I have in the above remarks confined myself to what I regard as absolutely essential by way of explanation and defence of the organic 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 requiring a most complicated series of unproved and improbable suppositions. The only other new features in the communication to which this 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 apparently different from _Eozoon Canadense_. They, no doubt, resemble the grains referred to by Gümbel as possibly organic, and also similar granular objects with projections which, in a previous paper, I have described from Laurentian limestones in Canada. These objects are of doubtful nature; but if organic, they are 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 related to Eozoon than are the curious vermicular crystals of a micaceous mineral which I have noticed in the Canadian limestones. The third and still more remarkable case is that of a spinel from Amity, New 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 containing 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. Rowney and King to confound other forms with those of Eozoon, accept their determinations in a matter so critical and in a case so unlikely.[AU] [Footnote AU: I have since ascertained that Laurentian limestone found at Amity, New York, and containing spinels, does hold fragments of the intermediate skeleton of Eozoon. The limestone may have been originally a mass of fragments of this kind with the aluminous and magnesian material of the spinel in their interstices.]