ON NEMATOPHYTOlSr AND ALLIES. 35 



holding Nematophyton, so great quantities of fossil resin occur, that it has been proposed 

 to inquire as to the possibility of its economic use. 



4. — General Relations. 



For the minute structure I may now refer to the careful examinations of Prof. 

 Peuhallow, who has had more complete material placed in his hands than has previously 

 been submitted to any botanist, and whose extensive knowledge of vegetable anatomy 

 well fits him for such an investigation. The only points on which I should be inclined 

 to hesitate as to his deductions are those which relate to the bark and the probable exist- 

 ence of an internal pith or axis. 



With respect to the first, though the coaly bark shows no distinct structure (the 

 fibrous structure referred to by Prof. Penhallow belonging really to the outer part of the 

 general tissue in contact with it), it is so constant in all the specimens I have studied and 

 so clearly defined in limit and state of preservation, that I cannot doubt that it was as 

 distinct as the similar coaly coating on other trees of the Erian and Carboniferous. It may 

 also have lost much of its exterior material by abrasion. This is, I think, faiiher indicated 

 by the strongly wrinkled and furrowed appearance which it presents in old stems. 



"With regard to internal axis or medulla, though this does not appt^ar, yet the partial 

 flattening and distortion of the stems shows that there was either an internal axis or an 

 internal cavity. This is well seen in the indented outline of the great trunk in the Bor- 

 deaux quarry, as seen in Fig. 4. It is to be observed here that in Carboniferous trees of 



Fio. 4. — Prostrate and partially compressed trunk of Nematophyton 2., feet in diameter — 



Bordeaux quarry, opposite Campbellton. (a) Flaggy Sandstone with 



resinous matter- (h.) Shale with Psilophyton. (c.) Sandstone. 



{d.) Silicified trunk with thin coaly bark. 



the type of Sigillaria, it is not unusitul to find a thick inner bark of long tortuous fibres, 

 often constituting nearly the whole of the trunk, and which is much less perishable than 

 the thin woody axis. I hold it, therefore, to be possible, that Nematophyton possessed 

 either a cellular medulla or a woody axis or an internal cavity, which in all the specimens 

 hitherto found has collapsed and disappeared. 



Lastly, under this head, palaeontology has made us familiar with many remarkable 

 botanical anomalies, as the possession of true exogenous structure by acrogenous plants 

 of the families of Lycopodacese, Equisetaceœ and Ferns, though this structure exists with 

 the same types of scalariform and cellular tissue found in the modern acrogens. It 



