"When animals," he says, "first crept forth from the newly formed earth, a dumb and filthy herd, they fought for acorns and lurking-places with their nails and fists, then with clubs, and at last with arms, which, taught by experience, they had forged. They then invented names for things and words to express their thoughts, after which they began to desist from war, to fortify cities and enact laws." They who in later times have embraced a similar theory, have been led to it by no deference to the opinions of their pagan predecessors, but rather in spite of very strong prepossessions in favour of an opposite hypothesis, namely, that of the superiority of their original progenitors, of whom they believe themselves to be the corrupt and degenerate descendants. So far as they are guided by palaeontology, they arrive at this result by an independent course of reasoning; but they have been conducted partly to the same goal as the ancients by ethnological considerations common to both, or by reflecting in what darkness the infancy of every nation is enveloped and that true history and chronology are the creation, as it were, of yesterday. CHAPTER 20. -- THEORIES OF PROGRESSION AND TRANSMUTATION. Antiquity and Persistence in Character of the existing Races of Mankind. Theory of their Unity of Origin considered. Bearing of the Diversity of Races on the Doctrine of Transmutation. Difficulty of defining the Terms "Species" and "Race." Lamarck's Introduction of the Element of Time into the Definition of a Species. His Theory of Variation and Progression. Objections to his Theory, how far answered. Arguments of modern Writers in favour of Progression in the Animal and Vegetable World. The old Landmarks supposed to indicate the first Appearance of Man, and of different Classes of Animals, found to be erroneous. Yet the Theory of an advancing Series of Organic Beings not inconsistent with Facts. Earliest known Fossil Mammalia of low Grade. No Vertebrata as yet discovered in the oldest Fossiliferous Rocks. Objections to the Theory of Progression considered. Causes of the Popularity of the Doctrine of Progression as compared to that of Transmutation. When speaking in a former work of the distinct races of mankind,* I remarked that, "if all the leading varieties of the human family sprang originally from a single pair" (a doctrine, to which then, as now, I could see no valid objection), "a much greater lapse of time was required for the slow and gradual formation of such races as the Caucasian, Mongolian, and Negro, than was embraced in any of the popular systems of chronology." (* "Principles of Geology" 7th edition page 637, 1847; see also 9th edition page 660.)