Orthis. 



530 



12, fig. 3, dorsal valve; 4, dorsal interior; 5, ventral interior; 

 6, cast of a dorsal valve. Lower Helderlerg. Dr. Barrett col- 

 lected it from the Stormville shale near Port Jervis on the 

 Delaware river (G. 6, p. 132.)— VL 



Orthis platys, Billings, Can. Nat. & Geol. Vol. 4, 1859, 

 ^jp^ — a> ^ ^^■^5-4> Geology of Canada, 1863, 



^^^ " '^ ^"^ ' page 129, figures 54 «, dor- 



sal valve; J, long section 

 to show the curvature of 



« ,, ^«^///ijiiui\\i^ ^^^^ ^^^ valves ; c, ventral 

 ConaVHa /5r,?^M»>^ ^al^e. Chazy, III. 



Orthis plicata. See Spirifera vanuxemi. VL 



Orthis plicatella. (Hall, Pal. N. Y. Vol. 1, 1847, Trenton 

 He. . Q^ ^^ . and Hudson river groups.) Emmons, 



Amer. Geol. I, ii, 1855, p. 193, plate 

 9, figs. 9 « to e. Rather small shell, 

 ^"^•Ai?- P'-9 with nearly equal valves; 24 simple 

 folds, more or less in different specimens.—// c. Trenton 

 limestone formation.— Also, Pal. Ohio, Vol. 1, 187i, page lo8, 

 plate 8, fig. la to j.—LLL K 



Orthis plicatella. Hall. Pal. N. Y. Vol. 1, 1847, Trenton 



Bs 



li GoQl.Can ^^^ Hudson river formatiovff. — Geol- 



m\ Jtf^ ^^ ^^^ ^^ Canada, 1863, pa^e 165, fi^s. 



Wf^S w ^ly W ^^^ ^1 ^/ ^^ 5^ different views two 



specimens from the Trenton limestone 

 of Canada. Lie — Pal. Ohio, Vol. 1, 1873, page 108. plate 9, 

 fig. 7 a. 5, ventral, dorsal valves; 7 c. inside dorsal; 7 d. e, /, 

 profile, front, back (hinge) views; 7 .^, enlarged surface to 

 show cross striae between the ribs, and minute traces of longi- 

 tudinal striae on and between the ribs : 7 h. i, ventral and dor- 

 sal valves, intermediate between this species and its variety 

 (below); 7 j?, inside of dorsal valve. — Cincinnati group, III^ 



