New calcareous nannofossil species from the Cretaceous Budden Canyon Formation, Great Valley Sequence, northern California (USA)

Two new species of calcareous nannofossil, Diloma californica and Prediscosphaera quasispinosa, are described from the Budden Canyon Formation of the Great Valley Sequence in northern California (USA). D. californica was observed from sediments of Aptian age and has also been observed in rocks of similar age in the Vocontian Basin (SE France), suggesting its potential for wide geographic correlation. P. quasispinosa, on the other hand, appears to be restricted to the Cenomanian, and is presently known only from sediments of northern California.