THE STORY OF THE EARTH. 



the tertiary strata, but have been recorded as 

 to the Trias, the beginning of the 

 • i ks. Indications of their existence 

 ;r in connection with each of the old land 

 - which the strata make known in the 

 th of England. Birds have been found on 

 two different horizons in the secondary rocks. 

 presence in th< ndary rocks of animals 



so remarkal s [chthyosaurs, Plesiosaurs, Or- 

 nithosaurs, Dinosaurs, and Anomodonts, fully 

 justifies the term, age of reptiles. The modern 

 type Qf crocodiles, lizards, turtles, and sna 

 which are the true reptiles of the present time, 

 do not extend back to very early parts of the 

 secondary epoch, so far as is known at present. 

 Extinct groups of reptiles such as the Anomo- 

 donts and LabyrinthodontS date back at least as 

 far as the time in which the Permian and Carbon- 

 Ms coal was accumulated. The great facts 

 which lif its to us when examined by nu 



of fo<sil remains, preserved in the succession of 



strata, are: first \ that it has been always changing 

 in the same locality, in the same way as a fauna 

 ( ,r flora und- hange at the present day. In 



the lifetime of individuals, plants and insects have 



:n the fen district of Cambridge- 

 shire under the influence of embanking and dram- 

 in historic tunes animals like the wolf, 



. beaver and roebuck, have disappeared 

 from South Britain. In other parts of the world 



lias become poorer by tin 

 Of birds like the Dodo, and the- .\b-a. 



This ' inction has never ceased. Its 



-main in the- extiix t species which 



ai deposit. 

 i extinction has extended to 



