ematician Leibnitz published his
"Protogoea" in 1680. He imagined this planet to have been originally a
burning luminous mass, which ever since its creation has been undergoing
refrigeration. When the outer crust had cooled down sufficiently to
allow the vapors to be condensed, they fell, and formed a universal
ocean, covering the loftiest mountains, and investing the whole globe.
The crust, as it consolidated from a state of fusion, assumed a
vesicular and cavernous structure; and being rent in some places,
allowed the water to rush into the subterranean hollows, whereby the
level of the primeval ocean was lowered. The breaking in of these vast
caverns is supposed to have given rise to the dislocated and deranged
position of the strata "which Steno had described," and the same
disruptions communicated violent movements to the incumbent waters,
whence great inundations ensued. The waters, after they had been thus
agitated, deposited their sedimentary matter during intervals of
quiescence, and hence the various stony and earthy strata. "We may
recognize, therefore," says Leibnitz, "a double origin of primitive
masses, the one by refrigeration from igneous fusion, the other by
concretion from aqueous solution."[55] By the repetition of similar
causes (the disruption of the crust and consequent floods), alternations
of new strata were produced, until at length these causes were reduced
to a condition of quiescent equilibrium, and a more permanent state of
things was established.[56]

_Hooke_, 1688.--The "Posthumous Works of Robert Hooke, M. D.," well
known as a great mathematician and natural philosopher, appeared in
1705, containing "A Discourse of Earthquakes," which, we are informed by
his editor, was written in 1668, but revised at subsequent periods.[57]
Hooke frequently refers to the best Italian and English authors who
wrote before his time on geological subjects; but there are no passages
in his works implying that he participated in the enlarged views of
Steno and Lister, or of his contemporary, Woodward, in regard to the
geographical extent of certain groups of strata. His treatise, however,
is the most philosophical production of that age, in regard to the
causes of former changes in the organic and inorganic kingdoms of
nature.

"However trivial a thing," he says, "a rotten shell may appear to some,
yet these monuments of nature are more certain tokens of antiquity than
coins or medals, since the best of thos