DEVONIAN AND MISSISSIPPIAN FAUNAS 281 
the Maxville limestone, whose fauna is to be correlated essentially 
with the Ste. Genevieve of southern Illinois and Missouri. It has been 
shown by Stevenson" that only the upper portion of the Pocono is of 
Mississippian age, and that this part is stratigraphicaly continuous 
with the Waverly group of Ohio. The basal member of the Waverly 
group, in the more general application of that term, is the Bedford 
shale in which occurs a fauna with Hamilton affinities.2 As has 
already been pointed out, this fauna is believed to be associated with 
the incursion of the Hamilton-like forms which constitute one element 
in the southern Kinderhook faunas. The composition of the succeed- 
ing Waverly faunas has been more carefully studied by Herrick than 
by anyone else, and they exhibit throughout more or less affinity with 
the Kinderhook faunas of the Mississippi Valley Basin. Numerous 
members of the fauna suggest a Devonian derivation sometimes from 
Hamilton and sometimes from Chemung progenitors, as if they were 
to some extent a mingling of the two Kinderhook faunas of the Missis- 
sippi Valley. These Waverly faunas are, however, in no wise to be 
considered as contemporaneous with the Kinderhook alone of the 
Mississippi Valley, but they must also represent the Osage. In the 
Appalachian Basin, with its continuity of clastic sedimentation, 
environmental conditions similar to those of the Kinderhook persisted 
through Osage time, consequently there is no sharp differentiation of 
the faunas as there was in the Mississippi Valley where the period of 
clastic sedimentation was displaced by the clear seas in which nothing 
but calcareous sediments were deposited. For this reason the typical 
Burlington and Keokuk faunas do not occur in the Appalachian Basin, 
but an occasional member of these faunas found its way into the basin 
and such forms left records which are of value in the correlation of 
the faunas. 
Outside of Ohio little or no detailed faunal study of these beds has 
been made, but Stevenson# has pointed out the stratigraphic correla- 
tion of the beds throughout the Appalachian Basin from Pennsylvania 
to Alabama. | 
t Loc. cit. 
2 Herrick, Geol. Surv. Ohio, VII, 507. 
3 Asummary of Herrick’s work is to be found in Geol Surv. Ohio, VII, 495-515. 
4 Loc. cit. 
