1913 



YORKSHIRE TYPE AMMONITES— II LXXIa 



Fig. i 



Fig. 2 



Ammonites subtriangularis, Young & Bird, 1822 



Whitby Museum, No. 927, Holotype — Plate xn, fig. 4 



Fig. 1, Side view ; Fig. 2, Apertural view 



DEROCERAS SUBTRIANGULARE, Young & Bird sp. 



