Page:Early Man in Britain and His Place in the Tertiary Period.djvu/65

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have, in the course of this chapter, to seek for evidence of man in the Meiocene life period, when the living genera of mammals first begin to appear. It must be admitted that the strict definition of the Meiocene from the Eocene period is one of exceeding difficulty from the imperfect preservation of the fossils, and from the impossibility of ascertaining the exact relative age of assemblies of animals found in isolated lake basins and in river deposits widely remote from each other. The only clue to their geological date is the stage of evolution presented by the mammalia, the more general having obviously preceded in point of time the more special forms.