PRINCIPAL MISSISSIPPIAN SECTION 45 



The nominal history of the major subdivisions of the 

 Paleozoic of the Mississippi basin need not be reviewed in 

 this place. Suffice it to mention that the term Subcarbonifer- 

 ous had in the beginning a very different meaning from what it 

 has had of late years. As originally proposed by Owen,* the 

 name was used merely to indicate an indefinite series of lime- 

 stones below the coal-bearing strata of the interior. Subse- 

 quently the same author limited the formation below to the blue 

 fossil-bearing limestoiies, now known as the Cincinnati beds. It 

 was in 1847, when Owen and Norwood t gave the "black slates" 

 as the upper limiting member of the Devonian, that "Subcar- 

 boniferous" was still further restricted ; thus for the first time 

 giving the name "Subcarboniferous" the meaning which has 

 been generally attached to it of late years. 



The most familiar names assigned to the subdivisions of the 

 Carboniferous along the Mississippi river are : Chouteau, 

 Kinderhook, Burlington, Keokuk, Warsaw, Saint Louis, Sainte 

 Genevieve, Chester, Kaskaskia and Coal Measures. 



Typical Sections Along the Mississippi Biver. 



A few of the most characteristic sections have been se- 

 lected for notice here, and their lithological details briefly 

 explained. By comparison with the general section on the 

 accompanying plate iv, the stratigraphical relations according 

 to the present understanding may be indicated in the briefest 

 possible manner. These sections are taken at places where 

 the most minute and satisfactory information has been obtained, 

 and they assume their names from these localities. They are 

 all marked on the general section (plate iv). 



* Researches on the Protozoic and Carb . Rocks of central Kentucky during the 

 year 1846. 1847. 



tRep. Geol. Rec, Indiana, 1837, p. 12. 1839. 



