talagmite as the water evaporates, and
thus a ring-like crust is produced at a little distance from the spot
where the drop falls. When a ring is once formed, it limits the spread
of the drop, and determines the position of the wall bounding the
little pool made by the drop. The floor of the cave gradually rises by
the accumulation of sand and travertine, and with it rise the walls
and floor of the cup by the deposit of successive layers of stalagmite
produced by the drop percolating into the limestone of the floor which
hardens it still further, but in this peculiar symmetrical way. From
the floor and sides of the cup the water oozes into the softer
limestone around and beneath; but, as in all these limestones, it does
not ooze indiscriminately, but follows certain more free paths. These
become soon lined and finally blocked with stalagmite, and it is
these tubes and threads of stalagmite which afterwards in the
pseudo-fossil represent the diverging rootlets.

[Illustration: A STALAGMITE CAVE.]

Sometimes when two or more drops fall from stalactites close to one
another the cups coalesce (Figs. 2, 3, and 4); sometimes one drop or
two is more frequent than the other, and then we have the form shown
in Figs. 3 and 4; sometimes many drops irregularly scattered form a
large pool with its raised border, and a few drops more frequent and
more constant than the rest grow their "palmetto stems" within its
limit (Fig. 5); and sometimes a number of drops near one another make
a curious regular pattern, with the partitions between the recesses
quite straight (Fig. 6).

I have already referred to the rapid denudation which is going on in
these islands, and to the extent to which they have been denuded
within comparatively recent times. The floors of caves, from their
being cemented into a nearly homogeneous mass by stalagmitic matter,
are much harder than the ordinary porous blown limestone; and it seems
that in many cases, after the rocks forming the walls and roof have
been removed, disintegration has been at all events temporarily
arrested by the floor. Where there is a flat surface of rock exposed
anywhere on the island, it very generally bears traces of having been
at one time the floor of a cave; and as the weather-wearing of the
surface goes on, the old concretionary structures are gradually
brought out again, the parts specially hardened by a localized slow
infiltration of lime resist integration longest and project abo