CLAT1IRARIA LYELLII. 



293 



bases of the petioles, the insertions of which are 

 rhomboidal and transverse. The external surface 

 of the stem is in consequence covered with lozenge- 

 shaped elevated scars, separated by lateral depres- 

 sions, which are surrounded by a parallel band of a 

 fibrous appearance (see lign. 2 C £). This outer portion 

 is sometimes consolidated into a compact cylinder 

 of stone, which will separate from the central axis 



LIGN. 22. WATERWOllN STEM OF THE CLATHRARIA LYELLII. 



From the shingle in Brook Bay. 

 [One-third linear, nat. size.) 



(Foss. Tilg. Forest, PI. II.) : the latter is solid, 

 and strongly marked externally with reticulated 

 interrupted ridges. This surface has generally 

 patches of vascular tissue adhering to it, but these 

 are in so friable a condition, that microscopical 



