A broken tooth from the Orthacodus family, an extinct group of sharks, has been found at Cemex Barrington Quarry, near Cambridge. This important find is a ‘first’ in UK or Europe, in an area where rocks date back to the Jurassic, Cretaceous and early Tertiary age that is, over 55 million years ago.
Orthacodus, also known as Sphenodus, first appeared 200 million years ago and lived just after the dinosaurs, outliving them by 10 million years. They appear to have prefered cool waters and so lived in the northern and southern oceans. Current evidence shows they existed in the areas near Peterborough and on the Dorset coast and now, Cambridge Greensand where Barrington Quarry is situated.
Although only teeth have been found to date, it is thought to be similar to a six-gilled shark.
Cambridge Greensand was part of the seabed 90 – 100 million years ago and is a deposit of silty green chalk with phosphate nodules restricted to the Cambridge area. In the mid 19th century, the area was actively quarried for the nodules, which were used to make agricultural fertiliser and the green mineral, glauconite, from which the greensand gets its name, was used to dye military uniforms a khaki colour.
The tooth is currently being studied by David Ward, a retired Veterinary Surgeon who is interested in fossil sharks and it will be housed by the Natural History Museum in London.