354 



A SYMPOSIUM 



the Carboniferous. We might therefore arrange the Carbonifer- 

 ous in some such way as this : 



9. I would prefer to leave the Cretaceous undivided, being 

 governed in this choice simply by the conservative desire to leave 

 things undisturbed. The literature of the Mesozoic is based on 

 the division into the Triassic, Jurassic and Cretaceous, and any 

 change will require a long period of adjustment and will involve 

 endless confusion. It is much easier, and just as convenient to 

 let the Cretaceous stand as a single system and divide it into a 

 Lower (Comanche ?) and an Upper (unnamed) series. 



The whole of the Upper Cretaceous, excepting the Laramie 

 and Denver, is well developed around the flanks of the Black 

 Hills. 



We can retain the established names in the Cenozoic and 

 adapt our nomenclature with perfect ease to the old arrangement 



