188 GEOLOGICAL HISTORY. 



bored through or split, with large wooden wedges and stones in 

 them, and broken axe-heads somewhat like sacrificing axes in 

 shape, and this at depths and under circumstances which ex- 

 clude all supposition of their having been touched since the de- 

 struction of the forest. . . . Near a large root in the parish of 

 Hatfield were found eight or nine coins of some of the Roman 

 emperors, exceedingly defaced with time." 



ORIGIN OF THE FAUNA AND FLORA OF YORKSHIRE. 



Whence came the fauna and flora to the insulated area of 

 Britain ? It will be useless to invoke a special creation within 

 this area, because the species are not confined to it, and there 

 will be the same difficulty in spreading them from it as in bring- 

 ing them to it. It will not be enough to call in the aid of sea- 

 currents, or aerial wanderers, to disseminate even a small portion 

 of the animals and plants. There remains then one only mode 

 to be further considered, a change of physical circumstances, 

 such that a land communication existed for a long period of 

 time between Britain and the Continent, whereby animals might 

 arrive by the usual processes of nature. 



In such a case migration, the process by which animals adapt 

 themselves to varying climate, procure suitable food, and obtain 

 the requisite conditions for reproduction, might bring us the 

 Elephant, Urus and Deer, with their followers, the Lion, Tiger 

 and Wolf. The irregular distribution of seeds and ova, which 

 takes place in many unexpected ways through air and water, 

 might give us the aquatic and terrestrial mollusca and plants ; 

 while the steady process of diffusion from a central space may be 

 appealed to for the more easy examples of animals less dependent 

 on climate, and less restrained from locomotion. Such a state 

 of physical geography would be represented, if, with De la Beche, 

 we raise the bed of the northern seas only 600 feet, a quantity 

 much within the admitted measures of moderate geological 

 movements. 



