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.