54 Trans. Acad. Sci. of St. Louis. 



16. Archaeocidaris norwoodi Hall. 



1858. Archaeocidaris norwoodi. Hall, Geol. Iowa, vol. 1, 



pt. 2, p. 701, pi. 26, figs. 5 a-e. 

 1867. Archaeocidaris Norwoodi '. Dana, Man. Geol., p. 312, 



fig. 535. 

 1874. Archaeocidaris N~omvoodi. Loven, Kongl. Svens. 



Vetens. Akad. Handl. Bd. 11, no. 7, p. 43. 

 1889. Archaeocidaris norivoodi. Miller, N. Amer. Geol. 



Pal., p. 225. 



1894. Archaeocidaris norivoodi. Keyes, Mo. Geol. Surv., 

 vol. 4, p. 129. 



1895. Archaeocidaris norwoodi. Keyes, Proc. Iowa Acad. 

 Sci., vol. 2, p. 188. 



Primary tubercles papilliforni with thickened sides raised 

 above the annulation. Margin of the annulation thickened, 

 rounded and spreading into a flattened disk. Space between 

 slightly depressed and sometimes having radiating ridges. 



Primary spines slender, elongated, slightly curving, longi- 

 tudinally striated below and muricate above. Fine sharply 

 elevated denticles and short round divergmo; spinules at inter- 

 vals along the spines. Intermediate surface granulose. 



Geological formation and locality: Kaskaskia Limestone, 

 Chester and Kaskaskia, 111. ; near St. Louis, Mo. 



17. Archaeocidaris ornatus Newberrv. 



1861. Archaeocidaris ornatus. Newberry, Ives' Colo. Expl. 



Exped., p. 116, pi. 1, fig. 2, 3, 3 a. 

 1874. Archaeocidaris ornata . Loven, Kongl. Svens. Vetens. 



Akad. Handl., Bd. 11, No. 7, p. 44. 

 1877. Archaeocidaris ornatus. White, U. S. Geog. Surv. 



W. 100 Merid., vol. 4, page 104, pi. 6, fig. 7. 

 1889. Archaeocidaris ornata. Miller, N. Amer. Geol. Pal., 



p. 225. 

 1895. Archaeocidaris ornatus. Keyes, Proc. Iowa Acad. 



Sci., vol. 2, p. 191. 



