[siK J. w. DAWSON] OX THE GENUS LEPIDOPHLOIOS 69 



the latter have usually been considered as characterized by the leaf-scars 

 being placed in vertical rows and often on continuous prominent ribs, 

 and also by the fact that the lateral vascular scars are much larger than 

 the central one ; but in such a case as Lesquereux's species, L. rosfatuni, 

 the confluent leaf-bases in vertical rows have the ettect of ribs, and in a 

 less degree the same remark applies to L. Murrayanum. I may add that 

 when one happens to tind young stems of Sujillaria not compressed, the 

 leaf-bases are seen to project in the manner of iho^Q oï Lepidodendron, 

 and that in some non-ribbed Sigillarids, as in aS'. elegajis, the very young 

 branches have the scars arranged spirally.' In connection with this I 

 may observe that Sauveur ' has described two species of Sigilloria, S. 

 ■angustata and S. undalata, which are scarcely distinguishable, so far as 

 the old bark is concerned, from Jj. Murrayanum ; and Groldonberg ^ has 

 two similar species, S. aspera and >S^. coarctata. Goldenberg's two species 

 are by the character of their scars unquestionably Sigiltaria, but S. 

 ■angustata and S. undulata of Sauveur, especially the former, might well 

 have been lepidodendroid trees very near to L. Murrayanum. This, how- 

 ever, coiild be certainly ascertained onl}^ if more complete specimens 

 could be found. On the whole one might infer that as the spiral and 

 Lepidodendroid characters of Sigillaria appear most prominently on 

 joung branches, the more Lepidodendroid and spiral Sigillaria are the 

 lowest in type and the ribbed Lepidodendra among the highest of that 

 genus. But such a conclusion must be received as liable to many excep- 

 tions." 



Subsequently to the appearance of this paper, in which I referred only 

 to the branches and cones, I was led, in arranging the specimens in our 

 museum, to stri]) otf some of the long leaves from the largest slab in my 

 possession, representing a portion of the trunk or a main branch, and 

 was surprised to tind that the leaves and leaf- bases were arranged on the 

 plan of Lepidophloios. My Clifton specimen thus showed characters 

 which combined those of Lepidodendron and X/epidophloios, and as the 

 leaves and fruit were those of the latter genus, I have now no hesitation 

 in referring it to this ; though it furnishes a very interesting illustration 

 of the clo.se approximation of the two genei'a, as well as an example of 

 the possibility of refeiTing fragments oï Lepidophloios to Lepidodendron. 

 At the same time, a specimen from the Clifton quarries which is evidently 

 a portion of the surface of a trunk or large branch, shows that in this 

 sj^ecies, which I think may be referred to Lepidodendron Wortheni, the 

 character of the leaf-bases and leaf-scars, which are contined to slender 

 branches in the associated Lepid.ojjhloios, may be persistent on the main 

 trunk. "Were it not for this specimen I would be induced to suggest that 



1 Acadian Geology, 1878, p. 434. 



2 Fossil Flora of Belgium, 1848, pi. Ivi. and Iviii, 



3 Brit. Mus. Catalogue, 1886, p. 151. 



