C 8 ] 
this our earth confifts: that the ftrata of moun¬ 
tains afterwards^ being laid open by the force 
of rains, torrents and accidents which often 
happen in all parts, were broke up, and the 
fhells contained in them, which lay uppermoft, 
with fome which lay deeper, were thrown out, 
and left expofed the furface: that at length 
thofe fhells, fo laid open, thrown out, and ex- 
pofed, were worn away,* or broke, but the 
matter enclofed in thefe fhells, whether ftone, 
flint, fpar, or any other, of a conflitution firm 
and folid, did flill retain, and reprefent the 
concave, or interior form of thofe fhells, in which 
it was moulded.’" 
The figures are of the fize of the fuljefi they re^ 
prejent, iinlefs where mention is made to the contrary^ 
FIG. 1. 
Roundifh: depreffed: furface unequal: mar¬ 
gin, where perfedl, flightly notched. Free Stone, 
Found upon the plowed fields. 
F I G. 
- ■ - 1 ---- 
* The fhells are often deftroyed in the flrata in which 
they were lodged by water containing in it vitriol, or 
other like fait, which pervading the ilrata, it diflblves 
them. Woodward’s Nat. Hill, of the Earth illuftrated 
and inlarged, p. 29, 
