TRANSACTIONS'OF THE SBCTIONa. 6i63 



rows ; and ii> the double rows those in one row alternate with 

 those in the other row, and the contiguous boundaries of each 

 are polygonal. In another from the vicinity of Whitby, the 

 discs are distinctly seen in several places. They occur in sin- 

 gle, double, and triple rows, and ai*e in some parts circular, 

 and in other parts polygonal. Their form, however, is often 

 rather indefinite on account of their boundaries being very much 

 obscured. 



After having examined the structure of many fossil Coniferce, 

 Mr. Nicol has not met with even one possessing characters essen- 

 tially different from those to be seen in one or other of the recent 

 tribes. The transverse section is analogous in both ; the discs, 

 wherever they are well defined, agree with those in one or otheir 

 of the divisions above mentioned. In some instances, it is true, 

 even where the reticulated texture in the transverse section is 

 tolerably perfect, the discs in the longitudinal section are often 

 very much obscured, and even totally obliterated ; but this is 

 no proof that they did not exist iu the wood before the com- 

 mencement of the petrifactive process. In some recent woods 

 the discs are very obscure, even nearly as much so as in some 

 of the fossil kind ; and were such to become petrified, it is highly 

 probable they would entirely disappear. The author has seen 

 fossil sections which on a cursory view seemed to have no 

 discs, but which on careful inspection showed traces of them 

 in several parts. '' ' -} 



The recent attempts to establish new fossil genera woulii 

 seem to have arisen from considering a single section of one or 

 two true pines as containing the characters of all the Coniferce; 

 and yet the discs in the Araucarias and Dammaras are so strik- 

 ingly different from those in the true Pines, that it is impossible 

 to mistake the former for the latter. Had even a single longi- 

 tudinal section of an Araucaria been examined, it would have 

 been seen that multiplicate rows of discs of a polygonal form 

 could not be admitted as a foundation for a new fossil genus. 

 Had a few sections of some of the common Pines been examined, 

 it would have been seen that double rows of discs existed in 

 recent as well as in fossil ConifercE, and therefore could not be 

 adopted as the foundation for a new fossil genus. Had even a 

 limited number of transverse sections of recent Coniferce been 

 examined, such a diversity in the size of the pith would have 

 been seen as to preclude the idea of erecting into a new genus 

 a single fossil, the distorted pith of which had a mean diameter 

 of about four tenths of an inch. The author has in his posses- 

 sion a portion of the stem of an Araucaria Brasiliensis the pith 

 of which is upwards of three tenths of an inch in diameter. Had 



