The Plateau of Sighs

From publisher blurb: Hex 13.22 -- The Plateau of Sighs -- features an old triceratops, out of place and out of time, and a plateau currently affected by a petrification curse caused by a gateway to the plane of earth. The gateway is at the end of a mini-dungeon, an abandoned druidic shrine to a powerful elemental prince. It includes rules for introducing ley lines into an Old School Essentials -- or any other OSR-style game -- and building ley engines, structures designed to collect and focus ley energy to be used by mortals.