Emery — Green River Desert Section, Utah. 571 



stone, massive in character, and much cross-bedded and 

 held together by calcareous cement. True bedding is so 

 irregular as to make it next to impossible to obtain a val- 

 uable dip reading with the clinometer and the irregular- 

 ity is especially marked near the contact with the 

 Todilto (?) into the irregularities of which the lower 

 Navajo beds fit. The irregularity along this contact 

 suggests an unconformity at this horizon. In general 

 the color of the lower massive Navajo is brick-red 

 but in places near the "Reef" the rocks vary in color 

 from cafe-au-lait to straw. This part of the formation 

 weathers into prominent cliffs with rounded, impassable 

 faces, or into deep pockets which catch and retain rain 

 water. A rather local and striking feature of weathering 

 is that near Gillis's ranch on San Rafael River where 

 the formation is veined with calcite — probably associated 

 with minor faulting, and weathers into low walls which 

 "fence" in circular areas. 



The thin-bedded upper part of the Navajo contrasts 

 strongly with the massive lower part just described. 

 The beds are sandstone and sandy shale and are for the 

 most part brick-red in color, but near the middle of the 

 series is a conspicuous zone of light-colored beds which 

 though of similar lithology to the associated beds, differ 

 in that they are light greenish in color. With them are 

 associated irregular bunches of quartz which weather 

 into small rounded red balls or lozenges resembling in 

 appearance red rubber bath sponges. These "sponges" 

 may be seen in profusion along the Hanks ville road two 

 miles or so south of San Rafael bridge. The very top of 

 the upper Navajo sandstone is characterized by a 90-foot 

 cliff of sandy shale interbedded with dirty gypsum. 

 There is about 15 feet of almost solid gypsum just below 

 the MeElmo, which is thought to uncomformably overlie 

 the Navajo. 



The character of the Navajo sandstone is shown by the 

 following section: 



Section of the Navajo sandstone near Gillis's ranch, 

 San Rafael River, Utah. 



1. Shale and thin sandstone with much interbedded 



gypsum, 15' of gypsum at top makes a vertical 



cliff 90' 



2. Shale, sandy, brownish, with interbedded gypsum, 



forms steep slope to cliffs above 63' 



