625 



Petal 



tooth, of this powerful fish first found in the Coal measure 

 limestones of Pennsylvania. The Crwoidal limestone of the 

 Barren measures {Pittshurgh series) is so full of sharks' teeth 

 in Ohio as to deserve the name of a '' fish bed." Most of them 

 are small, the species are of Petalodus^ Cladodus, and Ctenop- 

 tyohius. The largest and most abundant is this P. alleg- 

 haninsis^ which St. John considers to be the same as P, de- 

 structor of Illinois, but Newberry does not, because of its being 

 always smaller, and having a longer and narrower fang, while 

 the destructor fang is broad, flat and pointed. — XIV. 



Petalodus curtus, Newberry & Worthen. Geo. Sur. Illin- 

 ois, Vol. 2, 1866, page 

 ''^ 394, plate 12, fig. 12 a, 

 ^■^ convex lace of medium- 

 sized tooth ; crest worn 

 nearly plane, with con- 

 vex basal margin ; 12 &, 

 concave face, showing corrugated ornamentation ; 12 <?, pro- 

 file section. Keolcuk limestone^ Bentonsport, Iowa. XL 

 Petalodus destructor. Newberry & Worthen. Geo. Illi- 



Qe9lMij$uy9L 6, j>£cJt^ ,2, 



m\. A 



ZirtcL 



FifiT. 108. 



noi.-^, Pal. Vol. 2, 1866, page 35, plate 

 2, fig. 2, front, and 2 a^ back views of 

 crown faces of a specimen of this 

 powerful fish's tooth; 2 (?, a profile 

 section of the same. (Figs. 1, 1 <^, 2 

 S, and 3, omitted. Zittel has copied 

 it in his Handbuch, Vol. 3, p. 97, fig. 

 108, half size.) Low, Carboniferous. 

 — In Pennsylvania reported in the 



