Archeological Investigations | Page 5

depth is reached where the geological deposits are undeniably of such age as to antedate the possible appearance of man upon the scene. This is not assured until the excavation has reached the original floor, which may be either the bed-rock or the clay left by the eroding stream when its volume had become so diminished from any cause that it was no longer able to keep its channel cleared out. Unless a cave is almost perfectly dry--and few of them are--the bottom can not be reached until all standing or soil water has been drained off.
Notwithstanding the most explicit directions, a stranger without a guide is frequently unable to find a cave unless its position is plainly visible from some well-defined spot. The winding valleys and the multitude of ravines sometimes bewilder even those living among them.
A few definitions of terms, or explanations of statements in the report, may prevent misunderstanding.
"Refuse," "signs," "indications," "evidence," referring to habitation or occupancy, mean mussel shells; animal bones; burned or worked stones; broken pottery; wrought objects of bone or shell; flint implements, chips, or spalls; ashes; charcoal; in short, the material ordinarily found on the site of an Indian village, some or all of which are to be seen where the caverns have been used for shelter.
"Daylight" or "in daylight" is the greatest distance within the entrance to a cavern at which common print may be easily read or the nature of small objects lying on the floor determined with certainty.
"Drip rock," "cave rock," or "cave formation" are general terms including stalactite or stalagmite; also deposits of similar origin coating the walls. Not all of these may be present in the same cavern.
"Roof dust" is a substance, literally "lime sand," produced by the superficial disintegration of the roof or walls. This process is greatly accelerated where lichen or rock moss has gained a root hold on the stone. Roof dust in a dry cavern is the equivalent of stalagmite in a wet one.
"Cave earth" is the loose, loamy material usually found in the front chambers of large caverns. It is made up of roof dust, sand, and silt washed from the interior, outside dust and vegetable matter blown in by the wind, with minute amounts of clay or soil carried in by animals.
"Gravel" in a cavern is seldom noticeably water-worn, but is the angular débris resulting from the continued fragmentation of chert nodules released by erosion of the limestone.
A "rock shelter," or "shelter cave," is a room or recess formed by atmospheric erosion in the face, usually at the base, of a cliff. The depth from front to back, under the projecting or overhanging unremoved bedrock above, is generally much less than the length as measured along the face of the bluff. They are nearly always dry, more or less protected from storms, and when of suitable size and in a favorable location were much used as camping places. They are rather rare in limestone formations but frequent in massive sandstone.
"House mounds" are small, low piles of earth, similar in all respects to those so numerous in southeastern Missouri and southward. Although they are usually described as "standing in regular rows," they are in fact irregularly placed, though seldom as much as 100 feet apart in the same group.
Measurements of caverns explored were made with a tape line; others were estimated by stepping, or in the case of elevations, by sighting, consequently are only approximate, but the figures given will in no case exceed the actual distance.
Specimens reported from caves not excavated were found on the floor, sometimes in situations where no addition of cave earth had taken place since the objects were left there; at other times where they were brought from below by burrowing animals; and, again, where they are exposed in the bed or banks of a drainage channel.
In no cave so far examined has any evidence been found to show that the aborigines occupied any part of it beyond such point as was adequately illuminated from the entrance. No doubt they may, at times, have retreated beyond the reach of daylight and been compelled to dispel the darkness by means of fires; but such instances were rare and of short duration. Statements are sometimes made that specimens, usually flint implements, have been found far, possibly several hundred yards, within the cavern. Such objects do not predicate habitation at that distance; primitive explorers may have lost them. It has been pointed out, too, by Mr. De Lancey Gill, that a wounded animal, taking refuge in a cave and instinctively seeking its dark recesses, may carry in an arrow or spear whose point remains when the shaft has decayed. In the case of a large mammal, such as a bear or a panther, a number of arrow or spear heads might