Appalachian valley and ridge folds, Pennsylvania

The Appalachian Valley and Ridge province (https://www.nps.gov/articles/valleyandridgeprovince.htm) is an excellent example of the importance of bedrock geological structure and stratigraphy for the present-day landscape. Differential erodability of the Paleozoic sedimentary rocks, which were tightly folded during compressional mountain building, has created the beautiful and complex modern landscape. This model was made using tectoplot and USGS 1/3 arcsecond terrain. Topography is vertically exaggerated by a factor of 2. tectoplot -r -77.9 -77.6 40.6 40.9 -t ~/Downloads/USGS_13_n41w078.tif -t0 -tcpt R1 -tr -makeply maxsize 1000 sidebox 2 white topoexag 2