630 NORTH AMERICAN INDEX FOSSILS. 



Mississippic. Below the Romney, lies the Giles formation, a local 

 phase of the Helderbergian. The stratigraphic value of the Romney 

 is not uniform in the Appalachians. 



In eastern Kentucky, the late Devonic is represented by the Black 

 shale and a part of the succeeding Grainger formation. The upper 

 part of this formation extends into the Lower Mississippic. The 

 early and perhaps also the Middle Devonic beds are wanting in this 

 section. 



The Portage beds appear eastward as the Oneonta sandstone and 

 westward as the Naples beds. In central New York, the Ithaca 

 beds and fauna hold sway. In the west central sections, the sub- 

 division of the Portage beds is as follows : 



Portage beds. 



Wiscoy shale (Portland shale, westward). 

 Portage sandstone (Dunkirk shale, westward). 

 Gardeau flags (Angola shale, westward). 

 Rhinestreet black shale. 

 Cashaqua shale. 

 Middlesex black shale. 



The Genesee includes the West River shale and black Genesee 

 shale, and the Styliolina or Gennndezvah limestone. The Hamil- 

 ton-Marcellus is subdivided into: 



Moscow shale. 



Tichenor (Encrinal) limestone. 



. rHamilton. 



Ludlowville shale. 



Skaneateles shale. 



Cardiff shale. 



Stafford limestone. 



Marcellus black shale (including 



Agoniatite limestone). 



Marcellus. 



Westward, in Ontario, the Esopus is replaced by the Decewville 

 beds, which rest disconformably on the Siluric, the Helderbergian 

 being absent. Here and in Michigan and northern Ohio, the 

 Onondaga is represented by the Dundee limestone {Columbus 

 limestone of northern Ohio) which probably represents Marcellus 

 as well. The Hamilton beds are represented by the Traverse 



