352 A SYMPOSIUM 



possible, and with the same names for both continents, and for 

 the whole world. It is better to have everywhere the same 

 terminology with approximate parallelism in meaning than dif- 

 ferent names and no means of unconscious comparison. 



At the present time no series are formally recognized in the 

 Devonian. The system is doubtless as well differentiated in 

 this respect as the Carboniferous. 



It is exceedingly doubtful whether the term Permian should 

 be permitted to hold a place in American geological literature 

 or classification. The original Permian is perhaps applied to a 

 provincial series, taxonomically of the same rank as Mississip- 

 pian. In America the so-called Permian is also a series and 

 actually a subdivision of the Carboniferous. The same is true 

 of the so-called sub-Carboniferous. It follows that neither 

 should be coordinated with the Devonian. 



The use of the term sub-Carboniferous in American geology 

 is very unfortunate. As originally proposed, and as used for a 

 long time afterwards, it referred to an indefinite sequence of 

 strata extending downward from the "Coal Measures" even as 

 far as the Trenton. As more recently used the subdivision so 

 called would be better designated the Lower Carboniferous, the 

 serial rank being understood, Mississippian being regarded as the 

 equivalent provincial title as explained above. Neither Car- 

 boniferous nor any other unqualified term should be used for 

 both system and series, or any two subdivisions of different 

 taxonomic rank. 



Canadian seems wholly out of place in the sense used unless 

 it can be modified so as to denote a series. The use of Trenton 

 in two different senses should be discontinued. It appears 

 unnecessary to retain the word river in connection with Hudson 

 — even though it has been widely used. And similar double 

 geographic names are to be avoided. 



CONTRIBUTION OF SAMUEL CALVIN. 



Referring to your inquiries relative to the classification of 

 time and terranes best adapted to North American geology, I 



