1847.] BUNBURY ON FOSSIL PLANTS FROM EASTERN VIRGINIA. 28/ 



This obscure fossil seems to agree with the artificial character of 

 the genus Knorria (see Lindley and Hutt. Fossil Flora, text to t. 95 

 and t. 97), and I should conjecture that it is a relic of some coniferous 

 tree ; but it is not in a state to admit of satisfactory determination. 



15, 



" Duval's pit, near Blackheath, Richmond.'* 



Fragments, in a very bad state of preservation, of a plant with ap- 

 parently verticillated leaves, which seem to be linear, long and nar- 

 row, flat and thin, almost grass-like, and show some slight indications 

 of longitudinal veins. The specimens are in too bad a state to admit 

 of accurate description, or of even a conjecture as to the affinities of 

 the plant. 



The geological evidence afforded by the fossil plants here described, 

 is to a certain degree ambiguous. The most characteristic species ap- 

 pear to be the Equisetum columnare^ the Calamites, the Tceniopteris 

 magnifolia, and the Zamites, The first of these is a well-known plant 

 of the lower oolite, but is said to occur also in the Keuper. Cala- 

 mites arenaceus, if it be the same with the European plant so called, 

 seems to be eminently characteristic of the triassic series : it is not 

 mentioned, by any author I have met with, as a plant of the oolite ; 

 indeed, the great abundance of these conspicuous Calamites strikingly 

 distinguishes the Flora of the Richmond coal-field from that of our 

 Yorkshire oolites, of which it otherwise reminds us by several of its 

 forms. The Tceniopteris is closely allied to two species of the same 

 genus, which are peculiar to the oolitic series ; yet we must be cau- 

 tious how we conclude, from its affinity to those forms, that it must 

 necessarily belong to the same geological system ; for the T.Bertrandi, 

 another nearly-allied species, occurs in a tertiary formation. As, at 

 the present day, we find Ferns closely resembling one another in 

 very distant parts* of the world, so it is possible that very similar 

 forms of that tribe may have been repeated in successive geological 

 epochs. In fact, in the case of Ferns, I can hardly consider anything 

 but specific identity really important in a geological point of view. 



The Zamites belong to a tribe particularly characteristic, by its 

 abmidance and variety, of the Hassic and oolitic groups, though not 

 peculiar to them. In the triassic group it seems to occur more 

 sparingly, two species only being enumerated by linger from the 

 Gres bigarre, and three from the Keuper. 



Of the plants which occur less plentifully in the Richmond coal- 

 formation, the most interesting in a geological pomt of view is the 

 Pecopteris Whitbiensis, since it is one of the species most common 

 in our Yorkshire oolites, and, as far as I am aware, has been discovered 

 in no other formation. The new species of Ferns here described afford 

 us no information on this head, inasmuch as, both for the reason given 

 above, and because the principal genera of fossil Ferns are altogether 



* For example : — Pteris aguilina in Europe, Pteris caudata in the West Indies, 

 Pteris arachnoidea in Brazil, Pteris esculenta in the South Sea islands. 



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