. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Ch. XXIV.] STIGMARIA. 475 Dr. Hooker still inclines to the belief that the gigillarice may have been cryptogainous, though more highly developed than any flowerless plants now living. The scalariform structure of their vessel agrees pre- cisely with that of ferns. Stigmaria.—This fossil, the importance of which has already been pointed out, was formerly conjectured to be an aquatic plant. It is now ascertained to be the root of Sigillaria. The connection of tbe roots
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Ch. XXIV.] STIGMARIA. 475 Dr. Hooker still inclines to the belief that the gigillarice may have been cryptogainous, though more highly developed than any flowerless plants now living. The scalariform structure of their vessel agrees pre- cisely with that of ferns. Stigmaria.—This fossil, the importance of which has already been pointed out, was formerly conjectured to be an aquatic plant. It is now ascertained to be the root of Sigillaria. The connection of tbe roots with the stem, previously suspected, on botanical grounds, by Brongniart, was first proved, by actual contact, in the Lancashire coal- field, by Mr. Binney. The fact has lately been shown, even more dis- tinctly, by Mr. Richard Brown, in his description of the Stigmaria? occurring in the underclays of the coal-seams of the Island of Cape Breton, in Nova Scotia. In a specimen of one of these, represented in the annexed figure (fig. 528), the spread of the roots was sixteen feet, and some of them sent out rootlets, in all directions, into the surrounding clay. Fisr. Stigmaria attached to a trunk of Sigillaria.* In the sea-cliffs of the South Joggins in Nova Scotia I examined several erect Sigillaria?, in company with Dr. Dawson, and we found that from the lower extremities of the trunk they sent out Stigmarice as roots. All the stools of the fossil trees dug out by us divided into four parts, and these again bifurcated, forming eight roots, which were also dichotomous when traceable far enough. The cylindrical rootlets formerly regarded as leaves are now shown by more perfect specimens to have been originally attached to the root by fitting into deep cylindrical pits. In the fossil there is rarely any trace of the form of these cavities, in consequence of the shrinkage of the surrounding tissues. Where the rootlets are removed nothing remains on the surface of the Stigma
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