The Tors were out-croppings of layered rocks of the kind that Leibniz thought were built up in riverbeds. Wind had eaten out soft layers to make them flattened lozenges piled atop each other in teetering stacks that leaned together for support—like piles of time-rounded books made in a library by a scholar who was trying to find something. Remnants of fallen ones were scattered down-hill for some distance, half-sunk into the ground at crazy angles, like three-volume treatises hurled into the ground in disgust. The wind only became stronger as they went up; small brown birds flapped their wings as hard as they could and yet fell behind this invisible currency in the air, so that they moved slowly backwards past Daniel.