At 120 feet the side walls were only 5 feet apart. At 125 feet they again diverged slightly, and a recess on the left forms a chamber 12 feet across. At 150 feet they had drawn in to 8 feet at the widest interval. A section showed loose dry earth, some of it cemented by drip from the roof until about as hard as lump chalk; then compact clayey earth, also with travertine in small lumps; below this the gravel and sand. The latter, at this point, seems to have been deposited in the last stages of the formation of the cave. Occasionally, along here, a small patch appeared that seemed to be ashes; but none of it was more than 6 inches below the top of the ground, and the substance may not have been ashes at all, but the fine white limestone dust that wears off from the stone. There was nothing in the trench, at any depth, after the chalcedony pebble, that could possibly be due to human intervention, except these small patches of ashes, if ashes they are.
At 165 feet from the entrance the cave made its fourth turn and expanded into a chamber about 15 feet wide. Along the sides of this and in the various crevices opening from it were great quantities of clean ashes, plainly enough thrown there from fires made in the central part. The gravel came to within 3 to 5 feet of the top, being quite irregular. On the gravel was dry clay, seamed and fissured in all directions so that it fell out under the pick in clods like angular pebbles from an inch to 3 or 4 inches across. This was clearly the result of muddy water settling in a hole and thoroughly evaporating. There was also some travertine in small lumps here and there through the clay, and above it was a mass fully 2 feet thick at one side of the trench but running out before it reached the other side. It was porous, almost spongy, and seemed to be the lime dust from the roof and sides cemented by dripping water. Above all this, so far as the trench extended toward the sides of the cave, was an inch to 4 inches of loose, dry, dark earth, which on the left dipped down to the clay, thus replacing the travertine.
Fig. 35.—Cross section of Fort Deposit Cave at 175 feet.[ToList]
At 175 feet the gravel had leveled down and was more or less mixed with clay and sand. Above this was another "mudhole deposit" of clay which had thoroughly dried out and become checked and cracked in all directions. On the right this was covered with travertine slightly mixed with earth and clay; on the left, above it and also at one place within it, was a coarse gritty earth fallen from the roof but not converted into a compact travertine. The section appears in figure 35. At 180 feet the trench was carried to a depth of 6 feet. This exposed a fine clay and sand, or silt, like that deposited in the eddies of streams. Above this was another deposit of "mudhole" material which had thoroughly dried out, checked and cracked in all directions so that it formed angular masses of various sizes, and had then become wet again so that it was now soft and sticky. To the left of this, on the silt also, was a small amount of the gravel. It had the appearance common to a bank of such material on the side of a little stream which has undermined and carried away part of it. Clearly, these three formations were of an age that witnessed the erosion of the cave. Next above them was a stratum of loose dark earth similar to that noticed in the front part of the cavern; but here were found no traces whatever of man's presence. Into the right side of this stratum projected the wedge-like edge of a mass of travertine, which was not traced to a termination. Over all lay a deposit 3 or 4 inches thick of dark, nearly black earth, mixed with ashes. This is quite modern. The section appears in figure 36.
Fig. 36.—Cross section of Fort Deposit Cave at 180 feet.[ToList]
During the Civil War the cave was continuously resorted to by deserters, refugees, moonshiners, fugitives, and "food for powder, dodging the conscript." All these sought shelter in this chamber and behind it, in order that their fires might not be visible from the river. The piles of ashes in the crevices and corners were thrown there by these hiders-out, to get them out of the way. Similar but smaller piles of ashes are to be seen all along as far as the spring, 200 yards from the entrance.