I'm a new member seeking help identifying some marks we discovered on a vertical post on a circa 1800 barn attached to a 1651 historic register home in my town (Dwight-Derby house). There are a number of beams inside the barn with typical Roman numeral marriage marks, but these unique marks have us puzzled. The mark in question is a perfectly straight line with a perfect semicircle on top of it and at its midpoint, kind of like the "Kilroy" character looking over a wall, if you know what I mean. These lines are too perfect to have been chiseled. They seem to have been made by hitting some straight edged tool into the beam and then a half round chisel or gouge held at 90 degrees to make the semicircle. They are located where 2 beams join this post. This is mostly a scribe rule structure. Does anyone know what, if anything they mean? Their origin? Many of the beams, including the one with these marks appear to have been re-used in this barn from some other structure. This property is on the historic register and we would like to be able to state with some certainty what this mark means, as it will be on display. I tried to attach a picture, but couldn't figure out how to do so, short of creating a website or loading Mozilla. If you think you may know the answer but need to see a picture, please e-mail me and I'll send it to you. Thanks for your help!