Gkabatj — Faunas of the Hamilton Group. 



243 



OSTRACODA. 



Genus Primitiopsis, Jones. 



5. Primitiopsis punctulifera, Hall. 



1860, Leperditia punctulifera, Hall, 13th Rep. N. Y., State Cab. Nat. 

 History, p. 92. 



1890, Primitiopsis punctulifera,' Jones, Quart. Journ. Geol. Soc. vol. 46, 

 p. 9, pi. 2. 



Also 1891, Jones, Contr. Micr. Pal. pt. 3, p. 95, pi. 11. 



This species is frequently abundant in certain thin layers. It occurs 

 throughout the Lower shales, but has not been noticed above these. Asso- 

 ciated with this species are frequently other Ostracoda.* 



CEPHALOPODA. 

 Genus Goniatites, De Haan 

 7. Goniatites uniangularis, Conrad. 

 1879, Hall, Pal. N. Y. vol. 5, pt. 2, p. 444, pi. 71, 74. 



A single specimen beautifully pyritized, was found in a limestone band 

 between six and seven feet beloAV the lowest Trilobite bed, at Wanakah Cliff. 



Genus Nautilus Breyn. 



8. Nautilus magister, Hall. 



1879, Hall, Pal. N. Y., vol. 5, pt. 2, p. 422, pi. 62, 107, 108. 



This species was originally described as occuring "in some concretionary 

 calcareous layers, in the upper shales of the Hamilton group, on the shore of 

 lake Erie, in the town of Hamburgh, Erie county, N. Y." (p. 423).. The 

 original locality is Avery's creek and the cliff immediately adjacent on the 

 lake shore, both north and south. The concretionary layers are those of the 

 lowest Pleurodictyum layer (Nautilus bed) resting upon the Strophalosia bed. 

 These beds are here referred to the lotver part of the Hamilton group. The 

 individual specimens are usually large, but they are not very abundant. 



•The following species have been described from the Hamilton shales of Eighteen-mile creek, but their precise horizons 

 are not known: Primitia seminulum, Jones ; Entotnis rhomboidea Jones; Strepula tigmoidalis, Jones; S. plantaris, 

 Jones; Beyrichia Hamiltonensis, Jones ; B. tricollina, Ulrich ; Isochilina (?) fabacen, Jones ; Aechmina marginata, Ulrich ; 

 Ct enobolbina minima, Ulrich; Moorea bicomuta, Ulrich ; Bairdia leguminoides, Ulrich, Leperditia Hudsonica. Hall, 

 var. Jones. 



