Robbins Hill (2) Chelmsford - some lovely details

For me the neatest thing at the Robbins Hill site, described in the previous post, was this niche made from burnt (rusted) stones around a white feldspare "cue ball"In another spot there was what could have been a broken down platform pile, or it might have been a ledge of rock all broken up into cobbles from the heat of the fire. But all these rocks looked burnt. Then someone made a little nest on top of the pile. The little nest looked relatively new although the platform (if that is what it was) was as old as the rest of the site - pretty old I would guess.
How about this spot? The pointer rock sticking up from the wall is the same burnt looking rusted rock that is in all the piles here. Overall this site on the southern shoulder of Robbins Hill is a small site with perhaps 20 rock piles piles.