GRACE : THE GLACIAL GEOLOGY OF FUKNESS. 
413 
readies the 50 fee5 contour at Rusland village. It has been eroded 
to a considerable depth, and then silted up again to sea level. It was 
probably the site of a lake, either during the Glacial Period or since 
A thick deposit of peat covers much of its floor, the components of 
which show that a wide peat-water swamp followed the silting up, and 
in turn gave place to a moss." A rock barrier south of Kusland 
Beaches almost cuts this swamp into two basins. A number of 
morainic mounds near Rusland, and much undisturbed drift in several 
places suggest that the level of the lake can never have been much 
above present sea level. We have been unable to find any volcanic 
rocks among the boulders and drift of this valley, a fact which indicates 
that the ice filling it came from the north-east rather than the north- 
west. It is possible that quite early in the valley stage the ice ceased 
to flow over Hawkshead Moor, and that the Hawkshead area became 
either stagnant or continued down the Cunsey Beck Valley. Abundant 
suggestions of rounding may be found among the rocky prominences 
in the Rusland Valley, but slate rocks do not preserve this as well as 
the volcanic series. Smoothed rocks suggesting movement from 
east-north-east occur in Haverthwaite schoolyard, and others indicating 
motion from north-east near Causeway End. 
Only the southern part of Lake Windermere belongs to our area. 
The northern half and the valleys converging on the head of the lake 
are in Westmoreland. The Windermere Valley belongs to the radial 
scheme of drainage previously referred to, and in Pre-Glacial times 
continued southwards by Cartmel. The Backbarrow valley, now^ 
draining the lake, was probably commenced in Pre-Glacial times by 
tributaries of the Crake and Windermere, flowing in opposite directions 
with a col sufficiently defined to govern the route of the ice overflow. 
It is still possible to distinguish the glaciated U-shaped valley below 
Newby Bridge, where the present river has cut a trough about 6 ft. 
deep in the glaciated floor. A second ice-stream came over the 
Finsthwaite Valley, and joined the first above Backbarrow. The 
gradient of the River Leven seems to confirm the above theory of its 
origin. In the first two miles of its course until it reaches the bend 
above Backbarrow it only falls 28 feet from the lake-level to the 
100 feet contour. In the next two miles it drops from 100 feet to 
practically sea-level. The final part of its course is across an alluvial 
flat with very little slope. Probably the Pre-Glacial tributary originated 
above Backbarrow, and had a branch up the Finsthwaite Valley, 
if, indeed, the latter be not its real head. 
