7928 



TYPE AMMONITES— VII DCCLXXXIIIb 



Deroceras submuticum 



Radstock ; Middle Lias ; S.B. Coll. 1956 



Three stages of ornament— spinous followed by decay to subcostate 



which gives way to strong spinosity 



APODEROCERAS TRIORNATUM, NOV. 



Deroceratan, leckenbyi ; Holotype. See LXX1I 



