The Iron and Oil League was a minor league formed in the 1890s and existing from time to time in the 1890s and 1900s. In 1898 one of the teams was a black team, the Celeron Acme Colored Giants.
It is sometimes abbreviated as IOL.
Honus Wagner and his brother Butts Wagner played in the league in 1895. Among other major leaguers, Jack Glasscock and Buck Weaver also played in the league.
References
Iron and Oil League Wikipedia(Text) CC BY-SA