l^ew Brunswickj Maine, and Eastern Canada, 167 



Mr. Matthew states in reference to the mode of occurrence of 

 this interesting species, that the wood is always in the state of 

 anthracite or graphite, or mineralized by iron pyrites, calc spar 

 or silica. The pith is usually calcified, but in pyritised trunks it 

 often appears as a sandstone cast with the external wrinkles of 

 Sternbergia. The pith is often eccentric, and specimens occur 

 with two or three centres ; but these either consist of several 

 trunks in juxtaposition, or are branching stems. The annual lay- 

 ers vary from |-th to ^^^th of an inch in thickness, and adjoining 

 layers sometimes vary from y^^th to 2'^th of an inch. 



The trunks of this species appear to have had a strong ten- 

 dency to split in decay along the medullary rays, and in conse- 

 quence the cross section often presents a radiating structure of 



ilJ 



Fig. 5.~^Calamites transitiortis. (p. 168.) 

 alternating black lines representing the wedges of wood, and white 

 rays of calc spar. The heart wood seems to have had its cell 



