1. Transcontinental geophysical survey (35°-39°N) magnetic map from 100° to 112° W longitude / [cartographic material] Yale Public content 1968. 2012-10-10T13:43:42Z. 2013-03-18T22:22:41Z. Zietz, Isidore, 1919-. Dept. of the Interior, U.S. Geological Survey. English. Public. Great Plains and West (U.S.).