"(3) In the hydrous silicate (Loganite) filling the chambers of a large specimen of Eozoon from Burgess, there are numerous small pieces of foreign matter; and the silicate itself is laminated, indicating its sedimentary nature. Some of the included fragments appear to be carbonaceous, others calcareous; but no distinct organic structure can be detected in them. There are, however, in the Loganite, many minute silicious grains of a bright green colour, resembling green-sand concretions; and the manner In which these are occasionally arranged in lines and groups suggests the supposition that they may possibly be casts of the interior of minute Foraminiferal shells. They may, however, be concretionary in their origin (Fig. 51). [Illustration: Fig. 51.--Archæospherinæ from Burgess Eozoon. Grains included in Loganite. (Magnified.)] "(4) In some of the Laurentian limestones submitted to me by Sir W. E. Logan, and in others from Arnprior on the Ottawa, there are fibres and granules of carbonaceous matter which do not conform to the crystalline structure, and present appearances quite similar to those which in more modern limestones result from the decomposition of the algæ, etc. Though retaining mere traces of organic structure, little doubt would be entertained as to their vegetable origin if they were found in fossiliferous limestones. In limestones of Upper Laurentian age, near St. John, New Brunswick, more distinct fibres occur, and associated with these beds Matthew has found what seem to be spicules of sponges, some simple and others hexactinelled like those of Protospongia of the Cambrian. Though the abundance and wide distribution of Eozoon, and the important part it seems to have acted in the accumulation of limestone, indicate that it was one of the most prevalent forms of animal existence in the seas of the Laurentian period, the non-existence of other organic beings is not implied. On the contrary, independently of the indications afforded by the limestones themselves, it is evident that in order to the existence and growth of these large Rhizopods, the waters must have swarmed with more minute animal or vegetable organisms on which they could subsist. On the other hand, though this is a less certain inference, the dense calcareous skeleton of Eozoon may indicate that it also was liable to the attacks of animal enemies. It is also possible that the growth of Eozoon or the deposition of the serpentine and pyroxene in which its remains have been preserved, or both, may have been connected with certain oceanic depths and conditions, and that we have as yet revealed to us the life of only certain stations in the Laurentian seas. Whatever conjectures we may form on these more problematic points, the observations above detailed appear to establish the following conclusions:--