Joseph Lincoln Gillson (1895-1964) was the chief geologist for the DuPont Company's Development Department from 1929 to 1960. As chief geologist he traveled all over the world making explorations in search of sulfur, ilmenite, fluorspar, barytes, celestite, and other raw materials, as well as conducting investigations in search of ground water supplies, foundations, and general site studies. This is a small collection that consists of a set of notebooks and related documents from Gillson's time working for the DuPont Company, as well as a set of papers and related documents from consulting projects he did during his retirement.

Thomas Ellwood Gillingham, Jr. (1912-2004) was a geologist, he worked as an independet consultant and for the Atomic Energy Commission and the W.R. Grace & Company. The collection documents Gillingham's career as a geological consultant. The collection is arranged into six series: W.R. Grace & Co.; Uranium Mining; Phosphate Mining; Reports; Education; and Reference cards.