PLATE 10. 
FERN. IRONSTONE. 
FIG. 1, 2, 3, 4. 
PHYTOLITHUS Filicites (striatus) fronde bipln- 
nata-: pinnis ovato-oblongls : pinnulis lanceolatis 
integerrimls : ncrvis simplicibus confertis transversis. 
S. p. 
A fossil or petrified vegetable. The original a Fern — 
Frond bipinnate. Pinna? ovato-oblong, alternate. Pinnules* 
lanceolate, very entire, alternate. Nerves simple (not 
dichotomous) crouded, transverse, imparting to the surface 
of the frond a closely striated appearance. A deeply 
impressed midrib runs down the centre of the pinnae and 
each of the pinnules. The stipe appears to be (in such spe- 
cimens as exhibit it) cylindric and longitudinally striated. 
Found near Chesterfield and Alfreton — Sometimes in the 
coal-shale; but more frequently, and in better preser- 
vation, in the nodules of ironstone, abounding in the ivay- 
* It should be observed, that the subdivisions of the •pinn.ee, in general, 
extend down to the midrib : in some specimens, however, they are not 
divided quite so deeply ; in this case Botanists would describe the subdivisions 
as lobes or segments, rather than as pinnules, and the frond, as almost 
bipinnate. 
