MEMOIR OF WERNER. 
29 
united by a cement. It is in the midst of these 
commotions that life first begins to appear. Carbon, 
the first of these products, now shews itself. Lime, 
which was associated with the primitive rocks, be- 
comes more and more abundant ; and rich deposites 
of sea-salt, one day to be explored by man, fill large 
cavities. The waters, again becoming tranquil, hut 
having their contents changed, deposit beds less 
thick, and more varied, in which the remains of living 
bodies are successively accumulated, in an order not 
less determinate than that of the rocks which con- 
tain them. At last, the final recession of the waters 
spreads over the continent immense alluvial collec- 
tions of moveable substances, which form the ear- 
liest seats of vegetation, of culture, and of social life. 
Metals, like rocks, have had their epochs and their 
successions. The last of the primitive, and the first of 
the secondary rocks, have received them abundantly. 
They become rare, however, in deposites of more 
recent formation. They are usually distributed in 
particular situations, in those veins which seem to 
be produced by rents in the rocky masses, and filled 
after their formation ; but they are by no means of 
equal age. The last formed are known by their 
veins intersecting those of older date, and not being 
themselves intersected. Tin is the oldest of the 
whole ; silver and copper the most modern. Gold 
and iron — those two masters of the world — seem 
to have been deposited in the bowels of the earth 
at all the periods of its formation ; but at each pe- 
