398 M. DESIIAYES'S TABLES OF SHELLS. 



the species, or because the specimen examined was in rather an imper- 

 fect state. 



The specific names of the tertiary fossil shells \vhich have been found 

 by M. Deshayes to belong to one period only, and for which he has not 

 yet discovered any living analogues, are not given, as their enumeration 

 would have required more space than could be allotted to such a subject 

 in a treatise on Geology; but their aggregate number is included in the 

 subdivisions of the column in the right-hand page headed 'No. of species 

 in each genus in the following localities,' and in the supplementary table, 

 p. 4G. 



