Yol. 68.] STJCCESSION IX THE XORTH-WEST OF EX&LAND. 553^ 



Another vie^r, which has been strongly advocated for many- 

 years past by Dr. ^larr, supposes that the Lower Carboniferous 

 deposits were laid down upon an even surface of Palaeozoic rocks 

 over the whole site now occupied by the Lake District, and subse- 

 quently elevated into a dome which has been denuded to form the 

 present ring of Carboniferous rocks. 



The results of the investigation recorded above would appear to- 

 show that the latter view is almost certainly correct. The lowest 

 deposits met with in the North- Western Province occur in close 

 proximity to the present margin of the Lake District, namely, 

 between Pooley Bridge and Shap Wells, at the foot of the How- 

 gill Eells in Ravenstonedale, at Meathop in the Arnside District, 

 and near Elliscales and Marton in the Furness District. 



As we travel away eastwards and south-eastwards from the Lake 

 District, we find that the lower Shap dolomites thin out. Hence, 

 far from beiog an island at that period, the present site of the 

 Lake District probably represents the portion of the area first 

 submerged beneath the Carboniferous sea, Avhile land lay to the 

 east over the tract now occupied by the Cross-Fell range. Further 

 evidence of the same kind is forthcoming from the Ingleborough 

 and Penyghent area to the south-east, in which area submergence 

 does not appear to have taken place until a still later period after 

 the deposition of the Miclielinia Zone at Arnside. 



The present outcrop of Lower Carboniferous rocks, as shown in 

 the index-map published by the Geological Survey, forms an 

 irregular ring round the outskirts of the Lake District, and it is 

 possibly this arrangement which first gave rise to the suggestion 

 that they had been deposited against an island, in much the same 

 manner as the similar beds in Northumberland are regarded 

 as having been deposited against the denuded stump of the old 

 Cheviot volcano. A detailed examination, however, of the dip 

 of the Carboniferous strata which form this ring shows that 

 they constitute the inner edge of a denuded dome, and that, if 

 continued, they would easily clear the highest summits of the 

 Cumbrian Hills. 



The beds corresponding to the C Zone of the Bristol District are 

 most probably represented by all except the lowest portion of the 

 Athyris-glabristria Zone, together with the whole of the Miclielinia 

 Zone. The Seminula Zone appears to correspond exactly with the 

 Productus-corrugato-liemispliericus Zone, while the Lower and a 

 portion of the Upper Dibunopliyllum Sub-zones correspond very 

 closely in the two areas. A difficulty lies in drawing an exact 

 line in the North- Western Province which will represent the base 

 of the Cyatliaxonia Beds of the Midland Area ; but this may be 

 provisionally drawn somewhere about the Scar Limestone or the 

 beds immediately overlying it, at which horizon Cyatliaxonia cornu 

 has been found, though sparingly, in the Westmorland Pennines. 



