***Their great ceremony of the Sun Dance described by Catlin under the name of Okeepa ****
have you read Catlin's two volume work, NORTH AMERICAN INDIANS.
It will be worth your time. A great study!
George Catlin Public Domain Image archive.. U.S. Government database..
http://americanart.si.edu/catlin/highlights.html
Other Federal archived images on Indian Cultures.. Public Domain..
http://scout.wisc.edu/Archives/SPT--AdvancedSearch.php?vn=Classification&vv=%22Indians+of+North+America+--+Pictorial+works%22