How to complete quest "cold shoulder"?
I bet its the higher one (because that's the one I missed too :D), you can access it only by going back to the "main cave" (where you come from) then following the kind of road that ends up broken over the area where you were looking for the slices. When on the edge of the road's end look down and it should be on a rock below you.
You can watch this video (at 10:38) that give you all the location