Ever since ice age fossils were discovered by a crew digging a subway extension near Wilshire Boulevard in Los Angeles in 2014, a team of paleontologists have been working to recover fossils that date back 300,000 to two million years from the site under the streets of the city.

In the years since then, numerous fossils of several extinct creatures that roamed the surface of Earth several thousand years ago were uncovered.  The region under scrutiny was covered with grasslands and forests during the last ice age, around 10,000 years back.

Over the past few years, the subway crew and paleontologists have worked in unison under the city to make some remarkable findings. Some of the most prolific finds here include a partial rabbit jaw, a mastodon tooth, a camel foreleg, a bison vertebrae and a horse's ankle bone.

The team has also unearthed several fossilized geoducks, sand dollars, digger pine tree cones and seeds.

In the city’s west side, the team of paleontologists from Page Museum at the La Brea Tar Pits and the crew of Los Angeles County Metropolitan Transportation Authority made a startling discovery about a year ago.

During the construction of phase II of the subway's Purple Line, the team uncovered an intact skull of a juvenile mammoth. After 15 hours of careful excavation, the team was able to secure the well preserved fossil. The surprising part was that the tusks were still intact.

The team with help of the construction staff hauled the huge skull a mile or so to Los Angeles' La Brea Tar Pits and Museum, home to one of America's most fossil-rich sites.

In fact, in 2014 there were reports that the newly-discovered subway fossils were much older than the ones unearthed before at La Brea Tar Pits, and revealed the presence of an ancient beach and a time when an ocean covered Los Angeles.

The fossils also indicated a cooler climate during the Pleistocene epoch.

The 12-year-old Colombian mammoth was named “Hayden” after Hollywood actress Hayden Panettiere, who featured in the TV series "Nashville" and "Heroes."

Assistant curator Dr. Emily Lindsey was quoted in a Phys.org report as calling the discovery a "pretty remarkable find," noting that while thousands of dire wolf and saber-toothed cat remains have been uncovered in L.A., only about 30 mammoths have been uncovered.

"It's an absolute dream come true for me," said Ashley Leger, chief paleontologist in the team who spent the previous decade at a South Dakota mammoth site with no discoveries comparable to the one made in Los Angeles.

"It's the one fossil you always want to find in your career."

As the city expands its underground network, the team expects the the number of discoveries to grow too.