FOSSIL FLOE AS. 705 



Remains of forests formed of still existing species occur in many parts 

 of Europe, enclosed in diluvial beds. The city of Breslau stands on 

 the site of an ancient forest, whence the trunks of Quercus pedunculata 

 are dug out ; the same is the case with the city of Bamberg, where the 

 trunks of trees of great diameter have been found in excavations for 

 railways, &c. Similar trunks of Oak are occasionally dug out of the 

 diluvial beds in England, as in the upper part of the valley of the Med- 

 way. 



Submarine forests are known to exist off many points of the British 

 coast and the west coast of France ; wood obtained from a large sub- 

 merged bed ofl' the coast of Pembrokeshire is found to consist of Oak 

 and Alder, and of Pinus sylvestris : the Oak, Elm, Hazel, Walnut, &c. 

 are found in the British Channel. In the Lake-dwellings of Switzerland 

 seeds of Cereals, Apples, Nuts, &c., and Linseed have been found, indi- 

 cating not only the existence of these plants, but also, as in the case of 

 Cereals, of cultivation. 



These facts, together with the analogous but more complete evi- 

 dence derived from animal remains, show a gradual transition from 

 the Tertiary to the present geological epoch. 



As to the wider question of the descent of existing species from 

 their fossil representatives, or from preexisting forms now extinct, 

 such filiation can hardly be doubted in many cases, although the 

 exact line of descent is often not traceable. On the other hand, 

 many of the earlier types of vegetation were of their kind more 

 highly organized than their existing representatives ; hence it is a 

 question whether the latter are really degenerate descendants from 

 their progenitors, or whether the more highly endowed Lycopods 

 and Equiseta, for instance, have not died out and become extinct. 

 Thallophytes seem to have existed in all ages much as we see them 

 now. Vascular Cryptogams and Conifers early came into exist- 

 ence, and were, as we have seen, highly organized. Traces of 

 Angiospermous Dicotyledons are not visible till a much more recent, 

 but still inconceivably remote period ; while from the time of the 

 Eocene and Miocene periods > there is a gradual increase in the 

 number of forms, such as are now found in various parts of the 

 globe. 



It is clear, then, on the whole, that there has been a succession 

 of vegetable types, and a gradual progression in morphological 

 complexity, but that such succession has been interrupted and not 

 continuous in any one locality, that many links have been utterly 

 lost, and many forms become extinct, so that the attempts made to 

 create a " phylogeny " or genealogical history of the Vegetable 

 Kingdom on so imperfect a basis as is now available must be 

 accepted with great reserve. 



2z 



