680 



HISTORICAL GEOLOGY. 



afforded Newberry nine species of Eurylepis, three of Ccdacantlms, and a 

 Palceoniscus, besides some Selachian remains. 



A Selachian tooth from Illinois, related to the Petalodus from the Sub- 

 carboniferous, is represented of reduced size in Fig. 11U2. Fart of the 



1100-1104. 



1100. 



1103. 



:. / '■/.'■'/'M'/fl' 



1102. 



•1101. 



Ganoids. — Fig. 1100, Eurylepis tuberculata ; llol, Ccelacanthus elegans. Selachians. — Fig. 1102, Petalodus 

 destructor ; 1103, fin-spine ; llO-t a, b, dermal tubercles of Petrodus occidentalls. Figs. 1100-1102, Newberry ; 

 1103, F. H. Bradley. 



lower jaw of a Cestraciont Shark, named by Newberry and Worth en after 

 Agassiz, is represented of rediiced size in Fig. 1105 ; the actual length 

 of the specimen was nearly 24 inches, and the estimated length of the Shark 



1105. 



Cestraciont Shark. — Agassizodus variabilis (xg). Newberry and Worchen. 



15 to 20 feet. The teeth of the species have been found in the Upper Coal- 

 measures of Kansas, Illinois, and Iowa. A mouth so paved was a most 

 effective crushing organ. 



Fin-spines of Sharks occur of many kinds and sizes. A portion of a 

 small one is represented in Fig. 1103. The bony tubercles, Figs. 1104 a, b, 

 were found with the spine, and are supposed to be from the surface of the 

 body of the same Fish. 



Large spines of species of Eclesttis, having one edge armed with great 

 teeth, as in Figs. 1106, 1107, have been found in the Coal-measures of 

 Indiana, Illinois, and Arkansas. In E. minor of Newberry, Fig. 1107, the 

 teeth are nearly two inches long, and in E. giganteus Newberry, Fig. 1106,, 



