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RELICS OF PRIMEVAL LIFE 



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have been filled with calcareous spar and quartz, 

 the finest structures being preserved quite as well 

 as in comparatively unaltered specimens from the 

 coal-formation.^ No structures so perfect have as 

 yet been detected in the Laurentian, though in the 

 largest of the three graphitic beds at St. John 

 there appear to be fibrous structures which I be- 

 lieve may indicate the existence of land-plants. 

 This graphite is composed of contorted and slicken- 

 sided laminae, much like those of some bituminous 

 shales and coarse coals ; and in these there are 

 occasional small pyritous masses which show hollow 

 carbonaceous fibres, in some cases presenting ob- 

 scure indications of lateral pores. I regard these 

 indications, however, as uncertain ; and it is not as 

 yet fully ascertained that these beds at St. John 

 are on the same geological horizon with the Gren- 

 ville series of Canada, though they certainly under- 

 lie the Cambrian series of tlie St. John or Acadian 

 group, and are separated from it by beds having the 

 character of the Huronian, and thus come, approxi- 

 mately at least, into the same geological position. 



* "Acadian Geology," p. 535. In calcified specimens the 

 structures remain in the graphite after decalcification by an 

 acid. 



