The Allman Brothers Band, jamming at the Fillmore East, New York, March 1971, played this.
The resulting live recorded album was released in July of that year. Sadly, only a couple of months later lead guitarist Duane Allman was killed in a motorcycle crash near his home in Macon, Georgia. A year later, another member of the band, bassist Berry Oakley died the same way, less than a mile from the spot where Duane had crashed.
I recall that several of my friends said this track was "rubbish" I didn't agree with them then, and I don't now. I just love this. According to the band this was really jammed, it evolved there and then, on the stage of the Fillmore.
The origin of Mountain Jam was a song by Donovan,
I doubt that many of you will listen to it all. That's okay, I won't be offended.
I think this is a great example of improvisation around a theme.