126 RELICS OF PRIMEVAL LIFE 



cious infiltration, they have perished, and this more 

 especially in the case of those whose skeletons are 

 composed of aragonite. 



Carrying these facts with us, the next question 

 is, What manner of fossil remains should we expect 

 to find in the Upper Laurentian rocks, supposing that 

 any such are therein preserved? The answer to 

 this question follows at once from the facts as to 

 the succession of life noticed above. Only the marine 

 invertebrates have been traced as far back as the 

 oldest Cambrian, and only Worms, Sponges, and 

 Protozoa into the Huronian. We should therefore 

 have no expectation of finding remains of any ver- 

 tebrate animals or of any of the land invertebrates ; 

 and even allowing for the more favourable condi- 

 tions, as compared with the Huronian, evidenced by 

 the great limestones and the abundant carbon, we 

 could scarcely expect anything higher than some 

 of the lower types of invertebrate life, such as Worms, 

 Hydroids, Corals and Protozoa. We have next to 

 inquire what forms, possibly organic, have actually 

 been found, and what information we can derive 

 from them as to the beginnings of life. Since, how- 

 ever, such discoveries as have been made have been 

 the result of much labour and scientific skill brought 



