258 



JURASSIC. 



Except where otherwise stated, the zones are indicated by species of 

 Ammonites. The horizontal lines show the divisions of the Lias, adopted by each 

 author. See D'Orbigny, Prodrome de paleontologie, etc., 1850-1852; F. A. 

 Quenstedt, Das Flozgebirge WUrttembergs, 1843, ^""^^ Der Jura, 1858; Oppel, 

 op. cit. ; Wright, Q.J. xvi. 376, and Lias Ammonites (Paleeontograph. Soc.) ; 

 Judd, Geol. Rutland, etc., p. 89; Tate and Blake, Yorkshire Lias, p. 16. 



