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' <br /> The Douglas Creek member is fornicd of cross-bedded ripple-marked sandstone <br /> with some limestone and shale . it forms the prominent brown sandstone outcrop <br /> in Loyan lJash belor•+ the rich oil shale bed;. <br /> h m <br />de <br />G <br />l <br />b <br />Th <br />G rli <br />l <br />o <br />th <br />D <br />C <br />k b <br />d <br />li <br />d <br /> aa <br />n <br />u <br />c <br />em <br />er <br />e ve <br />oug <br />as <br />ree <br />es <br />e mem <br />er an <br />un <br />er <br />es the <br /> Parachute CrFCk member. The predominant rock type is p apery non-carbonate shale. <br /> Darren marlstone is also comm on along with some oolitic alyal limestone and very <br />' minor oil shale near the top of the member. The Garden Gulch member forms pro- <br /> nrinent gray sloping outcrops that can be confused with the overlying Parachute <br />' <br /> Creek member from a distance. The principal difference between the to-+o members <br />is the lack of carbonate in the Garden Gulch member shales compared with the <br />Parachute Creek member which is predominantly carbonate. <br />' The Parachu±e Creek member is comprised of shale and marlstone and is the <br />oil shale producing unit in the Logan lJash area. Donnell (1961) divides the <br />Parachute Creek merabcr into three zones, the upper oil shale zone, a middle <br />' barren zone, and a "middle and lover oil shale zones" comprising, in essence, a <br />lower zone. The double nomenclature is that of earlier workers. <br />The highest grade oil shale is in the 'Tiahoyany Ledge" in the lor+er part <br />' of the Parachute Creek member. The Mahogany Ced9e is approximately 90 feet <br />thick and is underlain by 100 feet of low grade oil shale and overlain by about <br />' 350 feet of medium-yrade oil shale. Retort 6, refer to Exhibit SD, is located <br />above and below this high grade oil shale zone. <br />' The retort interval shoo-+s a 15-20 yallon per ton oil shale average over <br />' its 300 feet. The A-groove marks the top of the Mahogany Zone and the 6-groove <br />the bottom. <br />The I•tahogany Ledge comprises approximately 90 feet averaying 25 gallons per <br />ton. Most of the oil shale below the Mahogany Ledye contains less than 10 gallons <br />per ton and does not constitute ore. <br />' -2- <br /> <br />