and, but this is now almost exhausted. The vein lay
between strata of slate, and was from eight to nine feet thick. As much
as L100,000 is said to have been realised from it in one year. Extensive
supplies of graphite are found in rocks of the Laurentian age in Canada.
In this formation nothing which can undoubtedly be classed as organic has
yet been discovered. Life at this early period must have found its home
in low and humble forms, and if the _eozooen_ of Dawson, which has been
thought to represent the earliest type of life, turns out after all not
to be organic, but only a deceptive appearance assumed by certain of the
strata, we at least know that it must have been in similarly humble forms
that life, if it existed at all, did then exist. We can scarcely,
therefore, expect that the vegetable world had made any great advance in
complexity of organism at this time, otherwise the supplies of graphite
or plumbago which are found in the formation, would be attributed to
dense forest growths, acted upon, after death, in a similar manner to
that which awaited the vegetation which, ages after, went to form beds of
coal. At present we know of no source of carbon except through the
intervention and the chemical action of plants. Like iron, carbon is
seldom found on the earth except in combination. If there were no growth
of vegetation at this far-away period to give rise to these deposits of
graphite, we are compelled to ask ourselves whether, perchance, there did
not then exist conditions of which we are not now cognisant on the earth,
and which allowed graphite to be formed without assistance from the
vegetable kingdom. At present, however, science is in the dark as to any
other process of its formation, and we are left to assume that the
vegetable growth of the time was enormous in quantity, although there is
nothing to show the kind of vegetation, whether humble mosses or tall
forest trees, which went to constitute the masses of graphite. Geologists
will agree that this is no small assumption to make, since, if true, it
may show that there was an abundance of vegetation at a time when animal
life was hidden in one or more very obscure forms, one only of which has
so far been detected, and whose very identity is strongly doubted by
nearly all competent judges. At the same time there _may_ have been an
abundance of both animal and vegetable life at the time. We must not
forget that it is a well-ascertained fact that in late