http://maps.google.com/maps?hl=en&ie=UTF8&ll=36.409126,-117.704086&spn=0.428826,1.148071&t=k&z=11

If you look at the Google aerial imagery, to the East of Lake Owens you will see dark terrain with some reddish tints. This is an area of volcanic lava flows and cinder cones.

Although, I am not familiar with the history of activity for the area. But there has definitely been volcanic activity in the past.

Brian