They're not found together or anywhere near each other. The first item was found in a campground and appears to me to be fire fighting related. They're the only ones I know of that use 5 sided bolts, but, ?? The bolt is non-magnetic stainless steel and the housing it's in is some sort of aluminum/magnesium/pot metal alloy. It's not broken off that I can tell. There are numbers on the octagon shaped end "P 35?" and "304 C" is on the head of the bolt. Something ferrous was probably under the head of the bolt at one time. The rusty remnants are still clinging there. The second item was found in a field with LOTS of history, although, I don't think this is particularly old. There again, it's made of some sort of aluminum or pot metal. Looks like it was cast in a 2 piece mould as there are seams on the sides that line up with the centerline of the hole. The hole is not threaded (or ever was that I can tell. The whole thing is slightly tapered and looks like it was a wedge fit into something at one time.