This on-line exhibit is drawn from material used in Prehistoric Alexandria, which was exhibited at The Lyceum, Alexandria’s History Museum, in the summer of 2002.
- A Slow and Rocky Start
- Virginia Dinosaurs
- The K-T Event
- A Brave New World: The Mammals Take Over
- The Chesapeake Bolide
- The Big Chill: The Late Pleistocene
- Virginia's Earliest Site
- Melt-Down: The Birth of the Bay
- The First Alexandrians
- Man Lives Well in Tidewater Virginia
- A Chip Off The Old Cobble
- And the rest is (recorded) history!
PREHISTORIC ALEXANDRIA
What do you consider to be the oldest area history? When the English sailed up the Potomac River in 1608? When the first American Indians began to inhabit the region? For most people, history means “recorded” history, that mix of stories and facts, wars, buildings and people that stretches back to ancient civilizations, such as the early cultures of Mesopotamia. Alexandria is not, of course, nearly that old, but what was here before Alexandria? How differently did the land, the river, the plants and the animals of the region appear in the prehistoric past? When did humans first arrive here, and what did they find? How did they, and the rest of nature, adapt to the significant changes in the environment that lay ahead?So much has happened in just the last 20,000 years that we do not need to go back very far to find a Virginia that was quite different from what we know today. Prehistoric Alexandria examines some of this area’s distant past, with a close look at the period since the peak of the last Ice Age 20,000 years ago.
A Slow and Rocky Start
Many scientists feel that the earth may have formed over 4 billion years ago, and underwent another billion years of cooling and consolidation. Several hundred million more years elapsed before the first life appeared, in the form of single-celled organisms, animals and plants, while enormous sections of the earth’s crust (super-continents) floated and collided with each other. It would be hundreds of millions of years more before the earliest sea life and land plants developed.
A geological cross section of the Virginia coastal plain. As you can see, most of the rocks are the result of sediments deposited by water. Department of Geology, The College of William & Mary.
Click to enlarge
Q --- Quaternary formations; most recent deposits
Tbc --- Bacon’s Castle Formation; river-deposited gravel, sand and clay
Ty --- Yorktown Formation; marine sand
Te --- Eastover Formation; marine sand and clay
Tb --- Bon Air Gravel; river-deposited sand, silt and clay
Tex --- Exmore Breccia (debris from bolide impact)
TK --- Older Tertiary and Cretaceous formations; marine and river-deposited sand and clayAbout 325 million years ago (mya), the continents that we know today were clumped around the world in different ways. North America and Europe had converged to form what scientists call “Euramerica,” while parts of Eastern Europe and Asia formed “Angra.” Africa, the rest of Asia, Antarctica, and Australia formed “Gondwanaland.” By the early Triassic Period, 235 - 245 mya, these continents had drifted together in one enormous land mass named “Pangaea.” It was during this period that the first dinosaurs appeared.
Click to enlargeAn early Triassic globe depicting Pangaea.
Dr. Ronald Blakey, University of Northern Arizona.
Click to enlargeA paleo-geographic view of late Jurassic North America. The Atlantic Ocean was just beginning to open as a major body of water.
Dr. Ronald Blakey, University of Northern Arizona.The Jurassic Period that followed (144 - 210 mya), which witnessed the dinosaurs at their peak and the earliest birds, also was a time of sea floor spreading and the breakup of Pangaea. North America, Europe and Asia gradually split away from South America and Africa, but the Atlantic Ocean had yet to form. The Earth was much warmer, overall, and sea level was higher; a large inland sea covered a large portion of the American West. Much of eastern Virginia would have been swampy at this time, with several large lakes in places where the Earth’s crust had pulled apart (rifting).
