[A little off-topic, but I wonder if he gets sick of the "The Island of Doctor Moreau" references (or if it actually isn't a common occurance).]
From the Wikipedia article on the Eastern Settlement (the largest of the Norse Greenland settlements): https://en.wikipedia.org/wiki/Eastern_Settlement
"In the Greenlandic Inuit tradition, there is a legend about Hvalsey. According to this legend, there was open war between the Norse chief Ungortoq and the Inuit leader K'aissape. The Inuit made a massive attack on Hvalsey and burned down the Norse inside their houses, but Ungortoq escaped with his family. K'aissape conquered him after a long pursuit, which ended near Kap Farvel. However, according to archaeological studies, there is no sign of a conflagration."
I don't know of any oral traditions about the Norse from Canadian Indians, though. Unlike the settlements in Greenland, L'Anse aux Meadows was just an exploration base that never developed into a permanent settlement. So unlike the prolonged periods of contact between the Norse and the Inuit, there might have been just a few isolated encounters between the Norse and the Canadian Indians that didn't leave enough of an impression to be preserved in oral tradition.
Anyway, the Dorset disappearance is usually blamed on the Inuit (whose oral traditions recount driving off the Dorset people), although they seem to have already been in decline when the Inuit arrived. It could be that Inuit pathogens may have partly been to blame, though we may never know.
The tale of indigenous extermination is not at all simple, and while European diseases certainly played a role, many other factors were also very important. One result of this was that some groups were wiped out almost immediately when Europeans entered the area, while others persisted and even thrived for some centuries after contact.
The most devastating effect of disease was likely in the West Coast groups, who left a large number of abandoned villages a few decades after first contact, where contact was very late (in the late 1700's) and colonization played a relatively small role in their destruction (the Interior groups were probably more strongly affected by colonization rather than disease, having had more contact with Eastern groups over the preceding centuries and therefore likely some immunity to disease.)
It's kind of racist to assume that Vikings "wiped out" a bunch of people simply because there is evidence that they were present in a certain place. "Viking" as a term has its origin in an expedition of some sort, whether to trade or colonize.
Hell, yes. Most cultures along the Western Atlantic seaboard have long oral traditions and solid historical evidence of devastating Viking raids.
>...whether to trade or colonize.
You forgot rape, pillage, burn, and slaughter. Then write songs about it afterwards.
The Greenland Norse probably sent expeditions to the Canadian islands and coast to get timber for a few centuries at least. An Icelandic document records that in 1347, a ship that was returning from "Markland" came off course and ended up in Iceland. Markland along with Helluland and Vinland is one of the Norse names given to regions in the North American coast and islands. So there could well have been opportunities to encounter Inuits who expanded to Northwest Canada by the 13th or 14th centuries. But even the Norse themselves haven't left many records about such expeditions or encounters with other peoples.
In comparison there are no historical sources that talk about pre-columbian communication between old-world and american civilizations, and no archaeological evidence either. The word "pyramid" is indeed used by later times to describe buildings both in America and in Egypt, but apart from a similar basic shape, they are fundamentally different in architecture and use.
The only reason to assume pre-columbian communication is basically that it would be cool if it were true. That is not good enough for historians though.
Square pyramids are what you get when you make a mound out of rectangular dressed stone. Making cones or other types of pyramids out of dressed stone is much harder because they demand more complicated shapes.
The sweet potato, on the other hand, does indicate at least some incidental exchange between the Americas and Polynesia: https://en.wikipedia.org/wiki/Sweet_potato#Origin.2C_distrib...
I don't agree with that, myself -- a pyramid is a fairly simple shape, and could easily have occurred to different groups of people.
As well I agree about pyramids being simple. Another problem with communication theory is that Mayans used different counting system.