2. Geology, Geography, Ecology

The Appalachian Mountains formed about 480 million years ago during the Ordovician Period. At their peak they were as tall as the Rockies (14,431 ‘) and the Alps (15,781’). But over the eons Appalachia was ground down by repeated Ice Ages and erosion leaving its highest peak standing at only 6,684 feet. Once part of the Pangaea Supercontinent, traces of the same range can be found in Morocco and it extends as far north as Scotland. No wonder the Scots felt right at home in the Southern Appalachians.

During the Ordovician Period our planet was very busy breaking up the Pangaea Supercontinent, and shifting plates around. It was the time of massive plate collisions, tremendous volcanic activity, and mountain building. Mountains were thrust and folded into peaks and canyons, eroded into plains, only to be thrust and folded again. One of the end results was the Appalachian Mountains. The Ouachita Mountains in Oklahoma and Arkansas were once part of Appalachia as well, but are now disconnected due to geological occurrences.

Appalachia runs thousands of miles NE/SW from Newfoundland to Alabama, and are 100 to 300 miles wide. The Appalachian Trail is 2,175 miles long and runs from Canada south into Georgia. During early European exploration and colonization this range was believed an impenetrable barrier between the eastern seaboard and what lay beyond, much as the Rockies were viewed centuries later.

The Appalachian Mountains are divided into three sections. The northern section includes areas of Canada (Newfoundland, Quebec, New Brunswick, and Nova Scotia); and areas of the US (Maine, New Hampshire, Vermont, Massachusetts, and Connecticut). The central section includes regions in New York, New Jersey, West Virginia, Pennsylvania, Ohio, Maryland, Kentucky, and Tennessee. The southern section runs through North Carolina, South Carolina, Georgia, and Alabama. Each of these sections is further divided into dozens of named ranges and areas such as the Berkshires, the Allegheny, the Blue Ridge, the Cumberland Plateau, the Smoky Mountains, just to name a few. For our purposes we will focus on the southern section and the southern portion of the central section, most commonly thought of as Appalachia, and the Potomac River Basin. But let me caution you about compartmentalizing this. Indigenous Americans from the north had a long reach into the south, and this will become more evident as the essays progress. A complex inter-tribal influence found its way into the early European culture of Appalachia, the Piedmont, and Tidewater regions.

The ecology of the Appalachians is thought to be the most biologically diverse in the entire Temperate Zone due to the region’s long and ever-changing geological history.  It has a wide range of elevation complicated by many changes in latitude. Deep river gorges provide stable microclimates and isolated peaks serve as habitat islands, so to speak, conditions that result in a tremendous genetic diversity of all species. Prior to present day climate change with its chaotic and unknowable consequence on this vast ecosystem, the temperatures in Appalachia were moderately cool (mean annual low of 40 F to a high of 61 F). Average rainfall was more than 87 inches and occasionally more than 100 inches, qualifying it as a temperate rainforest in certain areas.

More than 10,000 species have been cataloged to date with many new discoveries made annually, including species never before seen by the scientific community.  Species in all categories can range from unique to a specific microsystem, to having relatives that span the entire Temperate Zone. Many would have been familiar to early Europeans such as the squirrel, rabbit, hare, wolf, fox, deer, elk, moose, beaver, otter, and bear, with countless recognizable species of birds and fish. Although too numerous to estimate Europeans were met by familiar species of plants too. Oak, maple, birch, juniper, linden, pine, holly, and rhododendron relatives were easily recognized, as were many of the berry producing shrubs, as well as annuals, perennials, ferns, mosses, and fungi. But they were also met by an enormous range of trees both coniferous and deciduous previously unimagined by them, and that alone doomed the forest, its breathtaking diversity, and all the creatures, winged, two-legged, and four that were dependent on it.  Much like the Amazon Basin, wide-spread destruction drove countless species in all categories into extinction before they were ever actually seen. Therefore, it can’t be known how many species were lost.

The Potomac River Basin has a drainage area of 14,700 miles; the north and south branches of the Potomac River are 405 miles long. The headwaters of the north branch can be found at Fairfax Stone in West Virginia, and the south branch headwaters are located near Hightown, Virginia. Many tributaries feed both branches, some of which originate in Pennsylvania. The two branches converge near Green Spring, West Virginia forming the Potomac River. As the terrain drops from mountainous to piedmont, and from piedmont to coastal plain, the Potomac increases in salinity and becomes tidal. The Tidal Potomac begins about one mile below Washington DC. The estuary is eleven miles wide and can be found between Point Lookout, Maryland and Smith Point, Virginia. The Potomac then flows into the Chesapeake Bay.

The name Potomac is believed evolved from the Algonquian Patawomeke which became Patomack and finally Potomac. It is believed to mean either “a place where people trade” or “the place where tribute is brought”.

The Potomac River Basin is divided into five geological areas, each of which has its own unique ecology:
1.    The Allegheny Plateau (source of both branches)
2.    The Valley and Ridge Province
3.    The Great Valley
4.    The Piedmont Plateau
5.    The Coastal Plain

The Blue Ridge Mountains, east of the Great Valley, separate the Great Valley from the Piedmont Plateau. They are volcanic Precambrian and Cambrian, producing quartzite, sandstone, and rhyolite. West of the Great Valley are ridges and folds where can be found dolomite, limestone, and shale. The stone for points and lances was quarried in this region. Quartzite and sandstone were used in the production of pottery.

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Responses to “2. Geology, Geography, Ecology”

  1. Verda
    I’m in love with this particular essay’s story…all the history and geography it carries. You have exposed things I never would have know otherwise. I find it all tantalizing :)
    Thank you for your good works..

    • You are welcome. Your support of my work is deeply appreciated. I am so pleased that ultimately all of the Turtle Island essays will forward something quite tangible.