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 

 gaining 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 earthf . But it is evident, that Agricola was 

 not partial to inquiries respecting extraneous fossils ; his attention 

 was chiefly engaged in mineralogy, to the promotion of which his 

 industry added very considerably. 



In 1565, Conrad Gesner published, at Zurich, a work of great me- 

 rit, De Rcrum Fossilium, Lapidum, et Gemmarum, Figuris. About 

 this time John Kentman, a German, collected a cabinet of petri- 

 factions, which, considering the period in which it was formed, ap- 

 pears 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 Kircherianum, p. 198. Musaeum Calceolarii et Musaeum Com 

 Moscardi, p. 172. 

 t De Ortu et Causis Subterr. lib. iii. et De Natura Fossil, lib. vii. 



