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FOSSIL PLANTS. 



§ 5. The Specimens Nos. 46 and 47, Stigmaria ficoides. Plate XXIV, figs. 4, 5 y 



No. 4G ; figs. 6, 7, 8, No. 47. 



Fig. 4 represents, on a greatly reduced scale, the base of a stem (No. 46) having- 

 the irregular ribs and furrows so generally found on the outside of Sigillaria vascularis 

 when in a decorticated state. The greatest breadth across the specimen is about 

 four feet and six inches, from one of the main roots to the other on the oppo- 

 site side. 



Fig. 5, on a greatly reduced scale, represents the under side of the same specimen, 

 showing the crucial sutures. 



Specimen No. 47, fig. 6, on a greatly reduced scale, shows the base of another 

 decorticated stem, having its sides covered with the same kind of irregular ribs and furrows 

 as above described on No. 46. The greatest breadth across the specimen is about thirty 

 inches. As part of the secondary roots of this specimen remain, there is evidence of the 

 same system of dichotomization which has been observed in the Dixon Fold, St. Helens, 

 and other examples of large fossil trees of Sigillaria vascularis. 



Fig. 7 represents the under view of the same specimen, showing the crucial 

 sutures. 



Fig. 8 shows the distinct areola?, with a little round elevation in the centre, and the 

 convex corrugated lines so commonly found on the outside of Stigmaria. 



The above specimens are in the Museum of the Leeds Philosophical Society, and were 

 observed in 1839 by the late Mr. Bowman and myself. That gentleman made drawings 

 of them at the time, and the present figures are reduced copies. The specimens consist 

 of a fine-grained sandstone; and we were informed that they had been found in the 

 Lower Coal-measures near Bradford, Yorkshire. 



In alluding to these singular sutures Dr. Hooker, at page 417 of his memoir, 1 says — 

 " A yet more remarkable and anomalous structure in Sigillaria than either that of their 

 stigmaroid roots or fluted stems was pointed out to me by Mr. Binney. This is the 

 curious crucial mark which quarters the base of the trunk. The Sigillaria generally 

 divides into four main roots at the base, which unite to form the crown of the dome 

 described by Lindley and Hutton ; and it is along the line of union of these four roots 

 that these strongly marked lines run, all meeting at the centre of the dome. I know 

 nothing analogous to this in recent or fossil botany." 



Dr. Schimper observes 2 — " On remarque tres-souvent a la face inferieure du tronc 

 une suture en forme de croix, dont les extremites correspondent aux angles de bifurcation 



1 ' Memoirs of the Geological Survey of Great Britain,' vol. ii, part ii, p. 417. 



2 ' Traite de Paleontologie Yegctale,' vol. ii, p. 112. 



