Shale and fossils

[Tree!]

I like to go running through the hills here in Southern California and I've noticed a lot of shale. Is it worthwhile to bring my rock hammer with me next time and look for fossils in it? Does all shale carry fossils?

 

[Gaspipe]

No all shales are not fossil bearing. Check out your state geological society to see if shale in the area where you are going contains fossils.

 

[LanceHall]

In my experience large expanses of shale, especially the hard blue-gray shale, are generally fossil barren, like dead zones. I would focus on exposures where the shale is frequently mixed with limestone layers.