g this term to designate the predecessor of any
race or tribe known to history--ever existed in the Mississippi Valley
he would not find in any part of it natural features better adapted
for his requirements than in the Ozark hills. But, so far, not the
slightest trace of his presence has been revealed. Products of human
industry have been reported as occurring at great depths under other
conditions, even at the bottom of the loess; though in all such cases
there is some uncertainty as to the correctness of the observations.
No similar reports have been made in regard to any cave yet explored.
On the contrary, whatever may be the depth of the deposit containing
them, the artificial objects exhumed are uniform in character from top
to bottom; the specimens found on the clay or solid rock floor are of
the same class as those barely covered by the surface earth. Moreover,
when they cease to appear they cease absolutely; the rock was swept
bare, or the clay was deposited, by the stream to which the cave owes
its existence, and each is a part of the original formation. In these
circumstances habitation would be out of the question.

By careful search in the caves and rock-shelters of which the Indian
known to history availed himself, extensive and interesting museum
collections can be made. To find an earlier man it will be necessary
to investigate caverns which he found suitable for occupancy and in
which the accumulation of detritus, from whatever source, has been
sufficient to cover his remains so deeply that they can not be
confused with those of a later period; and it may be necessary, also,
to discover with them bones of extinct animals. Should such a place
exist, it is extremely probable that there will be no outward
indication of the fact.

No examination of a cavern is complete or is to be deemed satisfactory
unless a 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 withou