Allie:  This is not on the subject but  as a native Mandan, I was wondering if you had heard of the book
Encounters at the Heart of the World, A history of the Mandan People by Elizabeth Fenn, who won the
2015 Pulitzer Prize for History for writing this book about the Mandan people and their civilization.
I happened to see her on one of the CSPAN channels  a few days ago discussing the Mandan people and their
history.  
 Just thought I would pass it on.