GRANTS PASS, Ore. (AP) — Archaeologists have uncovered a stone tool at an ancient rock shelter in the high desert of eastern Oregon that could turn out to be older than any known site of human occupation in western North America. 
 
 The find was announced Thursday by the U.S. Bureau of Land Management, which controls the land on which the site was found. 
 
 University of Oregon archaeologist Patrick O'Grady, who supervises the dig, says the Rimrock Draw Rockshelter outside Riley has not been fully excavated. But the tool, a hand-held scraper chipped from a piece of orange agate not normally found in eastern Oregon, was found about 8 inches below a layer of volcanic ash from an eruption of Mount St. Helens that has been dated to 15,800 years ago. The depth was about 12 feet below the surface. 
 
 Bureau of Land Management archaeologist Scott Thomas said that if the age of the site holds up to scrutiny, it would be the oldest west of the Rockies, and another predating the so-called Clovis culture, once generally believed to be the first people to migrate from Asia into North America. The earliest Clovis artifacts, known for distinctive and elegant stone points, are dated to about 13,000 years ago. 
 
 O'Grady called the find "tantalizing," but he added that they want to continue digging this summer to see whether the volcanic ash covers the entire area. 
 
 Donald K. Grayson, professor of archaeology at the University of Washington, said the scientific community would be skeptical. 
 
 "No one is going to believe this until it is shown there was no break in that ash layer, that the artifact could not have worked its way down from higher up, and until it is published in a convincing way," he said. "Until then, extreme skepticism is all they are going to get." 
 
 Two pre-Clovis sites are well documented and generally accepted by scientists, Grayson said. One is Paisley Cave, located about 60 miles southwest of the Rimrock site. The other is Monte Verde in Chile. Both are dated about 1,000 years before the oldest Clovis sites. 
 
 If the date of Rimrock holds up, it would put people at the site about 1,500 years earlier, at the end of the Pleistocene era, when mastodons, mammoths, camels, horses and bison roamed the area. 
 
 The find has yet to be submitted to a scientific journal for publication, but it has been reported in newsletters and at conferences, Thomas said. 
 
 Thomas found the site several years ago, while taking a break from carrying supplies to a session of the University of Oregon Archaeological Field School nearby that O'Grady was overseeing. 
 
 Thomas said he noticed an outcropping of an ancient lava flow, with some very tall sage brush growing in front of it, indicating very deep sediment deposits. The soil was black in front of the rock, indicating someone regularly built cooking fires there for a long time. An ancient streambed ran by, which would have given people more reason to stay there. And on the surface, he found a stone point of the stemmed type, found at sites both older and younger than Clovis. Similar points have been found at Paisley Cave 
 
 Volunteers looking around the surface found some 30 stemmed points, and the field school started excavations in 2011, O'Grady said. Uncovered above and below the volcanic ash layer were fragments of teeth believed to be from ancient camels. 
 
 Tests by Archaeological Investigations Northwest Inc. of Portland on blood residue on the agate scraper were consistent with the bovid family of animals, Thomas said. The most likely bovine animal living in Oregon at that time would have been an ancestor of the buffalo. ||||| PORTLAND, Ore. - 
 
 Near the Rimrock Draw Rockshelter outside of Riley in southeast Oregon, archaeologists recently discovered evidence suggesting one of the oldest known human occupations in the western United States, officials said Thursday. 
 
 Archaeologists with the Bureau of Land Management and the University of Oregon Archaeological Field School have been excavating at the Rimrock Draw Rockshelter since 2011. 
 
 Their discoveries have included a number of stone projectile points and tooth enamel fragments likely belonging to a prehistoric camel (Camelops sp.) that became extinct approximately 13,000 years ago. 
 
 But what has the archaeological community most excited is a small stone tool found below a layer of volcanic ash. 
 
 Near the bottom of a 12-foot deposit, archaeologists discovered a layer of ash that was identified as volcanic ash from a Mt. St. Helens eruption about 15,800 years ago. 
 
 Beneath the layer of volcanic ash, archaeologists discovered a small orange agate tool believed to have been used for scraping animal hides, butchering, and possibly carving wood. 
 
 A blood residue analysis of the tool revealed animal proteins consistent with bison, the most likely species being Bison antiquus, an extinct ancestor of the modern buffalo. 
 
