The presence of phosphatic nodules and
bituminous matter, even in some of the lowest azotic rocks, probably
indicates life at these periods; and the existence of the Eozoon in the
Laurentian formation of Canada is generally admitted. There are three
great series of strata beneath the Silurian system in Canada, in the lowest
of which the Eozoon is found. Sir W. Logan states that their "united
thickness may possibly far surpass that of all the succeeding rocks, from
the base of the palaeozoic series to the present time. We are thus carried
back to a period so remote, that the appearance of the so-called primordial
fauna (of Barrande) may by some be considered as a comparatively modern
event." The Eozoon belongs to the most lowly organised of all classes of
animals, but is highly organised for its class; it existed in countless
numbers, and, as Dr. Dawson has remarked, certainly preyed on other minute
organic beings, which must have lived in great numbers. Thus the words,
which I wrote in 1859, about the existence of living beings long before the
Cambrian period, and which are almost the same with those since used by Sir
W. Logan, have proved true. Nevertheless, the difficulty of assigning any
good reason for the absence of vast piles of strata rich in fossils beneath
the Cambrian system is very great. It does not seem probable that the most
ancient beds have been quite worn away by denudation, or that their fossils
have been wholly obliterated by metamorphic action, for if this had been
the case we should have found only small remnants of the formations next
succeeding them in age, and these would always have existed in a partially
metamorphosed condition.
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