This collection, which spans the years 1934 to 1974, deals primarily with the Powell centennial celebration in 1969, family ties with 19th century explorer and conservationist John Wesley Powell, as well as Schnacke's successful efforts to secure a Powell commemorative stamp marking the 100th anniversary of the historic 1869 voyage down the Colorado River. Also included is the commemorative stamp issued on August 1, 1969 at Page, Arizona.