Eventually, however, the team was finding scores of fossilized paddlefish in the site—a rarity for Hell Creek. Other fossils included other marine creatures, terrestrial vertebrates, trees, branches, and plants. The 1.3-meter-thick sedimentology didn’t look like the Hell Creek or Fort Union formations; it was something that looked sandwiched in between, deposited very rapidly, like something you’d expect from a tsunami. The geochemistry of the area included pieces of ejected material associated with impact events, like shocked quartz and iridium-rich matter. Iridium is only found either deep in Earth’s core, or within meteorite materials. Subsequent dating techniques confirmed the ejecta matched well with the expected timing of a seismic shockwave to hit the region.