One “Great Coat” military button was recovered in 2006 from an early 1830s into the 1840s privy in Prairie du Chien, Wisconsin. The Great Coat button has an eagle and the letters “U.S.” on it and was generally associated with the greatcoat, an outer coat worn by military personnel during cold weather with a cape over the top. However, these buttons could also be worn on fatigue clothing, “overhalls,” and infantry soldiers’ coats when the proper buttons could not be obtained. The Great Coat button appears to be of a two-piece design manufactured until approximately 1840 (Wyckoff 1984:86).
Wyckoff, Martin A. 1984 United States Military Buttons of the Land Services 1787–1902. McLean County Historical Society, Bloomington, Illinois.