90 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [DeC. 3, 



legists are disposed implicitly to adopt his conclusions, and to dis- 

 regard altogether the evidence of fossil plants as to the former state 

 of the earth's surface. 



At the same time I readily admit, that the plants, of which we 

 now find the remains imbedded in the carboniferous strata, may 

 probably be but a very small proportion of those which at that time 

 flourished on the earth. If, as seems to be now most generally be- 

 lieved, the coal-beds are derived from the vegetation of ancient 

 swamps or lakes, existing in the very localities now occupied by 

 such beds of coal, we could not expect to find in them the remains 

 of other plants than such as grew in those bogs, or lakes, or swampy 

 forests, or immediately around them, together perhaps with some 

 which might be washed into them by occasional inundations. May 

 there not have existed at the same time, in other parts of the world, 

 (nay, perhaps, at no very great distance from the carboniferous re- 

 gions,) great tracts of country, indeed whole continents, in which 

 the local circumstances were unfavourable to the preservation of 

 vegetable remains, and of which, consequently, the flora is totally 

 lost to us ? If, on the other hand, as some suppose, (and as may 

 probably have been the case in some instances,) the coal was formed 

 out of vegetable matter drifted down by rivers, and accumulated in 

 estuaries or shallow bays, then it is clear that such deposits are not 

 likely to include anything like a complete series of the vegetation of 

 the then existing lands. 



I think, therefore, that we ought to proceed with great caution in 

 theorizing with respect to the vegetation and climate of the car- 

 boniferous sera. I do not admit that Professor Lindley's observa- 

 tions have destroyed the value of the evidence afl'orded by the great 

 proportional number of ferns in the Flora of the coal-measures ; I 

 believe that that preponderance, together with the other character- 

 istics of the fossil vegetation of that period, affords to a certain de- 

 gree good evidence respecting the climate of those particular regions 

 in which the coal-measures occur ; but we should not be justified 

 in extending our inferences farther. Those parts of Europe and 

 North America in which the coal-fields were accumulated, may 

 have existed at that time in the state of islands, like those of the 

 present Pacific Ocean ; but it would be rash to infer, as M. Adolphe 

 Brongniart seems disposed to do, that no extensive continents at 

 that time existed in any part of the globe. If, in all departments 

 of geology, it is necessary to advance with caution, and to avoid 

 dogmatism and rash generalizations, it is more especially necessary 

 in the department of Fossil Botany, where so much of the evidence 

 we possess is fragmentary and imperfect. 



Additional Remarks on Pecopteris emarginata. 



Since this paper was written, I have seen in the British Museum 

 specimens of Diplazites emarginatus, Gopp., from Wettin near 

 Halle. They are not in fructification, but exhibit the venation, and 



