Sources of Information   http://arctic.fws.gov/permcycl.html http://sis.agr.gc.ca/cansis/taxa/landscape/ground/nwt.html http://www.harrythecat.com/graphics/a.htm#arrows for use of gifs http://nunatak.geology.union.edu/courses/geomorph/picsforfinal.htm http://www.islandnet.com/~see/weather/almanac/arc2001/alm01feb.htm http://ecology.botany.ufl.edu/ecosystemdynamics/schuur/Siberia.html http://marciesalaskaweb.com/trivia.htm Prudhoe Bay, Alaska (Guidebook to Permafrost and Related Features); Rawlinson, S. E.,State of Alaska, 1983