The rocks of the Park are sedimentary, formed from sand, pebbles, and mud carried by twisting, braided channels that flowed through the rift valley. Bones of animals that roamed the rift valley, buried in the mud or swept along the rivers, are sometimes found in the rocks of Burntcoat Head.
Fossils are evidence of ancient life. Burntcoat Head Park has yielded skeletons of creatures that lived and competed with the early dinosaurs. These include the skull of a strange, beaked archosaur called Teraterpeton and the backbone of a huge, lumbering dicynodont. These bizarre reptiles became extinct at the end of the Triassic Period, allowing the dinosaurs to take over as rulers of the Jurassic and Cretaceous Periods before they too, met the same fate.