THE DEVELOPMENT OF BRITISH SCENERY. 279 



rocks in their vicinity, and they acted as " horsts " or 

 barriers of harder rocks which affected the strike of the 

 adjacent deposits. It by no means follows, however, that 

 they were uncovered at the time that the position of the 

 newer rocks was affected by their existence, for we actually 

 find the continuation of the Mendip ridge still buried 

 beneath the newer rocks underneath, and the same is 

 almost certainly the case with the rocks of the Pennine 

 Chain to the south, portions of which now stand out as 

 inliers of older rock through the new Red Sandstone deposits 

 of the central plain of England. 



The Mesozoic rocks lying east of the Pennine Chain dip 

 in such a way, that the position of the floor on which they 

 were deposited, would, if the dip were continued westward, 

 lie far above the summit of the Pennine Chain, and yet we 

 find new Red Sandstone running from the west of Cumber- 

 land, down west Lancashire to Cheshire, and so into the 

 central plain, and outliers of Lias (Rhaetic) near Carlisle 

 and near Wem in Staffordshire, far beneath the level at 

 which they should occur, if the easterly dip were continued 

 farther west. The conclusion seems inevitable that the 

 Pennine Chain was uplifted in Post- Rhaetic times, and 

 therefore probably during the Mid- Cretaceous or Miocene 

 periods of uplift, and in favour of the latter period is the 

 existence of Cretaceous rocks in the north of Ireland, and 

 possibly in the Irish Sea. 



I have elsewhere argued in favour of the elevation 

 of the Lake district in Miocene times (3), on account of the 

 structure of the district, and suggested its dependence 

 upon the formation of a laccolitic dome. 1 



The occurrence of Cretaceous gravels near Buckland 

 Brewer, in the extreme west of Devonshire, suggests that 

 though the Cretaceous rocks, as is well known, thin out 

 and assume shallow water characters when traced towards 



1 In the paper alluded to, geological details were largely omitted, 

 but the coincidence of the watershed near Shap with an anticlinal axis 

 should have been mentioned (though well-known to British geologists), as 

 the supposition that the Howgill Fells were uplifted after the initiation of 

 the waterways is largely dependent upon this fact. 



