as a Geognostic Character. 229 
another, in a mineralogical sense ; but that the organic remains 
which they envelope, have all the common character of the ge- 
neration established upon the earth, since the commencement of 
this epoch. To increase the number of examples, and, conse- 
quently, proofs of one and the same truth, would be unneces- 
sarily to protract a series of reasonings already somewhat long. 
It is not the same with the generations of organised beings ; 
they may, it is true, be destroyed in an instant, but a conside- 
rable time must necessarily be taken to reproduce them, so as 
that they may assume, in number and variety, the development 
which they commonly present. This development supposes a 
long series of ages, or at least of years, which establish a true 
geognostical epoch, during which all the organised bodies which 
inhabit, if not the whole surface of the globe, at least very ex- 
tensive tracts of this surface, have assumed a particular family 
or epochal character, which cannot be defined, but which yet 
cannot be misunderstood. 
I consider, therefore, the characters of the period of forma- 
tion , derived from the analogy of organised bodies, as of the 
first importance in geognosy, and as sufficient to counterbalance 
all other differences, however great they appear. Hence, even 
should the characters taken from the nature of the rocks, and 
this is the weakest distinctive mark, from the height of the de- 
posits, from the scooping of valleys, even from the inclination of 
beds, and their unconformable stratification, be found, in oppo- 
sition to that which we derive from organic remains, I would 
still consider the latter as of superior validity ; for all these dif- 
ferences may be the result of a revolution, and of an instanta- 
neous formation, which do not establish in geognosy a special 
epoch. Without seeking to prove this principle, by a longer 
train of reasoning, I shall content myself with citing a single 
fact. The formations of Calabria have been, for thirty-eight 
years, the theatre of fearful perturbations. Horizontal beds 
have been raised to a perpendicular position ; entire masses of 
deposits have been transported to a great distance, and have 
been placed in unconformable stratification, upon other deposits, 
and yet no geologist would regard these masses, and these depo- 
sits, as belonging to a different geognostic epoch. To produce 
a change of organic species, circumstances of a very different na- 
