﻿74 Canadian Record of Science. 



the remains of a porous structure, I do not know ; but 

 similar appearances occur in the calcareous fossils con- 

 tained in altered limestones of later date. Wherever 

 they occur in crystalline limestones supposed to be organic, 

 the microscopist should examine them with care. I have 

 sometimes by this appearance detected fragments of 

 Eozoon which afterwards revealed their canals. 



I have not space here to notice late observations on 

 ArchteospherintTe and other objects supposed to be organic 

 found in pre-Cambrian rocks in Canada and in Europe. 

 They afford, however, to some extent, corroborative evi- 

 dence in favour of Eozoon. 



Supposing a probability to be established of the animal 

 nature of Eozoon, we should naturally expect to detect 

 .links of connection between it and fossils known to us in 

 the succeeding geological formations. We have, however, 

 here to make allowance for the probability that an organ- 

 ism so very ancient may differ materially from any of its 

 successors, and may probably be a synthetic or generalized 

 type, or present embryonic characters. Analogy might 

 also justify the supposition that it might be represented 

 in later times by smaller as well as more specialized forms. 

 In this connection, also, the probable warmth and shallow- 

 ness of the Laurentian ocean, and its abundance in calcium 

 carbonate and in carbonaceous matter, probably organized, 

 should be taken into account. It should also be noted 

 that the formations next in ascending order are of a 

 character little likely to preserve organic marine forms of 

 the " benthos " or ground-living group. We might thus 

 expect a gap in our record between the fauna of the Gren- 

 ville Series and that of the next fossiliferous formations. 



Logan naturally compared his earlier specimens with 

 the Stromatoporai so abundant in the Ordovician and 

 Silurian Limestones ; and in this he was justified, for, 

 whatever may be the ultimate judgment of naturalists as 

 to these problematical fossils, and whether they are 



