50 proceedings of the geological society. [apr. 28, 



April 28, 1858. 



James Powrie, Esq., Eeswallie, near Forfar, Marcus Huish, Esq., 

 Castle Donnington, Derby, Henry D. M. Spence, Esq., Hyde Park 

 Square, and Parkin Jeffcock, Esq., Derby, were elected Fellows. 



The following communications were read : — 



1. On some Yegetable Eemains from Madeira. 

 By Charles J. F. Bxwburt, Esq., F.E.S., F.G.S. 



The vegetable remains procured by Sir Charles Lyell and M. Hartung 

 from the leaf-bed which they discovered* in the ravine of S. Jorge, 

 in the Island of Madeira, were entrusted to me for examination ; and 

 I propose now to lay before the Geological Society the observations 

 I have been able to make upon them. I have examined 140 speci- 

 mens, by far the greatest part of them in a very imperfect state, 

 mostly small fragments, often quite undeterminable, and, even when 

 most perfect, no more than single detached leaves, of which, how- 

 ever, the veins and margin are often very well displayed. Dico- 

 tyledonous leaves predominate, but are intermixed with numerous 

 remains of Ferns, always, however, in smaU fragments, insuiRcient 

 to give any idea of the general form of the frond. The very 

 fragmentary and incomplete condition of the remains of Ferns in 

 this bed is indeed striking. Something of it is attributable to the 

 nature of the stone, which is by no means fissile, but breaks quite 

 irregularly ; but something also would seem to be owing to the 

 original conditions of the deposit. The circumstance is unfortunate, 

 because Ferns are so variable, and show such differences even in 

 different parts of the same frond, that great uncertainty attends the 

 determination of them from such small fragments. 



Of the Dicotyledonous leaves, a large proportion, as I have said, 

 are too imperfect to be even described. Of those that are best pre- 

 served, a few kinds may, with a certain degree of confidence, be 

 referred to species now existing in Madeira ; others are manifestly 

 different from any known to exist there ; the rest have, in my 

 opinion, no character suiBftciently marked to determine their aiSnities. 

 On this point, however, I am aware there may be different opinions. 

 Botanists, indeed, are far from being agreed on the question, whether 

 the afiinities of Dicotyledonous plants can, as a general rule, be 

 determined from the leaves alone ; that is, whether the leaves by 

 themselves afford characters sufiiciently definite, and sufficiently in 

 accordance with those afforded by the fructification, to be safe 

 guides to the determination of genera or families. Some eminent 

 palaeobotanists of Germany and Switzerland, attaching great import- 

 ance to the characters of leaves, have assigned generic names to the 

 fossil plants of the tertiary age with a degree of confidence which, 

 in not a few instances, appears rather surprising. 



This question cannot be completely settled without a very exten- 



* See Lyell's Manual of Elementary Geology, 5th ed. (1855), p. 518. 



