The trail committee is doing something funny over there, with soil disturbances and a few stacked rocks next to the trail. One place I saw a trench of disturbed soil about 6 feet long. Can't figure that one out.
I did not see too much but, again, there are always a few traces.(closer)
Perhaps more would have been visible, if not for the snow. In the case of the next structure, the only mound-like object I saw, I am afraid more visibility would have revealed it as not ceremonial.
This is down in the southeastern-most part of the place, perhaps on private property. From there I swung back around to the east, passing this:
and then I saw one more interesting item as I headed back north.(closer)
Each of these different structures was familiar in its own way but isolated and lacking context.
As I headed out, I fell through the ice on a puddle I didn't notice. While floundering and trying to get out without falling through again, I didn't notice cutting my hand and seriously bruising my foot. I mostly felt embarrassed - not really a Jack London character.