A subway construction project in Los Angeles has unearthed a variety of 11,000-year-old fossils since last year and is likely to uncover even more in the upcoming months.

Because of the subway project’s proximity to the La Brea Tar Pits, the Los Angeles County Metro hired a team of paleontologists to monitor the excavation work at the three Purple Line Extension stations. The team, led by Dr. Ashley Leger, has been on hand since 2013, working alongside the construction crews.

The discoveries began with bones of Colombian mammoths from the Ice Age. According to the Los Angeles County Metro website, the first discovery—a three-foot section of tusk and mastodon tooth fragments—was made on November 23 of last year. Then a few days later a nearly-complete mammoth skull was found.

Since those first discoveries, the paleontologists have found the bones of an ancient bison, a giant sloth, an ankle bone from a horse, a leg bone from an extinct camel, a tooth from a mastodon and a turtle, according to CBS News.

"We've got mammoths and mastodons on one end," Leger said. "We're finding horses over here." 

[For more photos of the fossils discovered during subway construction click here.]

After being uncovered each fossil is carefully removed, covered in plaster for preservation and moved offsite (allowing construction to continue) for further study. At this point the fossils belong to the Natural History Museum of Los Angeles County, though pieces found surrounded by asphalt are sent to the La Brea Tar Pits and Museum.

In the upcoming months, the tunnel will close in on the tar pits, where Leger expects the number of finds to explode. Sticky, black tar—which still bubbles up from the ground near the museum—would have easily trapped a number of prehistoric mammals. According to the La Brea Tar Pits and Museum, more than 1 million fossils have been found in the tar pits. Leger is hoping to add to that number, keeping an eye out for more predators like a saber-toothed cat to add to the growing Purple Line collection.

"Under everyone's feet is this rich history that everybody misses. So, we get to open up people's eyes, open up people's imagination and bring the past to life,” Leger said.