Fossils of the Utica Slate. 23 



which so many rare specimens have been obtained. One is an annu- 

 lated shell with strong longitudinal striations which have the appear- 

 ance of having transverse striae crossing them. The fragment is of 

 the character of Ort/ioceras {vertebrale) olorus of the Trenton lime- 

 stone. The other is a very slender, finely cancellated, shell different 

 from any other form known to me; for the latter the name Ortho- 

 ceras Oneidaense is proposed. 



Formation and locality. Utica slate, town of Trenton, Oneida 

 Co., N. Y. 



Beyrichia Cincinnatiensis Millee. 



This species occurs, associated with Leperditia cylindrica and L. 

 mifiutissima, in the lower part of the slate on Rathbone's brook, 

 Deerfield, Oneida Co., N. Y. 



TRIARTHRUS BECKI Green 1832. 



Brongniartia carcinoidea : Eaton 1832. Geol. Text Book. 



Triarthrus Beckii : Monthly Journal of Geology, p. 560. 



Triarthrus Beckii : Green 1832. Monograph, p. 87, 



Triarthrus Beckii : 1835. Trans. Oeol. tSoc. Penn., vol. i, p. 105. ' 



Paradoxides arcuatus : Harlan, 1835. Trans. Geol. ISoc, Penn., vol. i, p. 265. 



Paradoxides triarthrus : " " " " " " " " 264. 



Paradoxides Beckii : Hall 1838. Amer. Jour. Science, vol. xxxiii, p. 137. 



Paradoxides Eatoni : " " " " " " *' " 



Triarthrus beckii : Mather 1842 Eep., 1st District, Geol. iV. Y., p. 390. 



Triarthrus beckii : Emmons " " 2d " " " " 399. 



Triarthrus beckii : Ya.n\ixem, " " 3d " " " " 57. 



Triarthrus Beckii : Hall, 4tli, " " " '* 504. 



Atops trilineatus : Emmons 1844. Taconic System, p. 20. 



Atops trilineatus : Emmons 1846. Agr. Eept., iV. T., vol. i, p. 64. 



Calymene Beckii : Hall 1847. Pal. N. T., vol. i, pp. 237, 250. 



Triarthrus Beckii : Logan 1863. Geology of Canada, p. 202. 



Triarthrus Becki : Barrande 1872. Syst. Sil. Boheme. vol. i, p. 259. 



Triarthrus Becki : Miller 1874. Cincinnati Jour. Science, vol. i, p. 146. 



Triarthrus Becki : Miller 1877, Cat. Amer. Pal. Fossils, p. 223. 



Many references are omitted where the species is named Triar- 

 thrvs Becki., as it has been so frequently referred to by authors. 

 Numerous figures and detailed descriptions of the species are given 

 in the first volume of the Palaeontology of New York. 



Before proceeding to the discussion of its metamorphoses, we 

 will first notice the references that have been made to changes 

 occurring in species of the genus Triarthrus by authors. 



