When Fossils Become Artifacts: Petrified Wood Tools and Fossil Beads in Southwest Parks

Paleontology — the study of the history of life from fossils in rock — and archeology — the study of past peoples through their artifacts, inscriptions, structures and other remains — are often confused, since both deal with old objects near the Earth's surface. They are distinct fields that share methods and standards of careful excavation.

Fossil inventories in national parks best known for their archeology have shown how often the two overlap. How people have known, valued and used fossils — seen through fossils found with artifacts, and through consultation with tribes — matters for how parks manage, protect and interpret them.

Fossils in human hands

• More than 3,000 pieces of petrified wood worked into artifacts — projectile points, scrapers, hammer stones, flakes — are catalogued across Park Service areas, mostly in the Four Corners region.
• Some fossils were made into effigies, jewelry and ornaments, and some built into structures.
• Some American Indian tribes have strong ties to fossils — spiritual, medicinal, scientific — and knowledge that tribal consultation can help parks appreciate.

A sample of catalogued finds:

Chaco Culture National Historical Park

Chaco protects hundreds of Ancestral Puebloan sites, occupied from about 850 to 1150 A.D., including multi-story great houses with hundreds of rooms.

• At least 8,500 records in the park's collection list petrified wood — trees turned to stone as minerals replaced their tissue — as a raw material.
• Coal from the Cretaceous Menefee Formation was made into beads and tools.
• Some fossils came from as far as the Gulf of Mexico, the Pacific Coast and Mexico.
• The Cliff House Sandstone used in Chaco's buildings holds Ophiomorpha — fossil crustacean burrows.

A petrified-wood projectile point from Chaco, late 900s to mid-1000s. NPS, Chaco Culture National Historical Park, CHCU 28466.

Mesa Verde National Park

Established on June 29, 1906, Mesa Verde protects the Ancestral Puebloans' cliff dwellings — more than 5,000 archeological sites, 600 of them cliff dwellings — from over 700 years of occupation, 1,400 to 700 years ago. 139 catalog numbers cover petrified wood from archeological collections, including drills, knives, scrapers, lithic cores, "medicine stones" and projectile points. A brachiopod with a drilled hole is on display in the park museum.

A drilled brachiopod fossil in the Mesa Verde museum. NPS, Mesa Verde National Park, MEVE 2109.

Pecos National Historical Park

Pecos spans 12,000 years of human history, from Pecos Pueblo and Spanish missions to the Santa Fe Trail and the Civil War battle of Glorieta Pass.

• Excavating Pecos Pueblo in 1915–1925, Alfred Vincent Kidder of the Robert S. Peabody Museum found "many hundreds" of fossils — mostly marine fossils from local limestone: corals, brachiopods, gastropods and crinoids. He also found a fossil rhinoceros tooth.
• Kidder thought many were collected as curios, and saw little sign of working — though the park's collection has fossil beads — and some fossils lay in "medicine outfits" buried with the dead.
• Petrified wood in ceremonial caches showed signs of heavy handling; Kidder thought it was prized for how it split and for the "clear, resonant tone" it gave when tapped.

Brachiopod shells from Pecos archeological sites. NPS, Pecos National Historical Park, PECO 21113, 19000 and 90.

A rhinoceros tooth found in 1932 in what is now Pecos National Historical Park. NPS, PECO 11854.

Four crinoid columnals, one polished by handling, probably once beads. NPS, PECO 1750.

Petrified Forest National Park

Proclaimed a national monument in 1906 and a national park in 1962 to protect Late Triassic petrified wood (about 200 million years old), the park also holds one of the world's best Late Triassic fossil records.

• In Navajo tradition the logs are the bones of the giant Yietso, slain by their forefathers (Yietso-bitsin); the Paiute saw them as arrow shafts shot by the thunder god Shinauav.
• Tools of the park's petrified wood turn up across the Four Corners, including projectile points of the extinct conifer Araucarioxylon arizonicum. John Wesley Powell saw American Indians still making axes and arrowheads from it in the late 19th century.
• Shells from the Gulf of California at Flattop Village suggest long-distance trade.
• Agate House, an eight-room pueblo built between 1050 and 1300 A.D., is made almost entirely of petrified wood. The Painted Desert Inn (first the Stone Tree House, 1924) also used a great deal of it, now hidden under stucco added by the Civilian Conservation Corps after the Park Service bought the inn in 1936.

