Stan Hedeen, Xavier University emeritus professor, will lead a one-hour geology walk in Ault Park on Saturday, November 12 at 11 am, and will repeat the hike on Sunday, November 13 at 2 pm. The walk will begin at the start of the Valley Trail at the bottom of the Observatory Avenue hill. Learn how limestone, shale, stream erosion, and an ice-age glacier shaped the park and surrounding area.