Picture of the Day - My Three-Bone Miocene Fossil Find

Today while hiking Pine Mountain in Atascadero, CA, I discovered this stone on the trail and immediately noticed the bone structure on the top-most flatish petrified bone. Given I was challenging myself headed up the inclined trail I did not stop to check it out until I summited at which point I realized it was actually three bones, probably from the same smallish Miocene marine mammal such as a seal or dolphin. All three bones are heavily silicified, but especially the bottom-most two as pictured here.
Photo by Kim Patrick Noyes (all rights reserved).