34 CAUSE OF VIOLATIONS OF CONTINUITY. [Ch. III. 
one being Roman, while, as in the former example, the lowest 
was Greek, and the uppermost Italian, he would then perceive 
the fallacy of his former opinion, and would begin to suspect 
that the catastrophes, whereby the cities were inhumed, might 
have no relation whatever to the fluctuations in the language of 
the inhabitants ; and that, as the Roman tongue had evidently 
intervened between the Greek and Italian, so many other 
dialects may have been spoken in succession, and the passage 
from the Greek to the Italian may have been very gradual, 
some terms growing obsolete, while others were introduced 
from time to time. 
If this antiquary could have shown that the volcanic pa- 
roxysms of Vesuvius were so governed as that cities should be 
buried one above the other, just as often as any variation 
occurred in the language of the inhabitants, then, indeed, the 
abrupt passage from a Greek to a Roman, and from a Roman 
to an Italian city, would afford proof of fluctuations no less 
sudden in the language of the people. 
So in Geology, if we could assume that it is part of the plan 
of nature to preserve, in every region of the globe, an unbroken 
series of monuments to commemorate the vicissitudes of the 
organic creation, we might infer the sudden extirpation of 
species, and the simultaneous introduction of others, as often 
as two formations in contact include dissimilar organic fossils. 
But we must shut our eyes to the whole economy of the 
existing causes, aqueous, igneous, and organic, if we fail to 
perceive that such is not the plan of Nature. 
