8 FOSSIL SHELLS. 



valued as articles of ornament, are obtained from 

 the oyster and muscle genera. 



*' Within a few years, conchology has become 

 a study of considerable importance, from its close 

 connexion with geology. Students in the latter 

 science must be well acquainted with fossil shells, 

 because they form so large a portion of organic 

 remains. Species of recent shells, or those still 

 existing, are also often found in a fossil state, 

 while many fossil genera are now totally unknown 

 in our earth and waters. 



" Thus you perceive that while you are ob- 

 taining knowledge in one science, you are pre- 

 paring yourselves for making advances in another, 

 most interesting and wonderful. You, Charles, 

 who are likely to become a traveller, will perhaps 

 in future years find the advantage of my present 

 brief lessons. 



" I shall first endeavour to make you ac- 

 quainted with the system of Linnaeus ; it is easily 

 learned, and you should be familiar with it, as it 

 is still adopted by some writers on conchology. 



"^ But in order to understand my instructions, 

 you must have a clear idea of the terms that I use 

 in describing a shell ; now, therefore, give me 

 your attention while I explain some of those 

 terms to you. 



^' To begin with the first division, Multivalves. 

 There is a group of Lepades, it is the species 



