mainly the position in which they were originally deposited. Therefore
we need not be surprised to discover that some, at least, of the
excavations are proportionately ancient; and that the Natural Bridges
are the last remaining positive evidence of their former existence and
final collapse. That the Natural Bridges of Missouri mark the
destruction of more ancient caves than the one preserved to geological
history by Virginia's grand attraction, seems quite evident. The greater
age of the rocks indicates the possibility of earlier excavation while
their undisturbed position suggests that destruction resulted, not from
violent earth movement, but from the slow action of agencies requiring
long periods of time.

Before proceeding to a discussion of the caves visited personally for
the gratification of private interest, it is desirable to know what
attention has been given to the subject, incidentally, in the course of
regular official duty on the Missouri Geological Survey.


CAVES DESCRIBED IN THE STATE REPORTS.

Although many unknown caves must yet be discovered in the imperfectly
explored portions of the vast Ozark forests, these finds are already so
numerous as to seldom attract attention according to their just
desserts.

One of the comparatively recent of these discoveries is Crystal Cave, at
Joplin, described on page 566, Vol. VII., Missouri Geological Survey
Report 1894.[1] It was opened in the lower workings of a shaft of the
Empire Zinc Company, and "The entire surface of the cave, top, sides and
bottom, is lined with calcite crystals, so closely packed together as