The text under the stamp on the margin of the sheet:
Sacred Bison Calling
As harsh winter descends, the explorers and Mandans hunt and kill over 50 bison, lured from their safe mountain hideaway by a sacred "buffalo-calling" ceremony of the Mandans. Clark documented the ceremony in his journal.

  On other stamps of the miniature sheet:
37 (c) - The Interpreters;
37 (c) - Teton Sioux Rob Men.

The Lewis and Clark Expedition (1804–1806) was the first transcontinental expedition to the Pacific Coast by the United States. The expedition was led by Meriwether Lewis and William Clark and had scientific and commercial goals – to study the area's plants, animal life, and geography, to discover how the region could be exploited economically, and getting an accurate sense of the resources in the recently-completed (in 1803) Louisiana Purchase.

Meriwether Lewis was an American explorer, soldier, and public administrator, Governor of Louisiana Territory in 1807-1809. Lewis was born in Ivy, Albemarle County, Colony of Virginia, on August 18, 1774 and died in Hohenwald, Tennessee, on October 11, 1809.

William Clark was an American explorer, soldier and public administrator, Governor of Missouri Territory in 1813-1820, Superintendent of Indian Affairs from 1822 until his death. Clark was born in Caroline County, Colony of Virginia, on August 1, 1770 and died in St. Louis, Missouri, on September 1, 1838.