There were some unusual features to the stone walls I saw the last time I was out in Delaware State Forest, NY.
As I followed the first stone wall up the hill, I came to a break. There was a rock pile in the break and another stone wall continued off in the same direction, but was not attached.
This photo shows the break in the wall. The view, off to the Southwest, is just visible in the background:
After the break, to the left in the photo above, the stone wall began to undulate. It went up, down, and even seemed to disappear in spots. Here is a photo showing the undulation:
And here are two photos showing the high, stacked portions of the wall:
This wall continued up toward the swamp on the Southwest side of the abandoned road which I commented on in the Boulders and Swamp post. I walked away from the stone wall to go around the swamp and, as I went to cross the road, I looked back toward the swamp and could no longer see the wall.
The next wall, on the Northeast side of the road, had two features that I found unusual. First, the wall was more prominent on the slope than at the top of the hill. At the top of the hill, it ran to the west, toward the swamp, but was not visible due to the snow. Second, there was a rock on boulder nearby. I couldn't tell, because of the snow, if the wall attached to the rock on boulder, but it was close enough to make it interesting.
Here is a picture of the wall coming up the hill. The view here looks off, roughly, to the North:
This is a close up of the rock on boulder that is just to the left in the photo above:
There were other vestiges of stone walls that I saw that day. They were so low and covered with snow that they weren't visible in photos. I'll go back out when the snow is gone to see what I can find.