MACLURE’S OBSERVATIONS ON THE GEOLOGY OF THE UNITED STATES–EARLY REVISIONS BY EDWIN JAMES AND JOHN HINTON

William Maclure’s (1763–1840) pioneering geologic account and map of the eastern United States, published first in 1809 in Observations on the Geology of the United States, provided a foundation for many later observations – a template from which geologists could extend their mapping westward from the Appalachians. Edwin James (1797–1861), botanist, geologist and surgeon for the 1819/1820 United States Army western exploring expedition under Major Stephen H. Long (1784–1864), published a full account of this expedition with map and geologic sections in 1822–1823. In this he extended Maclure’s geology across the Mississippi Valley to the Colorado Rockies. John Howard Hinton (1791–1873) published his widely read text: The History and Topography of the United States in 1832, which included a compilations of Maclure’s and James’ work in a colored geologic map and vertical sections. All three men were to some degree confounded in their attempts to employ Wernerian rock classification in their mapping and interpretations of geologic history, a common problem in the early 19th Century prior to the demise of Neptunist theory and advent of biostratigraphic techniques for rock correlation. However, they provided a foundation for the later, more refined mapping and geologic interpretation of the eastern United States.