There is an ancient astronomical instrument at Cahokia known as Woodhenge. This instrument would have been able to make very precise observations of the planets and stars and is one of the, if not the most complex of it's kind in the world. In Ontario we have the Brighton Stone Circles, which have yet to be fully evaluated. The archaeological Society is aware of it, but due to budget restraints no one has visited it yet. Compare the Circles to Woodhenge. There are many artefacts from the Gulf Coast in Ontario showing that there was an extensive trade network here to perhaps Mexico. Woodhenge is on the top and the site at Brighton is at the bottom. I plotted every stone on the map to the meter and hand drew it to scale. It is almost a kilometer from the one side of the map to the other side. North is to the right.  These configurations are very similar to ones seen in Great Britain and Europe. The stones weigh up to about 20 tons and many are hand drilled as can be seen on the background image on both sides of th page. The Birdstone is drilled with the same size drill which is much more narrow than hand drills used by 19th century mining in the area. There will be more discussion and related into posted on here soon.