Rev. J. Clifton Ward — Geology of the Lake District. 59 



action ; but while these beds do thus indicate shallow-water con- 

 ditions, and the presence of powerful currents around some land, 

 yet the material — in the case of Mell Fell, J etc. — is not derived 

 from the neighbouring Lower Silurians, but won from Upper 

 Silurian strata, which in the area around Mell Fell must have been 

 denuded away long since, for, be it remembered, these conglomerates 

 are laid clown partly upon Volcanic rocks and partly on Skiddaw 

 Slate (see Map), and the latter could not have been exposed until 

 long ages after the Upper Silurians had been removed. 



Since the Mell Fell Conglomerate must have had at one time a 

 much greater westerly extension, and since it now occurs up to a 

 height of 1760 ft., the Cumbrian nucleus must have been small, 

 though to what height it attained cannot be estimated. But what 

 could cause the peculiar composition of the conglomerate ? Why 

 should it not be made up of stones worn from the neighbouring 

 land? This is a puzzle. Was there no such neighbouring land 

 formed of Lower Silurian rocks ? Then why should there be 

 exposed Upper Silurian beds — whence the pebbles were worn — laid 

 bare at some point which one would infer, from the facts of denuda- 

 tion previously discussed, to be at a distance from the principal centre 

 of upheaval —farther from the axis of elevation and disturbance 

 (Plate II. Fig. 2). If Upper Silurian beds, forming the sides of 

 the anticlinal, were exposed, surely there is every probability that 

 some land existed nearer to the centre of upheaval. This anomalous 

 distribution of the material of the Conglomerate led me at one time 

 to speculate on the possibility of the Upper Silurian sandstone 

 pebbles having been drifted by current action " around the skirts of 

 a tract of high land, which; not rising in any lofty peaks, was 

 effectually protected from marine and subaerial denudation, at that 

 particular time, by an icy covering, leaving few or no rocks exposed 

 above its surface." 2 Even then it is hard to understand how ice- 

 borne scratched stones from the Lower Silurian high ground did not 

 freely mingle with the current-drifted pebbles of sandstone. Again, 

 how is the great development of conglomerate between Mell Fell 

 and Pooley Bridge to be accounted for? It would seem to thin away 

 very rapidly, both north and south, but especially to disappear 

 northwards. Can it have accumulated in an old valley 3 or fiord, or 

 in a narrow channel ? If in the former, how came it to be filled 

 with material foreign to the surrounding land ? If in the latter — a 

 channel or strait — may not the Mell Fell deposits occupy the site of 

 the eastern end of a strait, which at that earlv period had been 

 sketched out as the future great valley separating the Skiddaw and 

 Blencathra group of mountains from the more southern mass of 

 land. 4 In this case one might understand the banking up of shingle 



1 Mell Fell is a mountain of rounded form at the west end of the long patch of 

 Conglomerate marked on the Sketch-Map, Plate II. 



2 Survey Memoir, p. 76. 



3 Prof. Phillips long ago suggested that the Old Eed— so-called — may have heen 

 accumulated in old valleys. — Geology of Yorkshire, vol. ii. p 14. 



4 The east and west line of railway on the Map may be taken as the axis of this 

 now much-deepened channel. 



