Amber waves of grass, indeed, and another shot of a different arched rock. I'm not entirely sure what type of grass it is, sadly. I didn't care to take any samples of it even though it is fairly common. Looking at some brief photos I thought it may be some Purple three-awn or California melic, but I'm pretty sure I'm way off base.
EDIT: after some more research, I've decided it is either American marram grass (Ammophila breviligulata) or it's invasive sister, European marram grass (Ammophila arenaria)
And thus ends my shots of Mendocino, hope you enjoyed!