This is now the "Official" Skull Location Thread. Post your finds here.
Major Spoiler Alert!!!!!
You must be using the new graphics to see the skulls.
Located on the rock where the Pelican crash site is on Silent Cartographer. It's at the top.
This skull can be found on the level Truth and Reconciliation in the large hanger before the brig (which has the Covenant drop ship that Keys will pilot at the end) on the lower level. The skull is inside the door farthest from where you initially enter the room and to the right. The door is locked and only lets enemies enter the fight, so you need to run for the door when it is opening lest you should lose your chance.