Sunday, Aug. 10 at 2 p.m. — ORWELL — Geology professor Helen Mango from Castleton College will be rocking the Mount Independence State Historic Site on Sunday, Aug. 10, at 2 p.m., to lead a guided walk exploring the Mount’s ancient past. Come to “A Walk on the (Cambrian) Beach: The Geology of Mount Independence and Southern Lake Champlain” and learn about rocks. Mango will show you everything from the oldest rocks in the Potsdam Formation to chert outcroppings to the newer rocks of the Great Meadows Formation. These rocks were the foundation for the vast Revolutionary War fortifi – cation, Mount Independence, built in 1776 and 1777, and the chert in particular was used by Native Americans for thousands of years to make tools. Wear sturdy shoes and dress for the weather. This hike into history, co-sponsored by the Vermont Division for Historic Preservation and the Mount Independence Coalition, is open to the public. Admission is $5 for adults and free for children under 15, and includes entry to the museum with its extensive exhibits and access to all the trails. Meet at the museum, Mount Independence Road, Orwell. For more info, call 802-948-2000.