n Sir
Charles some four thousand four hundred years or so in the one item of
scooping out the bed of the St. Lawrence, at least expends the remainder
of the ten thousand,--his five thousand six hundred years,--in that work
of excavation alone, and leaves himself no further sums to set off
against the various geologic processes that may have preceded it.

In this case, as in the other, let us grant, for the argument's sake,
all the facts. Let us admit that the trench through which the St.
Lawrence now flows has been cut by the river in somewhat less than six
thousand years. But through what, let us ask, has it been cut? There can
exist no doubt on the subject: it has been cut through an ancient
graveyard of the Upper Silurian system, charged with the peculiar
fossils characteristic of what are known as the Clinton and Niagara
groups, and common, many of them, to the Upper Silurian of our own
country and of the European continent. _Leptaena depressa_ and
_Pentamerus oblongus_, two of the most frequent shells of the deposit,
occur also in equal abundance in the Dudley and Caradoc formations of
England; its prevailing encrinite, _Ichthyocrinus laevis_, is scarce
distinguishable from an encrinite which I have often picked up in the
quarries of the "Wren's Nest" (_Ichthyocrinus pyriformis_); while its
prevailing trilobite, _Phacops limulurus_, seems to be but a
transatlantic variety of our well known _Asaphus (Phacops) caudatus_.
Further, the sequence of the various formations both above and below the
Niagara group, is shown with remarkable distinctness in that part of the
world along the shores of the great lakes. They may be traced downward,
on the one hand, along the Lower Silurian deposits, to the
non-fossiliferous base on which the system rests, and upwards, on the
other, through the Old Red Sandstone and the Carboniferous Limestone, to
the workable Coal Measures. Both stratigraphically and palaeontologically
the place in the scale of the Niagara graveyard can be definitely
determined; and a superficial deposit on the heights in its immediate
neighborhood shows that the river did not begin its work of excavation
among its long extinct shells, trilobites, and corals, until after not
only the great Palaeozoic, but also the Secondary and Tertiary divisions
had been laid down, and the recent period ushered in. The superficial
shells of the adjacent heights belong to the Pleistocene age, and show
that in even that comparative