206 WALTEB KIDD, M.l)., F.Z.S., ON 



tration of this principle. It is also seen in the gradual slow 

 changes of climate, the slow emergence and submergence 

 of land, the restrained volcanic action of these early days. 



18 But equable conditions such as these suited not the prolific 

 outburst of higher life among animals, soon to appear in 

 early Cainozoic times, and the more hardy forms of plants. 

 The climate gradually altered from the mildness of Eocene 

 and Miocene times, Avhen palms flourished in Great Britain 

 and Siberia was a temperate abode much like that of the 

 Continent of Europe at the present time, to the gradual 

 cooling of Pliocene climate. Then became defined, much as 

 now, the frigid and torrid zones. Then arose the mountain 

 chains of California, Mexico, the Rocky Mountains and Alps, 

 Pyrenees, and Apennines. Volcanic action extensively pre- 

 vailed, more especially along the land-borders. The defini- 

 tion of land and sea proceeded till, " hitherto shalt thou go, 

 and no further, and here shall thy proud waves be stayed," 

 was the beneficent fiat to the restless ocean in the 

 approaching Quaternary Age of Man. During the Cainozoic 

 period a vast population, largely new to the world, was 

 introduced to this prepared home. Its name, the Age of 

 Mammals, indicates the predominant type, and these were 

 now placental mammals of a higher scale than the marsupials 

 of the Mesozoic. Lower vertebrates also of all kinds pre- 

 vailed in profusion ; reptiles, such as crocodiles, lizards, 

 snakes, and turtles : birds such as owls, eagles, cranes, 

 pelicans, ibises ; mammals such as the earlier herbivores, 

 tapirs, hogs, rhinoceros, deer, and the supposed ancestors of 

 the horse ; carnivores with forms like those of wolves and 

 dogs, greater mammals such as mastodons, elephants, thus 

 representing in earlier forms all the great brutes which in the 

 Quaternary times were to reach their climax. Monkeys 

 appeared in Miocene times so widely as to give occa- 

 sionally the name " Age of Monkeys " to this period, and 

 a few anthropoid apes, and extensive timber forests. 



19 When the last geological age, in which we ourselves are 

 living, was ushered in, the gradual cooling of the Pliocene 

 period culminated in the glacial period of the Quaternary 

 Age. The eff"ects of this time of low temperature witli, it is 

 believed, more than one glacial period were of profound 

 importance. The increasing cold killed ofi" many forms of 

 life unsuited for coming days, and man now entered upon the 

 scene with, for the first time, more difficult environments to 

 test this " fitness." Transportation of great masses of rock. 



