Observations on the Nature and Importance of Geology. S99 



the bosom of the earth can alone reveal them. We indeed ob- 

 serve that the Ibis, which was worshipped in ancient Egypt, and 

 preserved as a mummy, is still the same in modern Egypt ; but 

 what are the few thousand years to which the mummy refers, 

 in comparison with the age of the world, as its history is related 

 by geology. 



Geology likewise supplies us with instructive disclosures re- 

 garding the distribution of organic beings. If we, in all the 

 regions and climates of the world, meet with a striking unifor- 

 mity in the structure of the earth, we also, on the contrary, ob- 

 serve plants and animals of a most varied character scattered 

 over its surface. As there are among the dicotyledons, that is, 

 among the more perfect plants, no species, which are at the 

 same time indigenous to the hot climates of the old and new 

 world, so both halves of the globe in the same zone possess mam- 

 miferous animals, birds, reptiles, and insects peculiar to each. 

 Species common to both are found only among the inferior gra- 

 dations of organization, and species of a higher order are found 

 only in those high northern latitudes, where the continents were 

 undoubtedly at one time conjoined. From the combined re- 

 sults of organic geography, and the doctrine of petrifactions, it 

 will at once follow, whether the ancient population of the ter- 

 restrial globe was distributed according to the same laws as at 

 present. Even now, many of the petrifactions of cold climates, 

 whose species and families are produced only in hot countries, 

 indicate a great change in the temperature of their former si- 

 tuations, and phenomena, like that of the rhinoceros found on 

 the shore of the Wilhui, and of the mammoth at the mouth of 

 the Lena, are likewise indications of sudden changes in those 

 places. Along with the distribution of species, we also acquire 

 a knowledge of the distribution of individuals, and of their 

 modes of life, from their fossil remains, because these remains, 

 like living creatures, appear to us sometimes single, and dis- 

 persed at other times in numerous bodies, and closely crowded 

 together. 



The doctrine of petrifactions contains also the history of the or- 

 ganic world, as natural history contains its description. Like the 

 coins, inscriptions, and works of art, which make us acquainted 



