374 ORIGIN OF SPECIES 



Europe from La Plata, without any information in regard 

 to their geological position, no one would have suspected 

 that they had co-existed with sea-shells all still living; but 

 as these anomalous monsters co-existed with the Mastodon 

 and Horse, it might at least have been inferred 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 country, 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, includ- 

 ing the whole glacial epoch) were compared with those now 

 existing in South America or in Australia, the most skilful 

 naturalist would hardly be able to say whether the present 

 or the pleistocene inhabitants of Europe resembled most 

 closely those of the southern hemisphere. So, again, several 

 highly competent observers maintain that the existing pro- 

 ductions of the United States are more closely related to 

 those which lived in Europe during certain late tertiary 

 stages, than to the present inhabitants 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 somewhat older European beds. Nevertheless, 

 looking to a remotely future epoch, there can be little doubt 

 that all the more modern marine formations, namely, the 

 upper pliocene, the pleistocene and strictly modern beds of 

 Europe, North and South America, and Australia, from con- 

 taining 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 simulta- 

 neous 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 attention 

 to North America, and there discover a series of analogous 



