89 
To these must be added the Elm and the Hazel Bushes, whose 
fresh green foliage will have served to break the gloomy garb 
of the Pine-forest.’’* 
A bed of Lignite is coal in the process of forming; if then 
the origin of the Lignites of the Miocene (which is the age 
assigned to the deposits) coal was formed as above described, 
why should it not have been the same, or a modification of the 
same, during the carboniferous period, a delta perhaps being 
sometimes substituted for a lake ? 
It suggests itself to us that the occurrence of Stigmaria in the 
underclays may be accounted for in this way: there was a land 
surface gradually sinking, as it sank water advanced and the 
terrestrial vegetation was replaced by mosses and reeds, the big 
trees fell and drifted away, the ferns and other terrestrial 
vegetation also floated away or decayed, as we see the modern 
ferns at the present day when in water. 
In conclusion I would urge attention to the study of the 
Fossil Flora; it has not hitherto, it is true, rendered much 
assistance to Geology, but the reason is it has not been asked ; 
but if taken up and worked out upon the lines I have endeavoured 
to sketch out to-night, I think it would bear important fruit, 
and prove that Fossil plants, like Fossil animals, had each their 
prescribed limits in time and space. 
* Quarterly Journal Geological Society, page 69, 1878. 
