(4) the Appalachian Ridge and Valleys--This region is located west of the Blue Ridge and Valleys. The Appalachian Ridge consists primarily of a narrow strip of land thirty-five to one hundred miles wide. The Allegheny Mountains border Virginia along the west and numerous high, narrow ridges are found here. The Appalachian Valley in Virginia, like the Blue Ridge, originates at the junction of the Potomac and Shenandoah Rivers. This valley extends for approximately three hundred and fifty miles to the borderline of Tennessee. The eastern part of this valley is often referred to as the Great Valley or the Valley of Virginia. This valley is actually a series of valleys separated by crosswise ridges and drained by five rivers: the upper James, Roanoke, New, Holston and Powell. An abundance of limestone makes the soil exceptionally fertile and productive. In the northern part of the Valley of Virginia is the famous Shenandoah Valley, about 150 miles long and ten to twenty miles wide, divided in the north by the Massanutten Mountain, a high ridge approximately forty-five miles long. There is a great variety of soils found here, and most of them have a fair degree of plant fertility. Corn and winter wheat are the agricultural specialties of the Shenandoah Valley. Other valleys included in the Valley of Virginia are the Abingdon Valley, Dublin Valley, Fincastle Valley, Powell Valley, Roanoke Valley, New River Valley, Holston Valley and Clinch Valley. (5) the Appalachian Plateau--This region is located in southwestern Virginia and is often referred to as the Southwestern Plateau or Allegheny Plateau. It extends only a short distance into Virginia and consists mainly of rough, rugged terrain. Water gaps, gorges, sandstone walls, rock formations and dense forested areas make southwestern Virginia's scenery distinctly different and picturesque. The Cumberland Mountains form its western boundary. Coal-mining is the chief occupation in this region, and this is the area where the largest and most productive coal-fields of Virginia are located. Lumbering is also carried on extensively. In addition, some cattle, hogs, corn and vegetables are raised here. The combination of these five regions suggests a one-word description of Virginia's topography, namely, diversified. [Illustration: _Topographical Regions of Virginia_] [Illustration: VIRGINIA STATE CHAMBER OF COMMERCE _Natural Tunnel_] _Unique Features_ Each state of the United States generally has at least a few geographical oddities or unusual geographical formations. Virginia has been richly endowed with caverns, springs, unusual rock formations and a dense, swampy wilderness.