posits wherein the fineness of their particles, and the
absence of pebbles, implied that they were accumulated in a deep sea, or
far from shore. This author first remarked the alternation of marine and
freshwater strata in the Paris basin.[91]

_Fortis--Testa_, 1793.--A lively controversy arose between Fortis and
another Italian naturalist, Testa, concerning the fish of Monte Bolca,
in 1793. Their letters,[92] written with great spirit and elegance, show
that they were aware that a large proportion of the Subapennine shells
were identical with living species, and some of them with species now
living in the torrid zone. Fortis proposed a somewhat fanciful
conjecture, that when the volcanoes of the Vicentin were burning, the
waters of the Adriatic had a higher temperature; and in this manner, he
said, the shells of warmer regions may once have peopled their own seas.
But Testa was disposed to think that these species of testacea were
still common to their own and to equinoctial seas; for many, he said,
once supposed to be confined to hotter regions, had been afterwards
discovered in the Mediterranean.[93]

_Cortesi--Spallanzani--Wallerius--Whitehurst._--While these Italian
naturalists, together with Cortesi and Spallanzani, were busily engaged
in pointing out the analogy between the deposits of modern and ancient
seas, and the habits and arrangement of their organic inhabitants, and
while some progress was making, in the same country, in investigating
the ancient and modern volcanic rocks, some of the most original
observers among the English and German writers, Whitehurst[94] and
Wallerius, were wasting their strength in contending, according to the
old Woodwardian hypothesis, that all the strata were formed by Noah's
deluge. But Whitehurst's description of the rocks of Derbyshire was most
faithful; and he atoned for false theoretical views, by providing data
for their refutation.

_Pallas--Saussure._--Towards the close of the eighteenth century, the
idea of distinguishing the mineral masses on our globe into separate
groups, and studying their relations, began to be generally diffused.
Pallas and Saussure were among the most celebrated whose labors
contributed to this end. After an attentive examination of the two great
mountain chains of Siberia, Pallas announced the result, that the
granitic rocks were in the middle, the schistose at their sides, and the
limestones again on the outside of these; and this he conceive