Digging just below the surface of the Denver Botanic Gardens can turn up all kinds of things.

The reason: The gardens, one of the largest and most visited botanical gardens in the United States, sit atop an old cemetery.

Excavation for a new multistory parking garage at 1005 York St. came to an abrupt halt at noon today when the Denver coroner’s office announced that an old grave had been discovered.

“We will respond, and the bones will be removed and given to the mortuary for direct burial,” said Michelle Weiss-Samaras, Denver’s chief deputy coroner.

That bones were found was hardly unexpected, said Larry Conyers, an associate professor of archaeology at the University of Denver.

“It doesn’t surprise me. That whole area used to be the city graveyard,” said Conyers.

In 1858, when Gen. William Larimer claim-jumped land from the Arapaho tribe to create Denver, he put the city’s cemetery in a field now home to the current Cheesman and Congress parks and the Denver Botanic Gardens.

Conyers annually takes his students out to Cheesman Park, where he says many coffins remain buried.

“I know where there are a whole bunch of caskets — adults and children,” said Conyers, who is one of the world’s leading experts in ground-penetrating radar, which he compares to a CT scan of the ground.

He tests his students to see whether they can detect the caskets below the surface.

“I use it as a test case. I know where they are, and I see if they can find them,” said the archaeologist, who with his radar has found a Christian church in Tunisia, a buried Mayan farm village in El Salvador and Roman temples in Jordan.

Will Jones, spokesman for the Denver Botanic Gardens, said that excavation for the new three-story parking structure, which will hold about 320 cars, began about three weeks ago.

Because the Botanic Gardens didn’t want to block the view of people living in the surrounding neighborhood, a decision was made to have two levels below ground.

Knowing the history of the area, specifically that it used to be a cemetery, the gardens contacted the Denver coroner’s office to coordinate efforts should graves be found, said Jones.

“We didn’t think we’d find anything,” said Jones. But the coroner’s office said that “if you find anything that looks like anything, stop!” said Jones.

So when construction workers spotted what looked like splintered wood and possible human remains at around noon, everything stopped, and the coroner’s office was contacted.

Officials from the coroner’s office spent about four hours at the site today, and will resume digging at the site tomorrow morning.

Jones said that about 9,000 bodies were removed from Cheesman Park, Congress Park and the Botanic Gardens area around 1950.

But Conyers said the area is still full of caskets and corpses.

When Conyers goes to the area, he often notices lumpy depressions in the land. The topsoil covering graveyards often appears lumpy because of collapsed wooden caskets, said Conyers. Even in places where bodies were exhumed, refilling the hole with different soil can cause pits in the land.

Conyers said today that he has heard of people who live or work in the Cheesman-Congress Park area who have artifacts from the old graveyard.

Although he knows where caskets and bodies remain, he isn’t telling anyone where they are.

“We let them lie in peace,” said the archaeologist.

Howard Pankratz: 303-954-1939 or hpankratz@denverpost.com