 “The discovery of this tool below a layer of undisturbed ash that dates to 15,800 years old means that this tool is likely more than 15,800 years old, which would suggest the oldest human occupation west of the Rockies,” said Scott Thomas, BLM Burns District archaeologist. 
 
 Presently, Oregon’s Paisley Cave, also managed by the BLM, is considered home to the earliest known residents of North America based on human physical evidence. 
 
 In 2008, a team of archaeologists, led by Dr. Dennis Jenkins with the University of Oregon's Museum of Natural and Cultural History, discovered coprolites - dried feces - containing human DNA dated over 14,000 years old. 
 
 Dr. Patrick O’Grady, with the University of Oregon Archaeological Field School, has been directing the Rimrock Draw Rockshelter excavations since they began. 
 
 “When we had the volcanic ash identified, we were stunned, because that would make this stone tool one of the oldest artifacts in North America. Given those circumstances and the laws of stratigraphy, this object should be older than the ash,” said O’Grady. 
 
 "While we need more evidence before we can make an irrefutable claim, we plan to expand our excavation this summer and hopefully provide further evidence of artifacts found consistently underneath that layer of volcanic ash. That’s the next step,” he added, 
 
 The University of Oregon Archaeological Field School, in partnership with the BLM and volunteers from the Oregon Archaeological Society, will begin its fifth season this summer, offering students, researchers and volunteers invaluable field experience. 
 
 Stan McDonald, BLM Oregon/Washington lead archaeologist, explained the potential this discovery has for the archaeological community. 
 
 “For years, many in the archaeological field assumed that the first humans in the western hemisphere were the Clovis people – dating to around 13,000 years ago," McDonald said. "While a handful of archaeological sites older than Clovis cultures have been discovered in the past few decades, there is still considerable scrutiny of any finding that appears older.” 
 
 “With the recent findings at Rimrock Draw Shelter, we want to assemble indisputable evidence, because these claims will be scrutinized by researchers," he said. "That said, the early discoveries are tantalizing.” 
 
 Flickr photo album: https://www.flickr.com/photos/blmoregon/sets/72157651118216896/ ||||| Knife, bone, and dung cast doubt on Bering Strait theory and indicate humans spread through Americas 1,500 years earlier than thought, researchers say 
 
 A stone knife, mastodon bones and fossilized dung found in an underwater sinkhole show that humans lived in north Florida about 14,500 years ago, according to new research that suggests the colonization of the Americas was far more complex than originally believed. 
 
 Archaeologists have known of the sinkhole in the Aucilla river, south of Tallahassee, for years. But they recently dived back into the hole to excavate what they call clear evidence that ancient mankind spread throughout the Americas about 1,500 years earlier than previously thought. 
 
 Almost 200ft wide and 35ft deep, the sinkhole was “as dark as the inside of a cow, literally no light at all”, according to Jessi Halligan, lead diving scientist and a professor at Florida State University at Tallahassee. Halligan dived into the hole 126 times over the course of her research, wearing a head lamp as well as diving gear. 
 
 In the hole, the divers found stone tools including an inch-wide, several inch-long stone knife and a “biface” – a stone flaked sharp on both sides. The artifacts were found near mastodon bones; re-examination of a tusk pulled from the hole confirmed that long grooves in the bone were made by people, probably when they removed it from the skull and pulled meat from its base. 
 
 “Each tusk this size would have had more than 15lbs of tender, nutritious tissue in its pulp cavity,” said Daniel Fisher, a paleontologist at the University of Michigan who was a member of a team that once removed a tusk from a mammoth preserved in Siberian permafrost. 
 
 Of the “biface” tool, Halligan told Smithsonian magazine: “There is absolutely no way it is not made by people. There is no way that’s a natural artifact in any shape or form.” 
 
 When ancient people butchered or scavenged the mastodon, the sinkhole was a shallow pond: a watering hole for men, mastodons, bison, bears and apparently dogs. The researchers found bones that appear to be canine, suggesting dogs trailed the humans, either as companions or competitors for scraps. 
 
 The discovery makes the sinkhole the earliest documented site for humans in the south-eastern United States. The researchers published their findings in the journal Science Advances on Friday, writing that the artifacts show “far better” evidence of early humans than previous work at the site. 
 
 “The evidence from the Page-Ladson site is a major leap forward in shaping a new view of the peopling of the Americas at the end of the last Ice Age,” said Mike Waters, an archaeologist at Texas A&M University. 
 
