Vol. 58. ] GLACIER-LAKES IN THE CLEVELAND HILLS. 499 
through another chain of lakes in the direction of a continuous 
drainage, finally reaching Lake Pickering again. 
(1) The Vale of Pickering. 
The geological and physical structure of this valley is simple. It 
is a long faulted synclinal trough of Kimeridge Clay, lying 
between the dip-slope of the Corallian Series on the north, and 
the Chalk-escarpment on the south. On the west, it is to a large 
extent shut in by a much-faulted tract of Jurassic rocks, from the 
Corallian down to the Lias; while on the east, along the strike of 
the Kimeridge Clay, it opens out into Filey Bay. This structure 
of the solid rocks would naturally give rise to an eastward-flowing 
river carrying the whole drainage of the basin; but this simple 
hydrographical arrangement no longer obtains. Drift-deposits 
of great thickness occupy the seaward end of the valley, and con- 
stitute the materials of the cliffs for a considerable distance to the 
south of Filey. They rise to a ridge which extends quite across 
the valley, and attains a minimum altitude of 180 feet. 
At the western end of the valley there are two gaps in the 
Jurassic barrier—one broad and flat, va Coxwold and Gilling, 
having a summit-altitude of almost exactly 225 feet, at the village of 
Coxwold. ‘This valley coincides with a couple of faults which bring 
down the soft Kimeridge Clay between harder rocks. The other 
gap is the narrow deep gorge of the River Derwent. This latter 
valley cuts through a watershed from 200 to 225 feet in height, 
and it bears all the characters of a lake-overflow of the first type— 
a direct overflow (see p. 481). The existing water-level 
in the gorge is well below 50 feet O.D. The floor of the 
Vale of Pickering is occupied by alluvium, consisting in part of fine 
laminated clay (Warp), and in part of sand with a little gravel. 
The Glacial deposits extend up the valley only a short distance from 
the seaward end, but a few small patches of gravel and small hill- 
cappings, mapped as Boulder-Clay, are near the western end. 
The whole drainage of the country south of the Esk, except a 
strip a mile or two broad north of Scarborough, enters the Vale 
of Pickering, and instead of taking the simple and direct course 
to the sea at Filey, is all diverted, against the slope of the rocks 
and the grain of the country, and passes out into the Vale of York 
by the gorge at Kirkham Abbey. 
The first suggestion that this anomaly was due to Glacial agency 
must, I believe, be accredited to Carvill Lewis, who made Lake 
Pickering one of the examples of extra-morainic lakes in his paper 
read at the Manchester meeting of the British Association in 1887. 
Mr. Fox-Strangways appears to have arrived independently at the 
same conclusion, and has supported it by new and valuable evidence 
in his paper on the ‘ Valleys of North-east Yorkshire,’* and in his 
Trans. Leicest, Lit, & Phil. Soc. vol. iii (1894) p. 333. 
