i was born in Pasquotank Cty, NC in the early 1950s. i was told by my great-grandmother, who was born in Tyrrell Cty, NC in the mid 1880s---and she was told by her mother---this song was originally about the Pasquotank River. originally this song, so it has been told to me, goes like this---
"Down on the banks of the Pasquotanky
(note: originally the inhabitants of the Pasquotank River basin were a tribe of Native-Americans known in the late 1660s as the Pas-ka-tanki Indians of the Tus-ca-ro-roe Nation)
Where the bullfrogs jump from bank to banky
(further note: the Albemarle Sound area, which the Pasquotank River drains into, once was a wetland and was teeming with wildlife, including bullfrogs though not so much anymore and there was loads of vegetation that no longer exists for them to jump around all over on the river and sound)
and on and on as many have written----so goes the rest of the song.

i believe what i am telling you is more than likely true.