Together the Stirling, Wood Canyon, and Zabriskie units are about thick and are made of well-cemented sandstones and conglomerates. They also contain the region's first known fossils of complex life: Ediacara fauna, trilobites, archaeocyathas, and primitive echinoderm burrows have been found in the Wood Canyon Formation. The very earliest animals are exceedingly rare, occurring well west of Death Valley in lime-rich offshore muds contemporary to the Stirling Quartzite. Good outcrops of these formations are exposed on the north face of Tucki Mountain in the northern Panamint Mountains.