That lady's voice was beautiful, as beautiful as any folk singer of the last 100 years.
I grew up with PPM's children's album (Peter Paul and Mommy). Her singing on "Leatherwing Bat" makes the hair stand up on the back of my neck to this day. She just nails it to the floor.
And I love her interjection of an old playground rhyme:
I won't be my father's Jack/
I won't be my mother's Jill/
I'll be a fiddler's wife/
And fiddle when I will
into a medley of traditional childrens' songs.
She was much better than she needed to be — she could have just been the pretty blond one and sung in a breathy little girl voice, but she chose to be a real singer and artist instead.
RIP Mary, it's sad to see the 60s idealists fall.