The Calver Bühl is a small cone shaped hill at the southern valley slope of river Erms, one of the rivers that drain the Swabian Alb towards the Neckar. The cone covers a small volcanic pipe, whose Tuffstone at the top is extra strongly magnetic. Geology considers, that lightnings might be causative. The hill faces the community Dettingen an der Erms. The valley slopes are extensive meadow orchards.