Vol. 58.] G@LACIER-LAKES IN THE CLEVELAND HILLS. 52 
the Cleveland Hills, and the constant westerly aberration of the 
courses of the existing streams proves to my mind conclusively that 
in the closing stages of the retreat of the ice in Cleveland, the 
only escape for the water was into the Vale of York. (Some further 
deductions I shall draw in my conclusions.) A very notable instance 
of this aberration is the anomalous behaviour of Bocsbeck, which, 
instead of pursuing its course straight down the great open valley 
to which it clearly belongs, swerves westward through the gorge 
at Slapewath to join Eller Beck (see fig. 17, p. 526).* 
The conditions of drainage set up in Stonegate Beck during the 
maintenance of this overflow are very complex, and it is necessary 
now to return to the Valley of the Esk to obtain a new set of data. 
(5) The Low-Level Phases of Lake Eskdale. 
I suspended my description of the Glacial history of Eskdale at 
the stage at which, by the shrinkage of the ice-lobe which invaded 
the valley of the Murk Esk, Lake Eskdale became confluent with the 
Goathland Lake (p. 509). The overflow would now be by way of 
Fen Bogs, and the lake-level would gradually fall by the cutting of the 
sill down to its actual level, about 525 feet, or perhaps a little lower. 
The discovery of the subsequent events proved a great surprise to 
me. There are along the south side of Hskdale several rock-gorges 
excavated by lake-overflows, some of which are still occupied by the 
River Esk, * made in such relation to the moraines or to the open 
valley as to show that the ice-lobe overriding the northern hills 
must have persisted here after, not merely the mouth of the Esk, 
but practically the whole coast-line of Yorkshire down as far as 
Scarborough, was free of ice. 
Now, just as it will, 1 think, be conceded that a lake-overflow is 
ipso facto proof of a clear fall at or below the level of the outlet, 
similarly a deviation-channel to avoid a moraine-barrier must have 
Since these lines were written I have, with the help of my lamented friend 
the late Mr. J. A. Ridgway (of Beverley), put down a series of boreholes over 
this area. Within the great Tranmire Slack we made a series of four borings 
from south-west to north-east, beside the peat-holes near Roxby-Moor House. 
The first two indicated rock at 11 feet below the surface ; the next passed through 
about 8 feet of peat, and penetrated 4 feet into gravel ; and the fourth, beside the 
stream (on the outer curve of the valley), passed through 10 feet of peat, and 
stopped in gravel at 18 feet beneath the surface. As the ground-level is 
about 630 feet, the rock-floor must lie at an elevation below 612 feet. 
Another set of three borings was put down on the flat watershed, which is at 
about 635 feet O.D. Two of these were beside the stagnant drain which 
connects the northern and southern streams: they were both stopped by 
something hard, after passing through 5 feet of peat and 4 feet of clay. The 
third boring, 25 yards to the east of these, gave peat, sand, and gritty clay, and 
the boring was abandoned in the last material at 17 feet from the surface and 
about 618 O.D. These observations, so far as they go, are in complete corro- 
boration of the conclusions drawn from the two overflows at Stanghow : 
py: that overflow by way of Tranmire was possible at 625 feet, but not at 
300 feet. 
* This fact is referred to by Mr. Barrow in Mem. Geol. Sury. ‘North 
Cleveland ’ 1888, p. 70. 
