Hey Gary, Hope you got out to look around today. Sunday is National RockHound Day!

Well, the way that big black rock is all layered and broken jagged edges makes me think it's a big piece of Shale. But it looks like there may be some old chert nodules trapped in it, or even a vein of some hot lava rock like Rhyolite running next to it. Just for example; the Shale rock could've formed 50 million years ago and the lava rock could've cut thru it during an eruption 1-2 million years ago. (If there is any lava rock?)

I found this great little article on the geology of Southwest Oregon. Highly suggest you read it several times and let it sink in.
https://muleapi.blm.gov/sites/blm.gov/files/tablerocks_geol_intro.pdf