598 



REPORT 1882. 



The Limitation of the Inquiry. 



The most striking feature in tb.e study of tlie Tertiary period is the gradual 

 and orderly succession of higher types of Mammalia, so well-defined and so orderly, 

 that I have used it as a basis for the classificp.tion of the Tertiary period. We 

 find the placental mammals becoming more and more specialised as we approach 

 the frontier of history. The living orders appear in the Eocene, the living genera 

 in the Meiocene, a few living species in the Pleiocene, and the rest in the Pleistocene. 

 The cliaracteristics of this evolution of living forms may be summed up in the 

 following table : — 



Definition of Tertiary Period hy Placental Land Mammals. 



VI. Historic ; in which the 

 events arc recorded in 

 history 



V. Prehistoric ; in which 

 domestic animals and 

 cultivated fruits appear 



IV. Pleistocene; in which 

 living species of jila- 

 cental mammals are 

 more abundant than 

 the extinct 



III. Pleiocene ; in which liv- 

 ing species of placen- 

 tal mammals appear 



II. Meiocene; in which the 

 alliance between living 

 and placental mammals 

 is more close than be- 

 fore 



I. Eocene ; in which the 

 placental mammals 

 now on earth were re- 

 presented by allied 

 forms belonging to ex- 

 isting orders and fami- 

 lies 



Events included in history 



Man abundant ; domestic 

 animals, cultivated fruits, 

 spinning, weaving, pot- 

 tery-making, mining, 

 commerce ; the neolithic, 

 bronze, and iron stages 

 of culture 



ilan appears ; Anthropidw ; 

 the palajolithic hunter ; 

 living species abundant 



Living species appear ; apes, 

 Simiader, in Southern Eu- 

 rope 



Living genera appear ; apes, 

 Simiadrr, in Europe and 

 North America 



Living orders and families 

 appear; lemurs (Lcmiiri- 

 dfc) in Europe and North 

 America 



Founded on discove- 

 ries, documents, re- 

 fuse-heaps, caves, 

 tombs 



Camps, habitations, 

 tombs, refuse-heaps, 

 surface accumula- 

 tions, caves, alluvia, 

 peat - bogs, subma- 

 rine forests, raised 

 beaches 



Kefuse-heaps, contents 

 of caves, river-depo- 

 sits, submarine fo- 

 rests, boulder - claj% 

 moraines, marine 

 sands, and shingle 



Fresh-water and ma- 

 rine strata ; volcanic 

 debris (Auvergne) 



Fresh-water and ma- 

 rine strata ; volcanic 

 debris (Auvergne) ; 

 lisrnites 



Fresh-water and ma- 

 rine strata ; lignites 



The orders, families, genera, and species in the above table, when traced forward 

 in time, fall into the shape of a genealogical tree, with its trunk hidden in the Secon- 

 dary period, and its branchlets (the living species) passing upwards from the 

 Pleiocene, a tree of life, with living Mammalia for its fruit and foliage. Were the 

 extinct species taken into account, it would be seen that they fill up the intervals 

 separating one living form from another, and that they too grow more and more 

 like the living forms as they approach nearer to the present day. It must be re- 

 membered tliat in the above deiinitions the fossil marsupials are purposely ignored 

 because they began their specialisation in the Secondary period, and had arrived in 

 the Eocene at the stage which is marked by the presence of a living genus — the 

 opossum {Didelphys). 



