Michael Robinson, an employee of The Nature Conservancy, will teach a class on geocaching at 10:30 a.m. Saturday, June 25, at the Cathance River Education Alliances’ Ecology Center in Topsham. Participants are advised to bring appropriate foot wear, water, bug spray, a snack and be able to hike at least two miles without a break. The class is $15 for members of the alliance and $20 for others. For additional information, phone 798-2315 or email [email protected].