Of all the geological periods, the Triassic was the most fabulous

Everything has its pecking order, and geology is no exception. The cocks of the rocks are the big, swaggering periods of the past that fill books, television programmes and natural-history museums. The Cambrian, with its metaphorical explosion—the evolutionary burst that put animals in life’s pole position. The Cretaceous, with its real one, when a collision with a space rock slaughtered 70% of the species then around. The Permian, the Great Dying at the end of which dwarfed even the Cretaceous slaughterhouse. The Carboniferous, which bequeathed to humans the Faustian legacy of coal, permitting the industrial revolution at the cost of global warming. And the Jurassic, with its theme-park cast of dinosaurs (though most of those in the movie were actually from the Cretaceous).