After graduation, Marr used two research funds from the Worts Fund of Cambridge University to investigate the work done in Bohemia and Scandinavia to reorder the older palaeozoic rocks, his work in the Lake District having convinced him that it was possible to order the confusing succession of palaezoic rocks as it then stood. In 1879, he travelled to the collection of Joachim Barrande, who had found newer Upper Silesian fossils among older Lower Silesian ones and hypothesised that the two groups existed side by side. Marr instead proved that the younger fossils had "dropped" into the older rock as a result of faults in the stone. Barrande himself was not convinced, but Marr's work on recategorising the Silesian fossils won him the Sedgwick Prize in 1882.