TIIK SUCCESSION OF HTUATll IKI) KOCK8 6 



iliU'rivd essentially in their original nature and mode of formation. 

 Suli-i-ijiifiit investigation proved this idea to be an error, and 

 Professor Phillips consequently proposed another set of name* 

 based on palseontological facts, namely, Pahtozoic, Metozoic, and 

 Ccenozoic, signifying respectively times of ancient, middle, and 

 recent life. The two former of these have been very generally 

 adopted, but Tertiary is still preferred to Cienozoic, and there is 

 no reason now why its correlatives, Primary and Secondary, should 

 not be employed as time -words, instead of the more cumbrous 

 Paleozoic and Mesozoic. 



Professor E. Forbes thought that the faunas of the Secondary 

 and Tertiary had so great an affinity that the whole succession was 

 more naturally divisible into two eras, which he termed Palaeozoic 

 and Neozoic. No doubt this is strictly correct, but the triple 

 division has been found very convenient in Europe, and is more 

 generally adopted. 



Since these terms were proposed, however, a series of stratified 

 rocks has been discovered below those which were called Primary 

 or Palaeozoic, and for these several names have been proposed. Of 

 these Archaan is the best, for pre-Cambrian is too indefinite, 

 and the others, Azoic and Eozoic, are founded on the respective 

 assumptions (1) that they contain no organic remains, (2) that they 

 contain the relics of the first dawn of life in the world. Such 

 small traces of life as have been discovered in these rocks do not 

 suggest anything very different from that of Palaeozoic time, but 

 they may for the present be termed Eozoic. 



In the following table of systems the oldest is placed at the 

 bottom and the newest at the top to indicate their natural super- 

 position and order in the chronological scale. 



Bias. SyHtenu. 



ene. 



Tertiary or Crenozoic . . . irauBOgene . N 



[ Cretaceous. 

 Secondary or Mesozoic . . . ! Jurassic. 



'Permian. 



''ri Diary or Palreozoic 





Devonian. 

 Silurian. 



OrdorieiuL 



.Cambrian. 

 | Kparchaean. 

 Archtean or Eozoic . . Mesarcluwn. 



I 



Nomenclature. With regard to the names of the system* 

 in the above table some explanation is required. Such names as 



