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Large high-grade bedded barite deposits occur in and near East Northumberland Canyon, northern Toquima Range, Nye County, Nevada. The barite beds, which con-sist of massive and rosette barite rock and minor amounts of conglomeratic barite rock, are interlayered with dark chert and shaly mudstone of the eugeosynclinal western siliceous facies of Ordovician age. The barite rock is mostly dark gray and massive, has a specific gravity that averages about 4.0, and contains 70.7-93.9 percent BaSO4. Silica and dark carbonaceous material are the principal impurities, and other elements are low in amount. Phosphatic nodules are common in the barite conglomerate and adjacent chert and shaly mudstone beds. Delicate Radiolaria tests form nuclei of many barite rosettes, which indicates space for growth of barite before sediment compaction. Barite intraformational conglomerate is evidence of submarine erosion and redeposition during barite sedimentation. Graded bedding and the lateral continuity and conformity of barite beds in the enclosing chert and shaly mudstone beds, together with phosphatic nodules and organic material, strongly affirm a sedimentary origin of the barite facies. A modern analogue of the eugeosynclinal barite facies in Nevada is in the east-central Pacific Ocean basin where barite locally forms as much as 10 percent of the pelagic sediments