I am hoping someone can identify this iron object. Picture inserted. It is a square based pyramid of about 18 inches each base edge and about 10 inches tall from surrounding sand. No idea how deep it goes. The faces appear to orient to face magnetic NSEW. It is located at about the typical high tide level on marsh edge in Beaufort SC at eastern end of Hancock Street just behind the Tidalholm (or Big Chill house now very finely restored). National Geodetic survey map offers 32 deg 26 min and 9 sec N and 80 39 50 W. I suspect a geodetic marker however this one is NOT CK0883 as seen on NGS sat image as that is SW of pyramid by 30 or so feet.
Wow! That sure is interesting!
Is there a local historical society that you could contact ?
You’ve covered my guesses. Some sort of benchmark?
All I can think of is that alien craft they dug up in “The Tommyknockers”. Be very afraid.
The SC Lowcountry has long been known for paranormal events.
@string said:
The SC Lowcountry has long been known for paranormal events.
Got that right earthling…
Survey marker?
That stone shape is a common boundary marker placed to show the corners of a piece of surveyed property or the borders of a city or town. For instance, there are 40 of them around Washington DC which were placed at the orders of George Washington. When they are first set they usually have information like dates and place or personal names carved on them but that wears away over the years.
A local historical society would likely have information about why that one is there or would be interested to see photos of it and know its location if they are unaware of it.
It’s an iron dry bag. Before we had neoprene to seal stuff, we’d put our spare clothes and supplies in one of these, weld it shut, and use a hoist to get it into the kayak. 
A Liliputian pyramid.