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The Columbia Press
August 14, 2020
Hemisphere’s earliest people lived in Oregon
By Kristin Strommer
Museum of Natural and
Culture History
In 2017, an international
team of researchers joined
archaeologist Dennis Jenkins
at Oregon’s Paisley Caves.
Their aim? To re-examine
the site’s sediment and cop-
rolites, a nice way of saying
ancient fecal remains, in
hopes of resolving a long-
standing debate about when
people first arrived in North
America.
Results of their study, pub-
lished last month in “Science
Advances,” confirm Jenkins’
earlier finding that people
were living at the site a thou-
sand years before the appear-
ance of the Clovis people,
long thought to be the conti-
nent’s first. That culture was
named for the distinctive
spear points first discovered
near Clovis, N.M.
Paisley Caves is a system
of caves in southcentral Ore-
gon. Scientific excavations at
the site began in 2002.
Jenkins, a senior archae-
ologist at the University of
Oregon’s Museum of Natu-
ral and Cultural History, first
discovered the coprolites two
decades ago. Since then, ra-
diocarbon dating has firmly
established their antiquity,
with some specimens dating
back 14,400 years.
Further examination by
University of Copenhagen
geneticist Eske Willerslev
revealed that the coprolites
were human based on the mi-
tochondrial DNA they con-
tain. Still, questions about
the coprolites remained, with
researchers from Boston to
Milan challenging the speci-
mens’ human attribution.
“Critics pointed to the fact
that DNA can be mobile in
sediment,” Jenkins said. “So,
theoretically, some of the
DNA present in the copro-
lites could have been the re-
sult of contamination from
Left: Dennis
Jenkins inside
Paisley Cave.
Courtesy UO
Below: A BLM
archaeologist
outside Paisley
Five Mile Cave
outside the tow
of Paisley.
Courtesy BLM
overlying layers.”
The new study was a direct
response to these questions.
It zeroed in on fecal lipids, or-
ganic substances such as bile
acids and sterols that are far
less likely than DNA to move
around in sediment and can
reliably identify the species of
the organism that produced a
particular poop.
The study was co-authored
by University of Newcastle
archaeologists
Lisa-Marie
Shillito and John Blong along
with Jenkins, UO archaeolo-
gist Tom Connolly and Uni-
versity of Bristol chemists
Helen Whelton and Ian Bull.
The researchers analyzed
the lipids found in 21 sam-
ples taken from the Paisley
Caves coprolites. All 21 had
been identified as human
through earlier analysis, and
all but two had previously
been radiocarbon dated. The
analysis confirmed that three
of six coprolites identified
as human by mitochondrial
DNA were, in fact, of human
origin.
“The study demonstrates
that while there probably was
some degree of DNA move-
ment from younger human
occupations into older sed-
iments, people were indeed
living at Paisley Caves as
much as 14,200 years ago,”
Jenkins said.
To further confirm the age
of one of the coprolites, the
authors also radiocarbon
dated a bulrush fiber artifact,
likely a fragment of a basket
or mat, found in the cave sed-
iment.
“The fragment was dated to
roughly 14,000 years before
present, giving us a direct ra-
diocarbon age on a pre-Clovis
cultural artifact and confirm-
ing the stratigraphic integ-
rity of the cave sediment,”
said Connolly, director of ar-
chaeological research at the
Museum of Natural and Cul-
tural History and an expert
in the fiber artifacts of the
northern Great Basin.
Together, the results con-
firm that the Paisley copro-
lites are the oldest directly
dated human remains in the
Western Hemisphere.
The study is an example of
how the dialogue of science
operates, Connolly said.
“Our understanding is driv-
en forward by skepticism,”
he said. “When some ques-
tioned the attribution of hu-
man to the coprolites, DNA
studies confirmed the source.
When some questioned the
accuracy of the DNA find-
ings, scientists pursued novel
approaches to confirm them.
When multiple studies point
to the same result, we gain
much greater confidence in
our findings.”