TERTIARY PERIODS. mi 



and the iron ages, since the prehistoric animals are found in and around the dwellings 

 and the burial places of the men who lived in those times. 



The Historic Period embraces the lapse of time from the first authentic record of any 

 given country down to the present day, and its beginning necessarily varies in different 

 regions. In Britain it would begin with the first invasion of the Romans ; in Gaul with 

 its conquest by the Roman legions ; and in Germany with the Annals of Tacitus. In the 

 countries, however, bordering on the shores of the Mediterranean, in the great centres of 

 civilisation, Rome and Greece, it would extend much further back from the present time, 

 and would embrace a time during which there were no records of the regions lying to the 

 north, that is to say, of central and northern Europe. It is a most important thing to 

 bear in mind that there is no absolute historic period applicable to all parts of Europe. 

 While the master minds of Greece were earning imperishable fame by their writings, the 

 rude nations of Gaul, Germany, Britain, and the north were probably constructing the 

 dwellings, tumuli, and stone circles which excite our admiration. It would be as unfair 

 to call the Parthenon prehistoric as to term the Pfahlbauten of the Swiss lakes historic, 

 although it may be that both were in existence at the same point of time. 



Table of the divisions of the Tertiary or Canozoic Period. 



The following are the divisions of the Tertiary or Csenozoic Period adopted in this essay. 



Deposits containing Mammalia. 

 I. Historic = Recent, in part, of Sir I. Caves, Peat -bogs, Alluvia. Refuse- 



Charles Lyell. heaps, houses, camps, tombs. 



II. Prehistoric = Neolithic, Bronze, II. Caves, Peat-bogs, Alluvia, dwell- 



Iron Ages = Recent, in part, of Sir Charles ings and burial places of man. Refuse- 

 Lyell. heaps. 



III. Pleistocenes Quaternary of French III. Caves, brick-earths, and ancient 

 Geologists — Post-pleiocene of Sir Charles river-gravels-. Refuse-heaps. Glacial de- 

 Lyell = Palaeolithic age in part. posits. 



IV. Pleiocene. Deposits of rivers and ancient lakes. 



Estuarine deposits. River-deposits. Marine 

 deposits. 

 V. Meiocene. Ditto. 



VI. Eocene. Ditto. 



The Mammalia which lived in the first three of these stages or divisions, are those to 

 which this treatise will be principally devoted, but we shall be obliged also to examine the 

 relation of the Pleistocene to the Pleiocene, and those peculiar conditions under which the 

 mammals of the latter yielded place to those of the former age. 



