19 
made for answer, that it had been attempted to be accounted for 
in three different ways. Some attributed it to the vis plastica and 
formativa of Aristotle : others supposed these substances to have 
been real marine bodies, deposited in these places at the time of a 
general deluge : whilst others had adopted that opinion, to which 
he himself was most inclined; that the parts, where these marine 
bodies were found, had formerly been covered with the sea, which 
gaming insensibly, in some parts, on the dry land, gradually changed 
its bed, leaving the positions it had formerly occupied for the cul- 
tivation and possession of man.* 
In the sixteenth century. Agricola, to whose indefatigable spirit 
of inquiry, mineralogy is very much indebted, spoke much more 
explicitly of extraneous fossils than had hitherto been done. He 
particularly mentions the entrochi, and relates several instances of 
trees, and parts of trees, being found in a petrified state, at consi- 
derable depths in the earth.f But it is evident, that Agricola was 
not partial to inquiries respecting extraneous fossils ; his attention 
was chiefly engaged in mineralogy, to promote the knowledge of 
which his industry exceedingly contributed. 
In 1565, Conrad Gesner published, at Zurich, a work of great 
merit, De Rerum Fossilium, Lapidmn, et Gemmarum, Figuris. 
About this time John Kentman, a German, collected a cabinet of 
petrifactions, which, considering the period in which it was formed, 
appears to have been very respectable. The catalogue of it is con- 
tained in Gesner’s work. About the same time Valerius Cordus, a 
celebrated physician, undertook to publish a general oryctography 
of Germany ; but does not appear to have received such encourage- 
ment, as would have warranted the prosecution of his plan. 
Bonani Musaeum Kircherianura, p. 198. Musaeum Calceolai'ii et Musseum Com. Mos- 
cardi, p. 172 . 
t Oe Ortu et Causis Subterr. lib. Hi. et De Natura Fossil, lib. vii. 
