A mysterious triangle

After I finished putting out the sand skink boards Thursday and I was making my way to the fire (albeit the wrong one), I encountered what I can only conclude was some kind of makeshift cooking platform. There were three pieces of iron arranged in a triangle around a concrete block with a round piece the size of a frame under a gas burner. I'll retrace my path sometime and haul out the rest of it. This is on the northeast corner of the south tract, which is heavily wooded. There are also a lot of downed trees that have fallen over the past four years. After the sand skink project is over, I probably need to come up and clear what I can of these obstructions.