1853.] RIBEIRO AND SHARPE BUSSACO. 145 



mens are not in a sufficiently perfect state to allow of a complete 

 description. In the form and size of the leaflets it most resembles the 

 P. denticulata and P. insignis of the Yorkshire oolite, but its venation 

 is widely different. The texture appears very thin and delicate, from 

 which circumstance I have derived its name. The frond was evi- 

 dently at least twice pinnated ; the leaflets rather closely set, very ob- 

 lique to the rhachis, and somewhat curved forward, tapering gradually 

 from a broad base to a sharp point, deeply and sharply serrated, and 

 indeed somewhat cut (inciso-serrate) ; the first segment (next the 

 base) on the upper edge of each leaflet conspicuously larger than 

 the rest, and forming almost a lobe. The lower leaflets of each 

 pinna are as much as f inch long, but they diminish rapidly towards 

 the ends of the several pinnae. Midrib of each leaflet strongly 

 marked ; side veins, which terminate in the serratures, remarkably 

 wavy or zigzag, each pinnated with several alternate branches or 

 veinlets, which go off from it at a very acute angle. The venation 

 thus resembles that of Goeppert's Biplazites (Pecopi. longifolia and 

 emarginata), but the form of the leaflets and general habit of the 

 plant are widely different. 



This species should probably be placed in Brongniart's section 

 JJnitce. Its technical character may run thus : — 



" Fronde tenera bipinnata : pinnulis subcontiguis elongato-trian- 

 gularibus acuminatis subincurvis inciso-serratis, basi sublobatis ; venis 

 obliquis flexuosis pinnatis : venulis subparallelis." 



12. Sphenophyllum Schlotheimii. 



Found in the coal formation of Somersetshire, Saxony, Silesia, and 

 Nova Scotia. 



13. Annularia LONGIFOLIA, Brong. Asterophyllites equisetiformis, 



Lindl. and Hutt. 

 In the coal formation : Monmouthshire, Saxony, Silesia, and 

 Nova Scotia. 



14. Walchia. 



This appears to me to be the same with a Walchia which M. Adolphe 

 Brongniart showed me, from the slates of Lodeve near Montpellier ; 

 but as I have no specimens withiia my reach for comparison, and do 

 not know where any of his Walchiee are figured or described, I can- 

 not identify it. The slates of Lodeve are supposed to be Pe^^mian, 

 but have several fossil plants in common with the coal formation. 



Of the fourteen species or varieties here enumerated, all that can 

 be identified with plants previously described, belong to the true 

 coal formation, with the exception perhaps of the Walchia, which 

 may be Permian. Four out of the fourteen occur likewise in the 

 anthracite formation of the Alps. Only six out of the fourteen are 

 recorded as British ; for the Odontopteris obtusa of Lindley and 

 Hutton is generally considered as different from the plant origin- 

 ally so called. The abundance of Odontopteris and of Pecopteris 

 Cyathea, and the occurrence of Pecopteris arguta and P, oreo- 



