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.
The decision resulted in states being able to maintain 21 as the voting age in state and local elections, but being required to establish separate voter rolls so that voters between 18 and 20 years old could vote in federal elections.