First: those mummies that supposedly contained nicotine, etc., have been debunked as forgeries and contaminated samples.
Second, by "contact," I mean contact enough for the myths, stories, and legends of the "new" world to reach back to Plato in Periclean Greece.
i highly recommend people go to
www.skepdic.com, or even just snopes and look some of the stuff you keep quoting up, instead of just accepting it without question. A little research goes a long way.