The wooded deck provides visitors a unique view of the geology of North Chagrin Reservation. Buttermilk Falls Creek cascades down from Cleveland Shale to Chagrin Shale, both members of the Ohio Shale formation formed during the Late Devonian Period. The water from Buttermilk Creek travels over 300 million years of geologic history on its way to the Chagrin River, which flows into Lake Erie.