272 S. HAZZLEDINE WARREN,
Had it been a trail of Reading Beds or London Clay dragged
over the Mousterian deposit at High Lodge, no one would have
changed the established relative dating of the two.*
During the foregoing discussion I have not overlooked the
assumption that during the Mousterian period ice might have
pushed out very close to temperate vegetation. But the con-
clusion that it did so needs more proof than I have yet been
able to find, and I am thrown back upon the broad fact that the
fauna and flora of the Magdalenian is more distinctively boreal
than that of the Mousterian.
The problem of a Mousterian ice age should be given critical
consideration because very much hangs upon a correct solution.
If we go backward in time from the Mousterian, the climatic
evidences furnished by the fauna and flora indicate increasing
warmth, and there is certainly no place for a glaciation until
we have gone far below the Chellian.
Prof. A. P. Pavlow (13) has reached a conclusion which is
in part similar to my own, namely, that the Mousterian is not
glacial but interglacial. He, however, correlates the Aurignacian
with the Wurmian, although most authorities consider that
the Aurignacian is the mildest stage of the Later Palaeolithic,
which is another illustration of the unsurpassed divergence of
view upon every important point in our subject.
I would also quote the conclusion of H. Dewey (14) :—" From
the English evidence it cannot be said that Le Moustier man
lived in a sub-arctic climate—all that is known is that his
settlements Were overwhelmed by the partially frozen masses
which swept down from the neighbouring hills." I call these
frozen-and-thawed sludge-deposits by Osmond Fisher's name
of the Trail, and provisionally correlate the Trail with the
Ponders End Stage.
THE SICILIAN STAGE.
While I am scarcely prepared to accept the Deperet system as
a whole, I entertain no doubt of the importance of the Sicilian
stage in particular. The molluscan fauna of the raised beach of
the Mediterranean proves an extremely low water-temperature
at this date, which is approximately contemporary with the
Weybourne Crag at the close of the Pliocene. In fact, it is
the coldest episode yet recognised in the Mediterranean. It
represents a great change from the preceding epoch, and it
was followed by a climate milder than the present.
That is a momentous fact which must be reckoned with in
our theories, and it goes far to justify the Gunzian glaciation of
Penck.
* By " established " one does not mean " unalterable " ; alteration depends on the value
of the evidences. We do not alter the established order on account of the Epsorn or Shooters
Hill sections ; but if anyone wanted two London Clays, are below and the other above. the
Shooters Hill gravel—there they are.