58 THE DATING OF EARLY HUMAN REMAINS.
from other localities we find it to be later than the Mousterian
epoch, and that it passes down into the Low Terrace river
gravels, which yield an arctic fauna and flora, as has been noted
in the journal of this society.
The section exposed along the eastern side of Bolton and
Laughlin's pit at Ipswich, where the skeleton was found, shows
at one end the feather edge of the Chalky Boulder Clay resting
evenly upon the Middle Glacial sands below. Overlying the
Chalky Boulder Clay, and continuing over the outcrop of the
Middle Glacial Sands and down the valley slope, is found the
irregular stony loam of the Trail. Where the Trail overlies the
Boulder Clay it is undoubtedly composed, for the most part at
least, of decalcified Boulder Clay, and in order to prove this 
the Chalky Boulder Clay has been artificially decalcified and
found to leave a similar residue to that of the loam of the Trail.
This is, of course, perfectly true to a certain point. The material
composing the. Trail is not a new creation which has come down
from the skies! But neither is it the product of a still decalci-
fication of the Chalky Boulder Clay without movement or re-
distribution. The loss of bulk due to decalcification would alone
be sufficient to occasion movement. But the sludge action and
churning-up of the superficial deposits at a time subsequent
to the Mousterian epoch, has been very wide-spread. The
Boulder Clay areas have undoubtedly been involved in these
larger movements of re-distribution. In one of the channels
of Trail overlying the Chalky Boulder Clay here, I noted, on
one of the occasions on which I visited these sections, a washed-
out pocket of sand surrounded by the characteristic gyrations
of material drawn out by sludge-action, just as one might twist
round a piece of putty in one's hand. This is just what one
sees overlying a Mousterian drift. The skeleton was found far
beyond the utmost feather-edge of the Chalky Boulder Clay,
at the bottom of one of the channels of this stony loam which
mantles all formations alike.
That is to say, the skeleton was almost certainly an inter-
ment, but in any case it was not found beneath true Boulder
Clay, but under a stony loam which might be merely a local
"run of the bill" of indefinite age, but which in my opinion is
much more probably a part of the. post-Mousterian Trail which
there is some reason for identifying with the Ponder's End stage.