olutions of
the globe, translated by Abraham Ecchellensis,[25] seems to form a
singular exception to the general rule, for here we find the idea of
different genera and species having been created. The Gerbanites, a sect
of astronomers who flourished some centuries before the Christian era,
taught as follows:--"That after every period of thirty-six thousand four
hundred and twenty-five years, there were produced a pair of _every_
species of animal, both male and female, from whom animals might be
propagated and inhabit this lower world. But when a circulation of the
heavenly orbs was completed, which is finished in that space of years,
_other genera and species_ of animals are propagated, as also of plants
and other things, and the first order is destroyed, and so it goes on
forever and ever."[26]

_Theory of Strabo._--As we learn much of the tenets of the Egyptian and
Oriental schools in the writings of the Greeks, so, many speculations of
the early Greek authors are made known to us in the works of the
Augustan and later ages. Strabo, in particular, enters largely, in the
second book of his Geography, into the opinions of Eratosthenes and
other Greeks on one of the most difficult problems in geology, viz., by
what causes marine shells came to be plentifully buried in the earth at
such great elevations and distances from the sea.

He notices, amongst others, the explanation of Xanthus the Lydian, who
said that the seas had once been more extensive, and that they had
afterwards been partially dried up, as in his own time many lakes,
rivers, and wells in Asia had failed during a season of drought.
Treating this conjecture with merited disregard, Strabo passes on to the
hypothesis of Strato, the natural philosopher, who had observed that the
quantity of mud brought down by rivers into the Euxine was so great,
that its bed must be gradually raised, while the rivers still continue
to pour in an undiminished quantity of water. He, therefore, conceived
that, originally, when the Euxine was an inland sea, its level had by
this means become so much elevated that it burst its barrier near
Byzantium, and formed a communication with the Propontis; and this
partial drainage, he supposed, had already converted the left side into
marshy ground, and thus, at last, the whole would be choked up with
soil. So, it was argued, the Mediterranean had once opened a passage for
itself by the Columns of Hercules into the Atlantic; and perhaps