This has to be just a medieval theory. Or a joke. But uncle says that Arne Saknussemm was a serious man, a genius, the details check out. There really is a volcano called Sneffels. And there really is a nearby mountain called Scartaris, and its shadow would rest on Sneffels in July.

Should I point out that volcanoes kill you? Or should I remind him that humans cannot survive the heat and pressure deep under ground? Or just follow him to our deaths? Or should I do something else?