[Illustration: Lign. 32. Base of a Trunk of a Sigillaria. with roots, _standing erect with five other stems, in Carboniferous strata_. (_The original is four feet high._)] In the stratum through which the roots extend, a considerable quantity of the fossil cones, called _Lepidostrobi_, hereafter described, were imbedded (see _Lign. 40_). A thin layer of coal which invested the stems, was evidently the carbonized bark. All the stems were filled with blue clay, or shale, a proof that they were hollow when submerged in the mud, which is now consolidated into the shale in which they are imbedded. But it is not probable that they were originally tubular, like a reed: on the contrary, there is evidence to show that they were highly organized. Their internal structure may have decayed, or been destroyed by insects or other depredators; as is often the case in tropical climates, where the trunks of timber trees are speedily excavated after their fall, and afford shelter to innumerable insects and reptiles, as the weary traveller often finds to his surprise and annoyance.[96] The late Mr. Bowman affirmed[97] that these trees were dicotyledonous, and stated that medullary rays and coniferous structure could be detected; an opinion, which the researches of M. Brongniart on the Sigillariæ have fully corroborated. [96] Mr. Hawkshaw, Geol. Proc. p. 269. [97] Geol. Proc. vol. iii. p. 270. * * * * * [Sidenote: ERECT STIGMARIÆ.] Many other instances have been noticed of Sigillariæ standing more or less erect in the strata. In forming the railway tunnel at Claycross, five miles south of Chesterfield, through the middle portion of the Derbyshire coal-measures, in 1838, a group of nearly forty trees (_Sigillariæ_) was discovered, standing not more than three or four feet apart, at right angles to the plane of the strata.[98] On the coast of Northumberland, within the length of half a mile, twenty trees were observed by Mr. Trevelyan, in 1816 (_Bd._ p. 470). The coal-pit at St. Etienne, in France, described by M. Alex. Brongniart, is celebrated for affording an example of this phenomenon (_Wond._ p. 673); but the positions of many of those stems are inclined at various angles, and their roots implanted in different beds, so that the perpendicularity of the erect trees is probably accidental (_Bd._ p. 471). [98] Ibid. p. 272. The most remarkable instance hitherto observed, is on the southern shore of the Bay of Fundy, in Nova Scotia, where the cliffs, which are about two hundred feet high, are composed of carboniferous strata, consisting of coal, clay, grit, and shale, in which numerous erect trees, probably Sigillariæ, are seen on the face of the cliff; there are ten rows one above another, indicating, in the opinion of Sir C. Lyell, repeated subsidences of the land, so as to allow of the growth often successive forests![99] (_Wond._ p. 674).