These were in today's Post Dispatch. Some of our newer members might be interested in the first one, and there are several caches along the Al Foster Trail. Rich, do you have anything to do with the one at Greensfelder? Class will discuss how to use GPS A class on the use of global-positioning systems will be offered at noon on Saturday at the Greensfelder Park Learning Center, Allenton and Henken roads in west St. Louis County. Experts from the Alpine Shop in Kirkwood will show students how to use the many functions on GPS units. They will learn how to log waypoints in the wilderness, on rivers and lakes and on ski slopes. The program is part of the St. Louis County Department of Parks and Recreation's Outdoor Adventure Program. The class will cost $3. Advance registration is required. Call 636-391-3474. ST. LOUIS COUNTY First organized hike on Foster Trail is offered A wildflower nature walk on May 1 will be the first officially organized activity along the new Al Foster Trail, on the Meramec River banks. A St. Louis County Park naturalist will lead the relaxed, nearly 3-mile walk and help walkers identify wildflowers. The fee is $3. The walk will begin at the Glencoe access, off Highway 109 and Old State Road. Walkers will continue at a leisurely pace into Sherman Beach Park. The trail was dedicated last November to honor Foster, a free-lance writer and public relations man who died in 1992. Foster was a founder of Operation Clean Stream, an annual event to clean out the river and remove trash dumped on its banks, and the Open Space Council. For information and details on how to find the meeting place, call 636-391-3474.