11 



in their acuteness in difterent specimens, in, it would seem, 

 an almost endless variety ; forming surfaces apparently co- 

 vered with squamae disposed in an imbricated manner, and 

 frequently in quincunx order. 



Among the fossils of this description, the one which 

 claims our first attention, is, I. Pliytolithus verrucosus of 

 Martin; Petrificata Derbienjia, PL 11, 12, 13, and 13*; 

 Organic Remains, vol. i. PL III. Ji^. 1 ; and on a very 

 small scale, PL I. Jig. 1 and 2 of the present work. This 

 fossil appears to have foiled every one who has attempted 

 to explain its original nature and mode of existence. It is, 

 according to Mr. Martin's correct account, a subscylindrical, 

 subramose, tuberculated trunk, PL ^-fig. 1, with suppressed 

 tubercles in quincunx order, (a) having linear lanceolated 

 leaves horizontally disposed. Jig, 2 (h). In some parts of 

 it is a deep longitudinal sulcus, jig. 1 (c), beneath which is 

 a rough imbricated body of a slender cylindrical form, 

 Jig. 2 (d). This, Mr. Martin observes, after a certain dis- 

 tance, appears to strike out laterally, and form a branch ; 

 the trunk is then continued for some length, without the 

 furrow or the imbricated body ; after which it again appears, 

 and another branch is put out in another direction. 



Various opinions have been entertained respecting this 

 interesting fossil, so unlike any of the vegetable substances 

 of the present day, by Da Costa, Woodward, Whitehurst, 

 and others. The author of these pages had conjectured 

 that it belonged to some body resembling the strohilus or 

 cone of some vegetable, while the ingenious Mr. Martin 

 describes it as above. The examination of this fossil has 

 been since very assiduously prosecuted by the Rev. Henry 

 Steinhauer. This gentleman is satisfied that " those bodies 

 which were supposed by Mr. Martin to be leaves pro- 

 ceeding from the trunk, were cylindrical fibres which shot 

 out from the trunk of this vegetable, whilst growing in a 

 horizontal position. He supposes this fossil to have been a 



