68 Teirti-first Report on the State Museum. 



DESCRIPTIONS OF NEW SPECIES OF FOSSILS 



FROM THE CHAZY AND TRENTON LIMESTONES.* 



By C. D. Walcott. 



ARIONELLUS, Barrande, 1846. 



AllIONELLUS PUSTULATUS 71. Sp. 



Glabella very convex ; separated from the fixed cheeks by a strong dorsal 

 furrow ; short glabellar furrows outline a frontal lobe at the anterior third ; 

 a lateral lobe is indicated, on each side, by a short depression or furrow 

 parallel to the longitudinal axis of the glabella. Fixed cheeks depressed 

 beneath the level of the glabella. The strong dorsal furrow, extending all 

 around in front of the glabella, and the rapidly sloping outer margin gives 

 them a prominent rounded, almost tumid appearance. Occipital segment 

 broad, depressed, separated from the glabella by a narrow furrow. One seg- 

 ment of the thorax is preserved in one specimen. It is strongly arched on 

 the axial lobe ; pleurse with an elevated posterior ridge, and depressed ante- 

 rior margin. Surface pustulose or finely tuberculated. Eyes, movable 

 cheeks and pygidium unknown. 



Formation and locality. Chazy Limestone, Chazy, N. Y. 



CERAURUS, Green, 1832. 

 Ceraurus rarus n. sp. 



Glabella subturbinate, convex ; broadly rounded in front, separated from 

 the fixed cheeks by strong dorsal furrows ; frontal lobe large, occupying the 

 anterior half of the glabella; middle and posterior lobes small, diminishing 

 regularly in size toward the occipital segment ; glabellar furrows deeply im- 

 pressed. Occipital segment rounded, separated by a well defined furrow 

 from the glabella. Fixed cheeks crushed. Surface; fixed cheeks and frontal 

 Jobe of glabella pustulose ; posterior or glabellar lobes finely granulated. 



Formation and locality. Trenton Limestone, Beloit, Wisconsin. 



ENCRINURUS, Emmrich, 1844. 



Encrinurus Trentonensis n. sp. 



Pyg;idium triangular, convex; length and breadth about equal ; axial lobe 

 rounding, tapering toward and terminating within * the posterior margin ; 

 marked by twenty-three rings, beyond which are several, too indistinct to be 

 counted ; the first anterior ring has a node at its center ; then, in order, the 

 third, sixth, tenth, fourteenth, eighteenth and twenty-second have a similar 

 node at the center. Lateral lobes slope rapidly to the margin ; each has 

 nine elevated costae- running obliquely backward to the margin. 



Formation and localities. Trenton Limestone, Clifton, Grant Co., Wis- 

 consin, and two miles above Dunlith, 111., north of State Line monument. 



* Erroneously cited in Miller's Catalogue of Palaeozoic Fossils, as from the Twenty-ninth 

 Reyents' Report N\ Y. State Museum of Natural History. 



