PLATE XXI. 



Fig. -ovAC 



\a, h, c. Ammonites Lewesiensis; from the Grey Chalk, uear Dover; in the collection 

 of S. J. Mackie, Esq., of Folkstone, p. 46. 

 la, side view. 

 lb, front view. 

 Ic, outline of a septum. 



2. Ammonites leptophyllus ; outline of a septum of the specimen, Plate XXII, fig. 1. 



3«, b, c. Ammonites Wiestii; from the Chalk with silicious grains, Chardstock, 

 Somersetshire; in the collection of J. Wiest, Esq., p. 47. 

 Sa, side view. 

 3d, back view. 

 3c, section of a whorl. 



