I have no idea if this is Book of Mormon peoples or not. But it was at the same time as the Book of Mormon peoples lived, and supports the idea (long disputed, but in keeping with what's described in the Book of Mormon) that ancient inhabitants of this land had organized governments, large cities, culture and traditions and economic systems beyond the "small peaceful tribes and clans" model that was pushed for decades (and still is taught in schools, I've discovered). But this is a city of 200,000 (get that? As big as Provo and Orem combined), thriving sometime between 1000 BC and 200 AD. (One of the cities in the area flourished from about 1000 to about 400 BC--just exactly the timeline the Jaredites were in their prime and then killed each other off--you remember they crossed with the Mulekites, who arrived sometime after 600 BC, but not too long after).
Anyway, cool research done by fellow Mormons.