128 LAMARCK, HIS LIFE AND WORK 



though many fossil shells are different from all the 

 marine shells knowri, this does not prove that the 

 species of these shells are extinct, but only that these 

 species have changed as the result of time, and that 

 actually they have different forms from those individ- 

 uals whose fossil remains we have found. "^/ 



Then he goes on in the same strain as in the open- 

 ing discourse, saying that nothing terrestrial remains 

 constant, that geological changes are continually oc- 

 curring, and that these changes produce in living or- 

 ganisms a diversity of habits, a different mode of life, 

 and as the result modifications or developments in 

 their organs and in the shape of their parts. 



" We should still realize that all the modifications 

 which the organism undergoes in its structure and 

 form as the result of the influence of circumstances 

 which would influence this being, are propagated by 

 generation, and that after a long series of ages not 

 only will it be able to form new species, new genera, 

 and even new orders, but also each species will even 

 necessarily vary in its organization and in its forms. 



" We should not be more surprised then if, among 

 the numerous fossils which occur in all the dry parts 

 of the globe and which offer us the remains of so 

 many animals which have formerly existed, there 

 should be found so few of which we know the living 

 analogues. If there is in this, on the contrary, any- 

 thing which should astonish us, it is to find that 

 among these numerous fossil remains of beings which 

 have lived there should be known to us some whose 

 analogues still exist, from a germ to a vast multitude 

 of living forms, of different and ascending grades of 

 perfection, ending in man. 



" This fact, as our collection of fossils proves, should 

 lead us to suppose that the fossil remains of the ani- 



