Warhammer 40,000: Space Marine

This list taken from http://gamenac.com/warhammer-40000-space-marine/servo-skulls

All due respect to them

quick note the skulls do not appear in the same sequence as they are listed in the pause menu of the game.

1 Audio Log: Workshift 465 2 (Chapter Start) Before entering the building, destroy the ork barricade opposite of it, on the other side
2 Journal: Guardsman Alexander 2 (Chapter Start) After the conversation with Leandros and the ambush by gretchins, it’s on a path to the right, by some sandbags
3 Audio Log: Medicae Station Ventris 2 (Trenches) In the second bunker in the trenches, after meeting with Lt Mira
4 Battlefiedl log: 2nd Lt. Mira 2 (No Man’s Land) After heading into the building from the courtyard, near the grenades in a small room
5 Jounal: Guardsman Alexander 2 (No Man’s Land) After exiting the building, it’s in the first bunker to the left
6 Duty Log: Transmechanic Petronius 3 (Chapter Start) Once inside the fortress, to the right, destroy the barricade next to the ammo, and inside the room
7 Battlefield Log: 2nd Lt. Mira 3 (Armory) Off the elevator on the lower floor, the skull is ahead of you by some ammo
8 Audio Log: Medicae Station Ventris 4 (Train Station) End of the first walkway, before heading to the train, turn left
9 Journal: Guardsman Alexander 5 (Chapter Start) After seeing the Crane and fighting the orcs in the lower area, head behind the crate to the right of the ramp leading out
10 Encrypted Report: Inquisitor Drogan 5 (Cargo Bay) After taking the elevator down, on the walkway towards the manufactorum
11 Audio Log: Workshift 465 6 (Chapter Start) On your way to the elevator up, to your left is a walkway going down with some grenades
12 Encrypted Report: Inquisitor Drogan 6 (Chapter Start) Before activating the bridge and heading to the exit door, head to the ramp to the left of the door
13 Duty Log: Transmechanic Petronius 7 (Chapter Start) In the sewers, after the second big encouter with the works, in the left sewer entrance (the exit is in the right entrance)
14 Audio Log: Medicae Station Ventris 7 (Chapter Start) Before the elevator and after dropping to the catwalks, behind a barricade on the left
15 Audio Log: Medicae Station Ventris 8 (Chapter Start) Before entering the street, after dropping into some rubble, in a hallway behind you
16 Encrypted Report: Inquisitor Drogan 8 (Chapter Start) After the encounter with the Shoota Boyz and entering the building, in a room to the right
17 Audio Log: Workshift 465 8 (Chapter Start) Upstairs from the previous skull, in a room on the left
18 Personal Message: Worker Nathaniel 8 (Street Warfare) First underground tunnels, in an area to the right with ammo
19 Encrypted Report: Inquisitor Drogan 8 (Streeet Warfare) Before the ramp up, after the fight with Orks in the big room, to the left of the ramp
20 Personal Message: Worker Nathaniel 8 (Jump Pack) After jumping up to the first platform, follow the path to the right, then jump up to next level
21 Encrypted Report: Inquisitor Drogan 8 (Jump Pack) After the first encounter with Orks, head past the crashed Rok, and to the right of the stairs
22 Audio Log: Workshift 465 8 (Jump Pack) After the fight with the Wierdboy; head down the stairs to the right, near some grenades
23 Journal: Inquisitor Drogan 8 (Jump Pack) After exiting the area with the Weirdboy, before heading down the stairs, jump over some rubble straight ahead to reach it
24 Audio Log: Workshift 465 8 (Jump Pack) In the next area, it’s two levels above you on your right after climbing up the small stairs
25 Personal Message: Worker Nathaniel 9 (Kalkys Outskirts) Head left of the destroyed bridge, at the end of the canyon
26 Audio Log: Medicae Station Ventris 9 (Kalkys Outskirts) Where the canyons converge is a crashed Valkyrie, you’ll find it nearby
27 Battlefield Log: 2nd Lt. Mira 9 (Kalkys Outskirts) Before heading up the ramp after the canal area – it’s to the left of the ramp
28 Duty Log: Transmechanic Petronius 10 (Chapter Start) Head right at the intersection instead of left, after destroying the pair of servo turrets
29 Duty Log: Transmechanic Petronius 10 (The Labs) In the smaller lab with a turret, destroy it to find some ammo inside as well
30 Journal: Inquisitor Drogan 10 (Security Room) Before inserting the power source at the center of the room, head towards the side walkway with the destroyed door after clearing the remaining Shoota Boyz
31 Personal Message: Worker Nathaniel 12 (Chapter Start) After entering the pipe from the bridge, go upstairs and turn left, at the end of the hallway and behind the barricade
32 Journal: Inquisitor Drogan 12 (Chapter Start) Follow the hallway in the opposite direction, behind another barricade past the stairs is a large room with ammo, grenades and an Iron Halo
33 Battlefield Log: 2nd Lt. Mira 12 (Chapter Start) After the Chaos and Ork encounter, up the stairs and in a room to the right on the upper floor
34 Journal: Guardsman Alexander 12 (Enemies Aplenty) After reuniting with Lt. Mira, after fighting in the large room, near the back wall by some ammo
35 Journal: Inquisitor Drogan 12 (Enemies Aplenty) After the elevator, head down the hallway till there’s a hallway to your right, to the right of that hallway is a small area
36 Duty Log: Transmechanic Petronius 12 (Bastion Primus) Back to the original hallway from the elevator, at the end, down the catwalk by weapons and a shrine with a Plasma Gun
37 Journal: Guardsman Alexander 12 (Bastion Primus) After breaking from your squad and Lt. Mira, in a trench near a weapons cache
38 Battlefield Log: 2nd Lt. Mira 12 (Bastion Primus) Before the fight with the Warboss, under the bunker, behind some crates near the ammo cache and final door
39 Journal: Inquisitor Drogan 13 (Chapter Start) Before exiting the catwalks area, through the doorway on the left before the ramp
40 Journal: Inquisitor Drogan 13 (Free the Titan) After exiting the elevator, in the left corner of the room
41 Journal: Inquisitor Drogan 13 (Free the Titan) After breaking from your squadmates, go up the ramp to the left of the elevator, in a sideroom
42 Inquisitor Attacked 13 (Free the Titan) To the left of the walkway where you encounter the Chaos Drone, in a small room
43 Journal: Inquisitor Drogan 15 (Chapter Start) After exiting the elevator, to the right of the ammo and weapons
44 Personal message: Worker Nathaniel 15 (Traitor’s Arena) In a destroyed pipe to the right of where you fight some Renegades, before heading outdoors
45 Inquisitor Attacked 15 (Traitor’s Arena) After fighting some Bloodletter Daemons, before heading up the stairs to the next area, near the weapons
46 Journal: Inquisitor Drogan 16 (Ascent) After the first encounter with the Chaos Psyker, in a hallway, on the left
47 Journal: Inquisitor Drogan 16 (Vertigo) After exiting the hallway, on a floating platform above with a Chaos Space Marine
48 Inquisitor Attacked 16 (Vertigo) After an encounter with a Chaos Drone, in a small room to the right