PLATE XV. 



Fig- At^*^tV.of^Y<*5 



1*7, b, c, and d. Ammonites Sussexiensis ; a specimen given me by Dr. Mantell, from the 



Grey Chalk near Lewes ; reduced to two thirds its natural diameter. 



2a, b, and c. Ammonites Cunningtoni ; from a specimen belonging to T. A. Falkner, 

 Esq., of Manningford, reduced to two thirds its natural diameter ; from 

 the Grey Chalk of Upton Scudamore, near Warminster. 



