26 PROC. COTTESWOLD CLUB. vol. xiii. 



inheritance from .some earlier period of its development — 

 an inheritance which the power of the swift-flowing river 

 has not had time to efface in the part of its course where 

 it traverses hard Carboniferous Limestone, although it 

 has accomplished this effacement where it runs through 

 the softer Old Red Sandstone to the north of Tintern. 



To understand the past history of the river, a slight 

 geological sketch is necessary. In post-Carboniferous 

 times the Palaeozoic rocks of the district were elevated 

 from the sea-bottom to form land ; but about two miles to 

 the east of the Windcliff they were beneath the sea, which 

 was depositing Triassic rocks. And in the neighbourhood 

 of Chepstow the old Triassic shore line can be easily 

 traced. But as the accumulation of Mesozoic rocks con- 

 tinued, necessitating a gradual subsidence of the whole 

 area, and as at the same time there would be denudation 

 of the western land-area, it may be concluded that, before 

 the deposition of the Mesozoic strata ended, the whole 

 of the district of the Lower Wye Valley had been buried 

 beneath overlapping Secondary rocks. 



It was after the deposition of the Cretaceous strata that 

 the countrv was again elevated, and the river system, of 

 which the Wve forms a })art, was commenced. In the 

 development of that river system, with its accompanying 

 denudation, all the Mesozoic strata which formerly 

 covered the Lower Wye district have been completely 

 s\ve})t away. Once more the Palaeozoic rocks have been 

 bared, and in their turn thev have suffered much from 

 sub-aerial denudation. 



But l)efore the covering of Mesozoic strata had been 

 removed, there was a time when it is supposable that no 

 Severn Valley existed. The rivers of this Wye district 

 drained into the Thames system. The Usk and neigh- 

 bouring streams formed the head waters of a southern 

 branch of the Thames — a westward extension of the 



