"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 3½ 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 3½ 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.