892 FOSSIL GEOLOGY OF UNITED STATES. 
and massive mountains form, as it were, the great 
charnel-houses of preceding generations, in which 
the petrified exuviae of extinct races of animals and 
vegetables are piled into stupendous monuments 
of the operations of life and death, during almost 
immeasurable periods of past time. " At the sight 
of a spectacle," says Cuvier, so imposing, so ter- 
rible, as that of the wreck of animal life, forming 
almost the entire soil on which we tread, it is diffi- 
cult to restrain the imagination from hazarding 
some conjectures as to the causes by which such 
great eff'ects have been produced." 
It is but recently, then, that fossil remains have 
particularly engaged the attention of geologists. 
The celebrated Tournefort, who lived in the 17th 
century, believed that that they were stones that 
grew, or vegetated from seeds. " How could the 
Cornu Ammonis," says he, " which is constantly in 
the figure of a volute, be formed without a seed 
containing the same structure in the small as in the 
larger forms 1 Who moulded it so artfully, and 
where are the moulds Of the same opinion was 
the philosopher John Locke, who states in his Ele- 
ments of Natural Philosophy that " all stones are 
real vegetables ; that is, grow organically from prop- 
er seeds, as well as plants," It is somewhat re- 
markable, that even at the present time, notwith- 
standing the progress made in geological and other 
natural sciences, not only the uninformed and illit- 
erate, but even men of intelligence, should still 
hold to the same opinion, and maintain that the 
vegetable or animal fossil, dug deep from the bow- 
els of the earth, is either a fortuitous production^ 
or has grown to its present size from a seed or 
grain ! 
Animal or vegetable substances found imbedded 
in rocks are more or less impregnated with mineral 
matter, and have been called petrifactions, from pe^ 
tros, a stone, and facio. to make. The process of 
petrifaction consists in the infiltration of mineral 
