INTRODUCTION. 
Tue rapid development of the science of Geology has 
in Europe, within the last few years, called to its aid the 
attention and exercise of the highest talent. In this coun- 
try, we have been making a regular, though not so rapid a 
progress, in the knowledge of our widely extended and 
interesting deposits ; and it is to be regretted, that our inves- 
tigations have not yet been sufficiently extended to enable 
us to institute, in all the strata, such comparisons as would 
allow us to decide, with precision, as to their equivalents 
in Europe. This can only be done with success, after the 
fossil conchologist shall have developed a large portion of 
the genera and species of our different masses. 
Until recently, it was considered, that a single cataclysm 
had left behind its desolating sweep, all the organic re- 
mains inhumed within the bowels of the earth. The obser- 
vations of recent philosophers, more exact, prove to us, be- 
yond contradiction, “ that the earth’s surface has been, and 
still is, subject to incessant fluctuation and movements.”* 
If we turn our attention to the examination of the ear- 
liest_ period where organized matter has been discovered (in 
the lowest Fossiliferous group of De la Beche), we find the 
indications of animal life extremely rare, and we may con- 
clude that the change from the crystalline rockst to that 
* Geology of the South of England, by G. Mantell, p. xiv. of Intro- 
duction. 
t This class of rocks so well known under the name of Primitive rocks, 
