120b YORKSHIRE TYPE AMMONITES— II Mar. 



120. AMMONITES IMPENDENS, Young & Bird 

 (Plate CXX) 



Original Description 



[Young & Bird, 1828, p. 266.] 

 " We. have also, from the lias bands, a smaller ammonite [than 

 A. exaratus] with the inner edge of the whirl overhanging, as in A. Mul- 

 gravins ; but its ribs are fewer and more prominent, and instead of being 

 hook-shaped, are nearly straight. This species may be designated 

 A. impendens." 



Remarks 



Proportions, 72, 41, 22, 27 ; platy-, subleptogyral, sublatum- 

 bilicate. 



Stages, conch, platycone ; periphery, 4c ; ornament, 4c. 



The carina is not septate. 



Genus, Arieiites, YVaagen ; fam. Arietida^. 



Geological position : Blake (1876, p. 290), " Zone of A. oxynotus " ; 

 Simpson (1884, pp. xxn, 126), " L.L. 16 " ; Buckman (Geol. Whitby, 

 1915, p. 67), §1, 4, " stellare zone " with " Ar. denotatum ? " 



Result 

 Artetites impendens Young & Bird sp. 1828, Sinemurian, [stellare 

 (denotati.s) zone], Yorkshire [Coast]. 





