May 1902.] BOTANICAL SOCIETY OF EDINBURGH 237 



present day ; and, as Clement Keid^ points out, we may 

 at once dismiss that type of vegetation from any further 

 consideration in the present connection. Tracing the 

 course of events onwards, we find evidence that an 

 extensive break exists in Britain between the rocks of 

 Miocene Age and those next newer in the series here : 

 that is to say, we have no record of what plants or 

 animals lived in Britain during the ver}' long period that 

 intervened between the close of the Pliocene Period and 

 the commencement of that of Pleiocene Age. So we have, 

 as it were, lost our way there, so far as the ancestral 

 history of the British Flora is concerned. 



When we come to the Pleiocene rocks, which are well 

 represented in Britam, we find that the earlier deposits of 

 this age, such as the Coralline Crag and the Bed Crag, 

 do not help us much by any direct evidence as regards 

 their flora. But the general nature of their fauna does 

 help, if only in an indirect way, to throw some light upon 

 what was going on in the plant world ; for we may 

 safely assume that, if the facies of the animals of one 

 region betoken warm conditions, — or cold, as the case may 

 be, — the plants also must have been those adapted to the 

 same climatal conditions. The Coralline Crag has a dis- 

 tinctly Mediterranean fauna ; so we may safely assume 

 that the plants would be, in a general way, of much the 

 same kind as those found in the north-western part of 

 the "Mediterranean basin of to-day. It seems as if there 

 existed, in that part of Britain, at least, a sea closed to 

 the north and open to the south-east, and the Medi- 

 terranean facies of the fauna is evidently a consequence of 

 those geographical conditions. 



The fossils of the succeeding Bed Crag seem to show 

 that, with the changes in physical geography that were 

 taking place, a communication was being gradually 

 opened up between this southern sea and the colder 

 waters of the sea to the north. There is no clear 

 evidence to show that any large part of Britain at this 

 time existed as a land area. It is more probable that 

 only a small part did so — perhaps the northern part was 

 land, — but of even this one cannot feel quite sure. 

 ^ " Orisrin of the British Flora." 



