2ib 



YORKSHIRE TYPE AMMONITES 



Mar. 



21. AMMONITES IGNOTUS, Simpson 

 (Plate XXI) 



Original Description 



" 82. A[mmonites] ignotus. [M. Simpson, 1855, p. 61.] 



[" I. Without a dorsal keel or furrow." p. 35. 



" b. Armed with spines or distinct tubercles." p. 58.] 



" Volutions nearly J concealed, outer whorl nearly \ the diameter, 



sides flattish ; radii numerous, obtuse, equal to the intervening concave 



spaces, slightly curved towards the aperture, form a row of tubercles 



on the outer margin of the whorl, then pass undivided over the rounded 



back ; aperture elliptical ; diameter 2^ inches. Inner whorls imperfect. 



— L.L. ; R.H. Bay. Mr. Ripley's Col." 



Additional Details 



Simpson, 1855, p. 94. — " L.L., y, R.H. Bay " ; omits rest of the 

 second par. 



Remarks 



Stages, conch, serpenticone ; periphery, i ; ornament, 5*. 

 Genus Uptonia, S. Buckman, 1898, 453, — family Polymorphidae. 



Result 



Uptonia ignota, Simpson sp., 1855, Charmouthian, jamesoni-zone, 

 Robin Hood's Bay, near Whitby. 



