Ancient Dig

Archeological finds at Meadowcroft Rockshelter turned back the clock on humankind’s first migration to the new world
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Twelve thousand years ago, a Native American hunter left a flint spear point at a campsite beneath an overhanging rock along Cross Creek, a tributary of the Ohio River some 29 miles southwest of Pittsburgh. The three-​inch by one-​inch point was a re-​sharpened remnant of a larger spear or arrow head. But the wear and tear of the hunt had necessitated re-​sharpening the point to a shorter length, probably more than once.


In its diminutive state, the point was nearing the end of its useful life. It may have been left in the carcass of the animal that became that evening’s stone-​age supper. Maybe it was misplaced, or perhaps discarded. Nobody knows. And surely, nobody cared for 12,000 years. Eventually, however, that spear point would push back the date of the first human migration to the New World by thousands of years.

In the interim, the rock overhang under which our prehistoric friend slept that evening continued as a refuge from the elements for all who passed through the Cross Creek watershed, whether hunting, trapping, trading, fighting, prospecting or simply traversing the continent’s interior. In recent times, the site became known as Meadowcroft Rockshelter. Located in Avella, Pa. less than an hour from Pittsburgh, the rock shelter is part of The Historical Society of Western Pennsylvania’s Meadowcroft Village, a collection of architectural and cultural artifacts representative of human life in North America through the ages. The village is home to a one-​room schoolhouse from the 1840s, a fully functional blacksmith shop, a covered bridge, a 19th century wooden church, a museum of rural life, and a 16th century Indian village, complete with a palisade enclosure, wigwams, a sustainable garden and an atlatl throwing range.

The Meadowcroft property was owned by brothers Albert and Delvin Miller, whose family had farmed the property since the late 1700s. The pair held an abiding reverence for the preservation of rural American culture, and before Meadowcroft became archeologically important, they began to relocate and reassemble a collection of 19th-​century buildings on the plateau above the shelter. In 1993, the village merged with the Historical Society of Western Pennsylvania. Today the Millers’ collection constitutes much of Meadowcroft Village.

The village’s charm adorns what is now the main attraction of Meadowcroft: the rockshelter. The shelter showcases some of archeology’s most important North American discoveries and serves as a demonstration project for the best excavation and documentation practices in the world. No longer a mere refuge from the elements, no longer an archeological dig covered with plywood, two-​by-​fours and tarpaper, the shelter now is protected by an exquisitely designed steel and wooden structure fitted sensitively around the excavation. A wood and steel stairway of 65 low-​rise steps ascends from the parking lot alongside Cross Creek, up the hillside to a wooden, covered observation deck. Visitors can view the excavation, the locations of ancient fire pits, mollusk shells, animal bones, the original steel survey stakes laying out the site’s grid, and innumerable white, button-​like tags on the excavation’s vertical profiles marking precise coordinates within 11 distinct strata. Tour guides explain the dig’s features in concert with automated ceiling lights that shine upon the exhibit of the moment. Completed in 2008, the $2 million structure was designed by Pfaffmann+Associates and constructed by F.J. Busse Co. Inc., both of Pittsburgh.

Geology of the shelter

The Meadowcroft Rockshelter is essentially a hillside terrace beneath a large rock overhang about 30 feet overhead. The shelter’s openness and orientation to the prevailing winds would have made it a comfortable resting spot by discouraging insects and dispersing campfire smoke. Over time, large pieces of the overhang broke off, some tumbling into Cross Creek, others crashing to the shelter floor, making the roof smaller and reducing the protected area. Radio carbon dating has identified at least three calamitous roof falls. One massive 23,000-year-old slab rests in Cross Creek. Inside the shelter, a 12,000-year-old piece, known as the Old Roof Fall, is 10-​by-​18 feet across and 10 feet deep. More recently, between AD 300 and 600, what is known as the New Roof Fall came down. Extending through the roof of the new site enclosure, the 15-​foot-​thick stone remains buried in the earthen floor.

The shelter was formed millions of years ago, when Cross Creek flowed about 45 feet higher than today. Over thousands of years, the creek scoured a vein of soft sandstone from its bank, leaving the harder rock above, which became the shelter’s roof. Fortuitously for the million-​plus Meadowcroft artifacts, each day the roof rock sheds an infinitesimal quantity of rock dust from its surface. Through the shelter’s history, this continual “rain” of rock dust served to gradually blanket anything left behind — seeds, husks, shells, fibers, bones, stone tools… and our prehistoric friend’s forgotten spear point. Thanks to the roof dust, the Meadowcroft artifacts remained safe and sound year after year and millennium after millennium.

A woodchuck hole

On Nov. 12, 1955, Albert Miller noticed several charred bone fragments at the mouth of a woodchuck hole near the rear wall of the shelter. A gentleman farmer and amateur archeologist, Miller excavated 30 inches down, where he found a stone knife. Aware of its significance and wary of looters, he kept the discovery to himself and began what became a 17-​year search for a qualified archeologist. That search ended in 1972 when Professor James Adovasio came to the University of Pittsburgh to establish an archeological field school. Meadowcroft proved ideal.

In 1972, scores of students and researchers from around the world began coming to Meadowcroft each summer to teach, learn and undergo field training in Adovasio’s rigorous excavation and documentation techniques. As the diggers dug their way through what would become a 16-​foot-​deep excavation, they discovered evidence of thousands of years of human habitation. In the topmost strata, beer cans and hypodermic syringes mixed among campfire ashes told of modern day revelers. Deeper layers bore primitive cutting tools made by Native Americans from the glass shards of Revolutionary War gin bottles, followed by thousands of charred small animal bones, nut shells, seed husks and the waste remnants of stone tool manufacture.

