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.]