MIDDLEBURY If youre a Vermont history buff or just love stone architecture, then set aside Sunday, July 27 on your calendar. Middlebury was nationally famous for producing high-quality marble in the 19th century. The Henry Sheldon Museum presents: Middleburys Marble Heritage: A Walking Tour with Professor Glenn Andres of Middlebury College. The tour begins at 1 p.m. at the Sheldon Museum downtown. At the conclusion of the tour, visit the museum, the home of Vermonts first big marble magnates Eben Judd and Lebbeus Harris. The museum features fireplaces built of elegant Shoreham black marble. For information call 802-388-2117 or visit www.henrysheldonmuseum.