24 
notions, from his having attributed to the waters of the deluge, an 
almost universal solvent power ; by which he supposed the rocks and 
mountains were melted down, and thus allowed the admission of 
these substances into their external parts : not considering that, by 
the same power, these bodies would themselves have been reduced to 
a mass, not bearing their proper figures. 
Nothing, perhaps, contributed so much towards diffusing a proper 
idea respecting the origin of these substances, as the Historia Ani- 
malmmAngli(B, wluch contained some excellent remarks, Delapidihus 
ejusdem Insults ad Cochlearum quandam Imaginem Jiguratis. Land. 
16/8 • and the Historia seu Synopsis methodica Conchy liorum, 1685, 
all written by Dr. Lister. By these publications the student was 
enabled to form a comparison, between the original shell, and the 
similar shell in a fossil state ; since, in several instances, the Doctor 
had displayed in his plates, the same shell in both states. How 
much this must have contributed to the producing of a just judgment 
of the real nature and origin of these substances, must be obvious ; 
and to this circumstance, perhaps, we ought in part to attribute the 
change of opinion, which very generally took place at this period. 
Still however, the science was involved in that cloud, which had so 
lorg obscured it. The vis plastica, the vis formativa, and the sportive 
creations of nature, were terms yet in frequent use. Those that were 
more than half convinced, but had not quite shaken off the influence 
of a long adopted opinion ; as well as those who, though quite con- 
vinced, had not the courage to acknowledge having been in error ; 
spoke of these bodies in the indefinite language of lapides Jigurati, 
lapides idiomorpki, lapides qui Jiguram hahent conchse, cochlese, ^c. 
Some indeed would venture to term them conchce lapidecs, ostre^ 
lapidecE, carefully avoiding to speak of their origin, or to admit 
them to be bodies, changed from their original animal state to that 
Careful investigation, however, having rendered it manifest, that 
