 The Pant-y-ffynnon Quarry is composed mostly of Carboniferous limestone, but the fossils of "Terrestrisuchus" were recovered from Triassic sedimentary rocks that were deposited within fissures in the limestone (such as sandstones and marls).The age of the deposits has been historically debated, with older literature suggesting a Carnian to Norian age.However, palynological data has been used to determine a younger Rhaetian age, close to the very end of the Triassic.