STRATIGRAPHIC SUMMARY, 629 



Georgia and Alabama, the Frog Mountain sandstone and the 

 Armuchee chert (Floyd County) contain an Oriskany fauna. 



Northeastward, Helderbergian strata are known from New Eng- 

 land, in the Connecticut valley trough (Bernardston series) and in 

 Maine, also in the Montreal region (St. Helen's Island) and 

 especially in the Gaspe limestone (1,210 ft.) subdivided into the 

 St. Alhan's beds below, and Cape Bon- Ami beds above. These 

 represent the Helderbergian, while the Grand Greve limestones 

 (800 ft.) overlying them represents the Oriskanian. 



The higher Devonic strata are here represented by the Gaspe 

 sandstone (7,000 ft.) which conformably succeeds the limestones. 

 This is mostly of continental origin, carrying plant remains and 

 coal seams ; but in the lower portion beds of marine strata are 

 intercalated, carrying a Middle Devonic fauna. The sandstone 

 probably represents the Middle and Upper Devonic horizons. It is 

 unconformably overlain by the Bonaventure conglomerates of Mis- 

 sissippic or Carbonic age. 



In the southern Appalachians, the Devonic series consists largely 

 of shales and sandstones. The following succession occurs in 

 Maryland : 



SUPERFORMATION. 



Lower Mississippic beds. 

 Upper Devonic. 



Hampshire formation. 

 Jennings formation. 



Middle Devonic. 



Romney shales (representing Onondaga, Marcellus and 

 Hamilton). 



Lower Devonic. 



Monterey (Oriskanian) beds. 

 Helderbergian limestones. 



SUBFORMATION. 



upper Monroan — Corrigan formation. 



Southward, in Virginia and West Virginia, the Romney is suc- 

 ceeded by the Kimberling shale which may extend up into lower 



