Geology

A stream of lava
formerly
flowed
over
the bed
of sea,
triturated
recent shells and corals,
baked into
hard white rock.
A precarious matter.
I found
a curious
little stony
Cellaria.
Each cell provided with
a long
toothed
bristle
capable of various
and rapid motions.
Simultaneous,
and can be produced
by irritation.