30 Geological Age of Man, 



assume that the presence of the human race upon the land 

 could affect, still less utterly change, those laws which have go- 

 verned the organic world in the ocean for millions of years ; 

 and if we enlarge our ideas respecting the antiquity of man, 

 and concede those ten thousand or even twenty thousand 

 years which some ethnologists demand in order to account 

 for the early civilization of nations and the origin of their 

 la,nguages, we must hesitate before we affirm that such a 

 period has been one of stagnation or diminished fluctuation 

 in the animate world. 



The identity of the fauna and flora of England and the con- 

 tinent of Europe requires us to assign a very distant date to 

 the period when the existing species of animals and plants 

 began to spread themselves over the lands we now inhabit. 

 At the period of such migrations this island was still united 

 with the continent, but a large number of the existing species 

 of moUusca and some other tribes of marine animals can 

 claim a much higher antiquity ; so much so that they were 

 already created during the drift or glacial epoch, when the 

 physical geography of Europe bore no resemblance to that 

 now established. If, therefore, ten or twenty thousand years 

 were added to the chronology of the human period, it would 

 still constitute a mere fraction of that vast geological division 

 of time during which the species now our contemporaries 

 have been coming into existence. But how small is the pro- 

 gress yet made by us in ascertaining the order in which the 

 mammalia now living were created ! Some species are so 

 ancient as to have co-existed wdth a fauna of which nearly 

 all the species have died out, while others may be coeval in 

 their origin with man, and a few perhaps are of more recent 

 creation. Man himself has been multiplying on the earth 

 since he entered upon it, and enlarging the range of many 

 animals, both intentionally and against his will. These 

 species occupy, together with the human population, the places 

 left vacant by such as are exterminated from time to time. 

 Whether the amount of change in those ten or twenty 

 thousand years which immediately preceded our own times 

 has been greater or less than the average mutation during 

 equal periods of the past, from the Silurian to the Pliocene 



