https://phys.org/news/2019-01-year-old-eastern-north-american-quinoa.html

The charred seeds, about 140,000 in total, were discovered in Brantford in 2010 during a required archeological assessment conducted by Archaeological Services Inc. prior to site development. The Tutela Heights site, which has since become a housing development, yielded some stone tools, post holes, debris and the chenopod seeds. Jessica Lytle, a co-author of the resulting research paper, was one of the assessors who did the initial seed analysis and brought them to Crawford for further analysis, having studied with him at UTM. Their findings are published in the October 2018 issue of American Antiquity. The analysis took time, especially given the number of seeds and the need to document whether the whole collection was from the same crop.

"This discovery raises more questions than it answers. We had to consider whether the seeds were only traded here or grown locally," says Ron Williamson, Ph.D., of ASI, another co-author. "We also had to consider whether this was the beginning of agriculture in the province. It appears not, because we don't see any evidence of local cultivation. If it were grown in the region, we would have expected to see seeds of the crop in other pits around the site, but they were confined to this specific pit. We also don't see any sign of agricultural weeds or stone tools that may have been used for cultivation.