An extremely rare copy of one of the most important maps in the history of science has been found - and it could be worth a fortune.
William Smith's 1815 drawing of the geology of England, Wales and part of Scotland was the first of its kind in the world, and was presumed to have been lost.
Only around 70 copies are thought to still exist.
This first edition is likely to be among the first 10 to have been produced, with its value possibly into the six figures.
It was found in the archives of the Geological Society, and happily coincides with the 200th anniversary of the map being drawn.
John Henry, chairman of the society's History of Geology group told BBC News: "It just wasn't where people expected it to be.
"I guess the person who put it away knew where it was, but then they left and that was it - it became lost."
It was found in a leather case which has preserved many of its striking colours.
Henry said: "The concept which enabled him to do the mapping and that drove him along almost obsessively was this realisation that specific fossils were unique to a specific stratum, and that you knew where you were in a sequence if you could see what the fossils were.
"That was the breakthrough."
Despite modern recognition, Smith was frequently ignored in life and spent some time in a debtor's prison after becoming bankrupt.