Recent and Fossil Coniferce, 151 



that part where the structure is most perfect, there ar6 many cur- 

 vilinear lines of a darker colour than the general shade, and a si-; 

 milar shade in the form of belts often pervades those parts, where 

 the structure is most deranged. Small veins of white calcareous 

 spar are often to be seen throughout the whole mass. 



In the longitudinal section parallel to a i-adius of the present 

 Craigleith tree, the vessels in general are. vei-y much distorted, 

 and the whole texture very much obscured ; but wherever the 

 vessels appear with any distinctness, they often contain discs in 

 double, triple, and even quadruple rows. The discs are always 

 very obscurely seen, so much so, that in many parts they are 

 barely discernible. In several parts, however, they are suffi- 

 ciently distinct lo leave no doubt as to their hexagonal form. 

 The vessels in the concentric section are eren more distorted 

 than in the other. The partitions, however, in some parts, af- 

 ford traces of expansions similar to those in the Araucariae ; and 

 with the exception of the triple and quadruple rows of discs, the 

 Craigleith tree very much resembles, in its general characters, 

 the Araucaria from Moreton Bay. 



The siliceous specimen above mentioned from the vicinity of 

 Whitby, which is destitute of annual layers, affords no trace of 

 discs in the longitudinal section parallel to a radius, but their 

 absence now is no proof that they did not exist in the wood 

 when in a recent state. In the fossil Coni ferae, the discs in the 

 longitudinal vessels are in general very much obscured, and fre- 

 quently disappear even where the reticulated texture and parti- 

 tions of the longitudinal vessels are perfectly distinct. 



A specimen, for example, which I found on the beach un- 

 der the cliff of the upper lias in the vicinity of Whitby, which, 

 in the transverse section, displays not only distinct annual layers, 

 but also the most perfect coniferous reticulations, affords but 

 very few traces of discs in the longitudinal section. The longi- 

 tudinal section I allude to is two inches long in the direction of 

 the radii, and nearly one inch in the longitudinal direction, and 

 it is only in a small portion at one end that the discs can be seen. 

 They seem to l>e as large as those in many of the recent pines, 

 and like them they are either circular or slightly elliptical. 

 They chiefly occur in single rows, but some few traces of double 

 rows are observable, and in that case the discs are placed side 



