One last word on stone and spirits which will at least have the merit of being a plug for a book that I haven’t yet read but sounds very promising – and it has a foreword by Graham Hancock:
Spirits in Stone, The secrets of Megalithic America
by Glenn Kreisberg
I don’t know if any mention is made of gravestones in it but note that this practice is extremely ancient with meanings that go beyond the modern idea of "marker". And yes, I have read about it. Quoting someone out of context to make them sound stupid only serves to make you appear rather obnoxious. It’s also a personal attack that has no place in any serious forum. And no, I don’t want to know that it is the/your norm here.