EXPLANATION OF THE PLATES AND WOOD-CUTS. 



tachment ; from the structure of the frond they may, however, be considered to 

 belong to Cycadece, and to differ from Zamites in the obUque insertion of the pinnae 

 at the base, and from Coniferce by the absence of a primary vein in the pinnae. 



Ptilophyllum acutifolium, t.2\. f. I a, 2, 3. 



Frond pinnate ; pinnae narrow, Hnear-elongate, acute at the apex. 



This species differs from the Z. pectbiata of the Fossil Flora, in its pinnae being 

 narrower, longer, and more acute ; and more nearly resembles the Polypodttes 

 pecteniformis of Sternberg. 



P. CutcJiense, t. 21. f. 4. 



Frond pinnate ; pinnae short, scarcely overlapping at the base, apex obtuse. 



This specimen has been also referred to the genus from its pinnae (although 

 wider apart than in the other species) having apparently a rounded base ; but the 

 absence of all trace of venation in this fossil must render its correct determination 

 very doubtful. It resembles in form the Z. Bucklandii of Sternberg, parts 5 and 6, 

 t. 23, f. 2, or even Z. taxina of the Fossil Flora ; and it might also be compared 

 to some pinnatifid Polypodiums, as P. plumula and P. taxifolium. 



It is much to be regretted, that more numerous and better-preserved portions of 

 these specimens have not been obtained, so as to compare them more rigidly with 

 the already known forms of fossil vegetation ; for it is remarkable the analogy that 

 some of them present to the Stonesficld slate plants. 



Lycopodites affinis, t. 21, f. 5. 



Stem ? branches linear-elongate, leaves distichous, alternate, ovate-lanceolate, 



acuminate, adnate at the base. 



This specimen has been referred to Lycopodites from its resemblance to the 

 barren portions of Lycopodium Jussieni and L. voluhile. 



, t. 21, f. 1 6. f. 6. 



These specimens were probably portions of stems belonging either to Equisetites 

 or some monocotyledonous plant. 



Fucoides dichotomus, t. 21, f. 7. 



Frond compressed ? dichotomous ; branches unequal, patulate, apex obtusely rounded. 



The Shells in this and the following Plates are figured and described by Mr. James 

 de Carl Sower by. 



Fig. 8. Pholadomyal inornata. Transversely elongate, ovate, gibbose, concentrically 

 corrugated ; beaks very near the anterior extremity ; longitudinal ribs very ob- 

 scure, rounded. Width l^inch, length nearly 11 lines. 

 Loc. near Charee. 

 Fig. 9. Pholadomya granosa. Ovate, subtriangular, gibbose, ornamented with four 

 or five rows of transversely-elongated and but slightly-elevated tubercles ; the 

 anterior side nearly straight-flattened, the posterior produced ; beaks very pro- 

 minent. Length 2 inches, width the same. 

 Loc. near Charee. 



