The students in Natural Science 10, "Earth History and Present Patterns" all prepared to go on a field trip yesterday, as they had Saturday, to view rock formations in the Connecticut River Valley. But at 10:15 A.M., on their second stop, the bus broke down.

Lawrence Lipke, the course's head sectionman, tried to find the other bus and back-up cars on the field trip but they had taken a shortcut to the next stop and could not be found. In fact, students in the course said yesterday the busdriver and another car got lost.

Lipke said last night he called the bus line that had rented out the busses to the class, but could not get another bus. They were all rented out, primarily to groups wanting to see foliage.

He then called the state police, and asked them to locate the other bus. Apparntly the police could not find them either, but at 3 P.M. the other bus returned to the stop.

Meanwhile Lipke said he called a small bus line that had two busses, and the owner of the company drove out to rescue the stranded students.

The students, however, had wandered off. Some hitchhiked back to Cambridge, others were busy climbing the nearby steep rock face of Turner's Falls, and a few more were asleep in the stalled bus.

They headed back for Cambridge at 3:15, only six hours after the breakdown.

One student said she "wasted a day, but it sure was a good laugh."