The next time you’re motoring along Miracle Mile on Wilshire Boulevard, imagine what prehistoric finds are just under your vehicle. For five years, the Metro Purple Line expansion has been under construction–a portion of which is just outside the fence of the La Brea Tar Pits and paleontologists from near and far have flocked to the site to see what has literally been “unearthed.”
Construction on the first phase of the Purple Line expansion began in 2014. Two years later, the first fossils were found in soil dating back more than 10,000 years. So far, they’ve found everything from Ice Age-era gophers, camels, bison, horses and parts of mammoths and giant ground sloths. A team of environmental monitors is at the excavation to take great caution in diverting construction to another part of the subway when they would come upon anything that even looked remotely like a fossil. These bones are removed and taken to a lab in Riverside to be identified. The team of paleontologists was there from the beginning of construction and since then have come away with a trove of treasures that bear witness to LA’s prehistoric past.
“We’re there everyday looking for fossils and we weren’t disappointed at the findings,” said Ashley Leger who is among the paleontologists working at any of the three Purple Line station sites along the thoroughfare. Leger is the paleontological field director for Cogstone Resource Management, providing scientific services at the construction site. She teaches the environmental monitors there on site to look for irregularities in size, shape, color and texture in the soil that may indicate the bones of an ancient animal.
The icy life span of the Pleistocene Epoch (Ice Age) unfurled for more than 2.5 million years, from 2.6 million to 11,000 years ago. This time span represents the geographic and geologic engines that predestined and ignited our most recent ancestral Ice Age. As glaciers and cold climates advanced, land animal migration routes were closed off and animal populations were isolated from one another. Habitats and food sources began to push toward the equator. During these “interglacial retreats,” new migration routes began to form, and plant and animal population ranges shifted and expanded. This led to various ecosystems (e.g. “mammoth steppe”), scrublands and boreal forests that marched more toward the north and south poles. In response to the extreme geographic and climatic swings of the Pleistocene epoch, large-bodied, cold-adapted migratory mammals were selected to endure, hence the series of mammoth and mastodon findings locally.
At each stop, the scientists delve more into local geological history. “Most of the fossils were found at the Wilshire/La Brea site, but a lot of fossils were also discovered at the Wilshire/La Cienega site,” Leger said. “They were all well preserved, especially the nearly complete and pristine skull of a juvenile Columbian mammoth.” By completion sometime in 2027, you’ll likely see a number of these fossils at the Los Angeles County Museum of Natural History and some, possibly, at the La Brea Tar Pits. Fossil findings are not exclusive to Wilshire Boulevard simply because of the proximity of the La Brea Tar Pits: Workers excavating the Crenshaw Metro line uncovered a bone from a prehistoric bison and a fragment from a prehistoric giant sloth.
Leger said the entire team of scientists remains very excited about what they might discover in the fossil-rich area. Among those finds were camel bones which she said are “quite rare” in the fossil record of the Southland area. One camel bone was later identified as a roughly 20-inch-long radioulna (forearm) from the extinct Camelops hasternus.
All fossil discoveries are noteworthy, especially what is believed to be a femur of an Ice Age elephant–either a mastodon or mammoth. The bone is about 36 inches long. In time, excavation crews would find a tusk (again from either a mastodon or mammoth), tooth fragments, and various segments of vertebra likely connected to this animal.
It’s a challenge to precisely date any of the findings because soil layers don’t always provide specific information needed for scientific clarification. Leger said the fossils can be placed in the Pleistocene Epoch, conceivably making them more than 11,000 years old. This means that they could have co-existed with humans, which Leger explains could help to put their age into perspective. “They’re very relatable animals,” she said, “but it’s just exciting enough that you get to engage your imagination.”
While fossils found on federal lands are protected, few states match California’s strict environmental laws that require paleontologists to monitor excavation sites that carry the potential for fossil finds. Essentially, ancient remnants buried in state, local or private soil elsewhere nationwide can easily get lost or destroyed.
Leger believes that the finds being uncovered deep under Los Angeles streets are very important to the scientific community. With rising urbanization and development around the country, more and more fossils may soon be buried forever under layers of concrete and brick. That’s why taking advantage of these local findings is so crucial.
“We’re missing things all over the country,” she said. “You never know where that great fossil find is going to happen. You never know where you’re going to find that missing link.”
Next time you’re driving down Wilshire Boulevard, remember that you may well be travelling over some of the “fossil” fuels powering your precious “ride-or-die.”