A Treasure Map shows the player where to find buried treasure. While hovering the mouse over the map in your inventory the treasure map shows a certain area that has treasure and will have a red X on it. You will need to compare this area to your actual map and find its location with the few spaces it shown on the treasure map. You will require a shovel to get this buried artifact. Place your expedition on the "X" tile and use the shovel to dig. This will consume your shovel and give you the treasure. It does not consume the map. As they said, "X marks the spot."
A treasure map does not consume any weight capacity and is removed after expedition.
The player may still dig up the buried artifact even if the treasure map has been traded or discarded beforehand.