“...The Templeton thundereggs occur to the west of the town along Highway 146, in a roadcut. The famous Templeton biconoids are weathered thundereggs from this deposit that have washed down into the valley for millennia. The deposit was intruded through seafloor sediments, so these eggs contain finely disseminated Marcasite. They have a sulphurous smell when dry sanded. This egg is around 11.5 cm across the face...”

written by M. Ketsdever, Hillsboro, Oregon