DEVONIAN AND MISSISSIPPIAN FAUNAS 263 
of the province the entire Upper Devonian epoch is represented by a 
black shale which has been variously called the Ohio shale, the New 
Albany shale, or the Chattanooga shale, which is widely distributed 
in southern Ohio, Indiana, and Illinois, in Kentucky, Tennessee, and 
northern Mississippi, Alabama, and Georgia, and extends westward 
into northern Arkansas. Throughout the southern portion of the 
province this black shale rests unconformably upon the subjacent 
strata, and in some parts of Kentucky, at least, is unconformable 
upon Middle Devonian limestones. In the Ohio Valley the fauna in 
the basal portion of the black shale indicates its Genesee age, but as 
the shale was a transgressing formation toward the south and south- 
west, its age in these directions becomes younger and younger, and at 
the extreme limits of its extension it may even be younger than any 
true Devonian, and be contemporaneous with the basal member of the 
Mississippian. 
While these monotonous black shale conditions obtained in the 
south, a series of waves of faunal immigration were penetrating the 
northeastern portion of the province. In the Portage of western New 
York occurs the Intumescens fauna? characterized by its numerous 
goniatites of the type of Manticoceras intumescens. This fauna, like 
the Cuboides fauna of the Tully limestone, is of European origin. The 
path of its migration into New York is believed by Clarke to have been 
the same as that of the earlier fauna, by way of the Interior Continental 
Province, but Ulrich and Schuchert? express the opinion that it came 
in from the Atlantic basin by an eastern route. Following the Intu- 
mescens fauna, in the same general region, is a fauna in the High Point 
sandstone, at the extreme summit of the Portage group, characterized 
by Pugnax of the type of P. pugnus, which is another European immi- 
grant, and which has many species in common with the Lime Creek 
shales of the Interior Continental Province in Iowa. Succeeding the 
High Point fauna is the typical Chemung fauna with S pirifer disyunc- 
tus and its associates, which again are European immigrants, but are 
associated with other forms which are of Hamilton derivation. 
t For a summation of the opinions which have been held in regard to the age of 
the black shale, see Girty, Am. Jour. Sci. (3), VI, 385, 386. 
2 Clarke, “The Naples Fauna in Western New York,” Sixteenth Ann. Rep. New 
York State Geol., 1896, pp. 31-161; also Mem. N. Y. State Mus., No. 6. 
3 Loc. cit. 
