to 35
feet in diameter and are scattered promiscuously at intervals of 25 to
150 feet. The surface on which they are built reaches over a
succession of small knolls and ridges with slopes of 4 or 5 degrees.
Most of them are along the sides of a wide, shallow valley draining
northward, and of two or three small tributary depressions coming into
it from either side, though a number are also to be found beyond the
slight watershed which separates this drainage area from that to the
southward. They exist in woods, meadows, and cultivated ground, so
that some of them retain their original form, others are flattened and
widened, while still others are barely traceable. Probably some have
been entirely effaced by plow and harrow.

II. CAVE EXPLORATIONS IN OTHER STATES

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 ov