1. Map showing distribution, composition, and age of Late Cenozoic volcanic centers in Idaho, western Montana, west-central South Dakota, and northwestern Wyoming [cartographic material] Yale Public content 1983. 2014-04-01T14:58:36Z. 2014-04-15T22:13:38Z. Luedke, Robert G. Dept. of the Interior, U.S. Geological Survey. English. Public. Idaho, Montana, Western, South Dakota, and Wyoming. Cenozoic.