Virginia Dinosaurs
When people think of prehistoric times, they frequently think of dinosaurs. Unfortunately, except for a number of footprints, there is precious little evidence of dinosaurs in Virginia today. The area where the dinosaurs would have walked remained dry land for millions of years, subject to erosion. For fossils to survive, they need to be covered with sediment pretty quickly, and in a way that preserves them from scavengers and decay. These conditions are usually found in water, where soil is washed from the land and quickly covers the bones, which then have time to slowly turn into fossils. Therefore, evidence of dinosaurs in Virginia usually comes from places where there were deep lakes during the Mesozoic Era, the Age of Dinosaurs.Such an environment existed millions of years ago in what is now Pittsylvania County in south-central Virginia. During the Triassic, there was a large lake in this area, around which dinosaurs walked (leaving us their footprints), and which was itself home to various insects, fish and an aquatic reptile called Tanytrachelos. This creature was relatively small, perhaps no more than a foot long, but several very well preserved fossils of him have been found in the Solite Quarry, where the lake used to be. So well preserved are these Tanytrachelos fossils that you can even see impressions of the muscles and skin in some of them! The Solite Quarry is also well known today for its many plant and insect fossils, which are each like little snapshots of prehistoric Virginia.
Click to enlargeA tanytrachelos fossil found in the Solite Quarry.
The Virginia Museum of Natural History.Further north, where another large lake once existed near Culpeper, many footprints have been found that were made by a therapod (meat-eater, walking on two legs) dinosaur, such as Syntarsus or Coelophysis.
The K-T Event
Where did these fantastic creatures go? There are a number of theories, and many of them are relatively recent, due to advances in technology. German scientists during the early 20th century had been studying the mass extinctions that occurred approximately 65 mya, between the Cretaceous (Kreide in German) and the Tertiary Periods (hence “K-T” event), but their work was largely ignored until the 1950’s.Some scientists believe that the dinosaurs and other tropical plants and animals were already in decline during the late Cretaceous, due to a cooling climate and other environmental changes. Others attribute the extinctions to an enormous asteroid, measuring perhaps 6 or 7 miles across, that smashed into the Earth near what is today the Yucatan Peninsula. Traveling hundreds of miles per hour, this monstrous piece of rock would have created an explosion, shock waves, and subsequent debris and dust clouds that obliterated the majority of the living things in North America. Various after-effects of the cataclysm, such as a 7-storey-tall tidal wave and a “polar night” of dust, lasting months or even years, would have destroyed many other forms of life that managed to survive the blast itself.
Evidence of this event comes from around the world, where high levels of iridium are found in late Cretaceous rocks. Iridium is very rare in the Earth’s crust, but fairly common in meteorites. Paleontologists and geologists working in Canada, where many large dinosaurs lived during the Cretaceous, also find a light-colored clay layer over one of coal in rocks of this period. This evidence suggests a massive deposition of dust (the clay) that smothered plants and animals (the coal).
A Brave New World: The Mammals Take Over
Following the extinction of the dinosaurs, the earth went through millions of years of climatological change, during which the continents slowly moved into their modern-day positions. Various species of mammals evolved, at this time, and began to dominate the land. Many of the larger animals that lived in North America before the K-T event had been killed by it, and so the continent was gradually re-populated with many new species from Eurasia. Sea levels rose and fell with periods of warming and cooling, and eastern portions of Virginia were alternately dry land or under water. During the Miocene Period (23 – 5 million years ago), for example, the entire Delmarva Peninsula was covered by a vast shallow sea, which would have placed Alexandria on or near the beach. As Miocene land creatures died, their remains sometimes washed into the sea, resting on the bottom with deceased marine life. If they “survived” to become fossils, many of them can be found today falling out of the Calvert Cliffs, a Maryland state park in Calvert County.
Click to enlargeThe extent of the Miocene Sea.
From Fossils of Calvert Cliffs, The Calvert Marine Museum.After the Miocene Sea subsided, the Potomac River near Alexandria would have been much narrower than it is today, placing the city’s future location further inland. The river itself flowed into the ancient Susquehanna River, which then flowed out to the Atlantic Ocean across a broad plain (the continental shelf). Strange, long-extinct animals roamed the grasslands, forests and swamps of eastern Virginia, including early horses, camels, elephants, rhinos, peccaries and crocodiles.
The Chesapeake Bolide
About 35 MYA, another large bolide (meteor or asteroid from space) slammed into the Earth, this time hitting eastern Virginia and creating a crater more than 50 miles wide and a mile deep. Like the K-T event 30 million years earlier, this enormous rock would have caused a huge explosion and dust cloud, along with tidal waves that killed hundreds of thousands of plants and animals for miles around. The force of the collision also fractured many of the layers of rock in this area, leaving fault lines that remain today under the cities of Norfolk and Hampton. Within minutes of the impact, tidal waves of sea water would have washed over the land and sucked tons of plants, animals, rocks and soil back into the crater.
