and adventurer, collateral descendant of the Gabrielli who were lords of Gubbio in the Middle Ages. Culture Gubbio is home to the Corsa dei Ceri, a run held every year always on Saint Ubaldo Day, the 15th day of May, in which three teams, devoted to Ubald, Saint George and Saint Anthony the Great run through throngs of cheering supporters clad in the distinctive colours of yellow, blue and black, with white trousers and red belts and neckbands, up much of the mountain from the main square in front of the Palazzo dei Consoli to the basilica of St. Ubaldo, each team carrying a statue of their saint mounted on a wooden octagonal prism, similar to an hour-glass shape tall and weighing about . The race has strong devotional, civic, and historical overtones and is one of the best-known folklore manifestations in Italy; the Ceri were chosen as the heraldic emblem on the coat of arms of Umbria as a modern administrative region. A celebration like the Corsa dei Ceri is held also in Jessup, Pennsylvania. In this small town the people carry out the same festivities as the residents of Gubbio do by "racing" the three statues through the streets during the Memorial Day weekend. This remains an important and sacred event in both towns. Gubbio was also one of the centres of production of the Italian pottery (maiolica), during the Renaissance. The most important Italian potter of that period, Giorgio Andreoli, was active in Gubbio during the early 16th century. The town's most famous story is that of "The Wolf of Gubbio"; a man eating wolf that was tamed by St. Francis of Assisi and who then became a docile resident of the city. The legend is related in the 14th-century Little Flowers of St. Francis. The Gubbio Layer Gubbio is also known among geologists and palaeontologists as the discovery place of what was at first called the "Gubbio layer", a sedimentary layer enriched in iridium that was exposed by a roadcut outside of town. This thin, dark band of sediment marks the Cretaceous–Paleogene boundary, also known as the K–T boundary or K–Pg boundary, between the Cretaceous and Paleogene geological periods about million years ago, and was formed by infalling debris from the gigantic meteor impact probably responsible for the mass extinction of the dinosaurs. Its iridium, a heavy metal rare on Earth's surface, is plentiful in extraterrestrial