178 THE GEOLOGIST. 
insects, &c. They will probably be rewarded by finding some wing- 
cases of Ortliopterous tribes, and it will be tbeir first discovery ia 
Britain. 
Aracbnida (that is, spiders and scorpions) were probably not rare 
in the coal-period. A fossil scorpion was found at Prague ; and 
unless I am veiy much mistaken, I have seen relics of more than one 
large spider from Coalbrooke Dale, in Shropshire. 
In those celebrated trees described by Professor Dawson and Sir 
Charles Lyell,* and Avhich were found in the sandstone of Nova Scotia, 
millepedes (Xylohius), or at all events some members of the myriapod 
group, were found. They were associated, in the same hollow stumps, 
with numerous small land-snails. These Avere somewhat like the 
little Pupa, or chrysalis snail, so common on moss-grown 
trees, in the deep woods of Old England. But I shall 
never believe that coal-forests were like the woods of our 
own times, for reasons which will immediately appear. 
One word, though, about the other land animals found 
in these trees, for Prof. Dawson in his last communication 
Fig. 1.— to the Geological Society,t makes it extremely probable that 
Pupavetusta. Were land Hzards to feed on and restrain this 
insect-life within due bounds. They may have been amphi- 
bious lizards— the larger species {Dendreiyeton Acadianum), found in 
the coal-measures, certainly was so — yet the nature of the teeth of 
another (the Sylonomus), and its scaly armom*, look too much like 
those of living land lizards, to allow us readily to believe that it too 
was a Batrachian reptile, modified for and adapted to this sort of life. 
We must wait for more complete information. 
And now, with all these proofs that the creatures of the land lived 
and died in the old coal-forests, why should we refuse to believe that 
these grew upon dry land ? 
That dry land was not far ofi", I must, of coui^se, admit. The muddy 
sediment and sand that form the mass of the coal-measm^es were 
derived from land ; and must have been formed, as sand and mud are 
now formed, by the washing away of rock and earth — the daily 
action of the tides and rivers. 
But the question is, whether the plants gTewonthe land, and were 
then submerged ; or whether they grew in the water, and so were 
mixed with the " spoils of animals, savage and tame," that lived in 
the water. 
The commonest fossil in the coal measures — the one which par 
excellence, is "the coal fossil" — is the Anthracosia, or Unio, as it used 
to be called. 
This is a bivalve shell with closed valves, looking not at all 
unlike the common Unios of our streams, but never showing any of 
those peculiar wrinkles about the beak, which living Unios always 
exhibit. 
* Quart. Joum. Geol. Society, vol. ix., p. 58. 
t Ibid. vol. xvi, p. 275. 
