From my friend Emily Sandberg of Charlottesville Virginia:

Green Gravel Green gravel your grass is so green.
She's the fairest young princess that ever I've seen
She rode on a black horse she rode on a gray.
She's locked in a tower, and she can't run away.

This was sung as part of a game like London Bridge or Oranges and Lemons. Two girls held hands and when the line "She can't run away, the hands dropped around the girl between them. Sorry! This isn't much help. My computer's full of gremlins.!