12 
such was also the nature of the primaeval forests, antecedent 
to the formation of our coal fields, we can have little doubt, 
whose vast accumulation of debris on the surface, continually 
augmenting through long periods of time, would, by their 
deposition, consolidation, and submersion, contribute mate- 
rially to form the various seams of coal now again brought 
to the light of day for the benefit of man. The plants at 
that epoch, however, being primarily gigantic Sigillariae, 
rising to seventy feet in height, Lepidodendra, Ulodendra, 
Bothrodendra, &c, with an under-growth of Ferns, Cala- 
mites, Equisetums, Sphenophyllum, Asterophyllites, &c, 
hence we conclude, that as at the present day, so it would 
be in the past, no very large number of different species of 
plants would grow in the densely wooded parts of the globe, 
from the causes before stated.* A greater variety would be 
found, however, in the plains, marshes, and mountain sides, 
which would make little or no figure in the present flora of 
the coal strata, from the fact that only a very limited number 
could bear the long submersion, and yet leave us their 
remains to the present day. This has been most satisfac- 
torily and clearly demonstrated, in a series of experiments 
instituted by Professor Lindley, for the express purpose of 
testing the durability of various genera and species of 
plants. He says:— " On the 21st of March, 1833, I filled 
a large iron tank with water, and immersed in it 177 
specimens of various plants, belonging to the more remark- 
able natural orders, taking care, in particular, to include 
* Since the above passage was written, I have been pleased to find this view 
corroborated by my friend, Dr. Hooker, whose duties as botanist to the Ant- 
arctic Expedition would give him ample opportunities for observation. In 
his paper " On the Vegetation of the Carboniferous Period, as compared with 
that of the present day," he says, — " A luxuriant vegetation is, however, no 
index to a varied one ; and as many of our modern woods, and even great area 
of tropical forests, consist of but a few species multiplied ad infinitum, so may 
the forests of the carboniferous period have been composed of but a few 
Sigillariae and Lepidodendrons, sheltering an under-growth of a limited number 
of kinds of Fern." — Edinburgh Philosophical Journal, vol. xlvi., p. 77. 
