m THE SOUTH-WESTEKN COUNTIES. 51 



ieebergs or floes entails either (a) the participation of the South- 

 western Counties in the submergence affecting Wales and the Mid- 

 land Counties, and to such an extent as to allow the notation of 

 large bergs over the lesser elevations, and to admit of their strand- 

 ing on the greater heights, then existing as shoals in an Arctic sea ; 

 or (/3) the depression of these counties to a depth not sufficient to 

 allow of the notation and stranding of large bergs, but suitable for 

 the accumulation of pack and floe ice. In either case the impact 

 of bergs or floes upon tracts barely submerged would be capable of 

 producing considerable disturbance in beds at and near the surface, 

 but could scarcely produce uniformity in their disturbance or re- 

 versal*. In the case of bergs one would certainly expect to find 

 some evidence in the form of Boulder-clay and scattered erratics ; 

 yet no instances of either can be adduced. 



The clay deposits of Roundswell, &c, near Barnstaple, described 

 by Mr. Maw f , and the clay with worn fragments near White 

 Staunton, on the Blackdown, mentioned by Mr. H. B. Woodward 

 (in a letter to the ' Geological Magazine/ quoted by Mr. Croll) cannot 

 be regarded as Boulder-clays, as the former is of subsequent date to 

 the raised beaches, and the latter appears to have resulted from the 

 redistribution of Cretaceous material and old gravels (probably Ter- 

 tiary) by fluviatile agents. 



With the exception of the granite boulder of Saunton, described 

 by the Rev. D.Williams J, which from its position does not apply to 

 my objection, no erratics have, so far as I am aware, been detected 

 in these counties. 



These appear to me to be fatal objections to the idea that Devon 

 was totally submerged during the Glacial epoch. 



To admit Mr. Mackintosh's remaining hypotheses would entail the 

 submersion of heights now among the most considerable in the area, 

 which is contradicted by the foregoing objections : to deny its applica- 

 tion in these cases and allow of it in districts of less elevation would 

 entail a partial submergence. The raised beaches of Devon and 

 Cornwall do not indicate a maximum depression of more than 60 feet, 

 and on an average do not exceed 10 feet above spring-tide high water. 

 Mr. Pengelly's Lithodomous perforations at about 235 feet above 

 the sea at Petitor, near Babbacombe, have been cited by Mr. Mac- 

 kintosh as proof of a Pleistocene depression to that amount in South 

 Devon. " They clearly show," he says, " that the sea has been the 

 last modifying agent to which the land has been subjected." This 

 conclusion is at variance with Mr. Pengelly's opinion that " the 

 Pebitor borings are older than those of Kent's Cavern; yet the latter 

 belong to a period of higher antiquity than that in which the red 

 loam teeming with remains of extinct mammals was carried into 

 the cave"§. 



* Near Raleigh's Cross Mr. Mackintosh notices the prevalent S.S.E. direction 

 of the reversed laminae. His other observations tend to prove a comparative 

 uniformity in the direction of the curvature. 



t Quart. Journ. Geol. Soc. vol. xx. p. 447 et seq., and Geol. Mag. vol. ii. p. 525. 



\ Trans. Geol. Soc. 2nd ser. vol. v. p. 287. § Trans. Dev. Assoc, for 1866. 



E 2 



