North Amerioav, Cai'bo)iiferoHs Trilohites. 



60 



^'l. — Tlic Genera and Sj)edes of North American Carbuniferoiis 



Trilohites. 



BY AXTHONY W. YOGDES. 



Read, March ^th, 188r. 



CUXTENTS : — 



I. Int]-oduction. 



II. ChiFsification of the Carboniferous strata of the United 



States. 



III. The genus Proetiis, Steininger. 



].V. The genus FhilUpsia, Portlock. 



V. The genus GriffitJUdes, Portlock. 



VI. 'Jlie gt nus Bracliymetopiis, McCoy. 



\\l. Desci'iption of tlie American species, with remarks. 



I. — InTROD UCTIOis'. 



The known Carboniferous Trih>bites of North America con- 

 sist of several species of the genus Proetiis, ranging from the Che- 

 mung to the Waverly series ; twelve species of the genus Phil- 

 lipsia, viz. : P. insignis, P. Doris, P. Rockfordensis, of the 

 Waverly series ; Phillipna tuberculata, Burlington series ; P. 

 Mcramecensia, Keokuk ; P. Stevensoni, Chester series ; P. Hoiui, 

 and P. F//z<Zo&oweyi.w*S' .? Lower Carboniferous, and four sj^ecies 

 from the Middle and Upper Coal Measures. The genus Grif- 

 fithides has five species, which range from the Keokuk to the 

 Coal Measures. 



Brachymetopns has only one species, appearing in the Waverly 

 series. 



The following brief diagnosis of the characters may be found 

 of use in separating the genera : 



