168 Mr. T. R. Jones on Beyrichise. 



I think that the resemblance is not real. I can trace no exact 

 counterparts in the two figui-es ; our specimen is imperfect pos- 

 teriorly, and it seems to me probable that Kloden's specimen 

 also was not quite perfect. Under the circumstances, I prefer to 

 consider the two specimens as very old individuals of their 

 respective species. 



3. Beyrichia lata, Vanuxem, sp. PI. VL fig. 13. 



Agnostus latus, Vanuxem, Conrad's Report Geol. New York ; 

 and Vanuxem, Geol. New York, p. 80 etseq. 



Beyrichia lata, Hall, Palaeontology of New York, vol, ii. p. 301. 

 pi. A 66. figs. 10 a-e. 



Surface of valve divided into three unequal ridges or lobes ; 

 posterior lobe largest, broad, its ventral portion curved forwards 

 to meet the constricted neck of the middle lobe ; anterior lobe 

 smallest, depressed, forming a narrow oblique ridge which is 

 scarcely separated at its lower end from the advanced extremity 

 of the hinder lobe. Marginal rim well developed, uniform. 



The specimens here described, and referred to the B. lata 

 figured by Prof. Hall, are dispersed in great numbers, together 

 with fragments of Trilobites, in the ferruginous (weathered) por- 

 tion of a compact sandstone or quartzite, from a locality three or 

 four miles south of Utica, New York State, and marked " Hud- 

 son River Group *." All trace of the carapace itself has disap- 

 peared, and the casts and impressions afford no good evidence 

 either of a smooth or an ornamented state of the surface of the 

 carapace-valves. (In the IMuseum of Practical Geology.) 



Prof. Hallf describes his specimens (which are from the fer- 

 ruginous rocks of the Clinton group of the State of New York J) 

 as having on one valve a subcentral ridge, and on the other a 

 subcentral and corresponding depression. But, guided by Mr. 

 Hall's figures and by the specimens before me, I think that this 

 description caimot be applicable ; and that it has arisen from the 

 relatively great breadth of the subcentral furrow, between the 

 middle and hinder ridges or lobes, and from the sometimes 

 almost obsolete condition of the anterior ridfre. 



* Most jirobiibly incorrect. 



t Witli regard to the Beyrichia; of the New York State, Prof. Hall re- 

 marks (loc. cit. p. 301), that "we have three or four species o{ Beyrichia 

 in our successive groups, beginning with the Chnton group." 



X " In the ferruginous shale associated with the iron ore at Wadsworth's 

 quarries, and in the ferruginous sandstones below, at New Hartford, Oneida 

 County ; in numerous localities in the same position farther west, and in 

 the green shale of the grouj) at Sodus and Rochester." — Hall, op. cit. p. 301 . 



