THROUGHOUT THE WORLD. 353 



ferred that they had lived during one of the later tertiary- 

 stages. 



When the marine forms of life are spoken of as having 

 changed simultaneously throughout the world, it must not 

 be supposed that this expression relates to the same year, 

 or to the same century, or even that it has a very strict 

 geological sense; for if all the marine animals now living 

 in Europe, and all those that lived in Europe during the 

 pleistocene period (a very remote period as measured by 

 years, including the whole glacial epoch) were compared 

 with those now existing in South America or in Australia, 

 the most skillful naturalist would hardly be able to say 

 whether the present or the pleistocene inhabitants of 

 Europe resembled most closely those of the southern hemi- 

 sphere. So, again, several highly competent observers 

 maintain that the existing productions of the United States 

 are more closely related to those which lived in Europe 

 during certain late tertiary stages, than to the present in- 

 habitants of Europe; and if this be so, it is evident that 

 fossiliferous beds now deposited on the shores of North 

 America would hereafter be liable to be classed with some- 

 what older European beds. Nevertheless, looking to a 

 remotely future epoch, there can be little doubt that all 

 the more modern tnarme formations, namely, the upper 

 pliocene, the pleistocene and strictly modern beds of 

 Europe, North and South America, and Australia, from 

 containing fossil remains in some degree allied, and from 

 not including those forms which are found only in the 

 older underlying deposits, would be correctly ranked as 

 simultaneous in a geological sense. 



The fact of the forms of life changing simultaneously in 

 the above large sense, at distant parts of the world, has 

 greatly struck those admirable observers, MM. de Verneuil 

 and d'Archiac. After referring to the parallelism of the 

 palaeozoic forms of life in various parts of Europe, they add, 

 " If, struck by this strange sequence, we turn our atten- 

 tion to North America, and there discover a series of ana- 

 logous phenomena, it will appear certain that all these 

 modifications of species, their extinction, and the intro- 

 duction of new ones, can not be owing to mere changes in 

 marine currents or other causes more or less local and 

 temporary, but depend on general laws which govern the 



