144 ARBER : FOSSIL FLORA OF SOUTH YORKSHIRE COALFIELD. 
be clearly seen, the former arising in the axils of the bract. Weiss 
appears to have been somewhat doubtful as to the attachment 
of the sporophylls in the type specimen, but this feature is clearly 
seen in the present example. 
Calamites sp. 
Plate XIII., Figs. 1 and 2. 
The external surfaces of Calamite stems are much rarer 
fossils than the pith-casts. The cast and impression of the 
external surface of a specimen, from the Lower Coal Measures of 
Trowell Colliery, which is figured on Plate II., Figs. 1 and 2, shows 
two nodes, one of which bears five large, oval, branch-scars. The 
internodes are smooth, and not ribbed as in the case of the pith- 
casts. In this specimen the internodes are probably of unequal 
length, though this cannot be ascertained with certainty. From 
the British Carboniferous rocks, apparently only three species of 
Calamites are at all well known by their external surfaces. Two 
of these, C. hritannicus Weiss and C. ramosus Art is, belong to 
the section Eucalamites, which possess branch scars on every node. 
The third, Calamites gospperti (Ett.), which is probably the 
external surface of the plant, whose pith cast is known as C. varians 
Sternb., belongs to the Calamitina section. The present speci- 
men has similar affinities. It differs from C. goepperti, however, in 
the oval form of the branch-scars, the longer axis of which is 
transverse or horizontal. In C. gospperti, the branch-scars are 
more nearly square or oblong in form, and somewhat larger in 
size. The specimen, while apparently distinct from any hitherto 
described, is not sufficiently perfect to serve as the type of a new 
species, and for the present it is best described as Calamites sp. 
Calamites approximxitus , Brongniart. 
Plate XIII., Fig. 3. 
1828. Calamites approximatus , Brongniart, Hist. Veget. Foss., 
p. 133, Plate XXIV., Figs. 2-5. 
1855. Calamites approximxitus^ Geinitz, Vers. Steinkohlenf. 
Sachsen, p. 7, Plate XII., Fig. 3. 
1884. Calamites approximxitus , Weiss, Abhandl. Geol. Specialk. 
Preuss., Vol. V., Part 2, p. 81, Plate XXV., Fig. 1. 
