PLATE XIII. 



Fig. 



la and b. Ammonites catinus; reduced to one half its diameter; from the Grey Chalk 



near Devizes ; in the collection of William Cunnington, Esq., of that 



town. 



2 and '3a, b, c. Ammonites Portlocki ; from the Hard Chalk of Tamlaght, in the County 

 of Derry ; in the Museum of Practical Geology, London. 



4a, b, and c. Ammonites euomphalus ; from the base of the Lower Chalk at Man of War 

 Cove, Dorsetshire ; in the collection of E. H. Bunbury, Esq. 



