262 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 8, 



^'Eozoonal" to any rock which shows any of the characters, whether 

 mineral or organic, thus arbitrarily attached to the Canadian Eozoon, 

 This is obviously a process by which the structure of any fossil 

 might be proved to be a mere lusus naturae. 



A notable illustration of this is afforded by their regarding the 

 veins of fibrous serpentine, or chrysotile, which occur in the Cana- 

 dian specimens, as identical with the tubulated cell-wall of Eozoon 

 — although they admit that these veins traverse all the structures 

 indifferently and do not conform to the walls of the chambers. 

 But any microscopist who possesses specimens of Eozoon containing 

 these chrysotile veins may readily satisfy himself that, under a 

 high power, they resolve themselves \\s.io 'prismatic crystals in imme- 

 diate contact with each other ; whereas, under a similar power, the true 

 cell-wall is seen to consist of slender, undidating, rounded threads of 

 serpentine, penetrating a matrix of carbonate of lime. Under polarized 

 light more especially, the difference is conspicuously apparent. It 

 is true that, in many specimens and parts of specimens, the cell- 

 wall of Eozoon is badly preserved and fails to show its structure ; 

 but in no instance does it present the appearance of chrysotile, or 

 of any other fibrous mineral, when examined with care under sufii- 

 ciently high powers. In my original examination of Sir WiUiam 

 Logan's specimens from Grenville and the Calumet, I did not detect 

 the finely tubulated ceU-wall, which is very imperfectly preserved in 

 those specimens ; but the veins of fibrous serpentine were well 

 known to me ; and when Dr. Carpenter discovered the tubulation of 

 the ceU-wall in the specimens from Petite ISTation, I compared this 

 structure with that of these veins, and satisfied myself of its dis- 

 tinctness before acceding to his conclusions on this point. 



It would also appear that the radiating and sheaf-like bundles of 

 crystals of tremolite, or similar prismatic minerals, which occur in 

 the Canadian serpentines, and also abound in those of Connemara, 

 have been confounded with the tubulation of Eozoon ; but these 

 crystals have no definite relation to the forms of that fossil, and 

 often occur where these are entirely absent ; and in any case they 

 are distinguishable by their straight prismatic shape and their 

 angular divergence from each other. Much use has also been made 

 of the amorphous masses of ojDaque serpentinous matter which 

 appear in some parts of the structure of Eozoon. These I regard as, 

 in most cases, simply results of alteration or defective preservation, 

 though they might also arise from the presence of foreign matters 

 in the chambers, or from an incrustation of mineral matter before 

 the final fiUing up of the cells. Generally their forms are purely 

 inorganic ; but in some cases they retain indications of the structures 

 of Eozoon. 



"With reference to the canal- system of Eozoon, no value can be 

 attached to loose comparisons of a structure so definite with the 

 forms of dendritic silver and the filaments of moss-agates ; still less 

 can any resemblance be estabhshed between the canal-system and 

 vermicular crystals of mica. These occur abundantly in some ser- 

 pentines from the Calumet, and might readily be mistaken for 



