II. CAVE EXPLORATIONS IN OTHER STATES[ToC]
INTRODUCTION
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.
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.