Or is it Ewe Crag Slack?
Where the watershed lies between the two slacks is not obvious.
For almost a kilometre the broad depression that crosses the North Cleveland watershed at 236m. asl. on Danby Low Moor, cuts no contour line. To the north it drains into Sandwith Slack then into Haw Beck and the Cleveland Plateau; to the south, it falls into Ewe Crag Slack and Eskdale.
I find it a fascinating place, an almost unique feature on the moors.
10,000 years ago, much of Eskdale was covered by an enormous lake, stretching from Kildale church to Grosmont, both ends dammed up by glaciers. 11 miles long and 400ft deep! The branch valleys of Danbydale, Great and Little Fryupdale, and Glaisdale were also flooded.
The ice sheet never managed to cover the higher ground of the plateau of the North York Moors.
But eventually, the water could not be held back any longer.
In a cataclysmic torrent, it burst out releasing millions of tons of water and cutting the deep gorge that is now Newtondale.
There is no doubt that Ewe Crag Slack is another feature of this glacial landscape, but how it formed has been a matter of some debate. Percy Fry Kendall, writing in 1902, suggested that it had been formed subaerially by the drainage from another glacial lake, centring on Moorsholm, discharging into Lake Eskdale1Jones, R.L. (1971) A contribution to the late quaternary ecological history of Cleveland, North-East Yorkshire, Durham theses, Durham University. Available at Durham E-Theses Online:http://etheses.dur.ac.uk/9095/ Page 114..
This view has been challenged by [Kenneth John] Gregory (1962) who showed that Ewe Crag Slack had a ‘hump profile’ (formed by the uphill movement of water across a divide) and breached a pre-glacial watershed, concluding that its origins were likely to have been sub-glacial rather than sub-aerial2Ibid..
I thought I was clear in my imagination but now …
- 1Jones, R.L. (1971) A contribution to the late quaternary ecological history of Cleveland, North-East Yorkshire, Durham theses, Durham University. Available at Durham E-Theses Online:http://etheses.dur.ac.uk/9095/ Page 114.