Complex sentence: Archeological sites in Greenland and Newfoundland have uncovered structures very similar to traditional Scandinavian farm saunas, some with bathing platforms and "enormous quantities of badly scorched stones".
Split into simpler sentences: Archeological sites in Greenland and Newfoundland have uncovered structures very similar to traditional Scandinavian farm saunas. Some with bathing platforms and "enormous quantities of badly scorched stones".