At 90 feet there was evidence of fire at one side, the ashes and burned earth being 5 inches thick at the wall, and thinning out to a feather edge within 4 feet. This was the last fireplace discovered which may not with certainty be attributed to white men. The yellow earth, presenting no evidence of having been disturbed since originally deposited, reached from the superficial layer of loose dry earth to the bottom of the trench, a depth of 4 feet 8 inches. Below this point the walls were less than 4 feet apart, and the space filled with gravel, as shown in figure 33. This gravel had exactly the appearance of that in gullies on the hills outside, and plainly dates back to the period at which the cave was formed. The stream which aided in the erosion, or which flowed through from some sink hole or other outside opening, carried this gravel into the crevice. Consequently, even if the space between the walls had been ample for dwelling purposes, an attempt to live here when the gravel was being carried in would result in the intending settler having his effects washed out into the river.
At 93 feet the side walls confining the yellow clay narrowed to a little less than 5 feet apart. The upper portion of the one to the left has been eroded into a recess or cavity, forming the chamber above mentioned. The earth on the rock floor in this recess is nowhere more than a foot deep. A section is presented in figure 34.
Fig. 33.—Cross section of Fort Deposit Cave at 90 feet.[ToList]
At 100 feet the room came to an end. The space between the walls was 7½ feet at the floor level and 4 feet at a depth of 4 feet. At 105 feet the nearly vertical walls were only 5 feet apart on the floor; at 112 feet the space increased to 7 feet. A section showed about a foot of loose earth mixed with ashes; 3 feet of yellow clayey earth, rather compact; then gravel and sand. The latter was dug into for a foot, at which level the walls were converging and it was useless to go any deeper. Enough was done, however, to verify the supposition that this stratum was due to the action of running water seeking its outlet at the mouth of the cave.
At 103 feet, at the bottom of the yellow clay and on top of the gravel, was a chalcedony pebble about 2½ inches in diameter. The material is foreign to this locality. It had plainly been used as a hammer stone, and is the only object of human origin found anywhere below the dark earth. There was not the slightest evidence of any disturbance of the clay in which it rested.
Fig. 34.—Cross section of Fort Deposit Cave at 93 feet.[ToList]