https://github.com/davepinch/pinchy.cc/blob/master/content/streams/the-manure-pile/8/the-monster-dragged-the-body-out-and-closed-the-door.md
The Olympics are made up of obducted clastic wedge material and oceanic crust. They are primarily Eocene sandstones, turbidites, and basaltic oceanic crust.