I was told by our Icelandic guide this ruins were just coral fences, used to keep the sheep inside after the round up in autumn. Today they use modern corals, so this abandoned one looks like some archeological remain. The only thing I wonder is how they get the sheep there since it is surrounded by steep walls. Not a place I would easily herd sheep to.
I adored this litle waterfall too in a wonderfull setting all around. A nice place to rest as well.