The Flush Plate Ordnance Survey Bench Mark Nr 1813, in the old bridge at Ponsandane; there is another plate at the bottom of Lariggan Hill, but it is damaged. Please do you know of any others in the area? These used to be used by locking in a baseplate on the theodolite and used as a trigonometrical station base. I suspect with satellite systems, these are now redundant, save for historical reasons, but I stand to be corrected.
