Dog Skull Mountain stands at 4024 feet and is located in the desert peaks south of Vegas. You are looking for a glass jar wrapped in duct tape at the summit cairn. The summit register is on one side and the geocache is on the other side of the register. Please note - while you should be relatively safe on the mountains and in the canyons between Dog Skull Mountain, North Twin & South Twin, if you are approaching from Las Vegas Blvd, be aware that a lot of people shoot guns in this area. I suggest driving past the open desert areas before hiking, hiking on weekdays, when there are less people shooting and/or wearing bright colors, so you can easily be seen. If approaching from Hidden Valley, I don't think you'll have this problem.