In early life he was in business as a merchant, but he became deaf and spent his leisure hours devoted to collecting fossils and studying the rocks of the neighborhood of Madison.
Being unsuccessful in business with delicate health he turned his whole attention to science, and in 1848 he gained employment on the United States Geological and Geographical Survey of the Territories as an assistant to D. D. Owen in Iowa, and subsequently in Wisconsin and Minnesota.
Meanwhile, in 1853 he accompanied FV Hayden in an exploration of the badlands of Dakota and brought back valuable collections of fossils.
[1][2] In 1858 following clashes with Hall he went to Washington, D.C., where he devoted his time to the palaeontological work of the United States geological and geographical surveys, his work bearing the stamp of the most faithful and conscientious research, and raising him to the highest rank as a palaeontologist.
[5] Besides many separate contributions to science, he prepared with WM Gabb (1839–1878) two volumes on the palaeontology of California (1864–1869) and a Report on the Invertebrate Cretaceous and Tertiary Fossils of the Upper Missouri Country (1876).