MINIATURE PERN CAVERNS. 
207 
how this little world of moss arid lichen was 
formed. Let him, however, but think a moment, 
and the big stone on which he has pensively 
seated himself will tell the story of this fairy 
cavern. 
Time was when the hedge-bank was dry and 
bare of vegetation, and no water trickled over its 
sides from the level above it. But Nature is never 
still. Her moods are always changing; and from 
time to time she makes the silent hills musical 
with the voice of some water spring which she 
causes to flow. The spring bubbles up, runs across 
the gentle crest of the uplands, and in its course 
falls over the face of our hedge-bank, permeating 
and moistening its substance. Vegetation follows 
the course of the stream, embowering the hedge- 
bank in leafiness. Its volume increases, its flow 
becomes perennial, and soon the action of the 
streamlet loosens one rocky mass in the stony em¬ 
bankment. The earth beneath by the same action 
is partially washed away, and the boulder drops 
from its place into the roadway. The water which 
had streamed over its surface now flows into the 
newly-made fissure, and makes it moist and cool. 
