A Day's Elephant Hunting in Essex. 43
lowered in height, and the contours of the old land-surface
defaced and wrecked. Though hidden from sight, sub-
marine England had a history of no little import for the
soils of the future land-surface. At length, on rising
slowly from the sea, as islands and future continents are
rising above the waves to-day, the emerging land appeared
with many of its old valleys and river courses choked up
with sand and gravel and overspread with the moraine of
the ice, its bolder mountain ranges and hills worn or
effaced, its minor contours obliterated. But the greater
watersheds survived the long-protracted waste: they began
to resume their functions in the slowly enlarging area of
the landscape.
Thus the larger of the ancient river valleys began to be
excavated afresh, and so the post-glacial Thames may be
an old river valley in part re-excavated, increasing in
width and depth as time went on.
The Lea, the Roding, the Thames, belong then to the
period which succeeded this great marine submergence.
They were the gradual effect of the atmospheric forces
which are always at work on a terrestrial surface, sculpturing
it with hydrographical contours, and so forming the hills
and valleys of the landscape.
But the land rose from an icy sea. The ice, which had
covered so large a part of the eastern and north midland
counties, retreated to the valleys of the mountain district
of the north of our island. East Anglia and Essex emerged
first from the waters, for here the submergence was only
a few hundred feet. How long the ice of the Chalky Clay
had held possession, excluding the return of vegetable and
animal life, we know not. Nor do we know how long the
land continued to be an island, or a group of islands. It
gradually became poorly stocked with the beginnings of
vegetable life, with a meagre herbaceous vegetation of
mosses and lichens. It was visited sometimes by sea-birds,
and in the severer winters by a few Arctic land animals—
by lemmings, hares, voles, and foxes, crossing the frozen
straits of Dover. It was only by so continuous and per-
sistent a rise of the land as would unite it with the continent
C