MESOZOIC TIME — TRIASSIC AND JURASSIC. 



785 



A restoration of a Plesiosaur, — a long-neckecl, somewhat Turtle-like, Sea- 

 Saurian, — reduced to -gL. the natural size, is given in Fig. 1317 ; and figures 

 of the vertebrae — here also biconcave — in 1318 a, h. Fig. 1319 represents 

 another species, Plesiosaurus macrocephcdus Owen, as it lay in the rocks. The 

 figures illustrate the long Snake-like neck of the species, the short body, and 



1319. 



f ".• 





s \ 



Eeptile. — Fig. 1319, Plesiosaurus macrocephalus (X35). Buckland. 



the character of the paddles. Pliosaurus is another genus. Out of 47 British 

 species of Plesiosaurids, 22 occur in the Lias, all but one pertaining to the 

 genus Plesiosaurus. The group continues into the Upper Jurassic, which 

 has afforded, in Great Britain, 12 species of Plesiosaurus, six of Pliosaurus, 

 and one of Dinotosaurus (Etheridge). 



The Coprolites (fossil excrements) of the Saurians are not uncommon ; 

 one is represented in Fig. 1322. They are sometimes silicified, and, notwith- 

 standing their origin, are beautiful objects when sliced and polished. 



Dinosaurs. — The earliest discovered of the Carnivorous Dinosaurs was 

 the Megalosaurus Bucklayidi (1824). The length of the skull was perhaps 

 two feet, and that of the body probably 30 or 40 feet. It appeared in the 

 Lower Lias and continued through to the Upper — a length of survival for 

 such a species that is most extraordinary, and indicates high supremacy 

 among its cotemporaries — if the apparent short life limit of other species is 

 Dana's manual — 50 



