Gerard Troost (March 5, 1776 – August 14, 1850) was born Gerardus Troost in Den Bosch, Netherlands. While he originally went into medicine with a Doctor of Medicine degree from the University of Leyden and a Master of Pharmacy from the University of Amsterdam in 1801, Troost shortly after served in the army as a medical officer, where he was wounded. He then turned from medicine to study mineralogy at the School of Mines in Paris, which led him to settle in Philadelphia, Pennsylvania. He lectured on chemistry and mineralogy and served as president of the Philadelphia Academy of Sciences before joining the short-lived New Harmony cooperative settlement in Indiana. Troost arrived in Nashville, Tennessee, in 1827, joining the University of Nashville as a professor of mineralogy and chemistry; while still serving as a professor, he also served as the State Geologist of Tennessee from 1831 to 1850. Troost died of cholera in Nashville in August 1850.

Julius T. Ducatel (1796–1849) was born in Baltimore, Maryland, and studied at Saint Mary’s College and in Paris. He lectured in geology, chemistry, and pharmacy at the Mechanics’ Institute of Baltimore, the University of Maryland, and Saint John’s College, all in Maryland. Ducatel was appointed to conduct geological surveys for a new Maryland state map from 1832 until 1841. He continued to make geological expeditions throughout the 1840s.

Gerard Troost was also an acquaintance of Thomas Jefferson, and in July 1818 forwarded correspondence to Jefferson through Julius Ducatel.