PLATE XXIX— Continued. 



Si'iRiFEU NOBiLis, Bainiiiclc. 



Fig. 16. A section along- the longitudinal axis looking into one of the coils. The apparent pi-ocess on the 

 second volution is casual. 



Niagara group. Near Chicagu, Illinois. 



Genus AMBOCCELIA, Hall 



Page 54. 



Ambocoelia umbonata, Connid. 



Fig. 15. A preparation, showing the loosely coiled spirals with but few volutions. X 6. (c) 

 Hamilton gi-oup. Western New York. 



Genus SPIRIFERINA, d'Okbigny. 



Page 51, 



Spirifeuina Kentuckiensis, Shumard. 



Fig. 17. A specimen whose brachidium is preserved in pyrite ; showing the united jugal [iroceesea which 

 form a continuous loop. The pedicle-valve is on the lower side of the figure. 

 Coal Measures. Vinton county, Ohio, 



