Cairns so far discovered in Schodack region

Late last fall while scouting out wooded area south of Green Avenue & Scott Avenue region of Castleton/Schodack I came upon a cairn. Essentially a man made pile of stones. Having traveled these woods as a kid I instantly remembered stumbling across this area before many yrs prior. In my estimation the cairn was originally constructed to be about three to three and a half feet tall. It has since had rocks fall or tumble off. The stones on the bottom appear of the flat variety with rounded smoother stones used from the base. Cairns are common throughout the world. Used for marking trails , gravesites in more ancient times and boundary markers to name a few more common uses. Sometimes a cairn is simply a stone pile left from over from farm field removal or from stone fence building. I found one such cairn in Dutchess County while investigating one of the many stone fence areas of that region a few yrs ago. I believe this particular cairn was a boundary line configuration. Nearby on another pass through the area many yrs ago I uncovered pieces of old brittle barb wire that ran for quite a distance. I contemplated deconstructing the cairn but decided to leave the original work in place as I should have. I doubt this is used as a marker anymore but leaving the original keeps the integrity of the setting. I estimate this cairn to be a minimum of 60yrs old. I have known of it's being in place for atleast 45 yrs. Boulders or trees were used often in yrs past. Some trees have surveyors spikes in them to show boundaries. these were common practices in the 19th and early 20th centuries. In England such places as the North York Moors have old concrete or carved stone structures some dating hundreds of yrs back. Probably in many cases boundary markers. One such edifice in North York is named Fat Betty { you can Google her}. I still have a photo of her I took yrs ago. As an afterthought there are two other small rock piles I have come across in Schodack region , one in wooded area of Maple Hill High School , another off Graw Rd. Both consist of appx 8 or so rocks. Their origin I don't at present have a speculation on. Perhaps debris collection.