122 Proceedings of the Royal Irish Academy. 
nature of Eozoon. It would be unprofitable to enter into the multitude 
of subordinate points raised by the authors, and their theory of mineral 
pseudomorphism is discussed by my friend Dr. Hunt ; but I must say 
here that this theory ought, in my opinion, to afford to any chemist a 
strong presumption against the validity of their objections, especially 
since it confessedly does not account for all the facts, while requir- 
ing a most complicated series of unproved and improbable suppo- 
sitions. 
The only other new features in the communication to which the note 
refers are contained in the supplementary note." The first of these 
relates to the grains of coccolite in the limestone of Aker, in Sweden. 
"Whether or not these are organic, they are obviously different from 
Eo%ooyi Canadense. They, no doubt, resemble the grains referred to by 
Giimbel as possibly organic, and also similar granular objects with 
projections which, in a previous Paper, I have described from Lauren- 
tian limestones in Canada. These things may be crystalline ; but if 
organic, they are radically distinct from Eozoon. The second relates 
to the supposed crystals of malacolite from the same place. Admitting 
the interpretation given of these to be correct, they are no more re- 
lated to Eozoon than are the curious vermicular crystals of a mica- 
ceous mineral which I have noticed in the Canadian limestones. 
The third and still more remarkable case is that of a spinel from 
Amity, JSTew York, containing calcite in its crevices, including a perfect 
canal system preserved in malacolite. With reference to this, as spinels 
of large size occur in veins in the Laurentian rocks, I am not prepared 
to say that it is absolutely impossible that fragments of limestone con- 
taining Eozoon may not be occasionally associated with them in their 
matrix. I confess, however, that until I can examine such specimens, 
which I have not yet met with, I cannot, after my experience of the 
tendencies of Messrs. Eowney and King to confound other forms with 
those of Eozoon, accept their determinations in a matter so critical and 
in a case so unlikely. 
On two points in conclusion it is necessary to say a few words. The 
first is the geological range of Eozoon. This, at present, is Lauren- 
tian, and possibly, even Primordial, according to Dr. Hunt. Similar 
forms, however, exist in the unaltered Lower Silurian rocks, and are 
at present included in the genera Stromatopora, Stromatocerimn, and 
Ardhaeocyatlius, along with corals and sponges properly belonging to 
those genera. I hope at some future time to refer jnore in detail to 
these facts which I am now investigating, with reference to the Palae- 
ozoic successors of Eozoon, some of which are very interesting. With 
regard to the Connemara ophiolites, I regard these as similar to certain 
more recent ophiolites from the Green Mountain range of the Eastern 
Townships of Canada, which have not afforded Eozoon, and I have 
never been able to satisfy myself of the occurrence of any definite 
organic structure in the Connemara specimens. With regard to the 
so-called Liassic specimens from Skye, without admitting the Liassic 
age of the specimens, which, I beg to suggest, is still somewhat doubt- 
