Literature Relating to Statex Island 



77 



divisions of the Triassic Period would be designated by the 

 author ; but we ma\- perhaps assume that inasmuch as he sub- 

 divides an era into periods a period may be subdivided into eras, 

 as they appear to be interchangeable in the code of terminolog}- 

 which he has adopted. 



The term " epoch " is also incidentally used, in connection with 

 the Trenton' group of limestones, in a sense coordinate with that 

 in which " period " is used in connection with the Lower Helder- 

 berg group of limestones. Thus "era,"' "period," and "epoch" 

 are inextricably involved, and the loose and more or less vague 

 application or explanation of other terms, such as " zone " and 

 " age "' add still further to the confusion. 



Another inconsistency may also be noted in the mixture of new 

 and old nomenclature in connection with names applied to the 

 primary time group divisions. The older and more generally 

 recognized names (Cambrian, Devonian, Cretaceous, etc.) are 

 used throughout, with one exception, the substitution of Carbonic 

 for Carboniferous. Under every consideration of consistency 

 and uniformity the older name should have been used; or else 

 Cambrian, Devonian, Cretaceous, etc., should have been replaced 

 by Cambric, Devonic, Cretacic, etc. It may be noted, however, 

 that the term "Carboniferous" is utilized in subdividing the Car- 

 bonic into Lower Carboniferous, Carboniferous, and Permian ! 



If represented in the usual conventional manner the author's 

 expressed ideas in regard to the geologic column would appear 

 as follows : 



