290 CALIFORNIA ACADEMY OF SCIENCES. 



CEKAURUS. 



[Chdrurus] niagarensis Hall, 1879; 28th Eej}. New York State Mus. 



Nat. His., p. 189, pi. 32, fig. 16. 

 Syn., Cheirurus himucronattis (Murch.) Roemer; Die Sil. Fauna W. 



Teuu., p. 80, pi. 5, fig. 19. 

 NIAGARENSIS Hall, 1882; 12tli Ann. Rej). Geol. Nat. Hist. Indiana, 



1881, p. 335, pi. 34, fig. 16; pi. 33, fig. 10. 

 Cheirurus numitor Bill, 1866; Catalogue Sil. Foss. Anticosti, p. 27, 



fig. 11. English Head. Hudson. 



Cheirurus nuperus Bill., 1866; Catalogue Sil. Foss. Anticosti, p. 61, 



tig. 20. East Point Div. 3. Anticosti group. 



Cheirurus perforator Bill., 1865; Pal. Foss., vol. 1, p. 287, fig. 275. 



All the species described from the Quebec group of Newfoundland 



by Billings are probabl}' of other genera. The genus Ceraurus 



belongs to the Trenton, Hudson and Niagara periods. Table 



Head, N. F, 



I'LEUREXANTHEMUs Green, 1832; Monthly Am. Jour. Geol., vol. 1, p. 



560, pi., fig. 10. Trenton and Hudson. 



PLEUREXANTHEMus Green, 1832; Mon. Tril. N. A., p. 84, fig. 10, pi. 



1, cast 33. 

 Syn., Calymene buclclandi Authonj-, 1838; Am. Jour. Sci., 1st series, 

 vol. 36, p, 106, figs. 1, 2. 



PLEUREXANTHEMUS Hall, 1847; Pal. New York, vol. 1, p. 242, pi. 65, 



figs. 1 a-n; pi. 66, figs. 1, 1 h. Middleville, Trenton Falls, etc., 

 N. Y. 



PLEUREXANTHEMUS Euimous, 1855; Am. Geol., vol. 1, p. 217, pi. 15, 



figs. 1 a-k. 

 Cheirurus pleurexanthemus Bill., 1863; Geol. Canada, p. 188, fig. 

 188. 



PLEUREXANTHEMUS Miller, 1874; Cincinnati Quart. Jour. Sci., vol. 1, 



p. 132. 



PLEUREXANTHEMUS Wal., 1875; Aiiuals Nat. Hist. New York, vol, 11, 



p. 155, pi. 11. 



PLEUREXANTHEMUS Wal., 1881; Bull. Mus. Comp. Zool. Harvard Coll., 



vol. 8, p. 211, pi. 5, figs. 1-6. 

 Cheirurus polydorus Bill., 1865; Pal. Foss., vol. 1, p. 286, fig. 274. 



Table Head, Portland Creek, N. F. 

 Cheirurus pompilius Bill., 1865; Pal. Foss., vol. 1, p. 181, fig. 162. 

 Large Island, Miugan Island. Chazy and Hudson. 



Cheirurus prolificus Bill., 1865; Pal. Foss., vol. 1, p. 285, fig. 273; 

 p. 325, fig. 311. Cow Head, N. F. 



? PUSTULOSA Hall, 1847; Pal. New York, vol. 1, p. 246, pi. 61, fig. 2 a-h. 



AVatertowu, N. Y. Trenton. 



RARus Wal., 1877; Advanced sheets 31st Rept. New York State Mus. 



Nat. Hist., p. 15. Beloit, Wis. Trenton. 



