 The Backbone is believed to have been formed by the processes of glaciation where a combination of ice sheet advances, meltwater flows and a diversion of the Ohio River left an isolated bedrock ridge remaining between two valleys.Rose Island, an amusement park popular during the 1920s that was destroyed by the 1937 Flood, stood on this rugged peninsula, at the base of the ridge on a level area.Charlestown State Park hiking trails do not provide access to the Backbone, but a loop around the old Rose Island site passes below the ridge.