The occurrence of conodonts in the pennsylvanian-Permian Bird Spring Formation of the Providence Mountains, San Bernardino County, California, is the first report of Carboniferous conodonts in California. Forty- four species of 16 genera, including one new species, occur in the lower 1,385 feet of the Bird Spring Formation. Pennsylvanian faunas are considerably more abundant and diverse than those of the Permian (Wolfcamp). Two •conodont zones, a lower Idiognathoides nodulifera-Idiognathoides convexa Zone and an upper Gnathodus roundyi-Idiognathoides corrugata Zone, are recognized in the Lower Pennsylvanian. Correlations of these zones with zones of other regions indicate the practicality for a zonal scheme in the Pennsylvanian. An age of Morrow to possibly Desmoines is determined for the Pennsylvanian sequence on the basis of conodonts. A sharp faunal break at the Pennsylvanian-Permian boundary indicates a hiatus of at least Missourian, Virgilian and possibly Desmoinesian.
