A year or more I sent some pictures of the rock piles I saw on a hike from the Walpack Center to Thunder Mt. on the Walpack Ridge Trail. Last week I went back to hike the other trail and I had the GPS with me so I included a map. The hike starts on the Military Road Trail which has quite a history and the Walpack Ridge Trail is off of that. Then I took the other part of the Walpack Ridge Trail back to the Military Road Trail and went back to the Walpack Center. Here is a link about the Military Road Trail:
There was lots of activity over the years. I even found some large clay pipe pieces in the creek near the bridge to get to the carns.
I've hiked in lots of places in the Delaware Water Gap NRA, from the Gap up to High Point. I've seen many old roads, rock walls, dams, etc., this is the only place I've see rocks piled up like this. Here is a link to the slide show I just sent out of the hike, I only put one rock pile on it because I had so many photos to include.