PRIORITY OF THE TERM " KARK ASK I A ." 297 



sand accumulations, lying in narrow gorges, have been regarded erro- 

 neously as local depositions of Kaskaskia grit intercalated in the shales 

 and limestones. Futhermore, these consolidated sands contain plant 

 remains, and inasmuch as they have been considered as parts of the Kas- 

 kaskia, it is quite probable that this will account for some of the reported 

 discoveries of terrestrial floras in the rocks of the Mississippian scries. 



Faunally,and especially stratigraphically, the Kaskaskia, as displayed 

 everywhere over a broad area adjacent to the line of the principal section. 

 appears separated from the St. Louis far more widely than any other two 

 members of the entire Carboniferous in the continental interior. 



The term " Chester " has been used by some authors for the beds here 

 designated as Kaskaskian. There seems to be, however, but little doubt 

 that the latter name was published some years before Chester made its 

 appearance in print. To be sure, Worth en, while an assistant of Nor- 

 wood on the geological survey of Illinois, did suggest, orally or in his 

 manuscript notes, the name " Chester" for the beds in question as early 

 as 1853; but the name was known for several years only to members of 

 Norwood's corps, as Worth en himself says.* It was at least a ddzen 

 years later before the term was published with definite stratigraphical 

 significance, and then with the full knowledge that it covered the same 

 ground as Hall's "Kaskaskia/ 1 Hall, as early as 1856, read a paper 

 before the Albany Institute, in which he proposed a classification of the 

 lower Carboniferous of the Mississippi basin; and two years later he 

 published essentially the same scheme in his Iowa report,f accompanied 

 by a clear description of this formation. Kaskaskia necessarily must be 

 retained, therefore, for the upper member of the Mississippian series in 

 preference to " Chester." If it is desirable to keep the latter term in 

 geological nomenclature, it might be advisable to restrict it to the upper 

 shaly division, which can advantageously be distinguished from the 

 lower massive limestones, and "Chester shales," as they are now often 

 called locally, could still be made a useful term. 



( !o \l Measures. 



Along the line of the general section the Coal Measures occupy an 

 unimportanl place. The exposures are chiefly of the basal sandstone 

 and the associated shales which outcrop along the river only at Long 

 intervals in old gorges and superimposed upon members of Mississip- 

 pian series. As already intimated, the St. bonis limestone above the 

 mouth of the Missouri, and a goodly proportion of the Kaskaskia below 



i leol -in-. Illinois, vol. i. 18C0, p II. 



; I low a, pi. i. 1868, p 109. 



