4 acs - + 
382 Say on Shells, &. * 
The greater portion of them are extracted, with somélimodi- 
fication from an essay which I read about three years, ago, to 
the Academy of Natural Sciences, without any intention at the 
time of giving publicity to them. But the rapid diffusion of a 
_ taste for geological research, scems to require correspondi 
mains, inasmuch as geology, in order to be -emimet 
nished with every advantage that may tend to the 
ment of many important results, must be in part founded on a 
knowledge of the different genera and species of reliquie, 
which the various accessible strata of the earth present. The 
accessory value of this species of knowledge, is now duly esti- 
mated in Europe, as affording the most obvious»means of esti- 
mating, with the greatest approximation to truth the compara- 
tive antiquity of formations, and of strata, as well as of identi- 
fying those with each other which are in their nature similar. 
Certainly very little is yet known about the fossils of North 
America, and very little can be known accurately, until we 
shall have it in our power to compare them with approved 
_ detailed descriptions, plates or specimens of those of Europe ; 
which have been made known to the world by the indefatiga- 
ble ‘industry, and scientific research of Lamarck and other 
naturalists. 
America is rich in fossils. In many districts of the United 
States, vast beds of fossil shells, zoophytes, &c. are deposited, 
which for the most part, are concealed from the inquiring ey, 
offering superficially a mere confused mass of mutilated frag- 
ments, ‘These rich repositories must finally be exposed to 
view, by the onward pace of improvement, and the more inte- 
rior strata will be unveiled by some fortunate profound exca- 
vations, the result of enterprise in the pursuit of gain. The 
very surface of the country in many regions, is almost over- 
spread with the abundance of casts, or redintigrate fossils, many 
of which are apparently specifically anomalous, and some ge&- 
nerically so. ‘The correct, and only useful mode in which the 
investigation of our fossils can be conducted, is attended with 
some difficulty and labor. 
he 
