128 LAMARCK, HIS LIFE AND WORK 
though many fossil shells are different from all the 
marine shells known, 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 cf the ani- 
