LINNEAN SOCIETY OF LONDON. 223 



though doubtless only a portion of the plants which took possession 

 of the island as its ice-covering disappeared, suffice to give us a 

 general idea of the vegetation. Mr. Carruthers referred to the 

 labours of H. C. Watson and E. Forbes in connection with the 

 geographical distribution of our existing Flora, and cited the 

 observations of Darwin, J. D. Hooker, and Hemsley, on insular 

 Floras, with the more recent ones of Dr. Treub on the beginnings 

 of vegetation at Krakatao, as showing that, in the case of new 

 islands, whether of coral or volcanic origin, the first vegetation is 

 borne by water and air-currents. Returning to our own island, 

 Mr. Carruthers gave a sketch of its condition when the first members 

 of our present Flora made their appearance. " The Tertiary 

 Period had closed. Only in the immediately preceding Upper 

 Cretaceous rocks had there been any association of species in a 

 Flora analogous to the geographical groups of our own day. The 

 plants that have been discovered in the Eocene beds possess the 

 facies of a tropical Flora ; the Miocene plants indicate a slight 

 decrease in temperature, and this continues till we reach the sub- 

 tropical Flora of the Pliocene. Then there appeared a remarkable 

 change in the climate, and the Pliocene plants perished before the 

 advancing boreal cold. The Pliocene plants do not belong to the 

 same genera, seldom even to the same orders, as the Flora which 

 follows ; and they could not consequently have any ancestral rela- 

 tion to it. The cold that drove before it the subtropical vegetation 

 was the forerunner of the ice age. Advancing in front of the ice, 

 the first representatives of our existing Flora reached us from the 

 north, where they had not however long established themselves, 

 seeing that the tropical and subtropical floras of the Tertiary Period 

 flourished far within the arctic circle. The remains of these 

 earliest members of our present vegetation are buried in the Cromer 

 Forest bed with the bones of the extinct mammoth, the rhinoceros, 

 the hippopotamus, and the cave-bear, and of the still living horse, 

 red-deer, beaver, mole, &c. Only in a single case has it been 

 impossible to correlate what appear to be empty follicles with the 

 corresponding parts of an existing plant ; and it is possible these 

 fruits may represent an extinct species, though the imperfect 

 materials could not justify our asserting this without great reserve. 

 Three of the species are no longer members of our existing Flora, 

 though they still persist, like the beaver, in other lands." 



Mr. Carruthers proceeded to enumerate and group geographically 

 the 53 species of plants found in the Cromer beds, which, with two 

 exceptions, Salioc polaris and Hypnum turgescens, belong to the 

 Germanic type of our Flora. Two of the Cromer plants, Trapa 

 natans and finus Abies, have been lost to us, driven from our laud 

 before the advancing cold, and having failed to return when the ice 

 retreated. 



After further remarks on distribution, Mr. Carruthers con- 

 cluded as follows : — 



" Various estimates have been made of the centuries that have 

 run their course since the glacial epoch. Beyond the date at 

 which man began to record time we can have no definite informa- 



