278 On the Structure mid Position of Eozoon Canadense. 



ON THE STRUCTURE, AFFINITIES, AND GEOLOGI- 

 CAL POSITION OF EOZOON CANADENSE. 



BY WILLIAM B. CARPENTER, M.D., F.R.S., F.L.S., E.G.S. 

 (With Two Illustrations.) 



Among the communications made to the British Association at 

 its recent meeting at Bath, there was certainly none of higher 

 scientific interest than the announcement by Sir William 

 Logan, the director of the Canadian Geological Survey, of the 

 discovery of large masses of a fossil organism referable to the 

 Foraminiferal type, near the base of the Laurentian series of 

 rocks in North America. The geological position of this fossil, 

 indicating the vast remoteness in time of its existence as a living 

 organism, is scarcely more remarkable than its zoological rela- 

 tions ; for, at what (so far as we at present know) was the dawn 

 of animal life upon our globe, it affords evidence of a most 

 extraordinary development of that Rhizopod type of animal life 

 which now presents itself only in forms of comparative insigni- 

 ficance, — a development which enabled it to separate carbonate 

 of lime from the ocean-waters, in quantity sufficient to produce 

 masses rivalling in bulk and solidity those of the Stony Corals 

 of later epochs, and thus to furnish (as there seems good 

 reason to believe) the materials of those calcareous strata, of 

 whose occurrence in the Laurentian series it had previously 

 been impossible to give a satisfactory account. 



Having been requested by Sir William Logan to verify the 

 conclusions regarding the nature of this fossil which had 

 been arrived at by Dr. Dawson of Montreal, and having been 

 kindly supplied by him with ample materials for the further 

 elucidation of its structure, I propose in the present paper to 

 direct attention to the points of most striking interest, Geo- 

 logical as well as Zoological, which this discovery brings into 

 view. And since the bare statement that the PJozoon occurs 

 near the base of the Laurentian series of rocks, will not convey, 

 save to such as have followed the most recent progress of 

 geological research, any definite idea of the extraordinary 

 interest that attaches to the marvellous glimpse which its pre- 

 sence there affords into the ancient life of our globe, I shall 

 in the first instance take back my readers to that stage in the 

 history of the science, which preceded the establishment of the 

 " Silurian system" by .Sir Roderick Murchison. 



Geological Position of Eozoon. — Under the general designa- 

 tion " Primary Rocks" was formerly ranked an immense series 

 of formations, some evidently stratified, others presumed to be 

 non- stratified, chiefly originating in the disintegration of the 



