How to find the last two pieces of gold in The golden lake?

In the cave where the torches are and spider mounds, before the room with the buttons, and machinery, there is a rope bundle you have to clear and it's behind there, and then once you've cleared that, there's s one more which will be revealed after look down line and you'll see a second chest sparkling. They are not just gold pieces but chests, believe me, I was down to need two "gold pieces as well, thought I'd try to help

One is behind the fire on the cave and the other one I'm still looking for it

How I found them all, was look for chests, energy vessels, or other shiny things on the edge of the fog and then find out how to get through. You’ll find it all eventually, you just have to look very carefully.