The Lower Paleozoic Eastern Carbonate Assemblage represents nearly 15,000 feet of shallow marine sediments deposited in the eastern or "Miogeoclinal" portion of the Cordilleran geosyncline. This assemblage has been limited to the upper Precambrian, Cambrian, and Ordovician through Devonian units of Devils Gate Limestone age. The section from the Devonian-Mississippian Pilot Formation through the Permian Phosphoria has been placed in the Upper Paleozoic Carbonate-Detrital Assemblage. In this way, these lower Paleozoic rocks are limited to sediments deposited in a passive continental margin setting, before modification of the depositional framework with initiation of the broad Antler foreland basin, which began receiving sediments during the late Devonian-early Mississippian.

The Lower Paleozoic Eastern Carbonate Assemblage is exposed across nearly the entire study area comprising much of the section in White Pine, Lincoln, and Elko Counties, as well as the autochthon or lower plate of the Roberts Mountains thrust within Lander, Eureka and Nye Counties. This facies consists mainly of thick shelf-deposited limestone and dolomite units containing an abundant shelly fauna, and minor amounts (less than 10 percent) of shale and fine grained carbonate and quartz-rich clastics.