Historic Places - The Geology of Virginia

Jamestown Island
Oblique aerial view of the bays
and swamps of Jamestown Island,
James City County

T

he Commonwealth of Virginia has played an important role in the history of the United States. The visitor to historic places should be mindful that in addition to nearly four hundred years of history, the landscape of Virginia’s historic locales records a story that goes much further back.

The first permanent English colony in North America at Jamestown was sited on sandy Pleistocene ridges that afforded elevation above the swampy valleys on Jamestown Island. The United States won its independence at Yorktown in 1781; four million years earlier Yorktown was a shallow shoal in a warm subtropical sea.

Large boats could sail up the wide Coastal Plain streams until rapids at the Fall Zone halted their westward progress. Here at the Fall Zone significant communities, such as the Confederate capitol of Richmond and Alexandria, home to George Washington's Mount Vernon plantation, developed along major streams.

Appomattox Court House, where the Nation reunited in 1865, is located in the Piedmont province.  It lies astraddle the Chatham fault on a body of transported rock known as the Smith River allochthon composed of metamorphic schists and gneisses, typical of the Piedmont.  In Buckingham County, the slate mines of the Arvonia formation have been producing roofing slate since Virginia's colonial period.   Further to the northwest is Thomas Jefferson's home of Monticello, resting on a hill of 570 Ma Catoctin greenstone--the remnants of ancient lava flows.  The hill can be easily seen from I-64, just east of Charlottesville. 

Old Rag Mountain
Old Rag Mountain, Shenandoah
NP, Blue Ridge province

Shenandoah National Park and Mount Rogers are excellent venues to observe the geology of the northern and southern Blue Ridge.  Units such as Shenandoah's Old Rag granite and Mt. Rogers' Fees rhyolite attest to the far-reaching geologic history of Virginia.

Near Buena Vista is Natural Bridge, a great arch of Paleozoic limestone 215 feet high (Niagara Falls is only 160').  Thomas Jefferson, enamored by the monument, purchased Natural Bridge from King George III of England in 1774 for twenty shillings. Natural Bridge is the remnant of a great cavern system--commonly found in humid regions underlain by carbonate layers.  Throughout the Valley & Ridge province can be found other karst (cave and cavern) features such as Luray Caverns, Natural Tunnel, and Natural Chimneys Regional Park.



(1/5/2000)