A geological occurrence where subterranean bitumen leaks to the surface, creating a large area of natural asphalt, smaller pools of such a substance surrounding the main one. Animals are usually unable to escape from the asphalt when they fall in, making these pits excellent locations to scavenge, but be wary, one wrong step and you're done for. One should be very careful when passing through, and the outskirts aren't much safer, littered with ancient trash and debris. Dangerous, but perhaps a useful place to scavenge..