540 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



Camarotcechia metallica White. 

 PI. LXIX, figs. 3a, 3b, 3c, 3d, 3e. 



Rlujnchonella metallica White, 1874: Wheeler's Expl. and Surv. W. 100th Merid., 

 Prelim. Eept.. p. 20. White, 1875: Ibid., -Pinal Rept., Vol. IY, p. 129, PL X, 

 figs. 10a, 10r?. 



Bhynchonella pustulosa (?) Hall and Whitfield, 1877: King's U. S. Geol. Expl. 40th 

 Par., Yol. IV, p. 257, PI. IV, figs. 12-14. 



This species was described by White from Carboniferous (Upper Car- 

 boniferous 1) rocks. It was found associated with Hemipronites crenistria 

 and Spirifer cameratus. My material occurs in the lower beds of the Madi- 

 son limestone, whose fauna is regarded as closely related to that of the 

 Kinderhook period. As far as is shown by a careful comparison with the 

 type specimen, this Waverly form is identical with White's species, and 

 were the latter of more nearly the same age I should consider the reference 

 unquestionable. As has been said, Bhynchonella metallica was described 

 from Old Potosi mine, and H. crenistria and S. cameratus are cited from the 

 same locality. 



Spirifer cameratus is closely related to S. striatus, and has sometimes 

 been mistaken for it, while almost any Lower Carboniferous Orthothetes or 

 Derbya might pass as Hemipronites crenistria. Therefore, it is not impossi- 

 ble that R. metallica was derived from lower strata than AVhite supposed. 



It is also more than probable that R. metallica is another representative 

 of the genus Camarotoechia, which fact is not without some stratigraphic 

 bearing, as Camarotoechia is not known in Upper Carboniferous rocks, nor 

 indeed as yet above the Waverly. 



The form here under discussion is the same as that described and figured 

 as R. pustulosa (?) by Hall and Whitfield, in King's U. S. Geol. Expl. 40th 

 Par., Vol. IV, p. 257, PI. IV, figs. 12-14, where it is cited from Waverly rocks. 

 The material from Yellowstone National Park, though scanty from any one 

 place, the localities being numerous, aggregates a number of specimens 

 which agree with one another and exactly with R. pustulosa (?) Hall and 

 Whitfield; but all are without the punctate shell structure characteristic of 

 true Rhynchopora pustulosa. C. metallica is also much smaller than mature 

 R. pustulosa, with thinner, sharper, and finer plications. These, as stated 

 by Hall and Whitfield, are more numerous than in R. pustulosa, and five of 

 them instead of four (as in the latter) regularly surmount the fold. 



