1918 



YORKSHIRE TYPE AMMONITES— II 



CXII 



Fig. i 



Fig. 2 



ttiyj 



n 



Fig. 3 



Ammonites semicostatus, Young & Bird, 1828 



Whitby Museum, No. 924, Holctype ? — PI. xn, f. 10 



Figs. 1, 2, Side & Peripheral views, N.S. ; Fig 3, Suture-line x 3 



ARNIOCERAS SEMICOSTATUM, Young & Bird sp. 



