In 1902 Kendall
published his monumental work "A System of Glacier Lakes in the
North York Moors." In it he explained how the existence of lakes
and glacial meltwater channels were the result of the moors being
completely surrounded by ice almost 1000ft. thick. The high moorlands
(over 800ft.)were not invaded by icesheets or glaciers and were not
of sufficient height to generate their own icesheets or glaciers.
At the maximum
extent of the last glaciation (Devensian), ice encircled the western,
northern, and eastern sides of N.Y. moors. The Vale of Pickering was
on the southern side. In the west near Coxwold and in the east near
Wykeham the Vale was blocked by ice.
Embayments between ice and higher ground as well as valleys plugged by ice became filled with meltwater from the glaciers and/or run off from the moors. Ice margins lying parallel to the hillsides would produce marginal drainage channels. Sometimes the overflow would come from the icefront itself after having "squeezed out" the lake, e.g. the Bold Venture Channel. There are localities which suggest that meltwater found its way through the ice, leaving eskers, e.g. at Hob Cross. Belcher, a traveller during the 19th. century described the channels as "furrows on the aged cheek where tears have ceased to flow".
The lakes gradually filled, sometimes overflowing so that one lake became an arm of another, e.g. Kildale with Eskdale. The lake overflow could be away from the ice, a direct overflow, or marginal to the icefront, a marginal overflow. According to Kendall, Eskdale lake overflowed via marginal channels into Wheeldale lake which in turn overflowed via the huge direct overflow channel of Newtondale gorge into Lake Pickering, now the Vale of Pickering. Others would overflow cutting a channel leading to another lake.
End of Tour
