298 THE TRANSFORMATIONS OF THE ANIMAL WORLD 



the Megalosaurus, a formidable carnivore with a 

 crenellated scimitar-shaped canine tusk, which 

 existed in Europe during the whole Jurassic and 

 Cretacean periods. It must have emigrated to the 

 South at the middle Cretacean period, for it is 

 found with insignificant modifications in the Chalk 

 of Madagascar, of India, and of Patagonia. 



It is the same with another herbivorous and 

 plantigrade Dinosaur, the Titanosaurus, which 

 dwelt in the British Isles at the lower Cretacean 

 epoch, and which survived in Languedoc and 

 Provence down to the Rognac strata, that is to say, 

 to the extreme end of Cretacean times. The 

 Titanosaurus has been discovered in the upper 

 Chalk of India, Madagascar, and Patagonia, and 

 these discoveries appear clearly to indicate that 

 this gigantic Dinosaur followed the Megalosaurus 

 in its migration to Southern lands. These various 

 facts are, therefore, an assured indication of two 

 migrations having occurred from the North to the 

 South, one at the commencement of the Trias, and 

 the other towards the middle Cretacean. 



If we continue to follow the evolution of the 

 continents during the Secondary era, we shall especi- 

 ally have to show the gradual parcelling- out of 

 the two great continental masses of North and 

 South. I have already stated that the Boreal 

 Continent comprised two distinct expanses at the 

 end of the Primary Era : an Asiatic expanse, the 

 Angara Continent, and a European - American ex- 

 panse separated from the first by an arm of the sea 

 in the Sub-Ural region. The complete absence of 

 palseontological documents relating to the Land of 



