» ( * 



to 



CANADIAN FOSSILS. 



Araucarian trees. If the tjpo of Dadoxylon was introduced in the Middle 

 Devonian, that oi Prototaxite$ ra&y then have been verging on extinction ; 

 and should forests of the Silurian period become known to us, we may hop©^ 

 to find in them additional species of Prototaxitet. In the meantime it is 

 certain that no species of fossil tree hitherto described presents histolo- 

 gical features more primitive in aspect, and more remote from existing 

 forms of vegetation than Prototaxitea. In this respect it presents a marked 

 contrast to Dadoxylon, and also to the contemporary acrogenous plants, 

 whoso structures, in so far as known, arc almost precisely similar to those of 

 their modem representatives. 



Genus Nematoxylon. — Dn. 



6. Nematoxylon crassum, Dn.— (PI. XI, Fig. 137.)— J. G. S.,XIX, 



366 ; PI. XIX, Fig. 24— M.D., Gasp^. 



" Fragments of wood with a smooth thin bark, and a tissue wholly composed 

 of elongated cylindrical cells with irregular pores or markings. No 

 pith, medullary rays, or rings of growth. " 



7. Nematoxylon tisnue, Dn. (PI. XI, Fig. 135-6.)— Ibid. 467 ; PI. 



XVIII, Fig. 23.— M.D., Gasp^. 



" Slender stems with thick coaly bark, and woody fibres of much smaller 

 ,. diameter than in the last species, and marked with minute dots." 



I place these plants here, simply because of the resemblance of their 

 tissues to those ofPrototaxites, with which it is possible that they may have 

 had some connection, being, perhaps, stems or slender roots of similar 

 species of smaller size. No additional specimens have been obtained, sines 

 the publication of my paper above cited, which would indicate that speci- 

 mens of these plants are rare at Gasp^ ; and they have not been found 

 elsewhere. The original specimens wore collected by Mr. Bell of the 

 Geological Survey, vvt - ■ ■:^>.- ,,j^- . ■■. . ;- «. : 



Genus Aporoxylon. — Unger. 



G. S., XVIII and XIX.— U.D., Malne^ 



8. Apokoxylon, sp. 

 New York. 



The plant originally described by Unger as Aporoxylon primigenium *' 

 and referred by him to Coniferae, may have been more nearly allied to 

 Prototaxitea than other described forms. It diflfers principally in the 



• PalaoBtologie deB Thuringer Waldes, 1836. 



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