Lyric discussion by Azraeldrah 

Cover art for Stonehenge lyrics by Spinal Tap

Dareka you're mostly right. Although it was particularly inspired by the more 'occult' bands, infact the performance is said to be based on a similar misshap that black sabbath apparently had to endure whilst performing a song with the same name.

Of course i may be missinformed but who cares. Its a great song and a great movie either way.