Well, that's part of the mystery. I labelled Manicougan impact crater because it is a clue, due to it's alignment with the three circles in Hudson Bay and in the Gulf of St. Lawrence. The circles follow the contours of the coasts. The mystery is finding the answer to the alignment and the perfect arc and perfect intersections. The first step is finding out what The Nastapoka Arc is, and then study Manicougan. But here's a clue about the clues, Manicougan is somewhat a red herring and misleading. But, it is part of the ultimate answer.
