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 Eogersi Norwood & 



Figs. 591-594. 



Brachiopods. — Fig. 591, Spirifer cameratus; 592, Productus Rogersi; 

 soloba ; 594, Athyris subtilita. 



593, Chonetes me- 



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

 common species ; fig. 594, Athyris (Terebratula) subtilita, very 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, 596. 



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



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

 P. semireticulatus (fig. 229, p. 183), Spirifer lineatus. 



(b.) Conchifers. — Fig. 595, Area [?~\ carbonaria Cox, Upper Coal measures of 

 Kentucky; fig. 596, Allorisma subcuneata, from Kansas. Aviculopecten recti- 



