Die flaschengrün-metallisch schimmernde Wand, sich steilend, sich höhlend, sich neigend und schaumgelöst niederprallend in immer wiederkehrendem Fall

From Thomas Mann

does it mean 'rising and falling' or something of the like? Something like 'undulating' maybe?

What about 'schaumgelöst'? Does it mean 'covered in foam', 'free from foam', 'mixed with foam'?? I can't think what 'gelöst' could mean here, perhaps something to do with dissolving?

Thanks