Some 210 million years ago, Britain consisted of many islands, surrounded by warm seas. Europe at the time lay farther south, at latitudes equivalent to North Africa today. Much of Europe was hot desert, and at this point was flooded by a great sea – the Rhaetian Transgression.Published in Proceedings of the Geologists' Association, the Bristol team's work is the most extensive study yet, based on more than 26,000 identified fossils, of the Rhaetian shallow sea sharks, bony fishes, marine reptiles, and other creatures. Unusually, five members of the team were undergraduates when they did the work, and this was part of a series of summer internships.The team was led by Ellen Mears, now a postgraduate at the University of Edinburgh, and Valentina Rossi, now a postgraduate at the University of Cork.Ellen Mears said: "I studied the shark and fish teeth, and found remains of at least seven species of sharks and four of bony fishes. The sharks were all predators, but some were quite small. The bony fishes were unusual because many of them were shell crushers."