This spring, a group of five students enrolled in Wesleyan's Geologic Field Mapping service-learning class undertook a project to map the geology of Gillette Castle State Park and develop educational materials for the general public based on this map. The 184-acre park, which was purchased by the State of Connecticut in 1943, sits atop a hill overlooking the Connecticut River. Here American actor and playwright William Hooker Gillette, known for playing Sherlock Holmes on stage, built and lived on this estate from 1919–1937. His 14,000-square-foot, fieldstone-faced mansion resembles a medieval castle, hence the park's namesake, Gillette Castle. The 'castle' is…