542 GEOLOGY OF THE YELLOWSTONE NATIONAL PAEK. 



be found on each of the sides. In every respect this very closely resembles 

 Hall's species, although only a provisional reference is possible, owing to 

 insufficient material. C. sappho first makes its appearance in beds of the 

 Marcellus period, but is known to extend up into the upper Waverly 

 (Herrick, 1888, loc. cit., p. 40). 



Formation and locality : Madison limestone, Limestone bluff south 

 side of Soda Butte Creek, northwest of Abiathar Peak, Absaroka Range; 

 J. P. Iddings. Marcellus to Waverly, Leroy, Geneseo, and York, New 

 York ; Licking County, Ohio. 



Camarotcechia camarifera Winchell (?). 



Rhynehonella camarifera Winchell (A.), 1862: Proc. Acad. Nat. Sci. Philadelphia, p. 408. 



This species is represented in a somewhat fragmentary manner, and 

 the material is too poor for illustration. It resembles C. herrickana, but at 

 the same time seems to be specifically distinct from it. Shape ovate; 

 length equal to or slightly exceeding the width ; convexity moderate. 

 Sides straight, meeting at the beak in something less than a right angle; 

 front deeply rounded. Plications rounded, four on the fold and three in 

 the sinus, with five or six on the sides. The plications are nearly straight 

 and not very divergent, which makes the shell look longer than it really is. 

 It can be distinguished from C. herrickana by the somewhat different 

 arrangement of plications on fold and sides. The proportions of the shell 

 are also different. The plications are slightly finer, less angular, and not 

 so strongly outcurved at their extremities. The nearest described species 

 which I have found is C. camarifera of Winchell. 



Length, 10 mm.; width, 9.5 mm. 



Formation and locality : Madison limestone, Crowfoot Ridge, Gallatin 

 Range, bed 26, bed 28, bed 30; J. P. Iddings and W. H. Weed. Marshall 

 group, Point aux Barques, Michigan. 



Camarotcechia sp. 

 PI. LXIX, figs, ia, 4b. 



This species is represented by a single specimen, which seems to be 

 distinct from any type occurring in the collection from the Yellowstone 

 National Park. It was found at the limestone bluff on the south side of 



