200 



RELICS OF i'KIMKVAL LIFE 



manner in which these arc occasionally arranged in 

 lines and groups suggests the supposition that they 

 may possibly be casts of the interior of minute Fora- 

 miniferal shells. They may, however, be concre- 

 tionary in their origin (Fig. 51). 



" (4) In some of the Laurentian limestones sub- 

 mitted to me by Sir W. E. Logan, and in others from 

 Arnprior on the Ottawa, there are fibres and granules 



Mm 



\m 



Fig. 51. — Archaospherimc from Burgess Eozoon. Grains 



included in Loganite. 



(Magnified.) 



of carbonaceous matter which do not conform to the 

 crystalline structure, and present appearances quite 

 similar to those which in more modern limestones re- 

 sult from the decomposition of the algae, etc. Though 

 retaining mere traces of organic structure, little doubt 

 would be entertained as to their vegetable origin if 

 they were found in fossiliferous limestones. In lime- 

 stones of Upper Laurentian age, near St. John, 

 New Brunswick, more distinct fibres occur, and 



