An engineer was researching a rock formation when he made a more significant discovery - a rare dinosaur footprint dating back 140 million years.
Jamie Codd, a geotechnical engineer, found the prominent mark when carrying out research near Hastings. The fossil is an important find for palaeontologists as it is further evidence of how dinosaurs once roamed Sussex. Complete fossil specimens are rare, so it adds valuable information to their research.
Mr Codd was visiting Lee Ness Ledge, near the Hastings Cliffs to Pett Beach Site of Special Scientific Interest on Saturday when he came across the footprint.
Mr Codd, 27, of Second Avenue, Hove, said: "I was absolutely stoked when I found this. I knew some prints like this had been found before but they are certainly not common and I would never have imagined I'd find one in a million years."
It is believed to have been made by an Iguanodontype dinosaur - an upright creature common in the Weald area during the Early Cretaceous Deltaic period.
The first dinosaur ever to be discovered was an Iguanodon, which was unearthed in Cuckfield in 1820.
The print has been verified as genuine by Professor Ian West, a lecturer in geology and sedimentology at the University of Southampton.
He said earth had probably filled the dinosaur's original imprint and solidified, like a mould being filled.
Recent storms are thought to have washed the mould away and left the cast on the cliff wall.
Mr Codd is doing a Masters Degree in engineering at Brighton University and works for Owen Williams, a highways engineering company.
The find supports evidence that Sussex was once a rich habitat for dinosaurs. In 2001, amateur geologist Geoff Toye, from Slinfold, was looking for insects when he found a dinosaur 130 million years old. He made the discovery of a lifetime while taking part in a field trip at a brick pit near Horsham. What he uncovered was one of the most exciting dinosaur skeleton finds of recent years, the remains of an iguanodon.
The specimen was so rare and scientifically important that the site was guarded 24 hours a day while experts carried out painstaking excavations. Mr Toye, 49, donated his find to the Natural History Museum.
In 2004, the fossilised toe of a 30-tonne diplodocus washed up on a Sussex beach, proving for the first time that the world's biggest land creatures roamed the county. Fossil collector Frank Hamill discovered the toe on Bexhill seafront.
Until then, the diplodocus, one of the giant planteaters of the Jurassic era, was thought to have lived mainly in what is now the United States