It's leftover asphalt from when roads ran through the canyons many years ago when the area was still supporting a huge silver mining industry. When the price of silver dropped, the silver mines went out of business. There are still a lot of deserted mines in the area you can explore, some go way in and some go up and down hundreds of feet via multiple levels. I used to explore them with friends when we were in college and some opened into huge "rooms" that were often 75-100' tall. They are interesting to explore if you use a little common sense.'80Toad said:Whats with the concrete looking stuff??
Good looking trip.