The stage is placed on the same area that 'Hayes', but from the moment of the underground river, so I took the fragment of the map used earlier :).
Run along with Ann and go against the stream to the bigger cave (you should remember it). Now, leave the cave using the wooden catwalk (through the waterfall).
Proceed further through destroyed rooms until you will reach the destroyed gate.
You'll see two dinosaurs fighting on the glade. Make advantage of enemies' inattention and run right to the place behind pillars - you'll be safe there.
Use bones and spear to kill remaining dinosaur (you'll need a few hits, but eliminating him shouldn't be a problem).
Now, run on the other side and enter the balcony with fire (if the other reptile returns, fight with spears). Fire the spear up and clear the way upwards, to the jungle.
You shouldn't lose the way, because you've walked here earlier. The level ends in the place, where 'Hayes' started. During the road, you'll notice that Kong is searching for you.