Here's the photo I saw at Larry Harrop's site:
If this were the inkblot test, I'd tell you I see not one large turtle - with a very nice nutchal notch and marginal scutes- but two (perhaps mating?) turtles, but not limited to two because I see a stone with a pronounced v-shaped beak in there. But I also see a stone there that reminds me of a bear as well as a similar stone I know fairly well. Is there depression the size of a clam shell on top of this one in Rhode Island?
And, on the inkblot record, I'd say it wasn't evidence of somebody stacking stones for fence building or field clearing, but a carefully and artisticlly made petroform incorporating important cultural forms of the Wampanoag. Beyond the inkblot is a stone row as well. I think I see where it has been reworked into a gate, but I suspect more artistic forms can be found in it and that it perhaps was a fire break, wonder about it's boundaries and connection to other rows...