TRANSACTIONS OF SECTION C. 811 
terminations of the branches, and in others in two opposite vertical rows (Uloden- 
dron, L. and H., zz part). 
In Lepidophioios the leaf-cushions are rhomboidal (as in LZ. laricinum) or 
elongated-truncate (as in Z. scoticum), and the leaf-scar is situated at the extremity 
of the cushion, having three punctiform cicatricules as in Lepzdodendron. The 
cones are borne on specially modified branches and are arranged in spirals 
(Halonia, L. and H.). 
The two genera are therefore very distinct in the position of the leaf-scar on the 
cushion, as also in their mode of fructification. The knowledge obtained of the 
structure of Lepidophloios since Sternberg’s time, and especially that acquired in 
recent years, has confirmed the view of its close affinity with Lepidodendron. 
Williamson has described the twigs, branches, stems, and fruits of Lepzdophloios 
brevifolium from Burntisland, and has shown that, fundamentally, these have the 
structure of the same parts of Lepzdodendron. 
Sohns-Laubach, in his ‘ Einleitung in die Paliiophytologie,’ states that Corda’s 
Lomatophloios crassicaule has a structure similar to that of the true Lepidodendron 
Harcourt. 
Inasmuch, however, as Corda’s genus Lomatophloios is Sternberg’s Leyrdophiotos, 
there is sufficient justification for his conclusion that the structure of Lepidodendron 
Harcourti may occur in Lepidophloios. 
Further, the same authority states that the plant described by Williamson as 
Lepidophloios brevifolium is intermediate in structure between Lepidodendron 
Harcourtit and Lepidodendron vasculare, Binney (L. selaginoides, Carr and Will.). 
Its primary xylem has zof the crenulated outline of the former species, though its 
structure is the same, but its leaf-trace bundles run downwards with only a slight 
projection, as in the latter. It further agrees, he adds, with the latter in the 
massive development of its secondary xylem. ‘To these proofs of the near relation 
of the two genera under consideration, we are in a position to add yet another, drawn 
from a specimen which we discovered some short time ago. This consists of a 
fossil stem whose external surface is marked by tolerably well-preserved characters, 
which leave no doubt that it must be referred to the genus Lepidophloios as defined 
by Sternberg. 
Transverse sections of it show, however, that in internal structure it is identical 
with the plant described by Williamson in his XIth memoir as Lepidodendron 
Harcourt, but since named by him Lepidodendron fuliginosum. 
The primary xylem has an outer periphery s/ightly crenulated, is in the form of 
a thin, hollow cylinder, and encloses a tolerably large pith composed of thin-walled 
parenchyma. Surrounding the primary xylem is a zone of dark, indistinct tissue 
in which are radially disposed elements, and which Williamson regards as the 
exogenous zone (secondary xylem) in an immature condition. Outside this is the 
thick cortex, which, in its general appearance as well as in the structure and the 
arrangement of several layers, is in close agreement with that of Lepidodendron 
Suliginosum. 
12. On the Changes of the Lower Carboniferous Rocks in Yorkshire from 
South to North.| By J. R. Daxyys. 
The author describes, without going into details, the chief changes which the 
rocks undergo from south to north. These may be summed up as follows :— 
1. The simple fourfold division of the Millstone grit prevalent in Derbyshire, 
ceases to be applicable northward, owing to the setting in of several fresh sand- 
stones. 
2. The Yoredale type of beds can hardly be said to exist south of Kettlewell. 
From Grassington northwards the carboniferous limestone becomes split up with 
beds of sandstone and shale, and north of Kettlewell important rocks, to wit the 
Underset and Main limestone, set in among the limestone shales, so that finally 
we have in Yoredale the well-known type of beds that go by that name. 
3. In the southern part of its course the Main limestone is immediately overlain 
} This paper is to be published in the Trans. of the Yorks. Geol. Sez. 
3a2 
