294 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [JuUC 1, 



alluvium contains only land and freshwater shells at points much 

 nearer to the sea than those at which estuary conditions prevail at 

 present. This fact, and the conclusion to be drawn from it, were first 

 pointed out by Mr. Austen, though he refers it to the commencement 

 instead of the close of the pleistocene epoch. He also insisted on the 

 evidence, afforded by this ancient alluvium of the Thames, of the land 

 having had a greater elevation at that period. Without adopting his 

 views on this point to their full extent, I am satisfied that there has 

 been some amount of depression, since this old alluvium of the Thames 

 was formed ; because those land and freshwater shells which I sent 

 to the Museum in 1841, from Faversham, were collected from a bed 

 which extended below the level of the sea. 



I have represented a gulf as running up the English Channel 

 from the west as far as Dover, and another as extending between 

 Wales and Ireland, as far as Wexford. To this period I refer the 

 ancient beach at Brighton, and the marls and gravels at Wexford, 

 which contain the southern forms described by the President in the 

 Memoirs of the Geological Survey of Great Britain. Those deposits 

 were first described by Mr. Griffith, in the Journal of the Geological 

 Society of Dublin*, as occupying an area of about 20 miles by .5. 

 They were also described to me by Captain Charles Le Hunte, on 

 whose authority I first drew Mr. Griffith's attention to them, as con- 

 fined to the valley of the Slaney. This was in 1835, and he then 

 spoke of having seen, in the houses of the peasantry, shells said to 

 have been derived from these beds, respecting which he thought 

 there must have been some mistake, in consequence of their resem- 

 blance to tropical forms. 



It was at this period that the Elephants and other now extinct 

 pachyderms returned, and became intermingled with the Megaceros 

 and Reindeer, which had arrived from the north during an earlier 

 portion of the period of re-elevation. To this second elephantine 

 period I refer the few remains of the Elephant which have been dis- 

 covered in Ireland. 



Dr. Scouler says (Journal of Geol. Soc. Dublin, vol. i. p. 202), 

 that in the only authentic instance on record of their occurrence in 

 that country, they were in a position indicating a date as modern as 

 those of the Megaceros. They were found resting on a bed of fern 

 leaves. 



At this period, the present physical features of the Weald and 

 North Downs were completely established ; and I shall show in a 

 future communication, that those deposits which Sir Roderick Mur- 

 chison calls angular drift, which Mr. Martin calls cretaceous and sub- 

 cretaceous drift, and which I call warp-drift, were subsequently 

 poured into the valleys of the Thames and Medway ; and that they 

 cover mammalian deposits containing land and freshwater shells. 



I off*er no opinion respecting the nature of the agencies by which 



this angular drift or warp-drift was formed ; nor whether they were 



connected with the final separation of England from the Continent, 



and the final disappearance of the great pachyderms, which are not 



* Vol. i. part 3. p. 152. 



