GRASSY BLACK SHALE 
307 
ERAL AFFILIATIONS OF GRASSY BLACK SHALE 
By Charles Keyes 
As a terranal title the term Grassy Shale was originally ap¬ 
plied in its present sense in 1898, to a thin black section beneath 
the Louisana limestone in northeastern Missouri. Recent collec¬ 
tion of a considerable assemblage of fossils from these shales, 
which were long regarded as absolutely barren, presents a num¬ 
ber of novel and critical features bearing directly upon the tax¬ 
onomic affinities of the formation. 
By curious stratigraphical coincidence the black zone is a median 
member of a four-fold shale section forming an unbroken shale 
sequence on the Devono-Carbonic boundary. To this singular 
circumstance is ascribed much of the early misinterpretation re¬ 
garding the geologic age of these beds. 
The Black Shales, of which the Grassy black shales of Missouri 
may be, partly at least, a northern extension, were early observed 
in the continental interior. In Indiana, Owen ^ called attention 
to the Black slate lying between the Encrinital limestone (Early 
Carbonic), and the limestones of the Falls of the Ohio River (De- 
vonic). Coming along two or three years afterward Hall ^ pro¬ 
posed to recognize in these black shales of the West the Marcellus 
beds of the New York section. After Owen and Norwood ^ 
described the “Protozoic and Carboniferous Rocks of Central 
Kentucky” and regarded the Black shale as the basal member of 
the Carbonic section of that region. Hall ^ revived his earlier 
opinion and correlated the western formation with a black shale 
younger than the Marcellus formation (Mid Devonic), referring 
1 Geol. Surv. Indiana, Second Ann. Kept, p. 17, 1839. 
2 Trans. American Assoc. Geol., 1842-3, p. 280, 1843. 
3 Researches among Protozoic and Carboniferous Rocks of Central Kentucky, 
Pamphlet, 40 pp., 1847. 
4 Am. Jour. Sci., (2), Vol. V, p. 269, 1847. 
