﻿Vol. 64.] HIGH-LEVEL PLATEOEMS OF BODMIX MOOR. 397 



EXPLANATION OF PLATES XLV & XLVI. 



Plate XLY. 



Wolfram-deposit, Buttern Hill (Cornwall). Distant view, showing tlie series 

 of step-walls devised to ax'rest the mud from the ' streaming ' or washing- 

 out of the wolfram. 



Plate XLVI. 



Old stream-workings in high-level wash, in the hollow on the watershed of 

 the Fowey and the Penpont Water, south of Buttern Hill. 



Discussion. 



Mr. Clement Reid remarked that the absence of disturbance in 

 these high plateaux suggested that they were probably of later date 

 than any of the great earth -movements of the South of England, 

 which extended down to Oligocene times. They were clearly more 

 ancient than the 430-foot plateaux of proved Older Pliocene date. 

 This left only the Miocene ; and to this unexplored period he 

 suggested that the high plateaux of Bodmin Moor might belong. 

 It was possible, however, that in the hard rocks of Cornwall 

 comparatively little movement had taken place, and that the 

 plateaux might be of earlier date ; unfortunately, up till now 

 no deposits found on them had given any clue to their age. 



Mr. H. Dewey congratulated the Author, with whom he had 

 traversed much of the area described. In mapping contiguous 

 areas, precisely similar features had been observed, especially 

 between Davidstow Moor and the coast near Tintagel. In this 

 district several fiat-topped ridges could bo seen, 1000 feet above 

 O.D., separated one from the other by recent valleys. They 

 thus constituted remnants of the ancient tableland. The speaker 

 referred to the preservation in fair condition of an old bluff, 

 the base of which was 920 feet above the sea ; from this height 

 the slope of the ground suddenly and rapidly increased until the 

 height of 960 feet or thereabouts was reached, when the plateau- 

 feature succeeded. This cliif-line was best seen on the main road 

 between Boscastle and Delabole, near Condolden Barrow. On 

 approaching the barrow from the south, a sudden rise in the road 

 and fields was seen ; and from several points of vieAV this bluff had 

 the appearance of a huge bank crossing the fields. When the road- 

 gradients were drawn to scale, the change of inclination, though 

 well seen, was not so striking as it appeared in the field. On first 

 seeing this feature, the speaker attributed it to a band of harder 

 rock ; but, after the area had been mapped, the feature was seen to 

 cut across rocks of varying degrees of hardness and different litho- 

 logical characters. Although this was rather slender evidence, he 

 considered the cliff' suggestive of a periodical pause in the elevation 

 of the land from the sea ; such a cause was not, however, the only 

 one to which the feature might be assigned. He welcomed the 

 paper as an important contribution to tlie study of the evolution 

 of Cornish scenery. 



