This gives me a never before thought of possible explanation whenever I read about discoveries of mass grave or fossil sites. Of course for fossils to form, or bones to be preserved, conditions must be just right. Meaning there can't be scavengers in the area. Perhaps lightning could kill a large group in a swamp or bog however where conditions can be just right. Just a new idea to me.
My Cree family from the Hudson Bay and James Bay coasts would often tell stories about how powerful lightning was and to respect it. The trees are short and stunted there. I have heard stories about people and animals getting struck by lightning along the coast. To this day, my Aunt still trembles and goes through a ritual whenever a thunderstorm passes through. She lives inland far from Hudson Bay and James Bay, but she still fears the lightning.
If you are interested in learning more about the Cree culture or to hear some of their stories and legends, click on the link below: