Fossil Vegetables. 109 
thick. The bark is converted into coal. In the great coal field of 
the north, fossil plants are generally found in a horizontal position or 
parallel to the strata, but much broken and compressed, with their 
parts far separated. But large and vigorous plants are sometimes 
found which appear to have been strong enough to withstand the force 
of torrents, if such existed, and to have remained in their natural posi- 
tions. ‘These vertical plantsare generally Sigillarie. The Stigmarie 
and the Equisetacee do not appear to have been strong enough ~ 
to have resisted such revolutionary influences. Great numbers of 
Gymnospermous Phanerogamic plants have been lately discover- 
ed in the shales of the mountain limestone group, much broken, 
and lving in a state of great confusion. Other discoveries of fos- 
sil trees have been made in the same quarry, in which the above 
named plants wére found, particularly two immense Conifere, and 
there appears strong reason to believe, that in a square mile of the 
same deposit, many other ancient relics of early vegetation will be 
brought to light, and thus induce the belief that these plants are as 
abundant in these deposits, as in those higher up in the strata. Some- 
times the composition of the fossil vegetables i is similar to that of the 
strata in which they lie, and sometimes it is either wholly or partially 
different, and the variation must be accounted for from the operation 
of local causes. The composition of the Craigleith fossil, named 
above, was carbonate of lime 62, carbonate of iron 33, carbon 5, and 
the specific gravity was 2.87. The composition of the Craigleith 
tree discovered in 1826 was carbonate of lime 60, oxide of iron 18, 
alumine 10, carbon 9, loss 3, and several specimens from other places 
had a similar composition. 
A fossil plant from the quarry of Neworth near Newcastle, between 
the encrinal or mountain limestone and the new red sandstone depos- 
its, was, silica 95, peroxide of iron and alumine 5. 
he discoveries of Mr. Witham induce us to believe that plants 
of the gymnospermous phanerogamic class are much more abundant 
in the early sedimentary _— than continental writers have sup- 
sed. 
We are led to the curious and unexpected conclusion that proper 
trees, of true ligneous fibre and of great size, existed, even earlier than 
the bituminous coal, and that the great coally deposits are probably 
due, in part, to them, as well as to the vascular cryptogamic plants, 
whose remains are so abundant in these strata. 
It is therefore possible that wood may be found, even with the ear- 
liest fragmentary rocks, probably with the grauwacke itself. 
