GEOLOGY. 549 



livened the foliage, not one edible fruit loaded its branches. 

 The echoes remained absolutely mute, and the branches 

 without a sign of life ; for no air-breathing animal had as 

 yet appeared amid these savage scenes of the ancient 

 world ! 



One might say, in fact, that there was then no animal life 

 to be seen, for amid so many remains of the coal flora, 

 which geologists have so admirably reconstructed, they 

 have only met with a few rare vestiges of one small reptile, 

 the Archegosaurus. This great contrast between the rich- 

 ness of the vegetable and penury of the animal kingdom is 

 explained by the great quantity of carbonic acid at that 

 time mixed with the atmosphere, which, though particu- 

 larly favorable to the life of plants, must have been fatal to 

 all animals endowed with active respiration. But though 

 the atmosphere was poisonous, the seas, on the contrary, 

 uniting together all conditions most favorable to life, were 

 peopled with shelled molluscs and fish. 



After having lent life to the primitive ages of the globe, 

 these strange forests completely disappeared in the lapse of 

 ages, and they have now become almost impossible to rec- 

 ognize, owing to the transformations they have undergone 

 in nature's immense subterranean store-houses. 



There can, however, be no doubt about the matter. It is 

 clearly the debris of these antique forests of our gradually 

 cooled-down planet that constitutes the coal of the present 

 time. Science, carrying its torch even into the dark regions 

 from whence this debris proceeded, has discovered all its 

 constituent parts. Amid the black and gleaming masses of 

 the coal strata abundant impressions have been found of the 



