1. Nebraska-Kansas Hebron quadrangle Yale Public content 1898. 2011-05-24T13:41:05Z. 2015-10-21T14:59:49Z. Geological Survey (U.S.). U.S. Geological Survey. English. Public. Clay County (Neb.), Fillmore County (Neb.), Nebraska, Nuckolls County (Neb.), and Thayer County (Neb.).