Living in Odessa, I find myself back in these woods all the time. I found these a long time ago and figured it was about time I shared it with the public.
In the middle of the woods there are some ruins. Given Odessa's strong milling history, I can only assume it was something to do with that type of industry. Wether it was an actual mill or some other kind of related building, it is a very interesting spot to visit. However, I've done lots of research, but have not actually found anything about them yet.
The main part of the ruins and old foundations is down below in a big pit, below the main level of the rest of the forest. *Be careful around the rock face. It drops off rather abruptly* The old ruins have multiple rods, knobs, gizmos, and other various metal things protruding from them, as well as two long concrete pieces that lay there.
If you enter from the other end and walk down the path along the water, you will come across another section of the ruins that I had only just noticed recently. These can be found at N44 16.467 W076 42.997. These are very cool because there are metal rings in the ground and more concrete and foundations which look very aged and are completely covered in moss.
These ruins extend a lot farther than I thought and it is a lot of fun to explore the woods and see what else you can find and to realize just how big this structure used to be. I'm sure there's more out there for you to find, all you have to do is walk around and keep your eyes open.