Steneosaurus Bone

It’s hard to believe, but large crocodiles were once a fairly common sight along this part of the Yorkshire coast. We’re talking, of course, about the Jurassic period, about 160 million years ago – but relics of their existence around here can still be found.

On a stormy Boxing Day afternoon in 1982, a local family found a piece of that evidence. They were walking on the beach at Robin Hood’s Bay when they spotted some ammonites on the cliff face.

Further investigation revealed that the ammonites were attached to what appeared to be a bone. The family managed to release the fossil from its home, and took it to what was then the Natural History Museum at Woodend on Scarborough’s Crescent, where it was photographed, and the picture sent to the University Museum at Oxford.

The photograph was examined by the museum’s Curator of Geological Collections Mr HP Powell, and leading vertebrate palaeontologists Michael Benton and Michael Taylor, now both with the Department of Earth Sciences at the University of Bristol.

The latter wrote a charming letter to Don Waterman, then Director of Tourism and Amenities at Scarborough Borough Council:

“It is difficult to be sure from the photo alone, especially as we are not sure what if any has been worn away by wave action, but we don’t think it’s plesiosaurauian. The nearest we can think of at the moment is that is the posterior portion of the skull roof of a gavial-like marine crocodile, such as Steneosaurus and Pelagosaurus (Upper Lias of the Yorkshire Coast).”

A hand-written note at the end of the letter further identifies the bone as “Upper Lias – 160 millions years ago. Probably Steneosaurus Bollensis, a marine crocodile about 2½ metres long.”

Dr Taylor also produced a rough sketch of the probable location of the bone at the back of the crocodile’s skull. 

Steneosaurus was a fairly modern-looking crocodile. Later Jurassic forms reached up to 13 feet (four metres) in length. It had a long narrow snout, similar to modern garials from South East Asia, and long slender teeth for catching and eating fish.

Fossil specimens of Steneosaurus have been found in England, France, Germany, Switzerland and Morocco. The largest species, Steneosaurus heberti, could grow to a mighty 5 m (16-and-a-half feet) long, although a fully-grown size of 2.5–3.5m was much more common.

If you’d like to see a spectacular complete crocodile skeleton, then pay a visit to Whitby Museum, whose most treasured fossil is that of a Teleosaurus chapmani. This three-metre-long marine crocodile was found in Whitby in 1824. A local carpenter, Brown Marshall, had spotted the beast’s snout sticking out of the cliff, and excavated the skeleton by hanging perilously from the cliff top on ropes. He sold it to the museum for the princely sum of £7 – the equivalent of around £685 today.

Many fossilised marine reptiles were found along this coast in the 18th and 19th centuries when vast quantities of alum shale were moved in order to extract the alum, which was used in the textile industry as a fixative for dyes.

This fossilised bone was donated by the family who found it at Christmas over 35 years ago, to  Scarborough Museums and Galleries, which is a member of the Museums Association (the only organisation for all museums in the four nations of the UK, which campaigns for socially engaged museums) and adheres to its code of ethics.