400 D. Macldntosh— Height of Glacial Drift. 



gravel-pits, tracks of imusually large rain-torrents, etc., which en- 

 abled me on some points to arrive at a more satisfactory classification 

 of the drifts of the country than I had previously succeeded in 

 devising. 



Traces of a Great Valley -ignoring Ice-stream. — It was not long 

 before I foimd myself constrained to return to the doctrine advocated 

 in " Scenery of England and Wales "—namely that a stream of land- 

 ice must once have assailed the central part of the Lake District 

 from the N.N.W., — a stream of sufficient thickness and possessed of 

 sufficient force to enable it to march over the irregular plateau 

 between the Stake pass and Dunmail Eaise — to glaciate the valleys 

 and ridges obliquely or directly across, from Far Easdale (if not 

 from a more northerly latitude) to Morecambe Bay, and over a 

 breadth of country extending from the upper part of the two Lang- 

 dales and the Coniston Old Man in the west, to Kentmere in the 

 east — the direction of the mammillation and primary striation within 

 this district ranging betweeti N. and N.W., the general direction 

 being about N.N.W. This great ice-stream smoothed nearly all, if 

 not all, the rocJies moutonnees, from the splendid series on the top of 

 the ridge (up to 1700 feet)^ between Easdale and Great Langdale, 

 down to the bosses in the two Langdales, Grasmere, Easdale, Rydal, 

 Ambleside, Windermere, and Old Man valleys, and those situated on 

 the watershed between Windermere and Stavely, and to the S. of 

 Windermere and Bowness. This valley-ignoring, or rather Lake- 

 district-ignoring ice- stream (for it treated high ridges as subordinate 

 obstructions) , would appear to have ground down a great part of the 

 country during its uphill, downhill, and across-dale progress.^ But 

 the comparative absence of smoothed and glaciated stones at high 

 levels, even where the roclies moutonnees are strikingly developed, and 

 the uniformly smooth (excepting where weathered) and curvilinear 

 character of the roclies moutonnees, would seem to indicate that the 

 rocks were mainly ground down by grit adhering to the base of the 

 ice, and that the large loose blocks the ice met with in its course 

 were either reduced to finer matter or jammed up in abrupt recesses. 

 If we except boulders more than nine inches or a foot in average 

 diameter, not one stone out of ten in the Pinnel of the central parts 

 of the Lake District is distinctly glaciated, whereas in the marine 

 boulder and brick clays of Cheshire, at least one stone out of three 

 is decidedly flattened, grooved, or scratched.^ These facts would 



1 I found Yery distinct strife pointing N.N.W. at a point more tljan 1600 feet above 

 the sea on this ridge. Lower down, the direction of the rock-smoothing and strise 

 crosses the outlets of Easdale and Blind Tarns. 



2 This ice-stream must have so smoothed and rounded the cliffs and rocky projec- 

 tions as to prevent their shedding much scree-matter for a long time afterwards, and 

 if to this consideration we add the possible disappearance of glaciers from the larger 

 valleys soon after the ice-sheet vanished from the immediately surrounding plains (for 

 even the inner ends of these valleys often lie lower than the plains), we shall see 

 reason for expecting to find comparatively little suhaeri^il moraine-matter represented 

 among the drifts of the Lake District. 



3 In some parts of the Lake District where the smaller stones are fine-grained and 

 not very hard, the proportion exhibiting scratches is greater, but even tbcn the stones 

 are scarcely ever much flattened or regularly grooved. 



