Traces of the Trade. 6 to 7:30 p.m., Feb. 24. College of Southern Maryland, La Plata Campus, Center for Business and Industry (BI) Building, Chaney Enterprises Conference Room, BI-113E, 8730 Mitchell Road, La Plata. Rescheduled from Feb. 10, a descendant of the largest slave-trading family in U.S. history, James DeWolf Perry will be on campus to discuss his familys discovery of their ancestors as well as answer questions about the documentary Traces of the Trade: A Story from the Deep North. Free. MCanizales@csmd.edu, 301-934-7659, http://www.csmd.edu/Diversity/.