904 BULLETIN 92, UNITED STATES NATIONAL MUSEUM. 



Orthoceras cornu-oryx Whitfield. See Orygoceras cornuoryx. 



Orthoceras cornuiiin Billings. 



Orthoceras cornuum Billings, Geol. Surv. Canada, Rep. Progr. for 1853-56, 



1857, p. 329. 

 Chazyan (Mingan): Mingan Island, Canada. 



Orthoceras (Kionoceras) Crawfordi Foerste. See Kionoceras crawfordi. 



Orthoceras crebescens Hall. See Protokionoceras erebescens. 



Orthoceras crebescens Hall and Whitfield. See Orthoceras rectum. 



Orthoceras crebriseptum Billings. See Actinoceras crebriseptum. 



Orthoceras crebristriatum Meek and Worthen. 



Orthoceras crebristriatum Meek and Worthen, Proc. Acad. Nat. Sci. Philadelphia, 



1865, p. 255; Geol. Surv. Illinois, 6, 1875, p. 503, pi. 26, fig. 2. 

 Niagaran (Racine): Joliet, Illinois; 



Orthoceras Crocus Billings. See Cycloceras crocus. 



Orthoceras cuvieri Miller. See Actinoceras cuvieri. 



Orthoceras Darwini Billings. See Kionoceras darwini. 



Orthoceras (Actinoceras) Daytonensis Foerste. See Actinoceras daytonense. 



Orthoceras decrescens Billings. 



Orthoceras decrescens Billings, Geol. Surv. Canada, Rep. Progr. for 1853-56, 

 1857, p. 337.— Foord, Cat. Foss. Ceph. British Mus., 1, 1888, p. 9. 



Black River (Leray): Chaudiere Rapids, St. Josephs Island, and Island of Mon- 

 treal, Canada. 



Orthoceras defrancil (Troost). 



Conotubularia defrancii Troost s Mus. Soc. Geol. France, 3, 1838, p. 90. 

 Orthoceratites Defrancii Troost, ibid., p. 93, pi. 9, figs. 7, ,7b; 5th Geol. Rep. 



Tennessee, p. 49; 6th Rep., 1841, p. 178. 

 Orthoceras defrancii Miller, N. A. Geol. Pal., 1889, p. 447 (gen. ref.). 

 Niagaran: Perry County, Tennessee. 



Orthogeras (Kionoceras) delphiensis Kindle and Breger. See Kionoceras del- 

 phiense. 



Orthoceras deparcum Billings. 



Orthceras deparcum Billings, Canadian Nat. Geol., 4, 1859, p. 363, fig. Ill; Geol. 

 Canada, Geol. Surv. Canada, 1863, p. 121, fig. 40.— Lesley, Geol. Surv. Penn- 

 sylvania, Rep. P 4, 1889, p. 547, fig.— Whitfield, Bull. Amer. Mus. Nat. Hist., 

 3, 1890, p. 34. 



Canadian (Romaine): Mingan Islands, Quebec. 



Orthoceras diffidens Billings. See Loxoceras diffidens. 



Orthoceras drummoudi Billings. 



Orthoceras Drummondi Billings, Pal. Foss., 1, Geol. Surv. Canada, 1865, p. 173, 



fig. 156. 

 Black River: Near Kingston, Ontario. 



Orthoceras duseri Hall and Whitfield. 



Orthoceras Duseri Hall and Whitfield, Geol. Surv. Ohio, Pal. 2, 1875, p. 97, pi. 

 3, figs. 2-4.— James, J. F., Jour. Cincinnati Soc. Nat. Hist., 8, 1886, p. 241.— 



