SECTION OF THE CRETACEOUS GROUPS. 157 



No. 10, 110 feet. Sandstones; homogeneous; massive; light gray; 

 indurated. 



Middle Hogback Sandstone. No. 11, 275 feet Sandstone ; buff; heavily 

 bedded with intercalated shales and seams of ferruginous clay. 



No. 12, 75 feet. Friable sandstones and carbonaceous shales. 



Golden Wall Sandstone. No. 13, 600 feet. Sandstones; yellow; rather 

 massively bedded, with intercalated carbonaceous shales. 



No. 14, 80 feet. Sandstone ; massive ; bright yellow. 



All the beds of the above group dip to the north about 45 degrees. 



SALT WELLS GROUP. 



No. 15 ? 1,860 feet. Friable sandstones and arenaceous shales. 



SULPHUR CREEK GROUP. 



No. 16, 2,000 feet. Dark argillaceous and arenaceous shales. 



HENRY'S FORK GROUP. 



No. 17, 25 feet. Conglomerates; pebbles very small, the largest not 

 being more than half an inch in diameter. 



No. 18, 80 feet. Sandstones; mottled light gray and yellow; showing 

 false stratification. 



No. 19, 70 feet. Shales; (teleost shales.) 



No. 20, 135 feet. Sandstones ; rather heavily bedded above, but thinly 

 bedded below ; drab. 



No. 21, 40 feet. Sandstones; coarse; buff. 



No. 22, 100 feet. Sandstones': very friable; gray, greenish-gray, pink, 

 purple, and chocolate. 



No. 23, 50 feet. Sandstones ; coarse ; sometimes appearing as a con- 

 glomerate of fine pebbles. 



No. 24, 100 feet. Sandstones; gray, greenish-gray, pink, purple, and 

 chocolate ; very friable. 



No. 25, 75 feet. Conglomerate ; dark ; in some places a coarse sand- 

 stone. 



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