DEVONIAN AND MISSISSIPPIAN FAUNAS 27 
Ww 
The Northern Kinderhook jauna.—North and west of the Kanka- 
kee peninsula, in the eastern portion of the Devonian Interior Conti- 
nental Province, the earliest Mississippian faunas were as distinctly 
different from those of the southern portion of the Eastern Continental 
Province, as had been the preceding Devonian faunas. The oldest of 
these northern Kinderhook faunas is that of the Chonopectus sand- 
stone? at Burling‘on, Ia., and elsewhere in Iowa and Illinois. This 
fauna contains a large Devonian derivative element, especially among 
the pelecypods, but its relationships are with the Chemung faunas of 
the Upper Devonian, and are totally different from the Devonian 
derivatives of the southern fauna. Another modification of the north- 
ern Kinderhook fauna is found in the Louisiana limestone, which is 
believed to be in part contemporaneous with, and in part younger than, 
the Chonopectus fauna. One of the most characteristic members of 
this northern Kinderhook fauna is the striated rhynchonelloid genus 
Paraphorhynchus which occurs also in the early Mississippian faunas 
of northwestern Pennsylvania. 
In the Burlington, Ia., section the Chonopectus fauna occurs at the 
summit of a series of shales, becoming arenaceous above where the 
fauna occurs, which have a total depth of 160 feet. The lower too 
feet of the formation lies beneath the level of the Mississippi River, so 
that the contact with the underlying formation and the age of the 
subjacent bed is not known. This lower bed, however, is probably 
Devonian, and is not unlikely the Cedar Valley limestone, since that 
formation lies unconformably beneath the Kinderhook beds farther 
south in Calhoun County, Il. If this is the case then these lower 
shales of the Kinderhook correspond in position with the Sweetland 
Creek shales of the Upper Devonian in Muscatine County, Ia. There 
is, however, perhaps insufficient faunal evidence upon which to base 
a definite correlation of these two shale formations. The most con- 
spicuous faunal character of the Sweetland Creek beds is the presence 
of numerous Ptyctodus teeth in the basal bed, occupying a few inches 
above the unconformity. A similar Ptyctodus bed occurs not infre- 
quently at the base of the Kinderhook in both the northern and south- 
ern provinces. Such is the case at the base of the Louisiana limestone 
at Louisiana, Mo., where Ptyctodus occurs abundantly in a thin shale 
1 Weller, Trans. St. Louis Acad. Sci., X, 57-129; also Jour. Geol., XIII, 617-34. 
