ST. PAUL — 911 calls moments after the ground gave way beneath students on a field trip to a St. Paul park show the frantic confusion as chaperones tried to account for the children.

A bluff at the riverside park collapsed, killing two fourth-grade students and injuring two others from Peter Hobart Elementary School in St. Louis Park last month. Six chaperones were with the 40 children at Lilydale Regional Park. One unidentified female caller struggled to tell a dispatcher where the collapse had occurred in the park. The caller directed someone to count the children as she talked to the dispatcher and tried to comfort a partially-buried child.