Instructions
Talk to Beth at the southern-most area of the Fossil Guild to choose a dig site to visit. Pick the Bottomsup Bay location.
Continue north and avoid the Denture Sharks that patrol this area. If one of the sharks hits you, you will be forced to restart the area.
Walk along the ocean floor to the northern area. Walk along the stone formation until you can exit through a pathway in the centermost upper area of Bottomsup Bay.
Hit the destructible rock on the left of the upper area of Bottomsup Bay to open a hidden passage. Fall into the hole and walk due north to find the Sunken Pirate Ship. Enter the ship through the massive splintered hole in its side.