The creature is from the Middle Cambrian Period (French: Cambrien moyen) and was found in British Columbia, Canada. I think the label says it was found on Mount Stephen or maybe it means Stephen Formation. See this web page on the Peabody Museum of Natural History at Yale University on the trilobite specimen they have. Theirs is from the Burgess Shale if I read that right.
The book, Life in Stone: A Natural History of British Columbia's Fossils by Rolf Ludvigsen, talks about this trilobite in the chapter The Trilobite Beds of Mount Stephen on page 61. He mentions that Charles Walcott in 1908 found so many of this species in the trilobite beds that he named the unit 'Ogygopsis Shales'. The trilobite reached of size of 12 cm so it was easy to spot and collect. As a result, many museums and universities worldwide obtained specimens. I am guessing the one in this picture was one of them. The author goes on to say that this trilobite became somewhat of an archetype of Cambrian trilobites even though it is rarely found elsewhere in the world. Learn more at this web link to the book.
