Old Peter and Gordon song I believe. Also performed by travelers 3.
Former folk singer now sees the light and goes classical
Lyrics
In the land of Oden, there stands a mountain,
One thousand miles in the air.
From edge to edge, this mountain measures
One thousand miles square.
A little bird comes winging,
Once in every million years,
Sharpens his beak on that mountain,
And swiftly disappear.
Thus when this mountain is all worn away,
This to eternity will be one single day.
(Repeat from the beginning)
Will be one single day.
