FOSSIL PLANTS. 



661 



These Lranches proceed from the joint, gradually 

 thicken towards the middle, and taper again to- 

 wards the extremities, the one of these branches 

 divides into two at the top. In this specimen, 

 which was found in the Edinburgh carbonifer- 

 ous sandstone, by H. Witham, Esq., there is no 

 trace of leaves. It appears identical with the 

 c. mungeotii, found by Brongniart in the new 

 red sandstone of the Vosges. Fig. b, is one of 

 the internal partitions of the joints, and such are 

 frequently found in iron nodules. The stems of 

 calamites were hollow, and readily yielded to 

 pressure, without being much altered. They 

 often contain in the interior fragments of ferns 

 and other plants. They probably had a distinct 

 wood and bark; at least, such is the opinion of 

 Brongniart. From this circumstance, tliey may 

 belong to the dicotyledonous plants, although 

 they have been compared to the equisetacese. 

 Young braiiches hqve been discovered, not, how- 

 ever, attached to the trunks, with small whorled 

 leaves. There are several species not by any 

 means distinctly identified. 



AsTEEOPHYLLiTES. Only fragments have hi- 

 therto been obtained of this genus, which consist 

 of cylindrical stems, with short joints, about 

 near as broad as they are long, with small verti- 

 cillate leaves. They bear a close resemblance to 

 the calamites, only the longitudinal furrows are 

 not present on tlie stem. -They were probably 

 dicotyledons. They are found occasionally in 

 the coal strata. 



Sticmaria Ficoides. This is, perhaps, the most 

 common and abundant plant composing the coal 

 seams, and lias been early taken notice of, and 

 described by many writers on the subject. It 

 appears, also, to differ so much from all known 

 vegetable productions of the present era, as to 

 merit the distinction of an entirely new class 

 of plants. From the numerous quantities of 

 this plant, which are found scattered among 

 the coal, shale, and accompanying sandstones 

 of the carboniferous series, there can be no 

 doubt that it was one of those vegetables 

 which have mainly contributed to the forma- 

 tion of coal, and on this account also, its struc- 

 ture and supposed habits merit particular at- 

 tention. The usual form in which the frag- 

 ments of this fossil are met with, is that of a 

 cylinder, more or less compressed, and generally 

 flatter on one side than the other; not unfre- 

 quently the flattened side turns in, so as to 

 form a groove. The surface is marked in quin- 

 cuncial order, with spots, or rather depressed 

 circles or areolsE, with a rising in the middle, in 

 the centre of which rising a minute speck is 

 often observable. From different modes and 

 degrees of compression, and probably from dif- 

 ferent states of the original vegetable, these 

 areola: assume very different appearances; some- 

 times running into indistinct rinw, like the bark 



of an aged willow ; sometimes as in the shale, 

 impressions exhibiting little more than a neat 

 sketch of the concentric circles. It is supposed 

 that these circles are the marks of the attach- 

 ment of the peduncles of leaves; these leaves or 

 spines also appear to have been cylindrical, and 

 often of considerable length. Woodward long 

 ago remarked, that along the flattened or grooved 

 side of the cylinder, there frequently ran an in- 

 cluded cylinder, which at one extremity of the 

 specimen would approach the outside, so as al- 

 most to leave the trunk, while at the other it 

 seemed nearly central. These internal cylinders 

 were frequently flattened from pressure. Occa- 

 sionally the specimens are found forked or 

 branched, and in one or two instances, a teimi- 

 nal portion has been discovered when the point 

 was obtuse, " closing from a thickness of three 

 inches, to an obtuse point." 



We have said that fragments only of the plant 

 are generally found, but several more entire and 

 perfect specimens have been discovered in the 

 Newcastle coal seams, by which the original 

 structure can be more accurately determined. 

 From these, it appears that the stigmaria, instead 

 of growing upwards and spreading out its arms 

 from a vertical trunk, was a prostrate plant, and 

 sent out its succulent cylindrical branches, which 

 were sometimes forked, from a central convex 

 cup or trunk. 



2,15. 





stigmaria Ficoides. 



The wood cut, which is an attempted restora- 

 tion of the original form of the plant, from the 

 various fragmentary views given of it, will point 

 out the mode of its growth. 



In one specimen obtained from the Jarrow 

 colliery, Newcastle, the central trunk measures 

 three feet in diameter; fifteen arms, four of which 

 are distinctly branched, were counted on another 

 specimen, the lengths of the fragments of which 

 varied from four feet downwards. Steinham 

 calculates that these arms may have exceeded 

 twenty feet in length. To show the multitude of 

 these fossil plants, no less than fourteen stems 

 were discovered in Jarrow colliery, within a space 

 of 600 yards square. Huge masses of shalely 

 sandstone, dug out of the upper beds of the Craig- 

 leith quarries, near Edinburgh, have also exhi- 

 bited innumerable fragments of the stigmaria ; 

 and one block of several tons' weight examined 

 by US, appeared to contain a large plant with 

 its long arms and massy central cup several feet 

 in diameter. From a fragment of stigmaria 



