Читать книгу Top Trails: Shenandoah National Park - Johnny Molloy - Страница 15

The topography of Shenandoah results from the weathering of one of the oldest mountain ranges in the world—the Appalachians. Shenandoah National Park overlays a long stretch of the Blue Ridge, whose billion-year-old rocks rise above the forest. The main spine of the park stretches 70 miles from end to end, dividing the bucolic Shenandoah Valley from the Piedmont to the east. Elevations vary from 4,050 feet atop Hawksbill down to less than 550 feet near Front Royal. This vertical variation is one of the reasons for the incredible diversity of life found within its boundaries.

Shenandoah National Park forms the headwaters to many a stream flowing west and east from the north-to-south-oriented Blue Ridge. The South Fork Shenandoah River system absorbs all waterways spilling west from the park. The South Fork meets the North Fork Shenandoah River just north of the park, melding their waters and contributing them to the Potomac River, which in turn flows through the District of Columbia to the sea. The streams draining to the east are a little more complicated. Tributaries of the Rivanna River, including the Doyles and Moormans Rivers, flow from the mountains of the South District to meet the James River, which flows through Richmond to the sea. In the Central District, the Rapidan River and its tributaries from the South River to the Thornton River find their way to the Piedmont and the Rappahannock River, which flows through Fredericksburg before pushing into Chesapeake Bay. In the North District, smaller streams also course east into the headwaters of the Rappahannock and beyond.

The dominant landform is the high, continuous ridge extending north–south from one end of Shenandoah to the other: the Blue Ridge. In addition to dividing river drainages, it also forms the boundary for numerous Old Dominion counties. Often-rocky shoulder ridges, like ribs protruding from a backbone, extend from the Blue Ridge and separate steep, deeply wooded valleys carved out by eons of precipitation.