16 A Period in the History of our Planet, 



and morasses of the diluvial period, were, upon that sudden 

 change of temperature, deposited in a solid form. A crust of 

 ice soon covered the superficies of the earth, and enveloped in 

 its rigid mantle the remains of organisms, which, but a mo- 

 ment before, had been enjoying existence upon its surface. 

 In a word, a period appeared in which the greater portion of 

 the earth was covered with a huge mass of frozen water ; a 

 period in which all life was annihilated, every thing organic 

 upon the earth was put an end to, — the Glacial period. It is 

 this period of our earth, to enquire into the existence of which, 

 and its intrenchment upon our present epoch, I have long as- 

 signed myself as a problem ; whose existence the men of science 

 at first would not even give themselves the trouble to deny, till 

 the force of truth obtained a triumph over many, if not over all, 

 and constrained a recognition of the justness of what used to 

 produce only a compassionate smile as the lamentable aberra- 

 tion of an overstrained fancy. 



This glacial period is the epoch of separation betwixt the 

 Diluvial period, as it has been termed by geologists, and our 

 present period ; it is it which, like a sharp sword, has sepa- 

 rated the totality of now living organisms from their prede- 

 cessors, which lie interred in the sand of our plains, or below 

 the ice of our polar regions ; lastly, it is it which has left to 

 our times the testimonies of its former greatness upon the tops 

 and in the valleys of our Alps, — the glaciers. 



If, upon a fine calm morning of spring or autumn, we ascend 

 the southern declivity of the Jura, it frequently happens that a 

 thick mist still covers the plains of the valleys ; whilst above, the 

 enlivening sun already sends down his uninterrupted rays, and 

 the sky is resplendent with the loveliest azure-blue. Nothing 

 can the enquiring eye discover in the depths below. A white 

 cloudy mass, often glancing like silver in the sunbeams, covers 

 the large plain of Switzerland, with its smiling green, its cheer- 

 ful meadows, its blooming villages and cities. Scarcely does 

 a gentle undulation of the surface betray to the attentive ob- 

 server how lightly mobile is the veil whose thick web conceals 

 the covered beauties from his eye. Opposite to him glance in 

 the remote distance the colossal Alps attired in their snowy 

 gannents. Clear and distinct is their outline relieved against 



