PLATE XI. 



Fig. •, > i^-, f , ' ' - 



la and b. Ammonites Woollgari ; from the Grey Chalk near Lewes ; the original 

 specimen in Dr. Mantell's collection, figured in his work, and in the 

 * Mineral Conchology,' and now in the British Museum. The portions 

 marked R are restored by the artist. 



2a and b. Ammonites Woollgari ; a young specimen from the Middle Chalk near Lewes ; 

 in the collection of Henry Catt, Esq., of Brighton. 



Sa, h, and c. Ammonites Griffithii ; internal cast from the Hard Chalk of the County 

 of Derry ; fig. 3« has been completed in the inner whorls from another 

 specimen, and fig. 3c drawn from a third specimen, all in the collection 

 of the Museum of Practical Geology, in London. 



