What is the symbolic significance of the mountain?Lord of the Flies by William Golding

In Lord of the Flies, the mountain, obviously the highest
point on the island, is, therefore, symbolic of the pinnacle of life.  The boys place
their fire atop it, but this fire goes out and is stolen by Jack and the other hunters. 
Simon and Ralph and Jack and Roger climb up, fighting the snake-like creepers in order
to discover exactly what it is that looms in the air over this mountain, but Simon is
killed when he brings his message that the beast is within them all.  Releasing a
huge pink granite "death rock," the stone--"that token of preposterous time"--from near
the top the mountain, Roger sends Piggy reeling to his
death. 

Thus, the mountain can be seen as the pinnacle of
life and civilization, a pinnacle that the boys are prevented from reaching by the
nature of the flaws that are inherent in their characters, flaws from which there is no
escape.