226 RELICS OF PRIMEVAL LIFE 



and more practicall)' useful researches. On this 

 subject it will not be out of place to quote the 

 remarks which I made in one of my earlier 

 papers on the Laurentian fossils ; — 

 111* " This subject opens up several interesting fields 



of chemical, biological, and geological inquiry. One 

 '' |, of these relates to the conclusions stated by Dr. 



., I Hunt as to the probable existence of a large 



\ ., amount of carbonic acid in the Laurentian atmo- 



,.^ sphere, and of much carbonate of lime in the seas 



'»* of that period, and the possible relation of this to 



the abundance of certain low forms of plants and 

 '^'* animals. Another is the comparison already in- 



'II 



I- 



h»»t* 



'i'0 stituted by Professor Huxley and Dr. Carpenter, 



between the conditions of the Laurentian and those 



•In; 



>.. 



"I 



of the deeper parts of the modern ocean. Another 

 is the possible occurrence of other forms of animal 

 life than Protozoa, which I have stated in my 

 paper of 1864, after extensive microscopic study 

 h« j of the Laurentian limestones, to be indicated by 



P2l 1 the occurrence of calcareous fragments, differing in 



structure from Eozoon, but at present of unknown 

 nature. Another is the effort to bridge over, by 

 further discoveries [similar to those of Cryptozoon 

 an4 Avoh^Qloovij, the gap now existing between 





I 



L..t. 



