xxviii PREFACE. 



doubtedly their production. The regular 

 prifmatical bafaltes feem to be their work ; 

 and it is highly probable, that the petrified 

 fifties are monuments of their heat, which 

 very often has been cbferved to make the 

 troubled ocean boil with violence in thofe 

 places, where Pluto and Neptune ftrove for 

 their kingdoms 



Quicquid dellrant reges, pkEluntur Achivl. 



The nimble motion and known voracity of 

 fifties when alive; their eafy putrefaction 

 and floating on the furface of the water 

 when dead ; and many other circumftances 

 coincide to indicate not a flood, which 

 certainly would neither have drowned nor 

 buried them under the water; but fome 

 fudden unnatural revolution in their own 

 element, which muft have killed and in- 

 volved them at once in the fediments of the 

 troubled ocean. On this account, many ar- 

 gillaceous flate-rocks, filled with petrified 

 fifties, are to be confidered as Tub-marine or 



