State Route 140 is a scenic drive, especially the last section where the road drops into the Lower Merced Canyon. The region is composed of heavily metamorphosed sedimentary and volcanic rocks from the Paleozoic era (some of the oldest in the Sierra). One day while passing through the area en route to Yosemite National Park I discovered a massive wall of multi-colored siltstone, decorated with a plethora of intricate fissures. Several years went by, however, before it dawned on me that a semi-abstract treatment is the perfect vehicle for reducing this complex geology to its most primitive state, thereby giving new meaning to the surface cracks, mineral deposits and micro-erosion patterns.