rises, as does also the ceiling; one is able to stand erect alongside
of another person. In face of one, the wall is cut perpendicularly and
seems abruptly to close the passage. However, at a few inches above the
soil is a little opening D, formed like the mouth of an oven, and
giving indications of a space beyond. In diameter it is about 1 foot 6
inches; by crawling through this hole, an achievement difficult to
accomplish, as one cannot even use the elbows to work one's way
forward, the explorer descends into a semicircular hall P whose vault
is arched and is supported by two oval pillars, 7 feet high. The hall
is 24 feet deep and 18 feet wide at the entrance, and is rounded at the
further extremity. The soil in this chamber is encumbered with stones
and rubbish thrown in from an opening at R, which seems to communicate
with other subterranean excavations." Nothing was found in these
chambers and passages that could give an approximate date, but in the
upper "abris" was some Gaulish pottery. The water that had half filled
the lower passage is due to the river having been dammed up for a mill,
and so having raised the level considerably. Originally the passage was
certainly dry.

Although this _souterrain refuge_ is curious, yet it does not
present some of the peculiarities noticeable in others--that is to say,
elaborate preparations for defence, by contriving pitfalls for the
enemy and means of assailing him in flank and rear.

The usual artifice for protection was this. The entrance from without
led by a gallery or vestibule to an inner doorway that opened into the
actual refuge. The passage to this interior doorway was made to descend
at a rapid incline, and as it descended it became lower, so that an
enemy entering would probably advance at a run, and doubled, and would
pitch head foremost into a well, from 20 to 30 feet deep, bottle-