276 STUART WELLER 
although it had its beginnings in the preceding Kinderhook. No local- 
ity in the world, so far as known, has furnished so large a number of 
crinoids of similar age, either in genera, species, or individuals, as 
this Mississippian province. The fauna, in its entirety, exhibits much 
in common with the mountain limestone of England, Ireland, and 
elsewhere in Europe. Many species of brachiopods in the formations 
either are identical or are so closely allied as to be difficult of separa- 
tion, and the correlation of the Osage with the Mountain Limestone 
of England, or at least of some part of it, is based upon substantial 
evidence. Evidence sustaining the indigenous character of the cri- 
noidal element in the fauna is found in a comparison of these forms 
from the Osage of the Mississippi Basin and from the Mountain 
Limestone of Europe. Every genus in the Mountain Limestone 
occurs also in the American faunas, while there are many genera which 
do not occur outside of the Mississippi Basin; furthermore, all of 
those genera which occur in both this Mississippian province and in 
Europe are represented by a larger number of species in America. 
These facts seem to indicate that the Mississippi Valley Basin was the 
metropolis for this great crinoidal fauna. 
During this period the Cincinnati arch was above sea level, and 
from this island clastic sediments were being deposited off its western 
and southwestern shore, which constitute, in part at least, the Knob- 
stone formations of Indiana and Kentucky, although the basal portion 
of the Knobstone is undoubtedly of Kinderhook age. The faunas 
associated with these clastic sediments are usually more meager than 
in the calcareous sediments of the clear seas farther west, and are 
somewhat different in character; however, they possess much in com- 
mon as is evidenced by the wonderfully prolific crinoid fauna of the 
Crawfordsville beds in Indiana. 
The later phases of the Osage sedimentation became more clastic, 
especially toward the north, doubtless because of the elevation of the 
land to the north, and in the Keokuk formation numerous shaly 
layers occur, intercalated between limestone beds. The shales become 
more and more dominant until, in the Warsaw formation, shales 
constitute the major portion of the sedimentation. In the southern 
portion of the Mississippian Basin this change in sedimentation was 
less or even not at all effective, since the Warsaw, as a distinct shale 