The first major find

In July 1974, the long-​forgotten spear point left or lost by our Stone Age hunter emerged from its ancient resting place. On one sunny morning, a Temple University archeology undergraduate named Joe Yedlowski, working in the deepest section of the dig, uncovered what appeared to be yet another one of many pieces of flake debitage, the waste material chipped from larger pieces of stone during the shaping of implements. Over the course of the morning, as he gingerly removed more soil — first with a six-​inch mason’s trowel, then with a single-​edged razor blade, and finally with a paintbrush — it became clear that the sides of the artifact were symmetrically curved to form a point and chipped to a sharp edge on both sides to form what archeologists call a bifaced projectile point — a spear point or arrowhead.

As the point’s significance became more apparent, the dig began to buzz in anticipation of a momentous find.

By the time it was exposed, we realized it was like nothing anybody had ever seen before,” Adovasio said.

By late in the day, after several hours of mapping, documenting and photographing the point in its ancient state of repose, Yedlowski gingerly lifted it from its resting place with his bare hands and handed it over to Adovasio, who phoned the local watering hole to assess its preparedness for a momentous celebration. By all accounts, the bar was adequately provisioned. The 100-​odd digging crew team reportedly finished off 10 kegs of beer.

Controversy

Elation, however, soon gave way to controversy. The “Miller Lanceolate projectile point,” as the 1974 discovery came to be called in honor of the site’s discoverer, was but the first in a series of finds that would become a proverbial shot heard ’round the world of archeology. Radio carbon dates indicated that the strata in which the Miller projectile point was found fell within the conventionally accepted timeframe of human habitation of the New World. But subsequent finds at deeper levels pushed the date back by at least 3,000 years and possibly 6,000. The oldest stone implement, a knife blade, was found in a layer dating back 16,000 years. Even older was a 19,000-year-old piece of charred bark. Almost overnight, the ancient transient campsite became the earliest known site of human habitation in the New World.

So began The Clovis Wars. As often follows breakthrough discoveries, the conventional wisdom fought to maintain its status. Prior to the Meadowcroft discoveries, the accepted date of the first human migration to North America had been set at 13,000 years ago by the 1936 discovery of a projectile point near the town of Clovis, N.M. The discovery of 16,000-year-old artifacts at Meadowcroft bumped the Clovis date out of first place on the migration-​to-​the-​Americas timeline and threw the field of archeology into a disciplinary tizzy.

The Clovis Wars were waged between two sets of professional archeologists. On one side were those whose minds were sufficiently open to allow new evidence to change their position about the date of human habitation of the New World. On the other, the Clovis Firsters had invested their careers in the Clovis date and were disinclined to change their views. Some never changed their minds, despite increasing evidence of Meadowcroft’s validity.

We weren’t looking for anything this different,” Adovasio said. “The Miller projectile point was the inadvertent lightning rod for all the flack about the site that emerged ever since. I underestimated the tenacity of people in terms of their retention of contrarian ideas. I didn’t think it would take a generation for them to alter their mindset.”

The Clovis Firsters had two basic arguments against Meadowcroft’s antiquity. First, they claimed the two-​mile-​thick Laurentian ice sheet, which extended as far south as Moraine State Park, an hour’s drive north of Pittsburgh, would have made human habitation at Meadowcroft impossible 16,000 years ago. Second, the carbon samples must have been contaminated, which would have made the radio carbon dates wrong. However, the sheer wealth of Meadowcroft finds, which include 20,000 human-​made artifacts, 95,000 animal remains, and 1.4 million plant remains, in combination with the exquisitely precise excavation and documentation techniques for which Adovasio has become renowned, give the site uncommon archeological status. Additionally, 52 radio carbon dates, ranging from 30,000 years ago to the time of the Revolutionary War, all correlate technically and chronologically with artifacts found at other sites. And since the time of the initial Meadowcroft finds, numerous other discoveries of pre-​Clovis habitation throughout North and South America have corroborated Meadowcroft’s age.

Meadowcroft is the single most complex archeological excavation I have ever seen,” said world-​renowned author and New World habitation expert Brian Fagan. “It’s a classic example of the very best in stratigraphic observation and meticulous recording in the field. The superb excavation methods give one great confidence in the important evidence for the first Americans found in the bottom layers of the site.”

In 1990, Adovasio accepted an offer from Mercyhurst College in Erie to establish a world-​class archeology program at the school. With the University of Pittsburgh’s blessing, he relocated the Meadowcroft collection and much of its staff to Mercyhurst, where he began building the new program. Today, he is Mercyhurst’s provost, dean of science and mathematics, and director of the Mercyhurst Archeological Institute. Active in archeological digs around the world, Adovasio travels to Meadowcroft several times a year to lecture on the site’s history and impact on archeology. Yedlowski, who uncovered the Miller Projectile Point, directs Mercyhurst’s Summer Field Training Program in Prehistoric Archaeology.

Meadowcroft Village is open Wed. – Sun. afternoons from Memorial Day to Labor Day and on weekend afternoons in May, September and October. Call (724) 5873412 or visit heinzhis​to​rycen​ter​.org.


Tom Imerito

Tom Imerito is president of Science Communications, a Pittsburgh technology communications consultancy.

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