PALEOZOIC TIME — CARBONIC. 



669 



dites, are slender, small-leaved, and much like those of Lycoiwdium dendroi- 

 deum, though often large. The Halonia, Fig. 1035, is a decorticated stem or 

 rootlet of uncertain relations. Two species of Sigillaria are represented in 

 Figs. 1037, 1038. The figures show that the scars are peculiar in having at 

 the center a dot, and a short convex line either side ; the exterior of the stem 

 is generally vertically banded or costate, as in the figures. 



1039. 



1040. 



1041. 



1039-1044. 



1042. 



1044. 



1043. 



IiYCOPODS. — Fig. 1089, Lepidostrobus hastatus (or cone of a Lepidodendron) ; 1040, Lepidodendron lauceola- 

 tum, Lx. ; 1041, Stlgmaria. Scaes of Tree-ferns. — Fig. 1042, Stemmatopteris punctata (x^) ; 1043, Mega- 

 phyton McLayi ; 1044, Oyathea compta. Figs. 1039-1043, Lesquereux ; except 1041, Dawson. 



In both Sigillarids and Lepidodendrids, the appearance of the scars of 

 the same species varied much with age ; moreover, the same scar is wholly 

 different in form at the surface from what it is below, as Figs. 1037, 1038 

 illustrate. The trunk, while woody and firm outside, consisted inside mostly 

 of cellular tissue, with usually a very large pith along the center ; and hence 

 the stumps easily became hollow by decay. Such hollow stumps, filled with 

 sand or clay, are common in the Coal-measures ; and sometimes there remain 

 only casts of them in sand having a scarred exterior. 



