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stratigraphic cross-sections of these units are located in Figure G-10, and are shown in Figures G-11, G-12, and G-13. It is the Boies Bed that is the target of the proposed mining operation, hence only this bed will be described in detail. The Boies Bed (L-5A1 is positioned stratigraphically near the base of the ' L-5 oil shale zone. It is the thickest (up to 30 feet) and richest nahcolite horizon in the Saline Zone. Compositionally, the Boies Bed consists of two distinct facies: nahcolite and nahcolite halite. Only the nahcolite facies is currently being considered for commercial exploitation. Sufficient drilling has been done in the lease area to broadly define the facies distributions of the Boies Bed. These data indicate that the Boies Bed is composed primarily of halite with a minor amount of nahcolite in the northern part of the lease area, while in the southern part it is mostly granular nahcolite. Between the halite and nahcolite facies is a "transition facies" where the Boies Bed is partly halite and partly C• nahcolite. Only two core holes, MMC-IRI-11 and Skyline-1, have penetrated the transition facies (Figure G-14). In each hole, the upper one-third of the Boies Bed is white granular nahcolite with the remainder being coarsely crystalline nahcolitic halite. Apparently, the transition from halite to nahcolite occurs be~i by bed, rather than as a gradual replacement of the entire horizon. Core holes MMC-IRI-1, MMC-IRI-2, and MMC-IRI-3 penetrated the Boies Bed nahcolite facies. In each hole, the Boies Bed is approximately 32 feet thick. Within the nahcolite facies, the Boies Bed is dominated by granular nahcolite that generally is white, light-brown, or tan in color. Thin beds, stringers, and laminae of dark brownish-black oil shale are common. The thickest oil-shale interbed (2 to 4 feet) occurs near the base of the Boies Bed, and makes a convenient stratigraphic marker for correlation purposes. • G-14