| Summary: | Life is ubiquitous on the Earth’s surface. Exuberant, fantastical, tough, and very, very persistent, it gets pretty well everywhere. Darwin marvelled at what could be found in a simple tangled thicket by a footpath, while a spadeful of soil can keep a zoologist occupied for weeks—all those mites and worms and springtails and leatherjackets—and a microbiologist busy for months. There is life in the hottest deserts and in Antarctic ice and nestling up against boiling volcanic vents. It flies high through the air too—not just birds and bees, but spores and pollen and aerial bacteria (so abundant that they can make rain fall more copiously by acting as nuclei for the raindrops). In death, too, the organisms can be tough. Not every corpse gets recycled back to form new generations of the living, and not all fossils are such scarcities that each becomes a museum piece or commands a handsome reserve price at an auction of ancient curiosities. The ghosts of the past are all around us, in solid form. Indeed, we owe to them the comfortable contemporary life (not enjoyed by all, admittedly), of centrally heated houses and easy travel and an abundance of food. The remains of dead plants and animals power contemporary human civilization, in the form of oil and gas and coal. At a price, of course, that is still to be paid. The pebble contains a little coaly stuff within it—tiny flecks of what is now essentially carbon, which gives the dark laminae their colour. It probably makes up, today, something over one per cent of the pebble; when the pebble stuff had been layers of mud and sand on that Silurian sea floor, it would have been nearer 10 per cent. That carbon was once living things—but how does one go about finding what kind of living things these once were? The easiest way to release the cornucopia of ancient life locked in the pebble might strike a disinterested bystander as a little harsh. Indeed, it would be quite terminal for the pebble, albeit highly revealing. The procedure is, by now, quite standard.
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