Marks left by men involved in the building of the Caledonian Canal 200 years ago have been found during work to replace lock gates on the waterway.
Scottish Canals has drained a 7,293m (23,927ft) long section of the canal to provide safe access to the gates at Fort Augustus and nearby Kytra.
Several stonemasons' marks have been found carved into stone of the walls that line the canal.
The marks would normally be hidden underwater.
Scottish Canals said: "There are a few of them in the lock flight.
"Each stonemason was required to have an individual 'mark' to sign his work.
"Counting the marks was often used to work out how much work each mason had done and how much they should be paid."