Click to enlargeThe area of impact of the Chesapeake Bolide.
Dr. Wylie C. Poag, U.S. Geologic Survey.Over time, the crater left by the bolide also diverted the rivers of eastern Virginia. The Susquehanna, Potomac, Rappahannock, York and James Rivers would have originally flowed out to the Atlantic Ocean in a more easterly course. For millions of years after the bolide, these rivers gradually changed course so that their waters flowed toward the huge underground depression caused by it. Furthermore, when sea levels rose following the last ice age (within the last 20,000 years), this depression helped to create the Chesapeake Bay.
Click to enlargeThe Mid-Atlantic coast during a period of much lower sea level, with the bolide impact area identified.
Dr. Wylie C. Poag, U.S. Geologic Survey.
The Big Chill: The Late Pleistocene
When people refer to “the Ice Age,” they are usually referring to the most recent (there have been several), which reached its peak about 20,000 years ago. At that time, continental ice sheets covered North America as far south as Pennsylvania. Although Virginia was not covered by glaciers, the local environment would have been very different from what we know today. Strong winds of arctic air sweeping down from the ice sheets created a colder climate. North America tended to become warmer and dryer as the glaciers gradually receded toward the end of the Pleistocene (about 11,000 years ago), with one brief exception --- the Younger-Dryas climatic reversal. During this period, which lasted perhaps five years, winters would have been much colder and wetter than they had been since the peak of glaciation, putting much more survival stress on plants and animals.Pleistocene vegetation consisted of a mosaic of open grassland areas interspersed with stands of spruce, fir, and other conifers. Dense pines covered the mountain slopes, except perhaps at the very highest elevations, above the tree line, and deciduous trees grew mainly in poorly drained areas and beside streams. A wide range of extinct and modern animal species would have roamed these forest and grassland areas including mammoth, mastodon, bison, caribou, horse, and giant sloth, as well as white-tailed deer, elk, raccoon and rabbit.
The ancient Susquehanna River system (including the Potomac) carried seasonal meltwaters from the glaciers southward to the sea. Since so much of the Earth’s water was locked up in glaciers, sea level was much lower and the continental shelf was exposed for over 200 miles to our east. The Chesapeake Bay had not yet formed.
There Goes the Neighborhood: Man Arrives in North America
20,000 – 10,000 years ago
Exactly when humans first appeared in North America and where they came from are questions that are still being hotly debated. The traditional view holds that man arrived here through major migrations across the Bering land bridge between Siberia and Alaska at the height of the last glaciation. As the glaciers began to retreat (melt), people followed herds of big Pleistocene mammals south, through an ice-free corridor in Canada about 12,000 years ago, gradually spreading out across North and South America.An alternative theory is that occupation of the Americas may have resulted from a series of migrations, perhaps going back as far as 30,000 years ago. These migrations could have been over land or water, with people working their way down both the Atlantic and Pacific coasts, settling on land that is now submerged by a rise in global sea levels.
Regardless of how they got here, there is evidence that these early hunter-gatherers, known as Paleo Indians, were living in Virginia at least 11,000 years ago. At this time, small bands moved frequently throughout the area, hunting game and collecting plant resources in the spruce/pine forests and grassland environments that predominated. They hunted mostly modern species like deer, elk or raccoon, for the mammoth and other large Pleistocene mammals were likely extinct in this area by then. (By the way, if you like controversies, there is another one raging about whether or not mammoths and mastodons are extinct because early man killed and ate them all.)
Click to enlargeEarly man hunting large game.
Paleo Indians in Virginia
Paleo Indian sites are identified by the presence of a characteristic type of spear point frequently made of chert or jasper, a high-quality stone which can readily be fashioned into tools. The point has a flute removed from each of its faces. In the local northern Virginia and D.C. areas, Paleo Indian finds are rare, consisting of just a few isolated points probably dropped by hunters. None have been found in Alexandria, which would have been located some distance to the west of the shoreline of the ancestral Potomac. However, at the Thunderbird Site in the Shenandoah Valley and the Williamson Site in the southeastern part of the state, Paleo Indians camped near outcrops of chert and jasper, which they quarried to manufacture their tools. At Thunderbird, archaeologists discovered remnants of the posts for a Paleo Indian dwelling measuring 30 by 40 feet, one of the oldest known structures in North America.
