At the base of a sandy slope lay shattered antlers. I picked them up; they were stone.

Fossil bone lay all over, a jaw with a row of tooth sockets, an ungulate’s durable knucklebone. The antlers belonged to a proto-antelope. The weight of overlying strata had cracked them, but old rain, bearing minerals in solution, had mended the cracks. I found the tiny parallel tracks left by the incisors of that briefest being, a mouse or vole.

These sediments are slightly over two million years old.

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