Notice the large-scale, horizontal crossbedding in the sandstone, which arises from the way the sediments were laid down—a set of beds was partially eroded, then filled by the next, overlying set. Each set differs slightly in its orientation. The vertical grooves, which give this formation its name, come from jointing—cracking related to the slowly changing pressures on the rock as it was buried and exhumed. Weathering by rainwash and freeze-and-thaw cycles brings these grooves out in relief.