 Topped by erosion resistant sandstone the mountain forms a barrier between Penns Valley, and Brush Valley, to the south and Nittany Valley to the north.The southern mountainous border of Penns Valley is created by Tussey Mountain which is one of the stratigraphic ridges of central Pennsylvania.Tussey Mountain is one of the longest running mountains of the Ridge and Valley complex starting in Flintstone, Maryland and running 80 miles into the Seven Mountains of central Pennsylvania.