521 



Orthis. 



■frnun rtn ■T[\ 



Orthis jamesi, Hall, Mth Reg. Report, 1861.— Pal. Ohio. 

 22 Vol. 2, 1875, plate 1, fig. 21, 22, dorsal view 

 and profile of the largest of the type speci- 

 mens of this species. 



Orthis keokuk. Hall, Geol. Rt. of Iowa, 1858. (Strepto 



rhynchus umbracu- 

 lum ? Von Buch ; 

 Orthis umbracu - 

 lum ? De Koninck ; 

 Owen, Geol. Wis- 

 consin, Iowa and 

 Minnesota, 1852, 

 plate 5, fig. 11, on 

 Missouri fiver, Key 

 creek, and Council 

 Bluff's ; differs from 

 the Belgian species 

 in many more ribs 

 or striae, 60 at the 

 beak and 120 + at 

 the margin; with 3 

 strong'; and one 



weaker circles of growth.) — Sulcarhoiiiferous. XI, 



Orthis lentieularis. Vanuxem, page 139, fig. 33, 4 ; the 



VI 



'Ow. O.k. 



a.ya 



Vina.. 70 z ^^^^ ^^^^^ *^ Orthis len- 

 — — tiformis^ Hall, page 175, 

 fig. 70, 4.— In the Corni- 

 ferous ( Upper Helderberg ) 

 limestone formation; but more abundant in middle than in 

 Western New York. VIII a, 



Orthis leptaenoides. Emmons, Geology of the Second 

 "^ District of the State of NewlYork, 



1843,~page 39671agrT07,^lT^ Trenton 

 formation^ II c. 



E.I07. 1 . 



