Ix PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



and they are all species which at present are forms either peculiar 

 to or abundant in the mountains of Spain and Portugal, and espe- 

 cially in the Asturias. At this period, he believes Ireland and Spain 

 were united, and that the plants in question extended over land, 

 which then occupied that part of the ocean that lies between the 

 Asturias and the west of Ireland, but which flora he supposes to 

 have been afterwards during the glacial epoch isolated, and in great 

 part destroyed ; such species as survived being the most hardy and 

 able to bear the lowered temperature. 



The Second^ or Devon Flora, — The great extent of land, formed, 

 in part at least, of the elevated bed of the Miocene sea, was destined 

 to give way again to the return of the ocean, either by subsidence 

 or denudation, probably by both causes, leaving many evidences 

 however of its former existence. The destruction of this land the 

 author conceives to have been in progress during the deposition of 

 the beds of the Pliocene epoch, but that the opening up of the 

 English Channel had only begun, and towards the west ; for this 

 flora, exhibiting features of transition between the great flora of 

 Central Europe and that of the Southern or Mediterranean region, 

 had its origin, he believes, in that part of France included in the 

 ancient provinces of Brittany and Normandy. 



The Thirds or Kentish Flora, — The condition of things our au- 

 thor believes to have undergone little change from what they were 

 during the passage of the Devon Flora, while the migration of this 

 flora was in progress, unless, perhaps, a still further scooping out of 

 the English Channel from the west. 



The Fourth, or Alpine Flora. — A very considerable change oc- 

 curred about this time. A great subsidence must have taken place, so 

 as entirely to change the relative proportion of sea and land, and which 

 must have been very diff'erent in the region now under consideration 

 from that which at present exists. A great part of the British Isles 

 the author believes to have been then covered by the sea, so that 

 our mountains were comparatively low islands. If we extend, he 

 says, a line from the coast of Norfolk westward across Ireland, and 

 eastward so as to strike against the Ural chain, all north of that line 

 he believes to have been at this epoch under the sea ; that is, the 

 whole of central and northern Europe, bounded by land, since greatly 

 uplifted, which then presented to the water's edge those climatal con- 

 ditions for which a sub-arctic flora destined to become alpine was 

 specially organized. This, he says, was the sea of the Glacial period, 

 when the climate of the whole of the northern and part of central 

 Europe was far colder than it is now. It exhibited conditions, phy- 

 sical and zoological, similar, indeed nearly identical, to those now to 

 be met with on the north-eastern coasts of America, within the line 

 of summer floating ice. It was during this epoch, he believes, that 

 Scotland and Wales, and part of Ireland, then groups of islands in 

 this ice-bound sea, received their alpine flora, and a small portion 

 of their fauna. The period of time that elapsed while the sea 

 covered the region above described, he terms The Glacial Epoch, 

 using that term to express the ice-charged condition of that sea, and 



