Join us at Sudbury Valley Trustees’ Gray Reservation in Sudbury from 9 to 11 a.m. and learn about the geophysical events that shaped this land, and see where the passage of glaciers left its mark on this landscape. A striking 40-foot-high ice-contact face rises just south of Hop Brook, eskers wind through these properties, and kettle holes pit the plain. Bruce Porter, physicist and Science Olympiad coach, will be our leader. Registration required.  SVT members are free, non-members are $10. For more information and registration visit "www.svtweb.org" or call 978-443-5588.