10,000 Year Old Structure Found

The discovery of this mystery rock formation (an assembly of now seven rocks) were thought to be compound perched erratics (found in northern North America), where 2 or even 3 rocks happened to land on top of each other, leaving behind a natural structure. However, when geologists and archaeologists saw images of the object - a 1,000 pound, elongated and south pointing rock sitting on baseball-sized stones at each end, which in turn, were resting on a massive, several thousand pound slab on top of the ledge, they expressed doubts about its natural origin. Foremost, the straight edges and lack of roundness, as would characterize rocks scoured by glaciers, prompted them to discard the erratic theory. But could the structure be of human origin? If so, how could that be established? Subsequent dives closely examined the structure for any signs of the use of tools, decorative images or other irregularities, to no avail. The thick layer of silt covering the vertical surfaces suggests that certainly within living memory no human has ever touched the structure.