I remembered the words from the song. Two of the parts of the 4 part round. Remember this is grade school.
Part One: (Kind of a chant) This is the land that I love, I love. This is the land that I love, I love.
Part Two: (A lilting choral part of the round.) I hear America singing, I hear her singing, varied carols I heeeeaaarrr.
Part Three: ?
Part Four: ?
Does anyone remember this song? Or am I making it up and thinking it’s a memory?
Although this evokes no memories of gradeschool singalongs, the lines you are stating in part two are directly from a Walt Whitman poem.