 “In the archeological community, there’s still a terrific amount of resistance to the idea that people were here before Clovis,” he added, referring to the so-called “Clovis people”, a group long thought the first band of humans in the Americas. 
 
 Facebook Twitter Pinterest Divers investigate the Page-Ladson archaeological site in Florida. Photograph: S. Joy/AP/Texas A&M’s Center for the Study of the First Americans 
 
 Waters said that the watering hole would have made for “easy pickings” for humans looking to corner prey. Halligan suggested the ancient hunter gatherers may have been the first seasonal nomads of the east coast, traveling south in the winter. 
 
 “They were very smart about local plants and local animals and migration patterns,” she said. “This is a big deal. So how did they live? This has opened up a whole new line of inquiry for us as scientists as we try to understand the settlement of the Americas.” 
 
 Humans are thought to have crossed into the Americas during the Ice Age, when land linked Siberia to Alaska, but the timing of the crossing is a question of long dispute. In the 1930s, archaeologists found distinctive spearheads among mammoth bones near Clovis, New Mexico. For decades the Clovis people were considered the first to colonize the Americas, around 13,000 years ago. Thousands of Clovis spearheads have been found around North America and as far south as Venezuela. 
 
 But in the last two decades, archaeologists have found an 11,000-year-old skull in Brazil, human DNA by way of feces in a cave in Oregon, evidence of humans in coastal Chile as long as 14,800 years ago, and spearheads in Texas that could date human arrival in the Americas to 15,500 years ago. Most of the manmade artifacts found in these disparate sites lack the signatures of the Clovis people. 
 
 At the Florida site, the researchers analyzed twigs in fossilized mastodon dung to date the bones and artifacts, finding them to be about 14,550 years old. The timing casts the Bering Strait theory into doubt, Halligan said: the ice-free land bridge was only open for a few thousand years. 
 
 “So the ice-free corridor is not our answer for how the Americas were initially colonized,” she told the Smithsonian. 
 
 “The logical way people could have come to Florida by 14,600 years ago is if their ancestors entered the Americas by boat along the Pacific Coast,” Waters told Discovery News. 
 
 “They could have travelled by boat to central Mexico, crossed and come along the Gulf Coast. They could have entered the Americas via the Columbia river and then travelled inland to the Mississippi river and followed it down and entered the Gulf Coast, eventually making their way to Florida.” 
 
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 Mastodon remains have been found as far north as Kentucky, she said. Fisher added that the discovery that “humans and megafauna coexisted for at least 2,000 years” casts doubt on another theory: that the Clovis hunters quickly made mammoths and mastodons extinct as they launched a “blitzkrieg” across the continent. 
 
 “That means that however humans and mastodons interacted, it took at least two millennia for the process of extinction to run to completion,” he said at a press conference. The main reason the giant mammals went extinct, he said, was probably the warming climate. 
 
 Several anthropologists not affiliated with the research said it added to the mounting evidence of a complex, many-staged migration into the Americas. 
 
 “I think this paper is a triumph for underwater archaeology and yet another nail in the coffin of the Clovis-first theory,” Jon Erlandson, an anthropologist at the University of Oregon in Eugene, told Nature magazine. 
 
 “I don’t know what else to tell you,” archaeologist Michael Faught, one of the reviewers of the research, told National Geographic. “It’s unassailable.”
– A small stone tool unearthed in eastern Oregon appears to be so ancient that the history of humans in the area may have to be rewritten, archaeologists say. The agate scraper found at a rock shelter was below a 15,800-year-old layer of ash from Mount St. Helens, making it potentially older than any other evidence of human occupation west of the Rocky Mountains, reports the AP. Analysis of the tool—which is made from orange agate not usually found in the area—revealed it had been used to butcher an animal believed to be the extinct buffalo species Bison antiquus, KTVZ reports. University of Oregon archaeologist Patrick O'Grady says the team plans to keep excavating the site after the "tantalizing" find, which may be older than any other find predating the Clovis people once thought to be the first in North America, NBC News reports. University of Washington professor of archaeology Donald K. Grayson, however, predicts there will be a lot of skepticism about the find. "No one is going to believe this until it is shown there was no break in that ash layer, that the artifact could not have worked its way down from higher up, and until it is published in a convincing way," he tells the AP. "Until then, extreme skepticism is all they are going to get." (Experts believe they have found evidence of a long-lost civilization in the Honduran rainforest.)