What I wrote:

"My experience with this song is that the line "Oh Mary, don't you weep" is sung after the first line of the verses given above {and the first line of other floating verses that fit this pattern}"
-snip-

The more I think about this, I think I'm thinking about another song. The verse is sung and then the chorus {refrain} is sung "Pharoah's army got drown-ded". Oh, Mary don't you weep".

**

Here's another verse to "Oh Mary Don't You Weep" -I'm sure about this..really and truly:

One of these days 'bout 12 o'clock
This old world's gonna reel and rock.
Pharoah's army got drown-ded.
Oh Mary, don't you weep.