PLATE VII 



PAGE. 

 Fig. 1-9. Orodus variocostatus, St. J. and *W 304 



1 a. View of outer face of small, anterior (?) tooth, base broken away; 1 6, crown from 



above. "Upper Burlington limestone ; Louisa county, Iowa. 



2 a. Posterior face of a minute posterior (?) tooth.; 2 b, crown from above; 2 c, profile sec* 



tion. Same horizon and locality. 



3 a. View of inner face of similar but larger tooth ; 3 6, crown from above, showing eccen- 



tric median prominence. Same horizon and locality. 



4 a. A. larger subcircular tooth, seen from above. Same horizon aud locality. 



5 a. View of inner face of larger and more laterally elongated tooth ; 5 b, crown from above. 



Same htrizon and locality. 

 G a. Similar tooth, posterior face, crown worn ; 6 &, view from above ; 6 c, profile section. 

 Same horizon aud locality. 



7 a. Outer aspect of medium-sized tooth, showing excavated anterior basal region, superior 



shoulder parallel with the coronal margin, and beveled inferior surface of the ba-se, 

 and the outer crown face ; 7 b, crown from above ; 7 c, profile section. Same hori- 

 zon and locality. 



8 a. View of inner face of similar tooth, the median cone truncated from wear ; 8 b, crown 



seen from above. Same horizon and locality . 



9 a. Posterior face of a large tooth, also more or les9 worn ; 9 b, crown seen from above. 



Same horizon and locality. 



Fig. 10. Orodus major, St. J. and¥ 302 



10 «- View of inner face of medium-sized tooth ; 10 b, crown as seen from above ; 10 c, pro- 



file section. Lower Burlington limestone ; Burlington, Iowa. 

 Fig. 11-18. Leiodus calcaratus, St. J. and"W 336 



11 a. Posterior face of large tooth; 11 &, view of outer face; 11 c, profile section. Upper 



Burlington; Louisa county, Iowa. 



12 a. Medium-sized tooth, inner face; 12 &, outline of orown from above. Same horizon and. 



locality. 



13 a. Smaller, apiculate tooth, outer face; 13 b, outline from above. Same horizon and 



locality. 



14 a. Outer face of small, robust tooth; 14 &, outline from above. Same horizon and locality. 



15 a. Outer face of a very small, acuminate anterior (?) tooth ; 15 b, posterior face ; 15 c, out- 



line of crown from above. Same horizon and locality. 

 1G a. Outer face of an eccentric acuminate tooth, anterior (?); 16 b, outline of crown from 

 above. Same horizon and locality. 



17 ft. View of outer face of posterior (?) tooth ; 17 6, posterior face ; 17 c, outline of crown 



from above. Same horizon and locality. 



18 a. Outer face of a similar tooth ; 18 &, view of crown from above; 18 c, profile section. 



Same horizon: Burlington, Iowa. 



Fig. 19. Orodus Alleni, St. J. and W 310 



19 a. View of inuer face; 19 6, view of crown from above; 19 c. profile section. Lower Coal 



Measures ; Iowa. 



