1. Maps for assessing thermal maturity (conodont color alteration index maps) in Ordovician through Triassic rocks in Nevada and Utah and adjacent parts of Idaho and California [cartographic material] Yale Public content 1980. 2015-05-05T19:27:40Z. 2015-05-19T22:10:50Z. U.S. Geological Survey. English. cartographic image. Public. Nevada and Utah.