348 



PALEOZOIC TIME — CARBONIFEROUS AGE. 



regarded by some as only a variety of it ; but it belongs exclusively, in this 

 country at least, to the Coal measures, and not to the Subcarboniferous in which 

 the S. striatus is found well marked. Fig. 592, Productus Royersi Norwood & 



Figs. 591-594. 



Brachiopods.— Fig. 591, Spirifer camcratus; 592, Productus Rogersi; 593, Chonetes me- 

 soloba ; 594, Athyris subtilita. 



Pratten, from Illinois, Kansas, and New Mexico ; fig. 593, Chonetes mesoloba, a 

 common species ; fig. 594, Athyris (Terebratula) subtilita, A^ery common in the Coal 

 measures, and not known in the American Subcarboniferous, although reported 

 from the latter in England. There are, however, Subcarboniferous forms dis- 

 tinguishable with difficulty from it. Spirifer Kentuckensis is an Upper Coal- 

 measure species from Kentucky, Missouri, and near Pecos village, New Mexico. 

 The following first appeared in the Subcarboniferous, and are continued into 



Figs. 595, 59G. 



Conchifers. — Fig. 595, Area [?] carbouaria; 596, Allorisma subcuneata. 



the Carboniferous : Productus 2wnciatus (fig. 545, p. 314), P. Cora, P. muricatus, 

 P. semiretictdatus (fig. 229, p. 1G3), Spirifer iineatus. 



(b.) Conchifers. — Fig. 595, Area [.?] earlovaria Cox, Upper Coal measures of 

 Kentucky; fig. 59G, Allorisma subcuneata, from Kansas. Avicidopeclen recti- 





