J. Hall on Carboniferous Limestones of Mississippi Valley. 193 
VII. Coal measures. 
vy, § Kaskaskia limeston askia and Chester, III. 
| , Or Kask: 
Upper Archimedes limestone, f St. Mary’s, Missouri, ete. 
Gray, brown or ferruginous ) Below St. Genevieve, Mo. 
V. 4 sandstone, overlying the lime- } Between Prairie du Rocher and 
stones of Alton and St. Louis, Kaskaskia, Iil. 
“St. Louis limestone,” or St. Louis i highest beds below 
" ( “Coneretionary limestone.” 
IV eokuk, 
Alton ; St. Genevieve. 
“ Arenaceous bed,” arsaw and above Alton, Tl. 
arsaw or Second Archimedes 
Tl. limestone, ; Keokuk, Towa. 
“ Magnesian limestone,” Spergen Hill, Bloomington, Ia. 
Beds of passage, soft shaly or marly bed with geodes of quartz, : 
chalcedony, ete. 
Il. omar limestone, or . ay 
Lower Archimedes limestone, Keokuk, UEC, Hy te 
of passage, cherty beds 60 to 100 feet—Rapids above Keoku 
I . , urlington, Iowa; Quincy, IIL; 
Burlington limestone, Hannibal, éte., Missouri. 
Oolitic limestone and argillaceous sandstone ) Burlington, Iowa. 
of the age of the Chemung group of New / Evans Falls. 
York, Hannibal, Mo. 
_ The difficulties which have occurred in the way of a reconcil- 
lation of the views of Western geologists have arisen in great 
part from the fact that these different limestones have not an 
ing 
a ned. The fossil forms which have mainly bee n 
or characterizing the divisions have been to a considerable ex- 
: Tic val ; and ific differences have not 
always been properly recognized. 
tion and the changes of | 
n it 
ee Character at different points we have yet much to 
helogi- 
learn. 
groups; and its gradually — edges stretch far towards 
t 
edges of the Keokuk limeston mingled with much earthy | edi- 
nent, and often consisting of : few thin beds of Encrinal li -. 
| 
