Meadowcroft Rockshelter: Human Evolution and Pre-Clovis Evidence

Introduction to Meadowcroft Rockshelter

Meadowcroft Rockshelter is an excavated archaeological site for human remains located near Avella in Washington County, Jefferson Township, in the southwestern part of Pennsylvania, United States. The site is a rock shelter overlooking the bluff of Cross Creek, a tributary of the Ohio River. It is situated approximately 27 miles west-southwest of Pittsburgh, within the Pittsburgh metropolitan area. The site was associated with the Monongahela Culture around 1570 and is operated within the Heinz History Center. Artifacts from the site suggest that it may have been inhabited for over 19,000 years, dating back to the times of the Paleo-Indians.

The objective of this paper is to apply the scientific method to investigate the impact of humans on the ecosystems and biodiversity reflected in the paleontological data of the Meadowcroft Rockshelter site. The paper also evaluates findings from linguistic, genetic, and paleontological perspectives to explore changes in geographical distribution, innovation (tool use), gene expression, language, and culture (architecture and art) within and across human societies.

Human Impact on the Meadowcroft Ecosystem

Human occupancy at the Meadowcroft Rockshelter has been dated to between 16,000 and 19,000 years ago. There remains, however, ongoing controversy regarding the exact date. A survey conducted by the Society for American Archaeology found that 38% of American archaeologists support the earlier date while 20% reject it. If the earlier date is confirmed as authentic, Meadowcroft would be the oldest known archaeological site in North America (Adovasio, Donahue, & Stuckenrath, 1998; James & Jake, 2003).

Selker (2010) suggests the site is approximately 16,000 years old. The archaeological team researching the site uncovered an array of artifacts including whole tools, projectile points, stone tool fragments, wooden instruments, and pottery fragments. To determine the precise age of these artifacts, the team conducted radiocarbon dating. As Selker (2010, p. 10) notes, "To everyone's surprise, the tests revealed that some of the artifacts dated back 16,000 years."

Meadowcroft is considered the first site to contain evidence of pre-Clovis populations. The sophisticated tools found there suggest that the early occupants were hunters and gatherers. Selker (2010) argues that the ancient inhabitants used flint spearheads for hunting and typically pursued large game such as elk and deer. When large game was scarce, they sought smaller protein sources, including birds, fish, and mollusks from nearby water sources.

One of the most significant human impacts documented at Meadowcroft is the extinction of megafauna. The site provided the earliest collection of fauna and flora materials ever recovered in North America. Based on the 149 animal remains excavated, there is evidence that inhabitants hunted smaller animals in addition to large game, and also engaged in agricultural activities, producing food such as corn, fruits, seeds, nuts, and squash. The site yielded pre-Clovis remains found at 11.5 feet beneath the surface, along with many tools including pottery, lamellar blades, bifacial fragments, chipping debris, and lanceolate projectile points. Goodyear (2007) argues that Meadowcroft presents the longest-standing archaeological evidence for a pre-Clovis presence. The debitage and stone tools constitute a highly significant collection of tool kits recovered from the site.

Several hypotheses have been proposed regarding the genetic and linguistic origins of the earlier settlers at Meadowcroft. The Clovis hypothesis argues that early settlers came from Siberia and were unable to return due to glaciation blocking the region now known as Canada. Archaeologist James Adovasio believes that the ancient people of Meadowcroft were among the earliest settlers in the United States, arriving via the Canadian ice-free corridor. Genetic evidence supporting a Siberian origin has been drawn from DNA comparisons between modern Americans and Siberians. The pre-Clovis evidence, however, also reveals genetic diversity among the site's inhabitants. Linguistic evidence similarly points to considerable language diversity among Native Americans.

Genetic and Linguistic Evidence of Early Settlers

Goebel et al. (2008) argue that the earlier settlers of Meadowcroft included people from both Siberia and South America. They support the view that colonization occurred following major glaciations in North America that prevented settlers from returning to their points of origin. A report by the National Park Service (2013) further indicates that Paleo-Indians were the earliest inhabitants of the site. Before 10,000 B.P., these Paleo-Indian inhabitants lived in and adapted to the late glacial environment. The Meadowcroft excavations have revealed the remains of a large variety of extinct megafauna, including mammoth, mastodon, symbos, and caribou.

The significance of the site with respect to human evolution and migration is that a large number of American descendants are believed to have originated from Siberia and the northern part of Alaska. Nevertheless, the Paleo-Indians remain recognized as the earliest settlers of the site, yielding remarkable findings about the earliest human occupation of the New World.

"Unquestionably, the human skeletal evidence across the Americas shows that the New World was populated by Homo sapiens" (Goebel et al., 2008, p. 1500). The data collected indicates that the Meadowcroft site dates back approximately 15,000 years, although a small group of foragers may have occupied North America before that time. Meadowcroft represents evidence of human presence between 15,000 and 16,500 years ago. The stratified, multicomponent site has yielded 20,000 artifacts, 33 fire floors, 150 fire pits, 52 ash and charcoal lenses, 1.4 million plant remains, and approximately one million faunal remains.