These relatively large beetles were crawling on and underneath redwood bark. They were ~2-2.5 cm long.
Here are a few more views, including a close-up of the head, eyes, and jointed antennae. There was something interesting about the way the beetles were slightly shimmery, and how that brought out a hint of shimmeriness on the bark.
Unfortunately, I'm not sure what species they are yet, but perhaps someone can assist with an identification?