The Bromide manganese district is in the eastern part of the Arbuckle Mountains of south-central Oklahoma, where folded and faulted lower Paleozoic sediments, chiefly calcareous, are exposed. The manganese deposits are small replacement bodies in the Chimneyhill limestone (Silurian) and are localized very sharply against faults.The ore consists of several manganiferous carbonates, manganite, hausmannite (?), and minor amounts of manganese silicates, calcite, barite, quartz, pyrite, and hematite---an assemblage very similar to that of Batesville, Arkansas. Carbonates are the most abundant ore minerals in the hypogene deposits, and include manganocalcite, Mn-Ca-Fe-Mg carbonates, calcium rhodochrosite, and manganiferous ankerite. The manganese in the carbonates ranges from less than 5 per cent in manganocalcite and some of the ankerite up to 31.50 per cent in calcium rhodochrosite. The carbonate-manganite ore marketed in the past contained approximately 38 per cent Mn, and the small amount of residual oxide sold has averaged between 40 and 45 per cent Mn.The manganese minerals are believed to have been deposited from warm, meteoric waters that had leached manganese from the sedimentary rocks of the region. The localization of the ore was controlled chiefly by pre-mineral faults.