34 GEOLOGICAL BIOLOGY. 



ous, the Hamilton, and the Chemung, including the Catskill 

 group, all typically represented in New York State. 



Carboniferous System. The CARBONIFEROUS SYSTEM, as 

 now limited, was first defined by Conybeare in 1822.* In 

 his original grouping he included with the Coal-measures the 

 Millstone grit ; the Carboniferous or Mountain limestone, and 

 the Old Red sandstone of England, typically represented in 

 north England in the Pennine range, and not fully repre- 

 sented in any other one section in England. In England the 

 Permian was regarded as a distinct system by Murchison, and 

 as lying unconformably upon the lower strata ; but the Per- 

 mian fauna and flora both have closer affinity with those of 

 the Coal-measures below than with the later Mesozoic types, 

 and on paleontological grounds the Permian is now classified 

 as the upper group of the Carboniferous system. In North 

 America the standard rocks of the Carboniferous system are 

 the Mississippian series, formerly called Lower or Subcar- 

 boniferous, of the Mississippi valley, having for its lowest 

 member the Kinderhook or Chouteau formation, and for its 

 upper member the Kaskaskia or Chester limestones and 

 shales. The middle member of the Carboniferous system is 

 the Coal-measures and underlying conglomerates, typically 

 represented in Pennsylvania ; but in the western part of the 

 continent it is not coal-bearing, but consists of massive marine 

 limestone. The upper member is typically seen overlying 

 the Coal-measures in Kansas and Nebraska and farther west- 

 ward and southward ; it contains a marine Permian fauna, 

 and is represented in Pennsylvania and Virginia by a plant- 

 bearing series terminating the Coal-measures. 



The Post-paleozoic or Appalachian Revolution. The chrono- 

 logical division-line between the Carboniferous system and 

 the Triassic is a very important one, both geologically and 

 palaeontologically. In America the point is indicated by the 

 Appalachian revolution. It constitutes the division between 

 the terranes of the Palaeozoic and the Mesozoic times in the 

 history of organisms. After the close of the Carboniferous 



* Conybeare and Phillips, " Outlines of the Geology of England and Wales," 

 London, 1822. 



