48 MEMOIR OF LAMARCK. 



at last obliged to renounce the labour as fruitless, 

 satisfied that, however important it would be to 

 foresee the state of the weather, it depends on 

 causes far too remote and complex to be made the 

 subject of calculation. 



Speculations of an analogous character regarding 

 the formation of the globe and the changes which it 

 has undergone, were laid before the public, in 1802, 

 in a work entitled " Hydrogeology, or Researches 

 on the Influence exerted by Water on the Surface 

 of the terrestrial Globe," &c. &c. His opinions rest 

 on the assumption that all composite minerals are 

 the remains of living beings. According to him, 

 the seas are continually hollowing out their bed in 

 consequence of being unceasingly agitated by the 

 tides, produced by the action of the moon ; in pro- 

 portion as the bed deepens in the crust of the earth, 

 it necessarily follows that their level lowers, and 

 their surface diminishes; and thus the dry land, 

 formed by the debris of living creatures, is more 

 and more disclosed. As the land emerges from the 

 sea, the water from the clouds forms currents upon 

 its surface, by which it is rent and excavated, and 

 divided into valleys and mountains. "With the ex- 

 ception of volcanoes, our steepest and most elevated 

 ridges have formerly belonged to plains, even their 

 substance once made a part of the bodies of animals 

 and plants ; and it is in consequence of being so 

 long purified from foreign principles that they are 

 reduced to a siliceous nature. But running waters 

 furrow them in all directions, and carry their mate- 



