From ‘Notes on the folk-lore of the northern counties of England and the borders’ by William Henderson (1879).
The following verse, though said to be popular in [nurseries in] Berwickshire, is unknown elsewhere:--
Rainbow, rainbow, haud awa’ hame,
A’ yer bairns are dead but ane,
And it lies sick at yon grey stane,
And will be dead ere you win hame.
Gang owre the Dramaw and yont the lea,
And down by the side o’ yonder sea;
Your bairn lies greeting like to dee,
And the big teardrop is in his e’e.The Drumaw is a high hill skirting the sea in the east of Berwickshire.
The New Statistical Account suggests Habchester is the place for this rather black rhyme.
There’s a nice aerial photo of the fort at Treasured Places, where you can see it crossed by a wall, one side ploughed down and the other still with its banks and ditches.