed this lamination, sometimes horizontal, sometimes curved, proving a long period of deposition. Further evidence of age is found in the travertine, 7 inches thick, that occurs on top of the earth at the back of the cave.

In the absence of all other evidence the specks of charcoal can not be accepted as proof of human life in the vicinity at the time these deposits were forming.

While the work was in progress three students from the university came through the central cave in a small boat, having entered through a sink hole 3 miles away in an air line. At some point of their course they lost their lanterns and made the remainder of the journey in absolute darkness, feeling their way along the walls, dragging or carrying the craft over shallows, and at one place lying flat in the bottom and propelling the boat by applying hands and feet to the roof, which was less than a foot above the water.

MARTIN COUNTY