356 FOSSIL FLORA OF SOUTHERN PORTION OF THE YORKS. COALFIELD. 
1907. Mixoneum obliqua, Zalessky, ibid., No. 135, Vol. 26, p. 479, 
pi. 19, figs. 1-10. 
1911. Xeuroptei is impar, Kidston, Mem. Mus. R. Hist. Nat. Belgique. 
Vol. IV., p. 83, pi. VIII., figs. 1, 2, 3 and 3a. 
1913. I Xeuropteris oblifpia, Gothan, Ahhandl. k. Preuss Geol. Lande- 
sanst., X. F. Heft 75, p. 207, ?pl. 50, fig. 5. 
Xeuropteris obliqua is a plant of very variable habit, wide variations 
occurring in the size, shape and insertion of the pinnules in different 
parts of the same frond. The pinnae of this species occurring at Bond's 
Main are the small-pinnuled forms, which in my experience are very 
rare in Britain. The minor pinnules of this plant were first figured 
by Brongniart, and there can be no doubt that the examples illustrated 
here on plate XLL, figs. 1, 2 and 3, are identical with the continental 
specimens described by Brongniart, and by others more recently. 
In these pinnse the higher pinnules are oblong, attached 
by their whole base, decurrent, and the nervation arises directly 
from the rachis, there being no true median nerve. 
In these characters these pinnules agree remarkably with members 
of the genus Odo)(iopteris. But the ])innules situated lower on the 
rachis tend to become Xeuropteroid, being more oval in form, con- 
tracted at the base to a point of attachment and not decurrent. These 
pinnules also possess a more distinct median nerve. The larger or 
major pinnules of the same plant, which, however, have not been 
found at Bond's Main, are also more X^europteroid than Odontopteroid, 
hence the species is retained in the genus Xeuroptteris. 
The specimen figured in Plate XLL, fig. 2, shows a pinna composed 
of small pinnules, part of which is seen enlarged on fig. 3 of the same 
plate. An enlarged view of the nervation of another, specimen is shown 
on fig. 1. 
There is also a more common British plant which I believe has 
often been mistaken for V. obliqua, but which I think is a distinct 
type. I have figured examples of this from Kent* and from Cumber- 
land,! ^^^^ I regard the frond to which Kidston and Jongmans t have 
attributed a large seed as another specimen of the same plant, which 
I propose shortly to redescribe under a new specific name. 
* Arber (1909), p. 26, pi. L, fig. 3. 
t Arber (1903), p. 4, pi. I., fig. 2. 
; Kidston and Jongmans (1912), p. 25, pi. (unnumbered), fig. 3. 
