Figure 1. The 25-km grid used in this atlas. Modern glaciers and lakes are omitted from the grid.
U.S. Department of the Interior | U.S. Geological Survey URL: <http://pubs.usgs.gov/pp/p1650-a/introfigs/fig01.html> Questions or Assistance: GS Pubs Web Contact Page Last Modified: Fri Dec 17 17:49 EST 1999