FIRST TERTIARY PERIOD. 



FIRST TERTIARY PERIOD. 



466. The first Tertiary stage in its mineralogical characters 

 corresponds with the lower part of the Eocene group of Lyell, the 

 Nummulitic formation of Grras and other geologists, the Plastic 

 clay of Dufresnoy, Elie de Beaumont, and Mantell, and the 

 Woolwich sands of Morris. 



467. After the general agitation produced by the geological 

 convulsion which closed the Cretaceous age had subsided, a new 

 fauna and flora were called into existence to people and clothe the 

 earth. A generic synopsis of the former is produced in the 

 following table : 



is of the Animal Kingdom (exclusive of Annulata) during the 

 First Tertiary Period. 



GENERA. 



With the addition of one genera of Crustacea (squilla), the 

 total summary of the generic forms of animal lite in this period 

 will then be 270, of which 156 were now first created, and the 

 remaining 114 revived from former periods. 



468. This period was remarkable for the great development of 

 fishes, of which 83 new genera were created. Of the Mollusca, 

 the Gastropods were most developed, 34 new genera having 

 appeared. The total number of species of Mollusca and Radiata 

 described in this period amounts to 678, which, however numerous, 

 are inferior in number to the same divisions in some former 

 periods. Before the Tertiary age, some few traces of the existence 

 of Mammifers were found, but with the exception of a few 

 isolated bones, such traces everywhere consisted of foot-tracks. 



469, The commencement of the Tertiary age was, however, 

 more especially signalised by a prodigious accession to this highest 



123 



