276 R. Chambers, Esq., on Glacial Phenomena 



posed of materials derived either from mountains forming 

 the north-western limits of the country, or from rocks of the 

 very district where the materials are found. {t Not only the 

 valleys, but various elevated combs and basin-shaped cavi- 

 ties, as well as the slopes and escarpments of hills, are 

 strewed sometimes with boulders, coarse gravel, and clay, at 

 others with finely comminuted materials. ... In pass- 

 ing to the south-east, the coarse boulders disappear, and the 

 gravel becomes more and more finely comminuted, shewing 

 that the direction of the drift has been from the north-west.'' 

 Connected with this drift are proofs of extensive denudation, 

 such as the conical hills called the Pyons, lying five miles from 

 the principal masses with which they were once connected, 

 the valley of the Severn lying between, — and the lofty peak 

 Pen-cerrig-calch, an outlier of the South "Wales coal-field 

 divided from its principal by an intervening valley twelve or 

 fifteen hundred feet deep. 



Sir Roderick further describes a central tract of Western 

 England, composed of large portions of Lancashire, Cheshire, 

 Shropshire, Staffordshire, Worcestershire, and Gloucester- 

 shire, where the local drift is overlaid by a drift which has 

 come from the north, bearing fragments of granite and other 

 rocks, of which the original position is comparatively distant, 

 and in which are found deposits of shells of existing species. 

 He conceives that Siluria had been dry land at the time 

 when a northern sea-current deposited this higher and later 

 drift. 



The same northern drift lies in large masses on the north 

 coast of North Wales, and in elevated portions of the Snow- 

 donian region, where shells have been found in it at 1392 

 and 2200 feet above the sea ; but, as has been remarked, it 

 seems to have been swept out of the Snowdonian valleys by 

 comparatively modern glaciers. 



Professor Phillips describes the drift in a part of England 

 more to the northward. Masses of the porphyrinic granite 

 of Shap Fell, and portions of other highly peculiar rocks be- 

 longing to the Lake country, have been carried " northward 

 in the vale of the Eden to Carlisle, southward by the Lune 



