318 THE CANADIAN NATURALIST. [Jan. 



fibrous serpentine were well known to me ; and when Dr. 

 Carpenter discovered the tubulation of the cell-wall in the speci- 

 mens from Petite Nation, I compared this structure with that of 

 these veins, and satisfied myself of its distinctness 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 Conne- 

 mara, 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 caee 

 they are distinguished by their straight prismatic shape and their 

 angular divergence from each other. Much use has also been 

 made of the amorphous masses of opaque 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 filling up of the cells. Generally their 

 forms are purely inorganic ; but in some cases they retain indica- 

 tions 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 established between the canal-system 

 and vermicular crystals of mica. These occur abundantly in 

 some serpentines from the Calumet, and might readily be mistaken 

 for organic forms ; but their rhombic or hexagonal outline when 

 seen in cross section, their transverse cleavage planes, and their 

 want of any definite arrangement or relation to any general organic 

 form, are sufficient to undeceive any practised observer. I have 

 not seen specimens of the metaxite from Reichenstein referred to 

 by Messrs. King and Rowney ; but it is evident, from the descrip- 

 tion and figure given of it, that, whether organic or otherwise, it 

 is not similar to the canals of Eozoon Canadense. But all these 

 and similar comparisons are evidently worthless when it is con- 

 sidered that they have to account for definite, ramifying, cylindri- 

 cal forms, penetrating a skeleton or matrix of limestone, which 

 has itself a definite arrangement and structure, and, further, when 

 we find that these forms are represented by substances so diverse 

 as serpentine, pyroxene, limestone, and carbonaceous matter. 



