Obol. 



478 



1 e, cast of inside of dorsal valve ; 1 d, diagram of inside dorsal 

 valve (by Ford) ; 1 ^, cast of inside of dorsal valve; 1 /*, dia- 

 gram of inside ventral valve (drawn by Ford) ; a, cardinal ; 

 5, central ; d^ lateral mnscnlar scars ; p^ pedicle groove. — 

 Troy, N. Y. ; Shodack Landing Quebec. Z, (7. 



Obolella gemma. Billings, 1872, Can. Nat. Vol. 6, p. 218, 

 ^ o figure 5. 



^'^■^ ^ '^^-' pKlO Walcott, 



Bulletin 

 No. 30, 



U. s. a 



S. page 

 116, plate 

 10, fig. 2, 

 outside 

 (weath- 

 ered ) o f 

 a ventral 

 valve, en- 

 larged ; 

 fig. 2 «, 



another, enlarged six times ; fig. 2 5, inside of another {a, 

 cardinal ; d^ lateral ; <?, central muscular scars ; j9, foot groove) ; 



2 {?, inside of another (difl'erences due largely to poor preserva- 

 tion) ; 2 d^ inside of dorsal valve, poorly preserved ; 2 c^ out- 

 side of another. {All enlarged.) Below Quebec; and near 

 Troy, N. Y. Lower Cambrian. L. C. 



Oholella lahradorica^ (Kutorgina labradorica), Billings 

 Iphidea labradorica^ Billings. Pal. Foss. Vol. 

 1861.— Geol. Can. 1863, page 284, fig. 291, dorsal 

 valve. Quebec group., called by Logan, here, 

 Potsdam. L (Walcott has renamed the genus, 

 and placed it in Lower Cambrian.) L. C. 



Obolella nitida, Ford, 1873, Amer. Jour. S. [3] Vol. 5, p. 



2 213.— Walcott, Bulletin No. 30, U. S. G. S. page 



118, plate XI, fig. 2, dorsal (?) valve, enlarged Hve 



times (drawing by Ford). Lower Cambrian xie^iY 



Troy,N. Y. (Walcott.) Z. C. 



**^-^4JL.JiilllJU"'''' 



LX.291 



iG^^l. 



C^rs 



