Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/726

 on the lower portion of this chain, on Stainmoor, over which the Wastdale-Crag blocks have travelled, escarpments of Carboniferous rocks facing westwards are common. Speaking generally of a section from Wastdale Crag to Hunderthwaite Moor, on the east side of the Pennine chain, showing the contour of the surface, it may be said that the escarpments face towards the west, and that the gentler slopes incline towards the east.

The mode by which the granite blocks of Wastdale Crag have been transported over the hilly portion of Westmoreland and from thence across the Pennine chain has excited the inquiry of geologists, but as yet no satisfactory conclusions have been arrived at concerning the process which effected this transport.

Among other causes glaciers have been regarded as the agents. There are, however, some circumstances which render this mode of transport very improbable.

It has already been shown that the valleys of the Lyvennet and the Eden, and their smaller dells, are of an age considerably anterior to the period of the dispersion of the Wastdale-Crag blocks ; and also that the outline of the surface of the country over which these blocks have passed has undergone comparatively little change since the time when glaciers furrowed the surfaces of the rocks upon which the Boulder- clays repose. These ancient glaciers have followed the courses of the present drainage of the country, or, in other words, have had a motion from south to north so far as the valleys of the Lyvennet and the Eden and their subordinate vales are concerned. A glacier of considerable size must have occupied the valley of the Eden, which was fed by tributary glaciers, especially from the west side of the Pennine chain ; and a smaller glacier, with still smaller feeders, must have had its course along the valley of the Lyvennet.

The country immediately east of Wastdale Crag is of such an outline as to furnish none of the conditions necessary for the formation of glaciers ; but on the north and south side of this hill the surface- outlines are in every way such as would give rise to such products.

On the south side there is a valley the head of which is Great Yarlside, attaining an elevation of nearly 2000 feet above the level of the sea. This valley is flanked at its N.E. termination by the granite of Wastdale Crag, which in some spots affords glacial scratches, the direction of which corresponds to the course of the valley, which, after running for about a mile N.E. of Wastdale Crag to Shap Wells, turns to the S.E., and flowing for about four miles in this direction, under the name of the Birkbeck, joins the Lune at Tebay. The direction of this stream is the course which a glacier would have taken had it occupied this valley and the country in front of it during the period when the granite blocks were being distributed.

On the N.W. side of Wastdale Crag is a valley known as Wet Sleddale ; this is drained by the sources of the river Lowther, which originate in the high ground on the north side of Great Yarlside. A glacier occupying this valley during the rigorous climate of the glacial epoch, would have extended itself towards the N.E.