genus Noggerathia to Living Plants. 105 



One of the best means of removing some of the difficulties in 

 the study of fossil plants, and especially of withdrawing part of 

 the veil which still obscures the affinities of the plants in the 

 coal-measureSj appears to me to consist in studying, in the mines 

 themselves, the manner in which the various forms of fossil plants 

 are associated in the rocks which accompany the same layer of 

 coal. In fact, in my opinion, each stratum of coal is the pro- 

 duct of a peculiar vegetation, frequently different from that which 

 precedes and that which follows it, — vegetations which have given 

 rise to the superior and inferior layers of coal ; each stratum re- 

 sulting, in this manner, from a distinct vegetation is frequently 

 characterized by the predominance of certain impressions of 

 plants, and the miners in numerous cases distinguish the dif- 

 ferent strata which they remove by the practical knowledge they 

 possess of the accompanying fossils. Any layer of coal and the 

 rocks which lie upon it should consequently contain the various 

 parts of the living plants at the moment of its formation, and by 

 carefully studying the association of these various fossils, which 

 form so many special floras, containing generally but few species, 

 we may hope to be able to reconstruct these anomalous forms of 

 the ancient world. This is what I have applied myself to in my 

 travels during the last two years, with the view of studying the 

 coal strata of part of France and the fossil plants which they con- 

 tain ; and although similar results cannot generally be obtained 

 except by long-continued researches, which the directors of mines 

 alone could make, still chance has sometimes favoured me, and 

 furnished me with useful materials for the solution of this import- 

 ant question. Thus, in the mines at Bessege, near Alais, I was 

 astonished at finding amongst the portions removed from one 

 gallery and from the same stratum, a large number of the follow- 

 ing fossils, which were almost unmixed with others : — 1. Nume- 

 rous fragments of the leaves of Noggerathia, with long, almost 

 linear leaflets, which were slightly cuneiform and lobed at the 

 summit ; 2. Other fronds of a crested form, and having a very 

 characteristic aspect ; 3. A large number of large elliptic or ob- 

 long seeds. These remarkable fronds, of which I had met with 

 rather small fragments only, but of which I have since seen al- 

 most perfect specimens in other mines, in the species at Bessege, 

 which is the largest I am acquainted with, would be about 50 

 centimetres long and about 30 broad. They are bipinnatifid, the 

 petiole and rachis large, flattened, expanding as they penetrate 

 the secondary rachides, and from thence into the rounded, re- 

 curved and fringed lobes, which constitute the foliaceous appear- 

 ance. This part has not in the least the aspect of the delicate and 

 well-defined leaves of the ferns, which are so common in these 

 strata ; in this it is rather a flattened, dilated petiole, thinner and 



Ann. fif Mag. N. Hist. Vol. xvii. I 



