Some kids find cool pebbles and some even a rare coin, but a 4-year-old girl in Wales in the southwestern U.K. may have blown all discoveries out of the water after coming across a dinosaur footprint on the beach.

Lilly Wilder was on a walk with her father and dog near Bendricks Bay in southern Wales when she caught a glimpse of an unbelievably well-preserved fossil of this prehistoric creature. The imprint is thought to date back 220 million years and has excited paleontologists worldwide.

"It was on a low rock, shoulder height for Lily, and she just spotted it and said, 'look Daddy,'" Sally Wilder, Lilly's mother, told NBC News on Saturday.

"She (Lilly) is really excited but doesn't quite grasp how amazing it is," she said, adding that it was actually Lilly's grandmother that encouraged them to reach out to experts with the photos they had taken.

Measuring 10 centimeters (4 inches) in diameter, the footprint's exact owner is still a mystery, but experts have conjectured that the dinosaur was about 75 centimeters tall and 2.5 meters (8 feet) long.

Cindy Howells, a paleontology curator at Amgueddfa Cymru - National Museum of Wales, said the dinosaur was likely a slender member of the dinosaur family that walked on its two hind legs and ate small insects and animals.

"It’s one of the best-preserved examples from anywhere in the U.K. and will really aid paleontologists to get a better idea about how these early dinosaurs walked," she said.

"It really is stunning preservation ... You can see every detail of the muscles and where the joints are in the foot," added Howells.

The fossil will now be transferred to the National Museum Cardiff to be further examined and preserved. The museum said Lilly and her classmates will be invited for a showing once the pandemic is over, and Lilly will be listed as an "official finder."

The National Museum Wales said in a statement that there were no fossilized bones from this 220 million-year-old dinosaur, but similar imprints discovered in the U.S. have belonged to the dinosaur coelophysis.

Bendricks Bay is also known for being an important paleontology site housing "dinosaur tracks of the Triassic Period" and "crocodilian-type reptiles."

The discovery follows a recent find by archeologists in Argentina, who found the fossilized remains of a gigantic, 98-million-year-old sauropod for what may be the largest-known dinosaur.