I learned "Above a Plain" at Camp Barree, Hemlock Girl Scout Council's resident camp in Barree, PA in the 1970's. We were taught it as follows:

Above a plain of golden green
A young boy's head is plainly seen.

Refrain:
A hoya hoya hoya yaaa, swiftly flowing laaabeee
A hoya hoya hoya yaaa, swiftly flowing laaabeee.

Oh wo, 'til not his lifted head
'tis Ifca's castle's spires instead.

Refrain

And for our pleasure it was made
This grand old castle, deep in shade.