septarium
Sep*ta"ri*um, n.;pl. Septaria. Etym: [NL., fr. L. septum, saeptum, an inclosure, a partition, fr. sepire, saepire, to inclose.] (Geol.) Defn: A flattened concretionary nodule, usually of limestone, intersected within by cracks which are often filled with calcite, barite, or other minerals.