552 THE UNIVERSE. 



a decidedly high temperature, which, combined with great 

 humidity, favored the luxuriant vegetation which developed 

 itself vigorously under the influence of the luminous bright- 

 ness of the sun. 



The more ancient of the secondary rocks have interested 

 geologists on account of the innumerable remains of shells 

 which they contain, and owing to which they have been 

 named conchylian. 1 



At the time when these strata were being deposited lived 

 one of the most extraordinary reptiles that we know of. It 

 was a kind of monster toad, so enormous as to equal an ox 

 in size, and the teeth of which, resembling the windings of 

 a maze, have procured it the name of Labyrinthodon. The 

 strata of this ancient epoch have contributed to teach us 

 some even of the anatomical details of this animal, having 

 preserved the impressions of its footsteps. On the same 

 beds have been observed the prints of three-toed feet, con- 

 sidered by some geologists as traces of the first birds that 

 animated our globe. 



To this period belong the Jurassic strata, which play so 

 important a part in the formation of the Jura Mountains, 

 from whence they derive their name. This formation is rich 

 in animal fossils, which give it quite a special character. It 

 may be divided into two sections, the Lias and the 

 Oolite. 



The liassic seas fed numbers of animals, and their deposits 

 are distinctly characterized by the gryphseas, ammonites, 



1 This era most probably means here the coarse, shelly limestone of the forest 

 marble, and the great oolite ; possibly also including the muschelkalk of German 

 geologists. TR. 



