Into
this controversy it is wholly unnecessary to enter here; and it
will be sufficient to briefly explain the structure of _Eozooen_,
as elucidated by the elaborate and masterly investigations of
Carpenter and Dawson, from the standpoint that it is a genuine
organism--the balance of evidence up to this moment inclining
decisively to this view.
[Illustration: Fig. 22.--Fragment of _Eozooen_, of the natural
size, showing alternate laminae of loganite and dolomite. (After
Dawson.)]
The structure known as _Eozooen_ is found in various localities
in the Lower Laurentian limestones of Canada, in the form of
isolated masses or spreading layers, which are composed of thin
alternating laminae, arranged more or less concentrically (fig.
22). The laminae of these masses are usually of different colours
and composition; one series being white, and composed of carbonate
of lime--whilst the laminae of the second series alternate with
the preceding, are green in colour, and are found by chemical
analysis to consist of some silicate, generally serpentine or the
closely-related "loganite." In some instances, however, all the
laminae are calcareous, the concentric arrangement still remaining
visible in consequence of the fact that the laminae are composed
alternately of lighter and darker coloured limestone.
When first discovered, the masses of _Eozooen_ were supposed to
be of a mineral nature; but their striking general resemblance
to the undoubted fossils which will be subsequently spoken of
under the name of _Stromatopora_ was recognised by Sir William
Logan, and specimens were submitted for minute examination, first
to Principal Dawson, and subsequently to Dr W.
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