1862.] 



DAWSON DEVONIAN PLANTS. 



305 



Anniilaria acuminata, sp. nov. 

 Sphenophyllum antiquum, Dawson. 

 Pinnularia dispalans, sp. nov. 

 Lepidodendron Graspianum, Dawson. 

 Lycopodites Matthewi, Dawson. 

 Psilophjton elegans, sp. nov. 



glabrum, sp. nov. 



Cordaites Robbii, Dawson. 



angustifolia, Dawson. 



Cyclopteris Jacksoni, Dawson. 



obtusa, Goeppert. 



varia, sp. nov. 



vaKda, sp. nov. 



Neuropteris serrulata, sp. nov. 

 polymorpha, sp. nov. 



Sphenopteris Hoeninghausi, Brongn. 



marginata, sp. nov. 



Harttii, sp. nov. 



Hitchcockiana, sp. nov. 



Hymenophyllites Gersdorffii, Goe'ppert. 



obtusilobus, Goe-ppert. 



curtilobus, sp. nov. 



Pecopteris (Alethopteris) decurrens, 

 sp. nov. 



■ ( ) ingens, sp. nov. 



( ) obscura(?), Lesquereux. 



Trichomanites, sp. nov. 

 Cardiocarpum cornutum, sp. nov. 



obliquum, sp. nov. 



Trigonocarpum racemosum, sp. nov. 



II. Desceiptions op the Species. 

 {Angiospermous Dicotyledon.) 



1. Stringoxylon mieabile, gen. et sp. nov. PI. XII. figs. 1 to 5. 



Woody tissue close, thicTc-w ailed. Ducts many times the diameter of 

 the wood-cells, thin-walled, with transverse pores in several series. 

 Medullary rays of two or more series of muriform cells, Growth- 

 tnngs distinct. 



This genus and species are founded on a small fragment of wood, 

 mineralized by carbonate of lime, silica, and iron-pyrites. It is 

 evidently the wood of an angiospermous exogen, and does not differ 

 materially from that of some modern trees. It is, in so far as I am 

 aware, the first instance of such wood in Palaeozoic rocks, and would 

 imply the existence in the Devonian Period of trees of a higher 

 grade than any that are known in the Carboniferous System. This 

 fact is not, however, in itself more remarkable than the occurrence 

 of a single Land- snail in the Coal-formation, more especially when 

 we consider the perishable character of the wood of angiosperms as 

 compared with that of gymnosperms and cryptogams, and the small 

 amount of attention usually bestowed by geologists on fragments of 

 mineralized wood. It is also to be remarked that, as I have else- 

 where had occasion to note, the Devonian flora has in other points a 

 more modern aspect than that of the Coal — a circumstance which may 

 perhaps relate to a different distribution of land and water, and to 

 the comparative absence of the wide inundated flats of the Coal- 

 period. It may, however, merely result from the unequal and 

 fortuitous preservation of some descriptions of plants rather than 

 others in the beds of one or both of these periods. 



The specimen is labelled as from Eighteen-mile Creek on Lake 

 Erie, and was collected several years ago by Prof. HaU from a lime- 

 stone in the upper part of the Hamilton group. It has unfortu- 

 nately no matrix attached to it ; but Prof. Hall assures me that he 

 has no reason to doubt its genuineness. 



