THE, 



EDINBURGH NEW 



PHILOSOPHICAL JOURNAL. 



The Theory of the Successive Geological Development of Plants, 

 from the earliest periods to our own time, as deduced from 

 PalcGontological evidence. 



Having already laid before our readers Sir Charles Ly ell's 

 view in regard to the geological distribution of Fossil Animals, 

 we now add his observations on the geological distribution of 

 Fossil Plants. 



In his introductory discourse he makes the following state- 

 ment : — If we consider the question of successive geological 

 development from a botanical point of view, we find that 

 naturalists are by no means agreed as to the existence of an 

 ascending scale of organization in the vegetable world cor- 

 responding to that which is very generally recognized in ani- 

 mals. " From the sponge to man," to borrow the words of 

 De Blainville, there is a progressive chain of being, often 

 broken, it is true, and imperfect, and in which some whole 

 genera or families seem to have no natural place. But if we 

 seek to classify plants according to a linear arrangement, 

 ascending gradually from the lichen to the lily or the rose, 

 we encounter incomparably greater difficulties. Yet the 

 doctrine of a more highly-developed organization in the plants 

 created at successive periods presupposes the admission of 

 such a graduated scale. 



There can, however, be no dispute that the cryptogamous 

 plants are the least perfect, a class to which the marine 

 vegetation almost entirely belongs. The sea, it is true, pro- 

 duces «ome flowering plants, such as Zostera and Caulinia, 

 but they are among the least-develop6d of the phaenogamous 



VOL. LI. NO. CII.^— OCTOBER 1851. P 



