21. Brother's Keeper
Note: The second journal note from Chapter 20 is actually found in this chapter.
Mughal Enamel Bird
At the first rope grapple point after finding Sam's footprints, swing back in the direction you came from to jump up to a higher ledge.
As you climb and swing forward, you'll come across an abandoned campfire, and the final note is found by the skeleton to the right.
At this point you should unlock the Lost History trophy.
After a slide and swing following a bridge collapse, you'll crawl into a cave with climbing wall sections to the left, and the treasure on the lower level to the right.
When you attach your rope to a wooden structure and lower yourself above a galleon, slide down to the end of the rope then carefully swing up to the small opening to the right of the stone overhang then climb inside to find this Crash Bandicoot reference.
At this point you should unlock the Relic Finder trophy.
Once you've survived the long slide into the water, look to where two waterfalls are coming down then go behind the right hand stream to find the treasure in a cave.