top of page


Image by Kasey McCoy
Oxford Geology Group logo

“An interesting discovery has just been made in the district.  A short time since, some workmen from Cumnor bought a basket of bones which … they had found digging the clay at the brickworks, now in course of large extension, at Cumnor hurst.”

So wrote Joseph Prestwich, Professor of Geology at Oxford, in 1879.  He cleaned the jawbone to reveal teeth that were very similar, although smaller,  to those of Iguanodon, a dinosaur which was then much in the news since the discovery eight years previously of 30 or so complete skeletons in a Belgian coal mine.  John Whitaker Hulke, a professional palaeontologist, completed the job of cleaning a repairing the bones and published a description, calling the new dinosaur Iguanodon prestwichii.


The skeleton represents an animal about 3.5 (c. 12’) metres long and about 1.2 (c. 3’) metres high at the hip.  It probably walked mainly on the hind legs, which are longer and stronger than the front pair, though it could drop down onto all fours for ambling and while feeding.


The jaws have long tooth rows with strongly enamelled, ridged and serrated teeth, evidently intended to deal with vegetation.  They show different stages of wear, from worn-down crowns to newly erupted teeth to replacement teeth still deep within the bone: dinosaurs like other reptiles, and unlike ourselves and other mammals, constantly replaced their teeth throughout life.

joseph prestwich.jpeg

Joseph Prestwich


Oxford University Museum
of Natural History

Screenshot 2021-09-26 at 00.14_edited.jpg

Cumnoria prestwichii  Image Credit: OUMNH

Screenshot 2021-09-26 at 00.13_edited.jpg

In 1888, Harry Govier Seely, a Cambridge palaeontologist put forward the view that the specimen showed sufficient differences from Iguanodon to warrant a separate name, proposing Cumnoria instead.  Dinosaur specialists used this name for well over 100 years until 1980 when a study by Galton & Powell found that the animal was indistinguishable from the North American genus Camptosaurus, and since the American name was published earlier than Cumnoria, the specimen should be known as Camptosaurus prestwichii.  However, Naish & Martill (2008), McDonald and colleagues (2010), and McDonald (2011) found that Seeley's original generic distinction was valid. Cumnoria has been recovered as a styracosternan, more closely related to advanced iguanodonts than to Camptosaurus dispar.

Dinosaurs are now so familiar an idea that we tend to forget how rare they are as fossils.  Cumnoria is the only specimen of its species.  It's discovery was a piece of luck.  A second lucky circumstance was the existence nearby of a geological museum where the workmen could exchange their bones for beer money.  And the third piece of luck is that when this young dinosaur died, around 150 million years ago in Upper Jurassic times, it was washed out to sea and quickly covered in mud and sand instead of being destroyed by scavengers on the land.

The holotype fossil of Cumnoria prestwichii (OXFUM J.3303) may be viewed in the Oxford University Museum of Natural History.

H. Philip Powell

bottom of page