he gives sections, from Verenius,
Buffon, and others, obtained in digging wells; distinguishes between
horizontal and inclined strata; and, in speculating on the causes of
these appearances, mentions Donati's examination of the bed of the
Adriatic; the filling up of lakes and seas by sediment; the imbedding of
shells now in progress; and many known effects of earthquakes, such as
the sinking down of districts, or the heaving up of the bed of the sea,
so as to form new islands, and lay dry strata containing petrifactions.
The ocean, he says, deserts its shores in many countries, as on the
borders of the Baltic; but the rate of recession has been so slow in the
last 2000 years, that to allow the Apennines, whose summits are filled
with marine shells, to emerge to their present height, would have
required about 80,000 years,--a lapse of time ten times greater, or
more, than the age of the universe. We must therefore refer the
phenomenon to the command of the Deity, related by Moses, that "the
waters should be gathered together in one place, and the dry land
appear." Gesner adopted the views of Leibnitz, to account for the
retreat of the primeval ocean: his essay displays much erudition; and
the opinions of preceding writers of Italy, Germany, and England, are
commented upon with fairness and discrimination.

_Arduino_, 1759.--In the year following, Arduino,[85] in his memoirs on
the mountains of Padua, Vicenza, and Verona, deduced, from original
observations, the distinction of rocks into primary, secondary, and
tertiary, and showed that in those districts there had been a succession
of submarine volcanic eruptions.

_Michell_, 1760.--In the following year (1760) the Rev. John Michell,
Woodwardian Professor of Mineralogy at Cambridge, published in the
Philosophical Transactions, an Essay on the Cause and Phenomena of
Earthquakes.[86] His attention had been drawn to this subject by the
great earthquake of Lisbon in 1755. He advanced many original and
philosophical views respecting the propagation of subterranean
movements, and the caverns and fissures wherein steam might be
generated. In order to point out the application of his theory to the
structure of the globe, he was led to describe the arrangement and
disturbance of the strata, their usual horizontality in low countries,
and their contortions and fractured state in the neighborhood of
mountain chains. He also explained, with surprising accuracy, the
relations of t