Much of the base of Caithness is made of flagstone - a commodity that when quarried has been shipped across the world. Pavements in many of the world's cities are made of Caithness Flagstone. Flagstone quarries still exist but many like this one at Achscrabster are now largely part of our industrial heritage.
A feature of this and other local quarries was the use of windmills for power. The surviving Achscrabster stump, one of several still existing, is about 12 ft diameter at the base and 13 ft high, and was probably operational pumping water in c1860.