2 FIRST FORMS OF VEGETATION. 
now appears on the surface less extensive, as com- 
pared with the page, than the buried and partially 
obliterated layers beneath, though the characters be 
less grand and imposing. The earth has lost much 
of its primeval fire, and has toned down the rank 
luxuriance of its green and umbrageous youth ; but 
it still retains a considerable portion of the vigour 
which characterized it during the first great period 
of organized being—the period distinctively of 
herbs and trees. The whole face of the earth, and 
almost every object which belongs to it, is stiil 
strangely instinct with vegetable life. Coeval in 
its origin, it is everywhere present with its indis- 
pensable conditions. Burn down the forest, or 
plough the meadow, and from the new soil thus 
exposed springs up spontaneously a new crop of 
vegetation. Hew a stone from a quarry, and place 
it in a damp situation, and shortly a green tint 
begins to creep over it. Construct a fence of 
wooden rails round an enclosure, and in a few 
months it is covered with a thin film of primitive 
plants. Expose a pot of jam, or a piece of bread, 
or any decayed vegetable or animal matter, to 
the air, and in a day or two it will be hoary with 
the grey stalks and powdery fructification of the 
common mould. Dam up a stream or the outlet 
of a lake, and convert it into a stagnant pond, and 
in a few weeks its sides and bottom are covered 
