Winchell’s background as the chief (often only) scientist of the Natural History and Geological Survey of Minnesota is reflected in his sample choices. While many are representative rocks from the main geologic formations the expedition traversed, Winchell paid special attention to rocks and minerals that might provide economic resources. Hence among the few samples he could bring back, he included bituminous slate, gypsum, selenite, siderite, tourmaline, limestone, hematite, and lignite. You can use the links below to see closeup views of the remaining rock and mineral samples.
July 1874 Samples
August 1874 Samples