Another interesting item found is this fitting on a metal post.  The top portion is a solid bar, and is corroded where it meets the fitting.  The fitting appears to be cast pipe -- a "reducing tee" fitting.   The fitting in turn is mounted upon another metal piece, but it is not clear if this is a pipe or a solid bar.  It is not clear what this device is for.  Maybe a water line, or maybe a "tie down" of some type.  If the footings were for steam equipment, then water would be very important for their operation.