The first one can be found at the bottom of a well. After you finish the conversation with Vargas and he uncuffs you, you’ll see a plateau with a well in the distance. Descend the stairs, slide down the rock, climb the ledges on the left to get to plateau. Jump into the well and look for an alcove inside. You’ll find a Panamanian Cat Pendant under it.
The other treasure is in the huge tower. As soon as you start climbing it using the ledges, look up. You’ll see a row with three windows – the rightmost will be barred. Climb through one of the other ones. On the lower floor, next to one of the pillars to the right, you’ll find the Navaja Folding Knife in a pile of rubble.