The young Lawrence Pritchard Waterhouse, visiting his grandparents in Dakota, follows a plow across a field. The diving blades of the plow heave the black soil up out of the furrows and pile it into ridges, rough and jumbled when seen up close but mathematically clean and straight, like the grooves of a phonograph record, when viewed from a distance. A tiny surfboard-shaped object projects from the crest of one of those earthen waves. Young Waterhouse bends down and plucks it out. It is an Indian spearhead neatly chipped out of flint.