Checkerboard mesa

From a park panel:

The horizontal lines, commonly called crossbedding, represent layers of wind-blown sand that built up into sand dunes. These dunes were then buried, and the sand grains glued together by calcite and iron oxide to form sandstone. Crossbedding can be seen in many places along the Zion—Mount Carmel highway.

The vertical lines are less common. They are actually shallow cracks that result from stress and erosion on the rock surface. These cracks are probably caused by expansion and contraction, temperature changes, wetting/drying or a combination of these processes.