A petrified-wood projectile point. NPS, Petrified Forest National Park, PEFO 2568.

Another petrified-wood point. NPS, PEFO 245.

Agate House, built by Ancestral Puebloans between 1050 and 1300 A.D. of petrified wood. NPS photo.

Salinas Pueblo Missions National Monument

The monument preserves 17th-century Spanish Franciscan missions and three large pueblos. It began as Gran Quivira National Monument (November 1, 1909), became Salinas National Monument (December 19, 1980) when the Abó and Quarai state monuments joined it, and took its present name on October 29, 1988. People reached the Estancia Basin 12,000 to 10,000 years ago.

• Excavations of Mound 7 at Gran Quivira turned up fossil shells of bivalves and brachiopods carved into bird effigies, and many shells cut with grooves. One rugose coral was shaped to resemble a person or a tooth.
• Two brachiopods at Abó were probably brought in by people.

A bird effigy carved from a brachiopod (Echinaria), from Mound 7 at Gran Quivira. NPS, Salinas Pueblo Missions National Monument, SAPU 5119.

A Texigryphaea pitcheri bivalve and a Composita brachiopod from Gran Quivira, both worked by people. NPS, SAPU 5118 and SAPU 5438.

White Sands National Park

A monument from January 18, 1933, and a national park from December 20, 2019, White Sands protects the world's largest gypsum dune field in the Tularosa Basin. For a decade, geologists, paleontologists and archeologists have studied a late Pleistocene mega-tracksite there — thousands of fossil footprints in old lake sediments, one of North America's largest concentrations of Ice Age tracks: mammoths, ground sloths, dire wolves, saber-toothed cats, camels and more, and hundreds of human footprints.

At one site, human and ground sloth tracks cross and overprint each other — the first known interaction between people and ground sloths in the fossil record, suggesting behaviors such as hunting.

Late Pleistocene trackways at White Sands showing humans and a ground sloth at the same moment, with a color diagram of the tracks (manus = hand, pes = foot). NPS photo.

Wupatki National Monument

Proclaimed on December 9, 1924, Wupatki protects red sandstone pueblos of the Ancestral Puebloans, centered on the 100-room Wupatki Pueblo, the area's hub in the 1100s. Its collection includes a fire hearth of petrified wood, a projectile point containing a possible fossil sponge, petrified-wood beads, scrapers, points and flakes, and a fossil coral.

In 1947, monument custodian David Jones, surveying with paleontologist Sam Welles and University of California students, found a hogan just outside the monument, built by Emmet Lee early in the 20th century. Slabs of Triassic Moenkopi Formation with obvious fossil vertebrate tracks were set inside and around it — placed, it seems, so the tracks could be seen.

A Triassic vertebrate track in a Moenkopi slab inside the historic hogan near Wupatki. NPS photo.

Another track slab at the hogan, on Bureau of Reclamation land just outside the monument. NPS photo.

What the examples show

Similar finds are known from many more parks, from Bryce Canyon and Canyonlands to Zion. Five lessons stand out:

1. Petrified wood was widely used for tools and projectile points across the Four Corners — Petrified Forest's points, for example.
2. Fossils found with artifacts can reveal long-distance transport, pilgrimage and trade — the horn coral at Bandelier.
3. Buildings sometimes include fossils, by design or by chance — Agate House.
4. Some fossils held sacred or ceremonial value — the petrified wood in Pecos "medicine outfits" with burials.
5. Because fossils in archeological sites matter to tribes, parks should consult with them on their care and interpretation.

Sources

Based on Vincent L. Santucci, Don Weeks and Rebeca Thornburg (National Park Service), "The Intersecting Crossroads of Paleontology and Archeology: When are Fossils Considered Artifacts?," National Park Service, citing Tweet and others (2009), Kenworthy and Santucci (2006), Kidder (1932), Bustos and others (2018) and others; a work of the United States government in the public domain. A caption's "Chaco Canyon National Historical Park" is corrected to Chaco Culture. Photographs from the parks' museum collections.