South Yorkshire's geography can be split into different types. The very west of South Yorkshire is part of Dark Peak which is part of the Peak District National Park and lies to the west of Sheffield. This extensive moorland is one of the largest semi-natural areas in England and has broad plateaus with rocky outcrops interspersed with valleys. Moving east the land elevation drops with a transition from the peak district to coal fields. Much of this area of transition has seen urban development with Sheffield being a good example.