Discovery By Accident

For about sixty years trilobites in the cement quarries in Metaline Falls, Washington were explored in a 10m thick zone near the bottom of the fossiliferous lower bedded member of the Metaline Fm. In 1973 I studied and measured the deformation structures for Washington State University Master's credit. I sat down on a ledge to eat my lunch and found two Poliella trilobites where I sat. This was about 20m above the lower zone. I started looking in the strata above this and discovered trilobites that were different and older. Most of the trilobites in bottom of fossiliferous zone had large ranges that made the age difficult to determine. The deformation of the trilobites from the near bottom zone made identification challenging. There are areas where deformation is not as significant. the photo is from the 73m level of 130m thick fossiliferous section. this is the #4 stop of the April, 2024 GSA field trip.