[XXll 



INTRODUCTION. [cH. 



beneficent care of Him through whom " we all live and 

 move and have our being/' The second consideration 

 discloses to us the ancient history of the globe which 

 we inhabit; and, by reason of the durable nature of 

 molluscous shells, which is capable of resisting the 

 action of many forces that destroy other organisms, we 

 can apply our knowledge of their living structure and 

 habits to the elucidation of some of those difficult pro- 

 blems which are necessarily involved in the study of 

 Geology. For this reason, shells have been aptly called 

 the " Medals of Creation ; '^ and they are as important 

 to this science as coins are for making us acquainted 

 with the history of past nations. The advantages and 

 pleasures of the fascinating pursuit of Natural history 

 have been so often and so forcibly expatiated upon by 

 popular writers on the subject, that I can hardly hope 

 to add anything to promote its interest. As a branch 

 of education, the benefit of such studies is incalcu- 

 lable. They impart and inculcate, in the most agree- 

 able form, the faculty of sound reasoning, the continual 

 exercise of memory, a love of order, habits of observation, 

 and, above all, the necessity of truth. No one can hope 

 to 1)6 a natm'alist who is wanting in accuracy. As a 

 source of intellectual gratification, no pursuit of any 

 other kind can excel it. It is entitled to bear equal 

 rank Avith the pleasures of " Hope," " Memory,^' '^ Ima- 

 gination," and " Literature," all of which have had able 

 poets and writers to celebrate their praises ; and, although 

 the great orator of ancient days had letters especially in 

 his view, his admirable remarks will apply A\ith equal 

 force to the study and love of Natural science. After 

 premising that such pursuits are most worthy of the 

 dignity of a thinking being, as well as most humanizing 

 and liberal in their tendency, he says, '' Other mental 



