A surface block is like a brick with a metal bolt imbedded into it. This is a great road to cycle along instead of the busy A9. Parking was not a problem for us since we had bikes. Not great parking if you are in a car so please be careful and leave kids and pets in the car. This surface block took us a while to find. Please leave the stamp in the container for others to use and bring an ink pad if you want to use the stamp in your book.
Trigpoints are the common name for "triangulation pillars". These are concrete pillars, about 4' tall, which were used by the Ordnance Survey in order to determine the exact shape of the country. They are generally located on the highest bit of ground in the area, so that there is a direct line of sight from one to the next. By sitting a theodolite (an accurate protractor built into a telescope) on the top of the pillar, accurate angles between pairs of nearby trigpoints could be measured. This process is called "triangulation". A major project to map out the shape of Great Britain began in 1936. The network of triangulation pillars, with accurately known positions, led to the excellent OS maps which we enjoy today.
