1123 THE MEDALS OF CREATION. Cuap. VI. 
Pacuypreris* (thick-fern). Lign. 17.—In this genus from 
the lower Oolite, the fronds are pinnated, or bipinnated, the 
leaflets entire, without visible veins, having but a single 
Lien. 17. PACHYPTERIS LANCFOLATA. 
Inferior Oolite. Whitby. 
midrib, and contracted at the base. The absence of veins, — 
and the leaflets not being lobed, are the essential generic — 
distinctions. 
SPHENOPTERIS (wedge- — 
“\\ leaf). Lign. 18.—The leaves 
are twice orthrice pinnated, — 
the leaflets wedge-shaped, — 
| contracted or narrowest at — 
| their base, and more or less _ 
deeply lobed: the lobes — 
divergent and palmated : 
the veins radiating from { 
_ the base. 
The ferns of this genus 
| / ave extremely elegant, and ~ 
// comprise upwards of forty — 
species. A beautiful Sphe- — 
nopteris (S. afinis, Wond. 
Lien. 18. SPHENOPTERIS ELEGANS. J). 716,) occurs abundantly ; 
Coal-shale, Waldenburg, Silesia. = in the fresh-water carboni- — 
\ 
Ain. 
a. 
* The names of the genera are derived from péeris, fern, to which — 
is prefixed a term indicative of the peculiar characters. 
