The Flow of History Along Gayley Run. Discover the hidden environmental and local history flowing right through Delaware County with Dr. Walt Cressler of West Chester University. In this engaging presentation, Cressler traces the cultural, industrial, and ecological impact of Gayley Run, examining how this local waterway shaped community development, land use, and the surrounding landscape over time. Whether you are a local history enthusiast, an environmental advocate, or curious about the hidden heritage of Media’s natural waterways, this talk offers a unique look at the intersection of geography, ecology, and community history. Lecture starts at sunset.