Tough Luck

This one is found almost at the end of the level Tsavo Highway. When your coming out of the tunnel and your going on the high type thing look to your left. There will be a wall/divider. go to it and jump through one of its gaps and fall to this mountain thing. Or if you perfer go to the right and just walk down the mountain if you chose the left path then keep walking towards this kinda support beam thats grey. If you took the right path then keep walking left towards the support beam thing. There is two support beams next to each other. Jump to one of these things sticking of the first support beam and to other same thing on the second support beam. From there jump on to a ledge that the skulls will laying on.

Sorry no pics