GEOLOGICAL AND PREHISTORIC TRAPS. 5
pits, apparently yield a fauna consisting of bones of frog in great
quantity, a lesser number of Microtus agrestis, kindly determined
by Mr. M. A. C. Hinton, and land shells.
Now this same part of the pit is also honeycombed with
badger holes which I have proved down to 15 feet from the
surface, and I obtained one complete skeleton of a badger, which
should be added to the apparent fauna. Some of these holes
remain open, others are in every stage of partial to complete
infilling, passing from the obvious to extreme obscurity where
the infilling would normally pass undetected. Now, although
some of the small bones are encrusted with calcareous deposits,
and from their condition might almost be called "fossil," I
have traced them through infilled and open holes alike and am
fully satisfied that the whole fauna belongs to the burrows and
not to the Glacial deposit, where it would be out of place.
Some of these holes are doubtless very old, and may even be
prehistoric.
Mr. Kennard tells me that there is a skeleton of a wolf in
the Museum of Practical Geology from Glacial Gravel at Blunham,
Bedfordshire, with which were found remains of voles and land
shells, which had gone into the wolf's hole for shelter. The
same authority also informs me that there is a number of species
of land shells that have the habit of passing down cracks in dry
weather, and like the wolf in Glacial Gravel, they do not always
get out again, but find a permanent home in geological deposits
to which they do not belong.
The Eolithic Gravels of Aurillac.—Going farther
afield to invade a foreign country for a moment, another kind
of Stratigraphical trap is illustrated from these deposits. The
original descriptions show these gravels as being interstratified
with the country rocks of the Miocene Period. Much was my
surprise upon visiting the site under the kind guidance of
M. Marty to find that this was not so. As the deposits were
excavated back upon the hillside they were found to abut
against a wall of the country rock, and the Eolithic deposits
did not extend back into the heart of the hill. These deposits
only occupied a narrow bench or shelf in the hillside, and at
the time of my visit they had been totally worked out, and
not a scrap had been left for subsequent examination. Therefore,