In the eighteen-eighties, workers carving a path for Canada’s first transcontinental railway began to notice odd creatures in the rocks. A geologist working for the railway, which would run through the Kicking Horse Valley, in British Columbia, examined the rocks and was astounded. The shale of the nearby Mt. Stephen was overrun with the fossilized remains of extinct marine animals, particularly trilobites, which look like a cross between horseshoe crabs and centipedes. Word of the Mt. Stephen trilobite beds spread, and Charles Doolittle Walcott, a prominent fossil expert and the onetime director of the U.S. Geological Survey, came to investigate. In 1909, exploring north of the mountain, he found shale filled with a variety of fossils that had never been seen before.