M The American Geologist. August, 1898 
I'd I, i mn ih, in iij'm-iii nsis. \ ii ml ii houghtoni and /'< rnopi xU m cir- 
c ulu8, &[bo several species of Productus and probably Productella. 
A red limestone occurs in the Chouteau on the Merrimac, in 
St. Louis county. The Chouteau is rarely present in St. 
Charles, Warren. Montg< sry and Callaway. It is better ex- 
posed in the Missouri bluffs in Boone county. The other 
members of the Chouteau have not been seen in these coun- 
ties. The Chouteau limestone is also round on Cuivre River 
in Lincoln county. 
The Burlington beds are easily recognized in northeast 
Missouri. The lower white beds are prominent in the bluffs 
at Hannibal and Louisiana. Where the upper beds are seen 
we find at top 10 to 17 feet of chert and red clay, as in the 
Missouri bluffs, St. Charles county.. At Peruque on the 
Wabash road it is 17 feet thick. Prof. Swallow defined about 
8 distinct groups and most of them are well exposed in the 
river bluffs in St. Charles county east of Femme Osage. At 
Columbia the upper 50 feet consists of gray limestone, then 
below are thick beds of coarse gray and brown limestone. 
The limestones are generally stylolitic and also contain many 
chert concretions. Fossils found at Columbia are: Spirifer 
plenus, Sp. grimesi, Sp. striatus, Athyris lamellosa, Prod, 
punctatus, P.Jlemingii. The lower beds contain Euomphalus 
latttSj Chonet.es shumardana, Orthis swallovi, Or. mitchellini 
and Athyris incrassatus] crinoidea are found throughout. 
The Burlington beds are often cavernous and from the 
caves there flow many excellent springs. 
In southwest Missouri the beds are not so easily separated 
from the Keokuk above, therefore Prof. H. S. Williams has 
offered the name of Osage to include the Keokuk and Burling- 
ton. Both are found on the Osage hills, hence the name seems 
appropriate. 
In northeast Missouri the Keokuk contains shale beds in- 
closing large geodes as they do also in Illinois and Iowa. The 
Keokuk in southwest Missouri is largely made up of chert 
beds with some layers over 10 feet in thickness. Prof. 
Swallow thought that there was 100 feet of chert on Shoal 
(reek. Newton county. 
The lead and zinc of southwest Missouri is mined in the 
Keokuk and there is often associated a good deal of chert. 
