612 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



Grypelea calceola var. nebrascensis Meek and Hayden. 



PI. LXXII, figs. 5-7. 



Oryphcea calceola var. nebrascensis Meek and Haydeii, 1S61: Proc. Acad. Nat. Sci. 

 Phila., p. 437. 18G5: Palaeont, Upper Missouri, p. 74, PI. Ill, figs, ht-e aiid figs. 

 A-E on p. 75. Whitfield, 1880: Geol. Black Hills Dakota, p. 349, PL III, figs. 

 13-10. White, 18S4: Fourth Ann. Kept. U. S. Geol. Surv., p. 290, PI. XXXV, 

 figs. 1-5. 



This is one of the most abundant species in the lower fossiliferous zone 

 of the Yellowstone National Park Jurassic, occurring in the collection from 

 south slope of ridge south of Gray Mountain; south end of northeast spur of 

 Signal Peak; east side of Fan Creek Pass; head of north fork of Fawn 

 Creek; saddle in ridge west of south branch headwaters of Gardiner; 

 summit of wagon road between Sentinel Butte and Terrace Mountain, 1 

 mile from head of Swan Lake Valley; hills west of Snake River, 4 miles 

 south of second crossing; on north side of old road to Mammoth Hot 

 Springs, and slopes of Mount Sheridan. 



The species was originally described from the Wind River Mountains 

 and from the Black Hills, though the specimens from the latter locality are 

 all very small. Similar small specimens, however, are very abundant in 

 the Park collections. 



Lima cinnabaeensis n. sp. 



PI. LXXII, fig. S. 



Shell small, obliquely elongate oval in outline; beaks large and promi- 

 nent; hinge line short, the triangular ears being small and inconspicuous; 

 anterior side straight or slightly concave ; posterior side broadly convex and 

 prominent; surface marked by lines of growth and by about twenty promi- 

 nent rounded radiating ribs, which are not quite equal in breadth to the 

 spaces between them. 



The species is represented by only two right valves, the larger of which 

 is figured. It measures 16 mm. in its greatest dimension, obliquely down- 

 ward and forward from the beak, and 10 mm. across the middle of the shell 

 at right angles to that line; convexity about 4 mm. 



No American Jurassic species has been described with which this 

 should be compared, except, perhaps, the form from Sigutlat Lake, British 

 Columbia, referred by Whiteaves to Lima duplicata Sowerby, from which 



