Precambrian-Ordovician Nonconformity outside Burleigh Falls, Ontario
Across Ontario there are several outcrops where you can see the precambrian-paleozoic nonconformity. One of these is approximately 3km West of Burleigh Falls, Ontario, on Peterborough Road 36.
A nonconformity is a missing part of the geological column where sedimentary rock was deposited on a crystalline igneous or metamorphic rocks. Here our igneous rocks are from the Grenville province of the Canadian Shield, and our middle Ordovician rocks are from the Gull River and Shadow Lake formations (part of the Simcoe group). The point of contact between these rocks represents approximately 550 million years of missing geological history, the Ordovician rocks are only 450 million years old.
I said I was going to give you coordinates for the site. After seeing it, and comparing it to what Google StreetView has from a few years ago, I'm not going to do that. Tourist erosion is a real problem in hobby geology. It shouldn't take long for anyone interested to locate the outcrop with this information. If you find yourself there, please respect those who will come after you, and please don't be a nuisance to the people who live nearby.