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EARLY MAN IN BRITAIN.
[CHAP. I.
These facts appear to me inexplicable on any other theory than that of evolution.
Fig. 1.—Specialisation of Mammalia in Tertiary Period.
No similar series of changes such as these has been observed in the reptiles, amphibians, fishes, or in the Invertebrates of the Tertiary strata, nor is it clearly marked in the Tertiary vegetation. In the birds, however, a similar specialisation has been pointed out by Professor Milne Edwards. The living orders, families, and genera of the lower Vertebrates had already appeared in the Primary and Secondary periods; first, the lower and afterwards the higher forms, preserving in their successive appearances the order in which they are arranged in the classification of the naturalists.
