4-Year-Old Girl Discovers Fossilized Dinosaur Footprint From Triassic on Beach in Wales A perfect fossilized dinosaur footprint was discovered by a 4-year-old girl on a Welsh beach last week. Scientists say the print dates back to the Triassic period, and are calling it “the finest impression of a 215-million-year-old dinosaur print found in Britain in a decade.” Lily Wilder and her father, Richard, were taking a stroll along the beach in the Bendricks when Lily spotted the print. Initially, the Wilders thought the print was left behind by an artist, but it was in fact a real grallator, or a three-toed fossilized footprint, left behind by a bipedal theropod dinosaur.