GENERAL CONCLUSIONS. 413 
only in a fossil state, whilst others (and these 
chiefly in the lower Classes,) have extended 
through all geological Eras unto the present 
time. 
On these facts we may found conclusions 
which are of great importance in the investi- 
gation of the physical history of the Earth. If 
the existing Classes, Orders, and Families of 
marine and terrestrial Articulated animals have 
thus pervaded various geological epochs, since 
life began upon our planet, we may infer that 
the state of the Land and Waters, and also of the 
Atmosphere, during all these Epochs, was not so 
widely different from their actual condition as 
many geologists have supposed. We also learn 
that throughout all these epochs and stages of 
change, the correlative Functions of the suc- 
cessive Representatives of the animal and vege- 
table kingdoms have ever been the same as at 
the present moment; and thus we connect the 
entire series of past and present forms of organ- 
ized beings, as parts of one stupendously grand, 
and consistent, and harmonious Whole. 
^ 
