(Em0U00iUtVUS ricte&SOW, LYDEKKER (n. sp.) 1 

 SYN. Plesiosaurus plicatus, 



By J. C. MANSBL-PLBYDELL, Esq., 

 F.L.S.. F.G.S. 



OWARDS the end of the Mesozoic age a remarkable 

 diminution of the huge reptiles which swarmed in 

 the seas of that period commenced, and at the 

 beginning of the succeeding age, Tertiary, 

 their annihilation was nearly complete, occasioned 

 by great physical changes, especially affecting the 

 relative positions of land and sea, the sea predominating largely 

 over the land in Europe. We pass from strata of considerable 

 uniformity and of immense thickness over large and extensive areas 

 to beds of a great variety of structure, from deep to shallow seas, 



1 Catalogue of the Fossil Reptilia and Amphibia in the British Museum 

 (Natural History), by R. Lydekker, Part ii., p. 240, 1889. 



2 Proceedings of the Dorset Natural History and Antiquarian Field 

 Club, vol. ix., p. 26, 1888. 



