PLATE I. 



Fig. Page. 



1. Liopleurodon ferox, Sauvage; tooth. — Rushden. In the Northampton 



Museum. 23 



2. Liopleurodon ferox, Sauvage. — Smaller tooth from the same locality and 



collection. 2 a, side view ; 2 b, transverse section of the same. 23 



3 a, b. Mursenosaurus ; dorsal vertebra. — Rushden. In the Collection of 



Mr. J. F. Walker. 25 



4. Humerus of Plesiosaurus. — Scarborough. In the Leckenby Collection 



in the Sedgwick Museum. 25 



5. Machimosaurus rigauxi, Sauvage; tooth.— Handborough, Oxon. In the 



Collection of Mr. E. A. Walford. 



(a) Side view, nat. size, (b) Apex magnified, (c) Transverse section. 26 



6. Aster acanthus acutus, Agassiz ; spine. — St. Botolph's Bridge, Peterborough. 



In the Sharp Collection in the British Museum (no. 47131). 6 a, 

 side view ; 6 b, details of ornament. 28 



7. Strophodus tenuis, Agassiz ; teeth. 7a, from one of the two anterior 



rows; 7b, from one of the two posterior rows. — Peterborough 

 district ; St. Botolph's Bridge. In the British Museum (nos. 

 47132 a, P. 2662). 30 



8. Stropihodus rigauxi (Sauvage) ; posterior tooth. — Scarborough. In the 



York Museum. 8 a, natural size ; 8 b, magnified three times. 31 



9. Strophodus tenuis, Agassiz; posterior tooth. — St. Botolph's Bridge. In 



the Sharp Collection in the British Museum (no. 47132). 30 



10. Macromesodon bathonicus (Sauvage); central vomerine tooth. — St. 

 Botolph's Bridge, Peterborough. In the British Museum (no. 

 47148 a). 32 



