It looks like a dry creek bed at that lat lon
Interesting.
https://www.google.com/maps/place/39°32’31.2%22N+121°30’36.0%22W/@39.542,-121.5121887,596m/data=!3m2!1e3!4b1!4m5!3m4!1s0x0:0x0!8m2!3d39.542!4d-121.51