450 SEWELL : OVERFLOW CHANNEL IN NEWTON DALE. 
on Peak Hills to the south.* Again, the land must have been 
submerged to a great depth in the Pickering valley to allow of 
a lake with a water-line standing from the 700- to the 750-foot 
contour south of Wardell Rigg. May not this submersion 
account for the shaping of the tabular range of hills '. 
On the moor immediately south of Slavey Slack we note 
the following : — 
(a) Large deposit of gravel near the edge of Raindale, 
directly south of Slavey Slack, although on much the same 
level as the moor surrounding (650). This gravelly land is 
cultivated. 
(6) Large deposit of sand between the gravel and Slavey 
Slack. 
In connection with the water level, I may mention a beach 
or terrace found (and I believe the only one in the district) at. as 
far as I can trace, between the 750-775 contour ; it runs due 
north from Wardell Rigg along the western slope of the land, 
which would border to the east the post-Glacial " Wheeldale 
Lake," and must have formed its shore for some considerable 
time, and, unless the sill of Slavey Slack is hidden under many 
feet of peat, bringing it down to this level, we may believe that 
" Lake Wheeldale " drained into and through Newton Dale at 
the level of this beach for a very considerable time, the torrential 
rushes and overflow lake-bursts being at a minimum, while the 
ice-pressure on the land was at its maximum, t 
As the ice receded the power of the melting water would be 
very much increased, and it would not take many years to cut 
down the 250 feet to the sill level at Fen Bogs. No data are, 
* I have traced a large Shap boulder above the 800-foot contour 
lying near the Whinstone quarries at Goathland. Kendall's Lockwood 
Hills, 867 feet ; Basley Wood, 800 feet. Barrow says, " Drift disappears 
above 850 feet." 
t I think it possible that the level of " Lake Wheeldale '* rose at the 
date of its greatest extension to at least 900 feet O.D., overflowing into 
Raindale Head through Slavey Slack, and probably near Stape also ; flood- 
ing the moors to the east it would pour down into the Saltersgate drain- 
age at the north end of Newton Dale, thus preparing the gorge which the 
ice drainage afterwards took advantage of. This might possibly only 
occur when the summer melting of snow took place, and while the regular 
outlets were still blocked with winter ice. 
