ST. PAUL, Minn. --Mayor Chris Coleman battled the same emotions of any parent Thursday, as he briefed the media on the latest details of the mud slide that killed two boys on a school field trip.

"Our hearts, our minds, our prayers and our thoughts go out to the families of those who died and were injured," Coleman told a group of reporters who gathered at St. Paul Fire Station 1.

He said he could only imagine the joy in the hearts of the children hunting for fossils in the moments before the earth beneath them gave way. The mud slidepulledseveral of them down the hillside in Lilydale Park, where they were buried by more mud and sand.

Thecity's parks directorannounced that the popular fossil beds, built into the bluffs above Lilydale Road, will be closed indefinitely until the cause of that geological event can be fully investigated.

"We're taking steps to close that area and post it until we can complete the work and find out what happened here on site," Michael Hahm, director of the St. Paul Parks and Recreation Dept explained.

School groups have been visiting the site for decades, to see the imprints ofprehistoric organisms that were exposed when the cliffs were excavated by brick makersfor the clay deposits there.

"We issue an average of 400 fossil permits each year for the fossil grounds area," Hahm said.

"Last year we had 417 groups take out permits to dig for fossils there."

Construction Activity

Two large excavation machines were already perched atop a ravine in Cherokee Heights Park, above the bluffs where the accident occurred. And next to them were large drainage pipes that haven't been installed yet.

It's part of construction work the city has been doing in Cherokee Heights on roads inside the park, but Coleman said there's no indication activity on top of the bluff contributed to the mud slide.

"That activity was in another area," Coleman said.

"We can't answer that definitively at this point. We're going to find out. But there's no indication at this point that had anything to do with it."

He said much of the construction in the park was the trail system up above the bluffs, and that the ravine where the constructionequipment could be seen is to the east of the clay pit where the accident occured.

Coleman, a two-term mayor also found himself asking questions about whether the fossil hunting area should've been declared off-limits due to steady rains in the days preceding the tragedy.

He said it has always been treated as a wild and natural, but a massive sloughing off of rock, sand and soil had never happened in the area where fossil hunters frequent.

Hahm added that there had been no formal claims filed against the city for injuries in the fossil beds in the past five years. A financial claim must be made before any civil lawsuit can go forward.

Liability Waivers

But the permits issued by the city for the area are full of disclaimers and other clauses designed to protect the city from frivolous lawsuits.

The permit itself contains the phrase, "The park user at all timeswarrants that full and adequateadult supervision will be providedfor any minor persons the park user brings to Lilydale Park."

Thecity webpage advertising the fossil bedsincludes several other phrases intended to reduce the city's liability.

"The park user agrees to indemnify and hold harmless the City of Saint Paul from any and all claims of whatever kind or nature that may arise," one reads.

Another says, "The park user fully acknowledges that some of the conditions and locations within the Lilydale Regional Park area are hazardous to persons or property.."

It continues, "And park user specifically assumes the liability of the City of Saint Paul as such claims or injuries may arise to persons or property due to its unsafe conditions."

Mayor Coleman said the purpose of the language is to establish it's a wild and natural area, and that caution is advisable.

"The language isjust to say when you're in an area like this, be careful."