Click on your original picture (top of this page,) and you notice the "gravel" is red? Yes - it is volcanic cinders - pavement is red in places and the cinders spread on ice and snow are red. Lava flow at the next curve that Highway 97 goes around, heading towards Weed CA (yes that is the name of the town, named after Abner Weed) and I-5. There is potential for treasure hunting on the original railroad grade but - it is now all private property, and access would be difficult. That grade was abandoned in the 1920's. Lots of rattle snakes, loose cattle (county is open range - fences are to keep cattle out, not in), and dead deer along the roads from all sorts of vehicles colliding with them. Did I mention bears?