|  When the marine forms of life are spoken of 
having changed simultaneously throughout the world, it must not be supposed that this expression relates to the same 
or 
→hundred-thousandth year, 
or even that it has a very strict geological sense; for if all the marine animals 
→which live at the present day 
in Europe, and all those that lived in Europe during the pleistocene period 
remote period as measured by years, including the whole glacial 
were 
compared with those now 
in South America or in Australia, the most skilful naturalist would hardly be able to say whether the 
or the pleistocene inhabitants of Europe resembled most closely those of the southern hemisphere.  So, again, several highly competent 
that the existing productions of the United States are more closely related to those which lived in Europe during certain 
tertiary stages, than to 
→those which now live here; 
and if this be so, it is evident that fossiliferous beds 
→deposited at the present day 
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 
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 containing fossil remains in some degree allied, and from not including those forms which are 
in the older underlying deposits, would be correctly ranked as simultaneous in a geological sense.  |