Thousands of people have walked over the remains of 385 million-year-old fish in the slab of Caithness flagstone outside Inverness Town House.
James Ryan, who works at a National Trust for Scotland museum dedicated to Highland geologist Hugh Miller, spotted the fossils while on a wander.
He said: "Whilst fossil fish are known in pavements in cities like Glasgow and Edinburgh, to my knowledge these fossils seem to have gone amiss."
...
Mr Ryan said: "These fossils in the paving slab are the remains of ancient fish dating to around 385 million years ago - around 140 million years before the first dinosaur.
“Caithness flagstone was laid down as sediment over a period of thousands of years at the bottom of a giant freshwater lake which stretched from the Moray coast up north to Orkney and Shetland."
The fish date from the Devonian period, which are thought to include evidence of a fin.
Mr Ryan said: "I brought them to the attention of a palaeontologist who studies these fossils and they were not aware of them.
"The staff at Inverness museum likewise were not aware of these fossils either."