530 NORTHERN DRIFT IN VALE OF WORCESTER — (MALVERN STRAITS). 



the elbow made by the latter from Oswestry to Bridgenorth can be explained satisfac- 

 torily by inferring, that the Silurian region constituted an ancient line of shore, during 

 the period when the whole of the present valley of the Severn, from the Breiddens to 

 the mouth of the river, was submarine. 



We shall hereafter afford independent proofs of the existence of dry land on each side 

 of the narrowest portion of the region then submerged, by showing that fluviatile and 

 land remains were washed into it from both sides and mixed up in shore detritus. In 

 the mean time, I would simply remark, that as the northern detritus with sea shells, where 

 it advances to the south, is never found on the ranges which flank the present estuary 

 of the Severn, but is strictly confined to the level country ; so the form of the tract 

 strongly supports the belief in the existence of a great channel of the sea, extending 

 southwards through Worcester and Gloucester ; the eastern and western shores of which 

 were the Cotteswold and Malvern Hills. The former chain presents sloping escarp- 

 ments to the valley of the Severn, with salient and re-entering angles, precisely like the 

 headlands of a shore, formed by the action of a sea acting upon the soft and hard ma- 

 terials. At the base of these oolitic hills are masses of local detritus, in the form of 

 sand and shingle as before described. On the opposite side the sharp ridge of the 

 Malverns stands out like a mural buttress on the flank of the Silurian region, remind- 

 ing the traveller of rocks of similar form and composition on the sides of straits 1 . How 

 far over the kingdom the eastern limb of the northern drift may have extended, and 

 whether even the whole drift under consideration, is not a portion of that which covers 

 such large tracts in the east and south-east of England, remains to be determined. 

 There is, however, every reason to believe, that in the tracts adjacent to the eastern 

 limits of the annexed map, the north and south valleys, such as those of the Evenlode 

 and Cherwell, may have been under the sea during the same period. The excellent and 

 clear description of the physical features of these tracts given by Dr. Buckland (Geol. 

 Trans., Old Series, vol. v. p. 516 et seq.), and his account of the transport of the quartz 

 pebbles derived from the Lickey Hills and the conglomerates of the New Red Sand- 

 stone of the central counties, mixed with fragments of northern origin, seem to me to 

 indicate, not as is inferred in that paper, the rush of diluvial waters over pre-existing 

 land, but that the tracts, so covered, were under the sea during the period of the 

 northern drift, the Cotteswold and other ridges, as before stated, being then above them. 

 Judging, however, from the vast mass of gravel, occasionally charged with modern 

 marine shells, which covers such large portions of the eastern counties, the area which 

 was then submerged must have been very great, and consequently the amount of existing 

 dry land inconsiderable. 



I have said that the drift under consideration is specially distinguished from all local 

 detritus by containing fragments of northern rocks, many of which are of vast size, and 



1 If the valley of the Severn were under the sea, the Malvern ridge would strikingly call to mind the rock of 

 Gibraltar. 



