USGS map of Appalachian zones in the United States
USGS, SVG version by <a href="//commons.wikimedia.org/wiki/User:Jo_Weber" title="User:Jo Weber">Jo</a>
2009-03-21
JPG version below; originally from <a rel="nofollow" class="external free" href="https://3dparks.wr.usgs.gov/nyc/images/fig51.jpg">http://3dparks.wr.usgs.gov/nyc/images/fig51.jpg</a> (see also <a rel="nofollow" class="external free" href="https://3dparks.wr.usgs.gov/nyc/common/captions.htm">http://3dparks.wr.usgs.gov/nyc/common/captions.htm</a>)