he 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 marked in the
geological survey maps as covering a space of about two square miles south
of Pickering, but the deposit is probably much larger, for Dr. Thornton
Comber states that the gravel extends all the way to Riseborough and is
found about 6 feet below the surface, everywhere digging has taken place
in that direction. The delta is partly composed of rounded stones about 2
feet in diameter. These generally belong to the hard gritstone of the
moors through which Newton Dale has been carved. Dr. Comber also mentioned
the discovery of a whinstone from the great Cleveland Dyke, composed of
basaltic rock, that traverses the hills near Egton and Sleights Moor, two
miles above the intake of Newton Dale at Fen Bogs.

The existence of this gravel as far towards the west as Riseborough,
suggests that the delta is really of much greater magnitude than that
indicated in the survey map. It has also been proved that Newton Dale
ceased its functions as a lake overflow, through the retreat of the
ice-sheet above Eskdale long before the Glacial Period terminated, and
this would suggest an explanation for the layer of Warp (an alluvial
deposit of turbid lake waters) which partially covers the delta. The
fierce torrents that poured into Lake Pickering down the steep gradient of
this canon would require an exit of equal proportions, and it seems
reasonable to suppose that the go