The song lyrics are here, with the following:
The black brook calls It sings a chorus While the gathering swells The flames grow tall Right before us As drums keep pounding And the masses now are fusing Bodies pressed and tangled As we revel in confusion Our inhibitions thrown into the fire
Wiktionary lists the following meaning for the noun:
- a body of running water smaller than a river; a small stream.
- a water meadow.
- low, marshy ground.
Does this word really mean the soil, ground in this context?