NEW SCOTLAND — Two vanloads of students stopped along the Onesquethaw Creek on Friday for some geocaching before heading up the hill to John Boyd Thacher State Park.

The group was a seventh-grade class from Mizzentop Day School in Pawling (Dutchess Co.), a private school for students in pre-K through eighth grade.

The class was headed to Howe Caverns to learn about an important aspect of physical science: rock. The group, led by teacher Jane Justo, detoured through New Scotland to visit the Indian Ladder Trail at Thacher Park to see the rock striations the trail is known for.

Adding to the value of the trip, Justo said, were multiple stops for geocaching — an activity that has grown in popularity for the last decade. Geocachers use GPS (Global Positioning System) coordinates to find hidden caches that can contain a logbook for finders to sign, and other small, weather-protected treasures.

For the seventh-graders, the game was more interesting with the addition of a competitive element: one vanload versus the other.

“They learn how to make maps, and read maps,” Justo said about the inclusion of geocaching on her field trip.

Asked why they do geocaching, the students called out, “It’s fun.” With prompts from Justo, they also said that they learn orienteering, mapping, and navigation.

One 12-year-old girl spoke what seemed a new language as she described a tangram with an encryption for the students to solve. A tangram is a puzzle made with a series of shapes. In geocaching, a hidden tangram often hints at coordinates for another cache to be found nearby.

The group checked in at geocaching.com and noted that they had found the cache at the creek. The check-in was also in geocaching shorthand: TFTC translates to “thanks for the cache,” and P & G stands for “park and grab.” Four other persons had logged in to the website since March to say they had found the creek’s treasure. The cache was placed there in 2010.

The Mizzentop group left the creek and drove toward Thacher Park, but stopped for another cache along the steep Old New Scotland Road.

Justo, however, seemed anxious to get the students to Thacher. Having brought previous classes on a similar trip, she looked forward to seeing the reactions of her pupils when they were up close to the rock layers in the Heldebergs.

“She’s the best science teacher, ever,” said parent and chaperone Diane Impastato.