into the sides of porous lava or pumice to form a series of
habitations, a chapel, and one that is traditionally said to have
served as a prison. This rock settlement was occupied till the close of
the eighteenth century.

The Grottoes de Boissiere are twelve in number, on the side of the Puy
de Chateauneuf, commanding the road from Saint Nectaire to Marols, Puy
de Dome. They are excavated in the volcanic tufa, and are all much of
the same dimensions; one, however, measures 28 feet by 12 feet, and is
7 feet high. Below the grottoes the slope of the hill is parcelled out
into small fields or gardens by means of walls of stones laid one on
another without mortar, showing that the inhabitants of these caves
lived there permanently and cultivated the ground below their
dwellings. [Footnote: There are others, Les Grottes de Rajah, in the
same mass of rock, with near them an isolated rock carved about and
supposed to have been an idol.] More curious still are the Grottoes de
Jonas on the Couze, also in Puy de Dome, near Cheix. They are in stages
one range above another to the height of from 90 to 120 feet. The face
of the mountain is precipitous, and is of a porous tufa full of holes.
As many as sixty of these artificial caves remain; but there were at
one time many more, that have been destroyed by the fall of the very
friable volcanic rock. It is impossible to determine the period at
which these caves were excavated; they were probably prehistoric to
begin with, but were tenanted during the Middle Ages when--if not
later--the tracks leading to them were cut in the tufa and stairs to
connect the several stages. Then paths were bordered by walls as a
protection, and fragments of the parapet remain. Probably it was during
the English occupation of Guienne which extended into Auvergne, that a
castle and a chapel were sculptured out of the living rock. At the same
time a remarkable spiral staircase was contrived in like manner.