While in the fountain, look around near the stone blocks for the glint of the COG Tag.

They are outside of the fountain, during the fountain battle at the end of the chapter. Before heading out through the recently opened door, turn left while facing the door, look down and the tag is along the wall. Once the room has been cleared, a door will open. An Emergence Hole opens up in between two pieces of cover. You'll reach a ruins area with some Drones. Look in the grass between the stone blocks for the COG Tag. Approach it, and while facing the omen turn right. In the second area of this chapter, notice the Crimson Omen on the stone block at the far end. If you want this COG Tag, you must get to it before all of the enemies are dead, because if you don't you will be forced into the chapter end cutscene. As soon as you are at the top of the stairs, turn left and retrieve the COG Tag in the corner. In the last area of this chapter, where the helicopter lands to pick Dom and Marcus up, as soon as you step into this area turn left and head up the steps. Behind this pillar is a box of ammo and the COG Tag. Facing these pillars, turn right and notice the Crimson Omen on the standing pillar. From the door where the Locust broke through turn around and go straight until you reach the two downed pillars near the end of the room. In the first chapter, you will reach a point where some Drones break through a door. On the ground at the foot of this sheet of metal is the COG Tag. This sheet of metal contains the Crimson Omen symbol. Once you are out of the cell (it does not matter whether you choose left or right), in the initial area, look in the distance for a sheet of metal.

Gears of war cog tags