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 yeil which still obscures the affinities of the plants in the 
coal-measures, 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, m 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 Bessége, 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 Bessége, 
which is the largest [ 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 penctrate 
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. & Mag. N. Hist, Vol. xvii. 
