268 NATURAL SCIENCE [April 



of one impulse and not of a series lasting many ages. The unworn 

 character of the teeth and bones and shells, all derived and found 

 at different horizons in the beds, are also inconsistent with anything 

 but a single and violent impulse. For these and other reasons 

 which I have elaborated at length elsewhere, I must conclude, as I 

 have said, that these beds do not represent any prolonged period, but 

 a transient movement, a transient movement coincident with the 

 breach in continuity between England and the Continent. 



These last conclusions are, I know, far from being shared by the 

 geological prophets of these later days. They were the views, however, 

 of my masters — Murchison and Sedgwick, Conybeare, and Whewell, 

 Hopkins and Phillips. Where are better men to be found now ? 

 Where, in fact, are such men to be found at all now ? They nearly 

 all wrote, be it remembered, after the glacial craze had been published, 

 and all repudiated it. The views in question will, I am convinced, 

 again become the views of another generation which is rapidly 

 abandoning the extravagant teaching of Agassiz and his scholars. 



Whether true or false, however, they do not affect the earlier 

 part of this argument, which is supported by a large majority of the 

 geologists of the world — namely, the fact of the priority of the 

 Mammoth beds to the Drift. The Drift, in either case, forms a 

 great " divide," a great frontier, between two main divisions of the 

 Anthropozoic period. 



To myself it separates an antediluvian from a post-diluvian 

 period. These terms, however, are ambiguous, since they might be 

 accepted as in some way associated with the ideas of the theological 

 geologists with their Noachian or universal floods, an idea far from 

 any views of mine, and I would therefore apply some other nomen- 

 clature to them. I dislike the words palaeolithic and neolithic 

 as geological terms whatever virtue they may possess in archaeology. 

 The former use of stone instead of metal by man was an archaeo- 

 logical accident. Nor does the term neolithic include any but a 

 fraction of the beds which overlie the drifts. 



I prefer to differentiate these beds by their animal contents, 

 which are much safer criteria than the different shapes of chipped 

 axes, whose types sometimes overlap. The great cardinal difference 

 of the animal life before the drift and that subsequent to the drift 

 is the presence of domesticated animals in the latter and the 

 presence of wild animals only in the former, and by this test 

 I would separate them, calling the former Theriozoic and the latter 

 Himerozoic, the one connoting that division of the Human 

 period in which wild animals alone lived with man, and the other 

 the corresponding period in which tame ones did so. 



Let us proceed again. The Theriozoic or praedrift beds were, 

 so far as we know, continuous with each other, and if the geological 



