This very rare and beautifully produced Pattern marks the earliest appearance of the broad eagle, known conventionally as the Sonora eagle. The style perhaps derived from early Republican bronze, but it was used only in the North West of the country, at the Sonoran mints of Alamos and Hermosillo; Culiacan in Sinaloa; Guadalupe y Calvo and Chihuahua; but never at the other Republican mints.