Virginia’s Earliest Site
Cactus Hill near Petersburg, Virginia, holds the earliest evidence of man yet found in the eastern U.S. On sand dunes adjacent to the Nottoway River, archaeologists recovered quartzite points, blades and cores, along with charcoal and fragments of animal bone in a level about 5 inches below Paleo Indian artifacts. This stratigraphic position suggests that the material is earlier than Paleo Indian, and radiocarbon analysis indicates that the artifacts may be 18,000 years old. The use of quartzite and the manufacture of blades contrasts with the tool-making technology of the Paleo Indians. The tools are remarkably similar to types recovered in France and Spain that were made more than 18,000 years ago. Their recovery has suggested that the earliest settlers in North America came from Europe around the Atlantic rather than from Asia over the Bering land bridge.
Melt-Down: The Birth of the Bay
10,000 – 5,000 years ago
As the climate warmed and the glaciers melted, the environment began to change. Sea levels gradually rose, “drowning” the Susquehanna River and its tributaries, which all became much wider. The rising waters caused ponding and the development of marshes along the major rivers feeding into the bay. Oak, hickory and chestnut trees replaced the grasses and conifers of the late glacial period.The changing environment meant that many new and different resources became available. The numbers of deer and smaller mammals increased in the forest and forest-edge environments, and a variety of nuts, seeds, roots and berries proliferated. People living in the area learned to take advantage of this diversity and to exploit the resources as they became seasonally available. New tools were developed — axes and adzes for woodworking, along with mortars and pestles for grinding the nuts of the expanding deciduous forests. Hunters perfected the weighted spear-thrower, called an atl atl, which greatly enhanced their ability to kill large game.
The First Alexandrians
The earliest evidence of human activity in Alexandria dates to this period and comes from Jones Point, consisting of spear points probably dropped by hunters chasing game in the woods along the Potomac River. One of the points is made of quartzite and bears serrated edges; radiocarbon dates associated with similar points suggest that it may have been made over 9,000 years ago. Another early point, known as a “bifurcate” type because of its forked base, dates to about 8,500 years ago and was found at the Stonegate Site near Braddock Road and I-395.
Click to enlargeKirk Point, found at the Jones Point site.
Man Lives Well in Tidewater Virginia
5,000 – 3,000 years ago
By about 5,000 years ago, many years of warmer and dryer climatic conditions had created a dense oak/hickory forest environment in this area. A great variety of plant and animal species had developed in and along rivers and streams. The rate of rising sea level slowed, allowing for the creation of more stable environments supporting significant numbers of fish and shellfish in the rivers and bays. For example, the salinity (salt content) of the young Chesapeake Bay stabilized to the point that oysters began to flourish into the lower reaches of its tributaries, such as the Potomac River, where early shell middens (trash piles) have been found. Closer to the site of Alexandria, people harvested hundreds of anadromous fish, such as shad and sturgeon, that were making their way upstream to spawn in the spring. As more and more of these food resources became available and reliable, people began to congregate along the rivers and estuaries.Many more sites of human occupation date from this period, distinguished by a large, broad-bladed point style. The sites themselves are larger and more complex, and show a trend toward an increasingly sedentary lifestyle. The soapstone (steatite) bowl, an innovation in cooking technology, was developed during this period, and would have been too heavy to carry on long, nomadic treks. Thus, for the first time, man had a container that could be placed on the open fire; by the end of this period, the manufacture of pottery began, and ceramic pots replaced stone bowls for cooking.
