ON GEOLOGIC TIME-DIVISIONS 335 



view to inaugurating discussion. The questions were made spe- 

 cific to invite definiteness in the replies. They were made to 

 overlap somewhat to facilitate specific answers to different 

 aspects of the subject. It was not intended to specifically advo- 

 cate the scheme presented, but merely to submit a tangible 

 sketch for discussion. A portion of the replies are printed in 

 this number. The discussion of the subject by others who may 

 be interested is invited. The questions submitted are as follows : 



1. What classification of time (and terranes) , say to the third 

 or fourth division, seems to you best adapted to North America ? 

 If you are ready to express your opinion concerning such a 

 classification to the second division, but not farther, please do so. 



2. To what extent is it desirable to adhere to European 

 standards, if some other classification is better adapted to North 

 America ? 



3. What noun should be used in connection with the adjec- 

 tives Palceozoic, Mesozoic, etc., i° when time is meant, and 2° when 

 formations are concerned ? For example, Palaeozoic era ? Palaeo- 

 zoic group ? 



4. What noun should be used in connection with the primary 

 subdivisions of the Palaeozoic such as Cambrian, i° when time is 

 meant, and 2° when formations are concerned ? For example, 

 Cambrian period? Cambrian system? 



5. What is the best noun to be used in connection with divi- 

 sions of the third order, such as Lower Cambrian, Middle Cam- 

 brian, etc. ? For example, Lower Cambrian epoch ? Lower Cam- 

 brian formation ? 



6. Ditto for divisions of the fourth order. 



7. Would you approve of the separation of the sub-Carbon- 

 iferous and the Permian as divisions coordinate with the Car- 

 boniferous proper, the Devonian, etc. 



8. If you approve of the separation of the sub-Carboniferous 

 from the Carboniferous, as a division of the second order, would 

 you approve of retaining the name sub-Carboniferous or Lower 

 Carboniferous, or would a new name be better, say Mississip- 



