e deposits are laid down, then the slow
but combined alteration that these great masses undergo, left
uncovered and exposed to the incessant action of the air, light, and
a variable humidity, changes them gradually into fossils and
destroys their membranous or gelatinous part, which is the readiest
to decompose. This alteration, which the enormous masses of the
corals in question continued to undergo, caused their structure to
gradually disappear, and their great porosity unceasingly diminished
the parts of these stony masses by displacing and again bringing
together the molecules composing them, so that, undergoing a new
aggregation, these calcareous molecules obtained a number of points
of contact, and constituted harder and more compact masses. It
finally results that instead of the original masses of madrepores
and millepores there occurs only masses of a compact calcareous
rock, which modern mineralogists have improperly called _primitive
limestone_, because, seeing in it no traces of shells or corals,
they have mistaken these stony masses for deposits of a matter
primitively existing in nature."

He then reiterates the view that these deposits of marble and
limestones, often forming mountain ranges, could not have been the
result of a universal catastrophe, and in a very modern way goes on to
specify what the limits of catastrophism are. The only catastrophes
which a naturalist can reasonably admit as having taken place are
partial or local ones, those dependent on causes acting in isolated
places, such as the disturbances which are caused by volcanic eruptions,
by earthquakes, by local inundations, by violent storms, etc. These
catastrophes are with reason admissible, because we observe their
analogues, and because we know that they often happen. He then gives
examples of localities along the coast of France, as at Manche, where
there are ranges of high hills made up of limestones containing Gryphaeae,
ammonites, and other deep-water shells.

In the conclusion of the chapter, after stating that the ocean has
repeatedly covered the greater part of the earth, he then claims that
"the displacement of the sea, producing a constantly variable
inequality in the mass of the terrestrial radii, has necessarily caused
the earth's centre of gravity to vary, as also its two poles.[79]
Moreover, since it appears that this variation, very irregular as it is,
not being subjected to any limits