The present paper deals briefly with the main geological features of the Casavegas area (Northern Palencia, Spain). Though incomplete, the sequence of Carboniferous strata in this region is regarded as a reference-section for correlation purposes within the larger N. Palencia area. A local subdivision on fusulinids of a part of the Carboniferous is proposed. Three zones are distinguished: Protricites Zone F. ex gr. brañoserae Subzone Fusulinella Zone F. delepinei Subzone Profusulinella Zone Fusulinella bocki, var. delepinei is brought to species level as F. delepinei Van Ginkel, sp. nov.