An armoured jawless fish (a Cephalaspis, which is a kind of osteostracan). This creature evolved as it adapted to the transition from open sea to freshwater conditions in the Ludlow area towards the end of the Silurian. It had not evolved at the time the rocks beneath Whitcliffe were laid down, but fossils of the animal have been found in the younger rocks just to the east, downstream of Ludford Bridge.
Spirals are a beautiful shape. They have marvelous curves and convey energy and motion. Not only that, they are a truly efficient form used in nature, and we see them so many places in our every day lives!