Prebatholithic rocks are exposed near the town of San Felipe in northeastern Baja, California. Two spatially separated stratigraphic sections contain mature quartzite, marble, metaargillite, and interbeds of pelitic schist and micaceous quartzite. Eight mappable rock units of formational rank collectively measure at least 3,800 m. The depositional setting was in a shallow-marine environment, marginal to the craton. Based on lithology and stratigraphy, the sequence is provisionally correlated with miogeoclinal rocks of Late Proterozoic and Early Cambrian age in northwestern Sonora, Mexico. Unit G is correlated with the Proveedora Quartzite and units D, E, and F are correlated with the Puerto Blanco Formation of the Caborca area.