EASTMAN: CARBONIFEROUS FISHES FROM THE CENTRAL WEST. 195 
III. SPECIES OF FOSSIL FISHES FROM THE 
MISSISSIPPIAN SERIES. 
Under this head descriptions are given of several new species from the 
Kinderhook and Keokuk limestones of the Mississippi Valley, and the struc- 
ture and systematic relations of certain others are considered concerning which 
a difference of opinion amongst authors has existed. For an opportunity to 
examine some of the type specimens described in the Palaeontology of Illinois 
the writer is indebted to the courtesy of Prof. C. W. Rolfe, of the State Uni- 
versity at Urbana, and to Mr. C. H. Crantz, Curator of the State Museum at 
Springfield, Illinois. 
The following table shows the commonly accepted subdivisions of the Mis- 
sissippian series for this region: — 
SECTION OF THE LOWER CARBONIFEROUS. 
Chester limestone and shales (including 
the “ Kaskaskia limestone ”’). 
St. Louis limestone. 
Warsaw limestone (in part). 
Genevieve Group or 
Stage. 
Mississippian 
ees Augusta (Osage) Group { Keokuk limestone. 
or Stage. Burlington limestone. 
Chouteau limestone. 
Hannibal shales. 
Louisiana limestone. 
Kinderhook Group or 
Stage. 
ELASMOBRANCHII. 
PLEURACANTHIDAE. 
PHOEBODUS Str. Joun and WortHen. 
Of this genus three species are represented in the Devonian of this country, 
two in the Mississippian series, and one in the Permo-Carboniferous, including 
those described in the present paper. It is probable, however, that at least 
two forms ascribed by Newberry and Worthen to the “genus” Diplodus, 
namely, D. incurvus and D. duplicatus, should be referred to Phoebodus 
as commonly understood. 
