Harvest 6 dragon vertebra on The Shattered Weir. These are ground spawns located all around the Shattered Weir. All spawns are located by larger, easily visible fossils. Confirmed locations are:
To get out, move along the ledge on the western side until you get to ( -770, -460, 199 ) Copy/waypoint -770, -460, 199 where you can find a clickable rock.