Originally Posted by
big john
I don't know of any volcanic activity near there. I think it was scraped but I don't know why. There is a landfill above there and there are a lot of weird geologic formations around.
It's near Val Verde, north and west of Magic Mountain.
I'm going to stick with my earlier guess that it was a dirt source for filling/leveling. However, maybe not for just for the road, but for home site development.