110 THE ORIGIN OF SPECIES 



be so, it is evident that fossiliferous beds now deposited 

 on the shores of North America would hereafter be 

 liable to be classed with somewhat older European beds. 

 Nevertheless, looking to a remotely future epoch, there 

 can be little doubt that all the more modern marine 

 formations, namel}'^, 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 parallel- 

 ism of the paleozoic forms of life in various parts of 

 Europe, they add, "If, struck by this strange sequence, 

 we turn our attention to North America, and there dis- 

 cover a series of analogous phenomena, it will appear 

 certain that all these modifications of species, their ex- 

 tinction, and the introduction of new ones, cannot 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 whole animal kingdom." M. 

 Barrande has made forcible remarks to precisely the 

 same effect. It is, indeed, quite futile to look to changes 

 of currents, climate, or other physical conditions, as the 

 cause of these great mutations in the forms of life 

 throughout the world, under the most different climates. 

 We must, as Barrande has remarked, look to some 

 special law. We shall see this more clearly when we 



