Stock Pile Rock Pile? Possible Lighthouse?

Nobody at this point really knows what this tall mysterious structure is - especially me.

But it somehow has a familiar feel, the carefully constructed walls and all, still standing after 500 years of abandonment, washed by tides and hurricanes and messed with by looters...

...this fellow lives there, but had nothing to say about it.

Jan Brown said it might be like a Lowes or Home Depot, a stockpile for construction projects, but then again it could have been like a lighthouse or beacon perhaps, but the truth is that only the people who built it really know - and like that Iguana, they don't have much to say...

I couldn't help but be drawn to what looks like a wall, above that looter's pit:

Here's the detail from the site map, my own two centavos added:

When I returned for a second visit, Jacob and I walked on and around it. This somewhere around the top left hand corner of the structure to the left in the site map - and hopefully the photo captures that rounded feeling. One of the other larger structures, a platform mound that was probably an "elite" residence, had rounded corners that Jan said showed perhaps a later time of construction...

(approx. lower left corner, structure to left in site map)

(Above and below: slightly different camera angles)

There were sort of "points" to the outer edge, sometimes like a small circular stack:

Jacob plucked a loom weight from where the tide washes the edge:

It was "solid walking," no rocking when walking around the structure...

...and Jacob's opinion was that the whole thing was carefully constructed:

And I felt it was too:

 A link to some info by Dr. S. J. Mazzullo, Department of Geology

at Wichita State University: http://ambergriscaye.com/marcogonzales/