Stigmaria was probably dicotyledonous, and in its internal structure seems to have borne some analogies to that of the Euphobiaceæ.
Conclusion.
Besides these Genera which have been enumerated, there are many others whose nature is still more obscure, and of which no traces have been found among existing vegetables, nor in any strata more recent than the Carboniferous series.[1] Many years must elapse before the character of these various remains of the primeval vegetation of the Globe can be fully understood. The plants which have contributed most largely to the highly-interesting and important formation of Coal, are referable principally to the Genera whose history we have attempted briefly to elucidate: viz. Calamites, Ferns, Lycopodiaceæ, Sigillariæ, and Stigmariæ. These materials have been collected chiefly from the carboniferous strata of Europe. The same kind of fossil plants are found in the coal mines of N. America, and we have reason to believe that similar remains occur in Coal formations of the same Epoch, under very different Latitudes, and in very distant quarters of the Globe, e. g. in India, and New Holland, in Melville Island, and Baffin's Bay.
The most striking conclusions to which the present state
of our knowledge has led, respecting the vegetables which
gave origin to col are, 1st, that a large proportion of these
plants were vascular Cryptogamiæ, and especially Ferns;
estuary or sea, and there becoming surrounded by sediments of mud or sand. This hypothesis seems supported to the observations made at Jarrow, that the extremities of the branches descend from the dome towards the adjacent bed of coal.
- ↑ Some of the most abundant of these have been classed under the names of Asterophyllites, (see Pl., 1, Figs. 4. 5.) from the stellated disposition of the leaves around the branches.
