— 183 — 



cation of their vertebrce fully developed, we find the 

 gigantic frog-like Labyrinthodon, the great land 

 Dinosaurians, ( Zanclodou ), the swimming Sea- 

 reptiles ( Northosaurus, Simosaurus, Placodus. ) 



We come next to the Jurassic Era ( from the 

 deposits of the Jura Mountains ) which Period is 

 subdivided into the Lias ( name given to the parti- 

 cular calcareous clay of the Jura deposits ) where we 

 find legions of belemmites, — ammonites, and penta- 

 criuites so justly named " Sea-Lilies," the Vertebrae 

 as well as the Invertebrse show a fuller development 

 in the Lias, here are the whale-like Monarch of the 

 Ocean, the Ichthyosaurus and the Plesiosaurus ( the 

 Lizard-Crocodile-like fishes. ) 



From the Lias we come to the Oolite Era, which 

 has been so called after the limestones found in its 

 strata being of the shape of eggs. In this Era, Cy- 

 cadeous plants cover the ground, among which roam 

 the frightful Dinosaurians ( Megalosaurus, the gigantic 

 land Saurian ) and small Mammalians ( insectivorous 

 quatrupedes), (the Plagiaulax, etc.) The Sea abounds 

 in various forms of Molluscs, myriads of ammonites 

 and nautili, numerous generic forms of ganoid fishes 

 now more ichthyic in their aspect. The Oolitic Eras 

 may be considered a separate epoch of Geological 

 Life, in some of its minor features an analogy of 

 existing beings may be found, but in its entirety it 

 stands alone. 



From the Oolitic, we pass over to the Cretaceous 



