The Evolution of an English Town | Page 7

Vale seems to have been
capped by ice of a thickness of nearly 100 feet which efficiently
contained the waters of the lake until they overflowed through a
depression among the hills to the south of Malton. If the waters escaped
by any other outlet to the west near Gilling and Coxwold, it can
scarcely have been more than a temporary affair compared to the
overflow that produced the gorge at Kirkham Abbey, as the Gilling
Gap was itself closed by the great glacier descending the Vale of York.
The overflow of the lake by this route, south of Malton, must have
worn a channel down to a lower level than 130 feet O.D. before the ice
retreated from the seaward end of the Vale, otherwise the escape would
have taken place over the low hills blocking the valley in that direction
and the normal course of the drainage of the country would have been
resumed. The southern overflow evidently dug its way through the hills
fast enough to maintain that outlet, and at the present time the narrow
gorge at Kirkham Abbey is only 50 feet above sea level, and the hills
through which the Derwent passes at this point are from 200 to 225 feet
high.
[Illustration: A Map of North-Eastern Yorkshire showing Lake
Pickering during the maximum extension of the ice. The area covered
by ice is left unshaded. The arrows show the direction of the glacier
movements. (Reproduced from the Quarterly Journal of the Geological
Society, by permission of Professor Percy F. Kendall.)]

As the waters of the lake gradually drained away, the Vale was left in a
marshy state until the rivers gradually formed channels for themselves.
In recent times drainage canals have been cut and the streams
embanked, so that there is little to remind one of the existence of the
lake save for the hamlet still known as The Marishes. The name is quite
obviously a corruption of marshes, for this form is still in use in these
parts, but it is interesting to know that Milton spelt the word in the
same way as the name of this village, and in Ezekiel xlvii. II we find:
"But the miry places thereof, and the marishes thereof, shall not be
healed." The ease with which a lake could again be formed in the Vale
was demonstrated in October 1903 after the phenomenally wet summer
and autumn of that year, by a flood that covered the fields for miles and
in several places half submerged the hedges and washed away the corn
stooks.
The evidence in favour of the existence of Lake Pickering is so ample
that, according to Professor Kendall, it may be placed "among the
well-established facts of glacial geology."[1]
[Footnote 1: Quarterly Journal of the Geological Society, vol. lviii. part
3, No. 231, p. 501.]
We have thus an accredited explanation for the extraordinary behaviour
of the river Derwent and its tributaries, including practically the whole
of the drainage south of the Esk, which instead of taking the obviously
simple and direct course to the sea, flow in the opposite direction to the
slope of the rocks and the grain of the country. After passing through
the ravine at Kirkham Abbey the stream eventually mingles with the
Ouse, and thus finds its way to the Humber.
The splendid cañon to the north of Pickering, known as Newton Dale,
with its precipitous sides rising to a height of 300 or even 400 feet,
must have assumed its present proportions principally during the
glacial period when it formed an overflow valley from a lake held up
by ice in the neighbourhood of Fen Bogs and Eller Beck. This great
gorge is tenanted at the present time by Pickering Beck, an exceedingly
small stream, which now carries off all the surface drainage and must
therefore be only remotely related to its great precursor that carved this

enormous trench out of the limestone tableland. Compared to the
torrential rushes of water carrying along huge quantities of gravel and
boulders that must have flowed from the lake at the upper end, Newton
Dale can almost be considered a dry and abandoned valley.
[Illustration: A Diagrammatic View of Newton Dale during the Lesser
Ice Age. The overflow of the glacier dammed lakes at the head of the
dale came down Newton Dale and poured into Lake Pickering.]
At Fen Bogs, where there is a great depth of peat, Professor Kendall
has discovered that if it were cleared out, "the channel through the
watershed would appear as a clean cut, 75 feet deep." The results of the
gouging operations of this glacier stream are further in evidence where
the valley enters the Vale of Pickering, for at that point a great delta
was formed. This fan-shaped accumulation of bouldery gravel is