Dawson and Carpenter on Eozoon Canadense. 253 
tirely absent ; and in any case they are distinguished by their 
ht prismatic shape and their angular divergence from 
each other. Much use has also been made of the amorphous 
masses of opaque serpentinous matter which nt we in some 
parts of the structure of Hozoon. These I regard as, in most 
cases, simply results of alteration or defective preservation, 
though they might also arise from the presence of foreign mat- 
ters in the chambers, or from an incrustation of mineral mat- 
ter before the final filling up of the cells, Generally their 
ms are purely inorganic ; but in some cases they retain in- | 
dications of the structures of Eozoon. 
With reference to the canal-system of Fozoon, 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- 
ey and vermicular crystals of mica. These occur abun- 
tly in some serpentines from the Calumet, and might read- 
ily be mistaken for organic forms ; but their rhombic or hex- 
_ Sgonal outline when seen in, cross section, their transverse cleav- 
= planes, and their want of any definite arrangement or re- 
lation to any general organic form, are sufficient to undeceive 
any practised observer, I have not seen specimens of the me- 
taxite from Reichenstein referred to by Messrs. King and Row- 
om; but it is evident, from the description and figure given of 
_ 4, that, whether organic or otherwise, it is not similar to the 
. tanals of Eozoon Canadense. But all these and similar com~- 
< doer a are evidently worthless when it is considered that 
have to account for definite, ramifying, cylindrical forms, 
S rasa a skeleton or matrix of limestone, which has itself 
~y ee these forms are represented by substances so diverse 
ee tine, pyroxene, limestone, and carbonaceous matter. 
: rom isons of the chamber-casts with concretionary gran~ 
that the t have some plausibility, But it is to be observed 
Ss laminated arrangement is the typical one; and the 
i com- 
between which 
while the 
