• Naraoia, a soft bodied “trilobitomorph,” a trilobite-like arthropod from the new Burgess Shale locality at Marble Canyon. (Photo: Jean-Bernard Caron/ROM)

It’s not easy for 505 million years of biological and evolutionary history to sneak up on you.

But that’s just what happened when scientists discovered a massive new fossil deposit in Kootenay National Park.

Possibly the largest deposit of early Cambrian remains found to date, the fossils surfaced on a routine survey Robert Gaines and others were conducting of the larger area surrounding the Burgess Shale, currently recognized as one of the world’s largest Cambrian deposits. It was part of an expedition spearheaded by the Royal Ontario Museum.

Gaines, the chair of the geology department at Ponoma College in California, says that although the Royal Ontario Museum-led expedition was initiated in 2008, it wasn’t until 2012 that they discovered the new deposit while they were working about 42 kilometres southeast of the original Burgess Shale discovery. Gaines says they were doing some routine scouting when they suddenly became confused by the rocks along a slope. Members of the team started picking up Cambrian fossils one by one, including several that immediately appeared to be new species or creatures found only on the other side of the planet in China.

“There was a lot of whooping, shouting and exclamation,” says Gaines. “This isn't something you imagine is still out there.”

Molaria, a soft-bodied arthropod from the new Burgess Shale locality at Marble Canyon. (Photo: Jean-Bernard Caron/ROM)

The new discovery is probably 100,000 to 200,000 years younger than the original Burgess discovery — not enough to mark huge differences in evolution. “It may have provided differences in species communities, the animals living on the seafloor. But it’s still all about 505 million years old,” he says.

The Cambrian explosion was the first major animal era of the planet. “There was no life on land at this point,” he says.

But the fossils are important because Gaines says they tell us the structure of the animal tree at its very basic roots. The original Burgess quarry isn’t really open to further excavation, and Gaines says it’s not likely that new species will appear out of it.

A lot of the fossils are arthropods, but they have also found some problematic specimens. “They represent dead-end lineages that didn’t go on to form new groups.” Gaines says most of the major animal groups alive today began to form in this period. Some of the fossils even look similar to species alive today.

They’ve also been able to find some of the missing links between animal groups like arthropods and worms, animals that were alive at the time.

So far, the team has uncovered around 3,000 specimens representing 55 distinct species in the new deposit, at least 12 of which are new to science. The original Burgess site has resulted in approximately 200,000 between the ROM, the Smithsonian Institute, and the Geological Survey of Canada. Gaines says the team will be submitting an application to UNESCO to extend the World Heritage area to include the new discovery.