This collection contains content identified by the library as Culturally Sensitive to Indigenous People(s): Slides and descriptions of Assiniboine and Gros Ventres (Atsina) dances and ceremonies. For more information please see the Newberry Library’s policy on Access to Culturally Sensitive Indigenous Materials.

Copies of Wellington's collection of color 35 mm. slides, and accompanying narratives, essays, and slide captions, documenting Assiniboine and Gros Ventres (Atsina) dances and ceremonies at the Fort Belknap Indian Reservation in Montana, where he served as BIA superintendent, 1947-1954. Ceremonies photographed include the Assiniboine Fool Dance (July 1952) and Sun Dance (1952), the Assiniboine and Gros Ventres Social Dances (ca. 1950), the Gros Ventres Feathered Pipe and Bundle Opening (Summer 1952), and the Sacred Flat Pipe Bundle (1952). There are numerous photographs of and extensive commentary by Al First Sound (Fool Dance), Frank Wheeler (Sun Dance), His Right Thumb, Iron Man II, and Jessie Blue Sky (Feathered Pipe Bundle Opening), and The Boy (Sacred Flat Pipe). There also are slides Wellington took of the Gros Ventres warrior Red Whip's war bundle and an essay he wrote regarding the same. Some of Wellington's essays were written as late as 1975.