CONTEMPORARIES OF EOZOON 



207 



belonging apparently to the same band with that of 

 St. Pierre, there are many small rounded pieces of 

 limestone, evidently the debris of some older rock, 

 broken up and rounded by attrition. In some of 

 these fragments the structure of Eozoon may be 

 plainly perceived. This shows that still older lime- 

 stones composed of Eozoon were at that time under- 

 going waste, and carries our view of the existence 

 of this fossil back to the very beginning of the 

 Grenville series of the Laurentian. 



With respect to organic fragments not showing the 

 structure of Eozoon, I have not as yet been able to 

 refer these to any definite origin. Some of them 

 may be simply thick portions of the shell of Eozoon 

 with their pores filled with calcite, so as to present 

 a homogeneous appearance. Others have much the 

 appearance of fragments of such Primordial forms 

 as Arch(Bocyathus, now usually regarded as corals or 

 sponges ; but after much careful search, I have thus 

 far been unable to say more than I could say in 

 1865. 



It is different, however, with the round cells infil- 

 trated with serpentine and with the silicious grains 

 included in the loganite. Fig. 53 shows such bodies 

 found mixed with fragmental Eozoon and in seoa- 



