This is the metal shale; it’s black, very black. It’s black because it’s absolutely full of organic material. And the organic material of course is what gives rise to the oil for which this was commercially exploited. The rock is divided into terribly fine layers, sometimes less than a millimetre, and each one of those layers represents a season in a year called varves. But of course the rock also is famous for its fossils, and each one of these layers potentially could trap the remains of past life.