219 



It lias, however, been held by Geologists, that the action of 

 tides operating along lines of fracture would be essential to 

 the formation of the valleys of the Cotteswolds; and it is an 

 admitted fact, that lines of fracture are found in many valleys: 

 but before this theory can be accepted, the existence of the 

 necessary conditions, which would admit of the operation of 

 tides in hues of fracture, must be shown with reasonable 

 certainty. (1.) The land must have been at a level sufficiently 

 low to admit of being reached by tides. (2). The fractures 

 must have opened into fissures of sufficient width to admit of a 

 large volume of water into them, and of sufficient length to 

 account for the excavation of long valleys as they exist at the 

 present time. 



(1) As respects the first condition : I have already remarked 

 upon the action of the sea during the upheaval of land. It must 

 be assumed that there is no evidence to prove that the Cotteswolds 

 were submerged during the glacial epoch, except perhaps their 

 northern extremity; and as the outlets of the valleys are from 

 one to two hundred feet above the sea, it could only have been 

 during the course of upheaval, — if at all, — that the land was 

 subject to marine influence; but from the circumstance of our 

 not being able to find any existing traces of such influence, 

 either in the valleys or on the hills, it becomes difficult to 

 establish the fact of its operation. Surely there should be some 

 remains of ancient beaches at the heads of the valleys ; some 

 beds of Shingle; or some fissures in the Oolitic rocks fuU of sand: 

 but we search in vain for any trace of such evidence. True we 

 have drifts everywhere on the flanks of the Cotteswolds, which 

 following the course of the rivers and brooks extend to the 

 Severn, and sometimes they are found far up the valleys — as, 

 for instance, at Nailsworth. It might be suggested that these 

 drifts testify to the flow of tidal rivers by which they were 

 deposited; but, unfortunately for the suggestion, they are found 

 to contain land and freshwater shells in abundance, but no 'trace 

 of marine or estuarine shells, leading therefore to the inference 

 that they are not of marine or estuarine origin. 



