50 THE PALAEOLITHIC DEPOSITS AT HITCHIN.
of water. The section in which undoubted Boulder Clay ap-
peared is here given :—
The high level at which Chalky Boulder Clay was found,
and its absence, or representation by material derived from it, at
lower levels, in borings nearer the centre of the channel, suggests
to Mr. Reid the conclusion that "the channel was, to a large extent
excavated or re-excavated after the deposition of the Boulder Clay,
as was the case at Hoxne."
The ancient river alluvium is entirely overlapped and hidden
by the overlying Palaeolithic brick earth. The trend of the buried
channel is from south to north, and follows the general slope of
the ground, and the course of existing streams. The stony
brick earth yielded scarcely anything but Palaeolithic implements,
and the ancient alluvial deposits below, though full of plants and
shells, were without any trace of man. The mammalian remains
all came from the whitish marl and silt immediately below the
Palaeolithic brickearth. They consisted of Ursus, Equus caballus,
Linn; Rhinoceros; Hippopotamus (a waterworn bone), Cervus
elaphus, Linn; and Elephas primigenius, Blumb.
Mr. Reid notices the striking general similarity between the
beds at Hoxne and at Hitchin, and remarks that in each locality
the same story is told. In his own words :—
" Some time after the passing away of the ice, the land stood
higher than now, so that the streams had a greater fall, and
valleys were cut to a somewhat greater depth. Then the land
sank, and the valleys became silted up with layer after layer of
alluvium, to a depth of at least 30ft., the climate remaining
temperate. The next stage, when an Arctic flora re-appeared,
is only represented at Hoxne. The third stage in the in-filling
of the valleys is shown in the curious unstratified decalcified