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INSTRUCTIONS FOR USING 
period. Thus the number of fossil species named in the tables amounts 
to 782, consisting of — 
Species found both living and fossil .... 426 
Species fossil only, but common to more than one tertiary period 123 
Species fossil only, and named merely as found in two or more 
formations of the same period .... 233 
782 
A few will be found without specific names, because they have not yet 
been described or named by any authors. 
The tables are continuous from p. 2 to p. 45, and the description of 
each species extends across two pages. 
The following examples will best illustrate the object of the tables. If 
we take the first genus, Aspergillum (p. 2), we find that — 
Column 1 gives the name of the genus. 
„ 2 shows that four living species of the genus are known to 
M. Deshayes. 
„ 3 that he has seen one fossil species. 
„ 4 is left blank, because the single fossil species has not yet 
been identified with any living species. 
„ 5 is also blank, because the fossil species is only known in 
one period or formation. 
„ 6 is also blank, because the fossil species not having been 
identified with a living species, it was unnecessary to 
mention the habitation of any of the four living species. 
The columns of the three periods are left blank, because the fossil 
species has not been found in more than one period. In the column of 
localities on the right of the right-hand page, in the subdivision headed 
Bordeaux, the figure 1 denotes that one species of fossil Aspergillum 
has been found in that locality. 
To select another example: if we take the genus Solen (p. 2), we find 
that— 
Column 2 shows that twenty-six living species of the genus are 
known to M. Deshayes. 
„ 3 that he has seen nineteen fossil species of the genus. 
