﻿390 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



I may here further remind geologists, that the great line of dislo- 

 cation of the Wealden and its subsidiary parallels in the flanking hills, 

 when continued to the west, is coincident with the axis of the Vale 

 of Pewsey. This line is further parallel to the axis of the Isle of 

 "Wight and to many other lines of fracture in the South of England 

 and South Wales, along which great disturbances have also occurred 

 at the same comparatively recent epoch. 



Generalization of British and Foreign Drift Phenomena. — Let 

 us now endeavour still further to generalize the subject of the local 

 angular flint-drift of the South-east of England, by comparing it with 

 analogous phenomena in other parts of the world. 



On a former occasion*, I showed that the commencement of the 

 first glacial period in the history of the Alps was synchronous with 

 an enormous dislocation and upheaval of that chain, and coincident 

 with a vast change in the level of materials constituting the then 

 existing land and their debris, which had previously lain beneath 

 the waters. I also maintained, that such dislocation was of the 

 same date as that which submerged a pre-existing northern con- 

 tinent and brought it under the influence of an Arctic ocean. The 

 proofs of a sudden and violent change being, as I think, as well 

 demonstrated at our own homes, my conviction is, that here, as in 

 the Alps, one of the first steps in that great climatal revolution was 

 accompanied by very extensive fractures and changes of level in large 

 portions of the crust of the earth. At the same time we may fairly 

 infer from other testimony, that the first vibration which elevated 

 some tracts and depressed others having once passed away, subse- 

 quent accumulations were continued in Northern Europe under gla- 

 cial conditions during a very long period, including, as I am ready to 

 admit, the existence of terrestrial glaciers at certain points in Britain 

 (of which Snowdon is an example) on islands of no great altitude in 

 a glacial sea. Thus, we may explain the position of copious masses 

 of subaqueous detritus, and the transport of huge erratic blocks from 

 such terrestrial centres. In this sense, the drift of Britain which has 

 travelled from the North, and the Alpine drift and blocks of Bavaria 

 and the Jura which have proceeded from the South, belong to the 

 same great geological epoch, or the first period in the chronicles of 

 the planet in which we have distinct signs of glacial action. 



Prior to the origin of that glacial time, and, according to my view, 

 before England was severed from the Continent, the great extinct 

 quadrupeds had doubtless spacious feeding-grounds commensurate 

 with their abundance. As long as they flourished, these animals must 

 have contributed their remains from year to year to fluviatile, lacus- 

 trine, and estuary deposits ; and therefore it is, that in some places we 

 may find their bodies in such stratified masses ; although it is manifest 

 that by far the greater number of those creatures which died a natural 

 death must have disappeared (bones and all), when not imbedded under 

 some impenetrable sediment. This fact, however, is perfectly consistent 

 with the contrasting and collateral evidence which compels us equally 

 to believe, that the destruction of a multitude of those animals along 

 * See Quart. Jo-urn. Geol. Soc. vol. vi. p. 65 et seq. 



