This Wednesday is the first annual National Fossil Day, and in honor of this exciting occasion, read up on this small fossil that supports a big timeline of the history of Washington State: Murex sopenahensis (pictured above), is a type of rock snail fossil that can be found in the Burke Museum’s marine fossils collection. Although it is only 3 centimeters tall, this 40-million-year-old murex snail fossil provides evidence that the climate of Washington State was much warmer than it is today. Murex snails are carnivorous and only live in in subtropical seas; at the time this snail lived, the present location of Interstate 5 would have been beachfront! Murex snails would have lived in the Seattle area surrounded by palm trees and relatives of banana plants. However, as the world’s temperatures cooled, these tropical snails became extinct on Washington’s coastlines, leaving only their fossils behind.