. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. 474 SIGILLAEIA. [Ch. XXIV. Asterophyllites many vegetable fragments have been grouped which probably belong to different genera. They have, in short, no charac- ter in common, except that of possessing narrow, verticillate, one- ribbed leaves. Dr. Newberry, of Ohio, has discovered in the coal of that country fossil stems which in their upper part bear wedge-shaped leaves, corresponding to Sphenophyllum, while below the leaves are stalk-like and capillary, and would h
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. 474 SIGILLAEIA. [Ch. XXIV. Asterophyllites many vegetable fragments have been grouped which probably belong to different genera. They have, in short, no charac- ter in common, except that of possessing narrow, verticillate, one- ribbed leaves. Dr. Newberry, of Ohio, has discovered in the coal of that country fossil stems which in their upper part bear wedge-shaped leaves, corresponding to Sphenophyllum, while below the leaves are stalk-like and capillary, and would have been called Asterophyllites if found detached. From this he infers that Sphenophyllum was an aquatic plant, the superior and floating leaves of which were broad, and possessed a compound nervation, while the inferior or submersed leaves were linear and one-ribbed. " This supposition," he adds, " is further strengthened by the extreme length and tenuity of the branches of this apparently herbaceous plant, which would seem to have re- quired the support of a denser medium than ; * Sigillaria.—A large portion of the trees of the Carboniferous pe- riod belonged to this genus, of which about thirty-five species are known. The structure, both internal and external, was very pecu- liar, and, with reference to existing types, very anomalous. They were formerly referred, by M. Ad. Brongniart, to ferns, which they resemble in the scalariform texture of their vessels, and, in some de- gree, in the form of the cicatrices left by the base of the leaf-stalks which have fallen off (see fig. 527). But with these points of analogy to cryptoga- mia, they combine an internal organization much resembling that of cycads, and some of them are ascertained to have had long linear leaves, quite unlike those of ferns. They grew to a great height, from 30 to 60, or even 70 feet, with regular cylindri- cal stems, and without branches, although some species were dichotomous to
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