134 IMPORTANCE OP CONCHOLOGY. 



in the world's history. To understand and apply the 

 evidence derivable from this source, requires a most 

 careful study, not only of the different forms of fossil- 

 shells, but of the forms and habits of existing species. 

 In fact, it is impossible to understand the character of 

 these fossils without an intimate knowledge of Concho- 

 logy. To distinguish species, to insist on minute cha- 

 racters, to collect minute shells, appear often to the 

 unthinking utilitarian but trifling hobbies of mere tri- 

 flers. Yet on these apparent trifles depend some of the 

 most important problems of Geology ; and if the con- 

 chologist blunder in reading the " Medal of Creation," * 

 all the deductions of the geologist will be vitiated. To 

 trace the history of a species of shell, from its first 

 appearance in an early bed, to its final extinction in 

 a later formation, requires an intimate knowledge, not 

 merely of the species in question, but of the changes 

 which, under modified circumstances, other species un- 

 dergo, before their vitality yields to an altered condi- 

 tion. It is a highly curious fact, that there is a term to 

 the life of a species, as well as to that of an individual. 

 What that term is we know not ; but the remains of 

 extinct species and genera prove the fact. But before 

 the final extinction of a species, except the change 

 of circumstances be so sudden as to cause the instan- 

 taneous death of every individual of the kind, the fiy, 

 developed under altered circumstances of habitat, will 

 vary from the characters of their parents, and present the 

 peculiarities of the species in a weakened degree ; their 



* I need scarcely remind the reader that there is such a book as 

 Dr. Mantell's " Medals of Creation." 



