The Yuan Dynasty Jade Animal is the seventeenth treasure that can be found in Uncharted 2: Among Thieves.
The Yuan Dynasty Jade Animal is found in Chapter 3 - Borneo. What you're looking for is closer to the beginning of the area where you began the firefight than the latter half. You're seeking out a log on the right side of the watery path going up and to your right, where another isolated location can be found. This area will give you the treasure you seek -- it's atop what appears to be an ancient wooden barrel that has somehow found its way into this shallow water.