The Mahoosuc Land Trust will conclude its 2014 speaker series with a presentation on “The Changing Nature of Glaciated Landscapes,” a slide and discussion program by Bob Elliott about glacial features in the area, focused on the “Ancestral Androscoggin Esker.” The program is from 7 to 8 p.m., Sept. 24, in the McLaughlin Science Center Auditorium at Gould Academy, Bethel. Come a little early to look at topographic maps of the esker and related features.

We’ll begin with a brief overview of how the Ice Age glaciers worked and look at some local glacial features including “kames,” “kettles” and “plunge-pit pot-holes.” We’ll then focus on the esker, the remarkable gravel ridge, locally called the “whale’s back,” which dots the landscape for over 70 miles from Aziscohos, through Lower Richardson Lake, the Ellis River valley, Milton, Woodstock and down Route 26 through Oxford, Poland and on into Gray and Cumberland.

Bob Elliott, a lifelong naturalist and environmental educator, grew up on the Ellis River in North Rumford and is a retired University of Maine Associate Extension Professor with an MS degree in teaching, geology and ecology.

Bob will also offer a field trip to explore these features in the local area. The field trip is on Sept. 27 as part of the Great Maine Outdoor Weekend and will leave from the home of Jeff Newsom and Saranne Taylor: from Route 26, take Middle Intervale Road for 3 miles. Turn left onto Winslow Road and drive .4 mile to the second house. The field trip will be limited to three cars because of parking limitations; car-pooling will be arranged at the beginning of the trip. All participants are invited to a barbecue back at the Newsom home following the trip. Burgers, hot dogs and buns will be provided. Please bring a dish to share.

Bob is also preparing a “guidebook” to enable interested people to see area features on their own at any time.

The Mahoosuc Land Trust is an accredited community land trust encouraging public interest in conservation in central Oxford County and eastern Coos County, N.H., supporting a balance of growth and conservation and emphasizing sustainable and traditional land uses. For more information, visit www.mahoosuc.org or call 207-824-3806.