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Press, 18 June 1979, Page 4

A recent shipment of phosphate front Florida produced unexpected dividends for workers at the Ravensdown fertiliser plant at Hornby. The 800 tonnes of crushed rock was found to contain a lot of fossilised shark teeth. Workers at the plant are most interested in the finds, according to the plant’s laboratory supervisor (Mr L. W. Higgins). Eric Lewis, left, and Keith Wyber are shown with two of the teeth. One of the men has made himself a pendant necklace out of one of the teeth, which is about 4 cm long. Phosphate usually came either from Nauru Island,

in the Pacific, or from Christmas Island in the Indian Ocean, said Mr Higgins. Occasionally there was a slight shortage of supply, and the difference was made up with phosphate from another source.

This time it came from Florida, in the United States, where there were phosphate deposits of marine origin. The Nauru and Christmas Island deposits were from bird droppings. The shark teeth found in the Florida phosphate were sent to the Canterbury Museum for identification, said Mr Higgins. They were thought to be from three different varieties of shark, and to be

between five and 30 million years old. Interest in the teeth at the Ravensdown plant had been such that Mr Higgins had had to have dozens of copies made of the museum’s analysis. Very little of the shipment was left now, he said. Most of the phosphate was now in the form of fertiliser, after being further crushed and mixed with sulphuric acid to make it soil-soluble. Fossilised shark teeth are not unknown in New Zealand. They can be found in certain limestone quarries in North Canterbury and on the shores of the Chatham Island lagoons, among other places.