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boundary of glacial action in this country. Those superficial
deposits which I have formerly alluded to as Drift are mostly
of glacial origin, and sections have been exposed in the imme-
diate neighbourhood of London, as at Muswell Hill and
Finchley, and also on the hills of our county at Theydon
Mount, Buckhurst Hill, Epping, Stondon Massey, Hutton, &c.
I have thought it necessary to lay before you this brief
sketch of the existing knowledge respecting the Glacial Period
because the latter forms an epoch in the life of the earth
from which must be dated the present aspect of our country
and of its living forms, and further, because a large field for
labour here lies before our geological members in attempting
to determine the relative ages of the various Drift deposits of
our own district, and thus contributing our mite towards
erecting the structure of that noble science which regards
"ages as its days."
Although leading authorities arc now agreed that man
existed prior to the Glacial Epoch, the most convincing proofs
that we have of his existence are of inter-glacial and post-
glacial age. The savage predecessors of the various peoples
that have been known to successively inhabit our country
during the historical period—prehistoric man, who roamed
through Britain and dwelt in our caves when the mammoth,
the hippopotamus, the rhinoceros, the reindeer, and other
animals here extinct formed a portion of our fauna, has left
his traces in the rude flint implements of our ancient river
gravels. Our county is situated in that portion of England
which has been most prolific in yielding implements of early
human workmanship belonging to the old stone or Palaeolithic
age, and we are fortunate in having on our southern boundary
the broad alluvium of the Thames, with that of its tributary
streams, such as the Lea and the Roding. The Thames
alluvium stretches, according to Mr. Prestwich, from above
Maidenhead to the sea, varying in width from two to nine
miles, and in thickness from five to fifteen feet. Flint imple-
ments have been found at many places along the Thames
Valley, and quite recently Mr. Worthington Smith has dis-
covered such implements in the valley of the Lea. This
gentleman writes to me:—"Up to the present time I have