A complexly faulted block of sedimentary rocks located at the northwestern edge of the Soda Mountains, San Bernardino County, California, is dated as middle Early Triassic based on the presence of the cephalopod Flemingites cirratus. This general age also is supported by other longer ranging molluscs found associated with the cephalopod. The Lower Triassic section of the Soda Mountains consists of brown and red shales interbedded with gray, argillaceous limestones and minor conglomerates and sandstones. Because of a similar age and lithology, the Soda Mountain section is correlated with the Timpoweap member of the Moenkopi Formation.
