Go here to view a slide show on the evolution of Paricutin prepared by Scott Rowland. Sources of Information: Foshag, W.F., and Gonzalez-Reyna, J., 1956, Birth and development of Paricutin volcano: U.S. Geological Survey Bulletin 965-D, p. 355-489.
In 1971, the Twenty-sixth Amendment set the legal voting age at 18 for both US federal and state elections.
Subsequently, Oregon and Texas challenged the law in court, and the case came before the Supreme Court in 1970 as Oregon v. Mitchell. By this time, four states had a minimum voting age below 21 including Georgia, Kentucky, Alaska and Hawaii.