36 
PALEOZOIC FAUNAS OF MISSOURI 
(b.) Upon these, uncomformably, lies a remnant of the “Black 
Shale” formation of Tennessee. This is occasionally entirely ab¬ 
sent, locally, but its place is indicated on the more southern and 
south-western margin of the Ozark uplift, as seen in the more 
western of the northern tier of counties of Arkansas, and probab¬ 
ly in McDonald county, Missouri. This terrane thickens north¬ 
eastward across Tennessee and Kentucky, toward Ohio, but it is 
apparently replaced by other deposits on passing northward to 
Iowa. It is generally considered to be of Devonian age. In its 
south-western extension, in Arkansas and Missouri, it appears to 
be earlier than some of the Chouteau rocks, but it is not paleon¬ 
tologically evident that it is equivalent in age to the Devonian 
rocks of New York. 
(c.) Uncomformably upon the “Black Shale” formation rests 
some part of the Lower Carboniferous series, the lowest member 
of which is the “Chouteau group” of Broadhead, consisting of the 
three members defined in Swallow’s Report of the Geology of 
Missouri as — . , ^ 
“Chouteau Limestone, 
- Vermicular Shales and Sandstones, 
Lithographic Limestone.” 
Paleontologically this is a distinct formation, and stratigraphic- 
ally it is the lowest member of the Lower Carboniferous series 
of the Mississippi valley. In Illinois and Indiana this^ is the 
“Kinderhook group” of Meek and Worthen. East of the Cincin¬ 
nati uplift it is the “Waverly group” of the Ohio geologists, and 
in Michigan it is represented by Winchell’s “Marshall group.” 
Faunally these several groups are not strictly identical, but 
they are tied together by common species, and are probably chro¬ 
nologically of the same age. They appear to be related to each 
other in the order named, the Waverly and Marshall faunas 
nearer shore, the Kinderhook a zone farther outward, and the 
Chouteau a mid-ocean fauna, gathered about the Silurian island 
now represented by the Ozark uplift. 
Above the Chouteau group comes a series of limestones, cherty 
limestones and cherts with, in some places, shales and sandstones. 
The main part of this terrane represents the “Siliceous group” of 
Safford. As represented on the western margin of the Ozark 
uplift it is distinguishable into two formations. 