A Chip Off The Old Cobble
While the site of Alexandria was still slightly inland from the Potomac shoreline, evidence of tool manufacturing has been discovered in the city. Since there are no stone outcrops in our part of the Coastal Plain, tools were made from the cobbles deposited in ancient riverbeds and exposed by later erosion; numerous cobbles in Timber Branch show evidence of this quarrying activity. At the intersection of Braddock Road and I-395, archaeologists discovered the Stonegate Site prior to the construction of a townhouse development on a bluff top overlooking a small stream. Local Indians also left behind the remnants of their hearths as fire-cracked rock, along with thousands of small pieces of stone chipped off during tool-making (flakes), and numerous projectile points that were broken or discarded during the manufacturing process.During this period, people also began to visit Jones Point on a regular basis to manufacture stone tools and perhaps to establish fishing camps. As at Stonegate, they collected cobbles from the nearby river and streambeds to create stone tools, leaving behind thousands of flakes and their hearth stones, again in evidence as many fragments of fire-cracked rock. Artifacts recovered include spear points, knives and small fragments of steatite bowls.
Click to enlargeA cobble is struck with another stone to begin shaping it into a tool.
Click to enlargeSteatite bowl in various stages of manufacture.
The Woodland World
3,000 years ago to European Contact
About 3,000 years ago, the climate became approximately as it is today. The “first Alexandrians” continued to visit the area temporarily or on a seasonal basis, fishing and hunting along the riverbank. Studies of landscape changes (geomorphology) indicate that by this time, erosion had molded Jones Point into a long narrow peninsula extending out into the Potomac River. The peninsula was separated from the mainland by an extensive swamp or “pocosin” (an Eastern Algonquian word), which was drained by a small creek.In 2000, archaeologists working in the path of the new Woodrow Wilson Bridge project discovered evidence for a small village or camp site on Jones Point occupied about 2,000 years ago. The village consisted of a cluster of a few houses, with storage or trash pits, on a small rise or terrace overlooking the marsh. The houses themselves were identified by the presence of small circular stains, which represent decayed wooden posts, and the stains form oval patterns, each measuring about 9 by 12 feet. These houses were probably erected by bending saplings to form arches and then covered with bark or woven mats. The discovery of the remains of these 2,000-year-old structures is of great significance because so few have been found to date in the Potomac coastal plain.
Archaeologists assert that people visited the site seasonally to exploit the marsh resources, such as harvesting tubers in the early spring when other food resources were scarce, or the enormous fish runs during the spring and early summer months. By 900 A.D., local Indians began to cultivate maize, squash and beans, adding agricultural produce to their food supplies and establishing permanent year-round settlements in the fertile soils of the river floodplains.
Click to enlargeCord-impressed pottery rim sherd, found at Shuter's Hill in the 1930s.
Click to enlargeLate Woodland point, found at the Jones Point site.
And the rest is (recorded) history!
The peoples of Europe and the Americas rediscovered each other when Columbus’s ships bumped into the West Indies in 1492, and a new recorded history of North America began. When Captain John Smith sailed up the Chesapeake Bay and into the Potomac nearly 120 years later, he met cultures that had been evolving for thousands of years, since man first streamed across the uninhabited reaches of North America. Sadly, within four generations, the descendants of this first population had been largely driven out of northern Virginia, so that today, only small numbers of local people can link their families to the earliest residents of this continent. Yet, despite more than 250 years of construction and development, remnants of the prehistoric past still remain buried within Alexandria. To date, archaeologists have identified over 30 sites containing American Indian materials and have registered them with the Virginia Department of Historic Resources.The land and water continue to change, often at a much more rapid pace due to man’s involvement. For example, there are many more trees in Alexandria and other parts of Northern Virginia today than there would have been during the Civil War, as more land would have been cleared for farming. As the oak/hickory forests that once dominated this area were cut down, silt from the fields and from construction projects was washed into rivers and streams. Since the city’s founding in 1749, we have intentionally filled many coves and low-lying swamps; at Jones Point, the early historic land surface was covered by 4 to 5 feet of fill intentionally placed to raise the elevation. The Potomac River and the Chesapeake Bay have changed dramatically during the recent past, as both pollution and ever-increasing demand for fish and shellfish have affected all of their original plant and animal species. Alarmingly, what has taken millions of years to develop man can wipe out within a few generations. Around the world (including the Chesapeake Bay), sea level is rising; is this a sign of global warming or merely another of the Earth’s normal climate cycles? The past 20,000 years have included many big changes for this area; how will Alexandria and Northern Virginia look 20,000 years from now?
For more information on the region's prehistory, the book First People: The Early Indians of Virginia is available from our online Museum Shop.
