and depositing in the course of ages the regular layers of gravel, sand,
and marl, which now cover so large a part of Europe. This was still
further followed by a period in which the temperature of the earth was
lowered, and ice and glaciers had perhaps a part in forming the present
surface of the northern hemisphere. During the first period, which may
be called the "Quaternary Period,"[B] the mighty animals lived whose
bones are now found in caverns, or under the slowly deposited sediment
of the waters, or preserved in bog,--the mammoth, and rhinoceros, and
elk, and bear, and elephant, as well as many others of extinct species.

[Footnote B: We should bear in mind that the Quaternary or Diluvian
Period, however ancient in point of time, has no clearly distinguishing
line of separation from the present period. The great difference lies in
the extinction of certain species of animals, which lived then, whose
destruction may be due both to gradual changes of climate and to
man.--PICTET.]

We may suppose, that, if man did exist during these convulsions and
inundations, his superior intelligence would enable him to escape
the fate of the animals that were submerged,--or that, if his few
burial-places were invaded by the waters, his remains are now completely
covered by marine deposits under the ocean. If, however, in his
barbarian condition, he had fashioned implements of any hard material,
and especially if, as do the savages of the present family of man, he
had accidentally deposited them, or had buried them with the dead in
mighty mounds, the invading waters might well sweep them together from
their place and deposit them almost in mass, in situations where the
eddies should leave their gravel and sand.[C]

[Footnote C: Sir C. Lyell, in his remarks before the British Association