It seems quite feasible to me that at some time this rock formation was happened upon and used as a "foundation" for some entirely man-made structure. As I said in a previous post, if it could be shown that this "wall" turned corners and formed an enclosure which followed some evident plan then I would have to think again. Does any such evidence exist?
I have no opinion whatsoever about the existence or otherwise of a furnace or metalworks on the site. There seems to be evidence that there was and I am happy to accept that. I have the greatest respect for the "testimony of honest laymen" believing that, in general, they simply report what they find - "A little knowledge is a dangerous thing" but "no knowledge" I usually consider a safe bet! No doubt, very naive of me.