Figure 1.--Geology of the United States as represented by Maclure (1817).
Original map in color. Note: To facilitate comparison of figures
1 through 4, the original geological representations have been
replotted on the same projection and base. State and national
boundaries are retained as they existed at the times of
publication; in figures 3 and 4 the geography west of the
Mississippi River and within the coastlines is retained as
on the originals.