The Black Loch just outside sanquhar has a small island in the middle which is what remains of a cranog. A cranog is an iron age round house built in the middle of a loch, either on a small island as this one was or wooden poles would be driven into the bottom of the loch and then a platform built between them. It is believed that they were built in lochs as a means of protection, probably from both wild animals and from other people.
For many years the Black Loch was just a remote loch on a moor above sanquhar and the island was thought to be just that, an island of no particular interest. However in 1861 A man from the town disapeared after being seen wandering alone on the moor. Thinking that he may have drowned the loch was drained and sure enough the mans body was discovered. Along with the body however a log boat, roughly carved out of oak was also found. There was also a causeway leading to the island and excavations revealed that it had been a cranog.
The log boat was left in a garden in Sanquhar where it rotted away but similar boats have been found in other lochs in the region and can be seen in Dumfries Museum.