From 1870 to 1871, he conducted the geological survey of the copper region of Michigan, for which he prepared "Copper-Bearing Rocks," being part ii of volume i of the "Geological Survey of Michigan" (New York, 1873). He was called upon in 1871 to conduct the geological survey of Missouri, and for three years devoted his energies to that task, preparing "A Preliminary Report on the Iron Ores and Coal Fields," with an atlas, for the report of the "Geological Survey of Missouri" (New York, 1873).