Professor. General correspondence (1911–1957); papers (1923–1950) regarding the University of Oklahoma chapter of the geology fraternity, Sigma Gamma Epsilon; correspondence (1925–1942), membership lists, and expense records (1934–1935) from the Oklahoma Academy of Science; manuscripts, reprints, and research correspondence (1932–1934) from Decker’s research on the geology of Oklahoma and on grapholites; correspondence (1925–1946) and notebooks (n.d.) concerning the Methodist Episcopal Church in Norman, Oklahoma; correspondence and printed material (1931–1952) concerning the University of Oklahoma; and correspondence and printed material (1913–1955) from geological associations and other universities.