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Professor Goppert, after examining the fossil vegetables of the coal-fields of Germany, has detected, in beds of pure coal, remains of plants of every family hitherto known to occur fossil in the carboniferous rocks. Many seams, he remarks, are rich in Sigillariae, Lepidodendra, and Stigmariae, the latter in such abundance as to appear to form the bulk of the coal.
In accordance with their outside markings, certain types are known as syringodendron, favularia, and clathraria. Diploxylon is a term applied to an interior stem referable to this family. Stigmaria ficoides. But the most interesting point about the sigillariae is the root.
It has been asked how, during river inundations capable of sweeping away the leaves of ferns and the stems and roots of Sigillariae and other trees, could the waters fail to transport some fine mud into the swamps?
Yet the dead reeds, in spite of this change, remained standing in the soft mud, enabling us to conceive how easily the larger Sigillariae, hollow as they were but supported by strong roots, may have resisted an incursion of the sea.
Vegetation of the Coal Period. Ferns, Lycopodiaceae, Equisetaceae, Sigillariae, Stigmariae, Coniferae. Angiosperms. Climate of the Coal Period. Mountain Limestone. Marine Fauna of the Carboniferous Period. Corals. Bryozoa, Crinoidea. Mollusca. Great Number of fossil Fish. Foraminifera.
Dawson to be capable of walking and running on land. Xylobius Sigillariae, Dawson. Coal, Nova Scotia. a. Natural size. b. Anterior part, magnified. c. Pupa vetusta, Dawson. a. Natural size. b.
In many places distinct proof is seen that the enveloping strata took years to accumulate, for some of the sandstones surrounding erect sigillarian trunks support at different levels roots and stems of Calamites; the Calamites having begun to grow after the older Sigillariae had been partially buried.
In the case of the Sigillariae, the variations in the leaf-scars in different parts of the trunk, the intercalation of new ridges at the surface representing that of new woody wedges in the axis, the transverse marks left by the stages of upward growth, all indicate that several years must have been required for the growth of stems of moderate size.
At low tide a fine horizontal section of the same beds is exposed to view on the beach, which at low tide extends sometimes 200 yards from the base of the cliff. The thickness of the beds alluded to, between d and g, is about 2500 feet, the erect trees consisting chiefly of large Sigillariae, occurring at ten distinct levels, one above the other.
The climate of the period, in the northern temperate zone, was of such a character that the true conifers show rings of growth, not larger, nor much less distinct, than those of many of their modern congeners. The Sigillariae and Calamites were not, as often supposed, composed wholly, or even principally, of lax and soft tissues, or necessarily short-lived.
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