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Chapter Four Green River, Utah, to Hite, Utah Our departure point {()t' this segment was the Green River State Park at Green River, Utah. Our new boat crew assembkd in the beautiful, well-kept carnpgrollnd situated in a grove of mature cottonwood trees. A fair current sweeps past the boat ramp, but the surface of the water is smooth. Willow and tamarisk grow thickly along the shoreline. Looking upstream, we could see Gunnison Butte, near the mouth of Gray Canyon. About two miles downstream, the west bank has low relict: The tan, Iedge-f(Jrming Salt Wash Member of the .J urassic Morrison Formation f()t"ms the lower sixty feet of the east canyon wall..J ust ahead, the overlying banded red and gray Brushy Basin Shale Member of the Morrison f(>rIns slopes about 200 f(x~t high above the Salt \Nash and is in turn capped by the brown Burro Canyon Formation. However, the rocks dip gently upstream, and as we floated downriver we saw progressively older rocks. About f(HJr-and-a-half miles downstream fi"om the Green River boat ramp is Crystal Geyser, which erupts water fi'om a hole drilled f()r petroleum exploration. Eruptions arc periodic, callsed by buildup of carbon-dioxide pressure. Red, brown, and yellow terraces of calcareolls tllfil deposited by the well flow surround the site. lkllenbaughs Butte, named f(lI" the youngest member of the Powell expedition, is a major landmark on the east bank about twenty-eight miles downstream {i'om the town of Green River (Beaman photograph SBS). 'I'he c1iO'and the slopes and ledges beneath it expose a thickJ urassic section: the En trada Sandstone at the base, then the Curtis and Summerville Formations, and Salt \Vash at the top. Two miles below the mouth of the San Rafael River, exposures of Navajo Sandstone appear below the Entrada and f()t"m c1ills f()t, about a mile bcf()re Trin-Alcove is reached. Trin-Alcove is another spectacular landmark named by Powell: three steep-walled canyons, entirely in Nav<~jo Sandstone, converge on the outside of Trin-Alcove Bend. '1'he Powell party camped under a large cottonwood tree at the confluence of these three canyons (Beaman camera station 723) in early September of 1871. Across the river, Beaman took another picture (722) of the Trin-Alcove. The IB71 party explored the high ridge in the center ofTrin- Alcove Bend, taking additional pictures (7'27 and 7'2B) fi'om its crest. We {()LInd Indian arrow points in drainage catch basins on this sandstone ridge. As we floated downstream flJr two or three hours after leaving Trin-Alcove Bend, we could see older and older rocks. The base of the Navajo was exposed, then the purplish-red slabby sandstone of the 151