In 1773, a Franciscan friar named Francisco Palou erected the first boundary marker between Alta and Baja California. Commissioned by the Spanish Crown, it consisted of a cross made from alder wood and placed standing upright on a rock. In the British colonies, milestones were shipped from England to mark the Mason–Dixon line. A block cut from sandstone was placed at the intersection of Wyoming, Colorado and Utah in 1879, and stone posts were used along the western border of South Dakota. Boundaries were occasionally resurveyed and boundary stones replaced or restored, depending on their condition.